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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
30 Mar 2001 11:54 |
I's sure you all remember me whining about how I was looking for a low $$$ method to raise the rear on my '97 595 to stop the right side from dragging. Jack Lilley makes a beautiful adjustable dogbone set, but I am still trying to pay my taxes for last year and all my available cash went for a new set of tires.
So here's my plan for this weekend:
I picked up a piece of 3/16 x 1.25 steel stock. I'm goint to cut a few new sets of dogbones out of it, changing the spacing on each set. It looks like I'll have to figure out some tubing to join them, too.
Anybody else try this? Any hints?
Anybody buy replacement dogbones elsewhere? Can you give me an idea of how much I need to shorten them to get about a 1" ride height increase?
Thanks!
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
02 Apr 2001 12:27 |
It's done...
OK, the post mortem report....
As with many engineering projects, it didn't go quite as planned, but it was successful. My original concept of making swappable links was not possible as I couldn't get access to a metal lathe large enough with internal turning capability to to turn a replacement bearing carrier for the front of the link. I would want to turn a new one with a positive link locator. I probably will still do this in the future.
For now, I devised plan B - Shorten the stock dogbones. After playing around a while, I found I could relocate the rear holes by at least 7.5 mm without the shock interfering with the swingarm. Being conservative, I went for the 7.5 mm shortening.
I drilled new holes for the bolt 7.5 mm over from the stock. Since the holes are almost 11mm in diam, the result was a figure 8 shaped hole. I cut and ground crescent shaped filler pieces out of 3/16" stock and brazed them into the original hole. A coat of paint and link is done.
Results:
7.5 mm shortening of the link resulted in the rear ride height increasing 5/8", or 16 mm. Not as much as hoped, but a quite noticeable improvement. Analysis shows I could have gotten away with as much as 9mm on mine before the (Race Tech) spring would start hitting the swingarm. Shortening the links does result in the shock bottom moving forward so it is more vertical.
I also bumped up shock preload until my race sag is only 35 mm now (was 41) , for a total rear ride height increase of 22 mm.
Ride tests: Feels more like an R1 now. Stink bug rear end. More pressure on the wrists, more intimate with the front wheel. Think I'll raise the clip ons (TBR's). Lighter turn in for the corners, more nimble. NO NOTICEABLE TWITCHINESS OR HEAD SHAKE! That was a concern. Does feel slightly more firm - perhaps due to a change in progressive characteristics, or simply the change in shock angle? Whatever, it is slight and so far OK. I'll turn down comp. damping for the trip home. So far, I LIKE IT! And it was FREE!
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
02 Apr 2001 16:13 |
Interesting Solution.
It makes sense that a sailor would find a way to jury-rig it.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
13 Apr 2001 12:09 |
Martin - Any further feedback on the linkage modification? I think I'm going to try it. It looks pretty easy to do. Let us know how track day was.
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
13 Apr 2001 18:56 |
I'm still loving it! I am convinced the ride is slightly stiffer. Be interesting to see how it responds to the big G-out at the bottom of the Cyclone...
Now if only I could get a certain TEXAN to drag his butt and bike up here for a track day for some real time side-by-side comparisons!!!!!
I dropped the fork legs back down to stock (8mm), and the handling is still very light. I like it very much. Just spooned on a brand new set of D207's, too. Weather for Monday is partial clouds, breezes, low 80's. Must be praying to the right gods....
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
14 Apr 2001 11:18 |
I'm still focusing on paying down bills. Good news is only one more to go. Maybe after that, I can get out for a track day though. There are a couple of dealers around Austin who do track days at three different tracks in Texas. I will be checking into those one of these days. Much cheaper than getting my self and my bike out to California.
I can handle a little more rear stiffness to get lighter steering. Sounds like a good trade-off to me. Thanks.
You didn't really SPOON your tires on did you?
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Ernest Waterman
San Diego,California,
USA
Posts: 84
Daytona T595 (97-98)
16 Apr 2001 10:36 |
Martin - do you hit the collector pipe piece any more? Is it clear from the right hander scrape's?.... and have you seen any of jack lilley's product, is it worth it?.....
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
17 Apr 2001 11:56 |
Post track report: I was still kissing the collector in the right hand turns, but it was happening much later. I was incrementally bumping up compression damping and this was also helping. Overall, I call it a success!
I really liked the looks of Lilley's adjustable piece - just couldn't scrape up the cash..
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
17 Apr 2001 20:35 |
Thanks for the report. I am going to do it. Just haven't gotten around to it yet.
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aaron hlavaty
lawton,ok,
USA
Posts: 1
Daytona T595 (97-98)
18 Apr 2001 16:24 |
ride hieght
Simple Solution.......reach really deep in your pocket and install a shiney new Oliens shock. Retail price:$1095.00
Ouch!!
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
03 May 2001 00:19 |
It is done!
I just completed the rear ride height modification that Martin did. This was a relocation of the holes in the drag link. I moved my holes farther forward, though, to a distance of 0.515" (13mm) ahead of the old holes. This left a .030" (.75mm) web of material between the holes. This resulted in a rear ride height increase of 1.125" (28mm) with rider on the seat.
The improvement in the bike's handling is amazing. The steering is much more neutral now. I used to have to give quite a bit of countersteering pressure on the inside bar to keep the bike leaned over in a corner. Now the bike requires very little countersteering to keep it down. This allows you to concentrate more on holding the line than on keeping the bike leaned over. There is no noticeable instability as a result of this modification. The bike corners so much better, with no negative behavior. I've only taken one test ride so far on a very twisty, long road.
There is slightly more weight on my hands, but with the TBR bars adjusted for a perfectly neutral wrist angle, I do not really notice it. Anyone doing this modification needs to be sure that their bike will tolerate this amount of relocation of the holes. The two issues are: 1) assuring that the shock will not hit the swingarm, and 2) the farther forward the holes are moved, the thinner the link beam becomes around the holes.
The fact that this type of handling improvement can be had without inducing instability shows that Triumph really did a good job with the chassis design. They were just overly conservative with the steering geometry. This makes me wonder how many more of these bikes could have been sold if Triumph had not been so conservative. If the stock bike handled how mine does now, I am sure the magazines would have given a much more favorable review.
Thanks to Martin for the idea. Now on to the front end to install my new Race-tech fork springs!
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john underdown
redlands california,
USA
Posts: 302
Daytona T595 (97-98)
04 May 2001 16:21 |
Martin,
Where did you see the jack lilley adjustable dogbones was it on the web site? If I could find a good picture I might consider fabricating a set when I get some time. Incidently were they aluminium or steel also what was the price.
Thanks,
John u
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Chad Kincaid
Northern California,
USA
Posts: 41
Daytona T595 (97-98)
04 May 2001 16:37 |
Picie of the Adjustable Dog Bone.
Here is a pic of the adjustable piece.
http://www.jacklilley.com.....essories/38.htm
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Paul Kroll
Houston, Texas,
USA
Posts: 18
Daytona 955i (99-01)
06 May 2001 12:44 |
Martin,
I did my Daytona the $$$ way with a Penske. I'm just curious, have you measured your rear ride height and what is it? I'm still trying to dial mine in.
Thanks !
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
07 May 2001 11:57 |
Penske Rear Shock.
Paul, I also just installed a Penske. I have also had the bike to GMD Computrack, which worked out some preferred geometry for the 955i with the stock triple clamps and rear linkage. GMD recommended a 35mm increase in static sag. With the stock rear linkage I was only able to attain a 24mm increase with the Penske at maximum recommended extension. The Penske measures eye to eye equal to the stock Showa when it is not extended. The bottom extension allows for 12mm of increased shock length. This translated into 36mm of increased swing arm extension, from the point where I was measuring. Moving the bottom of the shock forward along the dog bone linkage will further increase the swing arm extension, ride height, and slow the speed of compression. GMD’s recommendation was almost half the ride height that Orange County Triumph had raised their race bikes. This was meant to be a good compromise between street and track use.
VERY IMPORTANT!! Make sure to check the Penske’s clearance where it mounts to the frame. Mine came with an eyelet extension that was 5mm too short. This caused the shock to bind against the frames mounting points preventing the swing arm to fully extend. Penske Tech replaced the top eyelet piece with a 5mm longer part, shortening the shock body by the same amount, keeping the length overall the same. They did this in 24hrs. Top notch service. I’d be interested to know if you found the same problem.
I had the bike on Summit Point’s full course this past Friday. Once I learned the circuit and started to relax the bike felt good but still required a lot of counter steering input to hold the line I wanted. This track has two long right hand sweepers that the Triumph’s rear-end wollowed in when encountering bumps. Not too badly, but just enough to make you not want to twist the grip much further. Once I have this bike’s geometry correct I’m going to be very interested in its new feel. The forks were flawless with the Race Tech springs for my weight.
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
07 May 2001 12:15 |
Hey Paul - Sounds like Brad had even better answers for you! I picked the top edge of the axle to the bottom of the first 5 in T595 to define where ride height was measured. I increased it 22 mm over what it was, which was at least 10 mm over original stock (I had installed a stiffer RT spring with extra preload). So that lines up pretty well with what Brad and Jess ended up with - something in the 30 to 40 mm increase over stock produces light but not twitchy steering. Mine does wag its head when under heavy power coming out of corners (on the verge of power wheelie), but if you relax it will self dampen within two or three shakes. Keith Code goes into detail about this being OK, perfectly normal, and not something to fear in his Twist of the Wrist II book.
To dial yours in, increase the ride height until you like the steering feel!
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
07 May 2001 12:20 |
FAO Brad and Jess
My quicky (not thorough) mental analysis lead me to believe shortening the dog bones would increase the shock compression rate. Brad - you mention decreasing. The gauntlet is thrown  who will be the first to fully analyze and provide the definitive answer????
(Somehow, I suspect Jess already did it... )
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
07 May 2001 13:13 |
i have done it
I did it by much more to my S3. The night before an arranged ride out i decided to have a go. Trouble is the lad who was helping me (an engineer!) measured it wrong, went 13mm from the edge of the whole not the centre, about 19mm then.
By the time i clicked on we had already drilled out to 9mm so I said we might as well try it.
Put it back together and the standard spring still cleared so I went to bed with fear of what awaited me on the trip out.
And you know what, its great. I had to back off the rear compression by half a turn as it was a bit bouncy off the bumps but after that it was just so much better. No more wondering if i could hold a line if the corner tightened. It just steers where I want.
Not only that but the bike feels so much more planted and safe through a bend. I thought it was going to be git to ride but quite the opposite. For no money and one hours work its amazing.
If anyone needs details of whats needed and how just ask.
Before you try it though a word of caution. At the same time I changed the front sprocket to a 17t ( another good idea by the way). However, after 300m the chain the was very slack indeed. I may have not torqued the thing up correctly with rushing. don't see how the ride height can have caused it but will check it tomorrow.
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
07 May 2001 13:20 |
chain
just occured to me that I adjusted the chain before I did the ride height so that might be why it was slack. Will tighten it back up tomorrow to make sure there is enough adjustment still. Did any body else notice this effect?
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
07 May 2001 13:55 |
Moving Bottom of Shock Pivot Point Forward Slows Rate.
Pick up a pair of scissors in you're left hand and open the end to about two inches. Imagine your shock is mounted between the scissors pivot and end of the top blade. The bottom of your shock is mounted a quarter inch further to the rear along the bottom blade. Now, by moving the bottom of the shock forward, let's say an eighth of an inch towards the pivot point, you will increase the open end of the scissors; i.e. your swing arm. Now, imagine the scissors closing and opening a little bit. Even though the ends of the scissors open and close by the same amount at the end, the distance between where you first mounted the base of your shock and where it is mounted now is not as great. By moving the shock closer to the pivot point you are decreasing the distance the shock ends travel. It is just like a wheel. Objects closer to the center spin slower then objects near the edge. This gives your wheel more leverage against your shock, which may require a stronger then anticipated spring.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
07 May 2001 21:38 |
I do not quite agree. I did attempt to assess this prior to my modification, and my conclusion was that the shock would compress at a faster rate. The reason is that the effective length of the drag link (dog bone) is not the only thing affected.
Before modification, the drop link is at about a right angle to the drag link. The reason that the linkage results in a rising rate, is because the more open the subject angle becomes, the more a given swingarm movement will compress the shock. For example, if you move the swingarm upward from the fully extended position, one inch of movement might result in 1/8" of shock compression. If you do the same thing for the wheel's last inch of travel, the shock will travel much more for the same one inch of wheel travel. It is the opening up of the drop/drag link angle that causes this. If we want to use the scissors example, hold the scissors by the tips, with the tips pointing straight up. Have the tips separated about 1 inch. Slowly open up the points, about 1/4" at a time while looking at the pivot screw. The more open the angle becomes, the more each 1/4" tip movement will move the pivot point upward, especially after the angle gets bigger than a right angle. You can also use a piece of string with a weight in the middle of it, if your scissors will not open beyond a right angle.
It is true that having the shock closer to the drag link's pivot should result in slower movement, but this assumes that the pulling member's (drop link's) upper pivot is always positioned directly above the shock eye through the range of movement. The linkage dynamics are a little more complex than that. Actually, the swingarm is pulling the drop link's upper pivot farther and farther rearward of the shock eye. The opening of the angle more than compensates for the decrease in effective drag length.
The effect on my bike is consistent with this example. The difference between the free sag and static sag measurements was less after my modification. I did no other shock adjustments. This means that it is behaving as though it has a stiffer spring (It settles less when I sit on it now than it did before).
I believe that this analysis is correct. If not, I'm okay with that too.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
07 May 2001 21:52 |
With respect to the chain, the ride height mod has the effect of loosening the chain at full suspension extension compared to what it was before. This means that if you use the stock freeplay adjustment spec, the chain may become too tight when the suspension compresses and the rear axle, swingarm pivot and front sprocket shaft all become lined up. When I was done with the linkage mod, I adjusted my chain to the maximum end of the spec range, hoping that it was enough. I guess the only way to truly test it is to adjust the chain to the desired freeplay, and compress the rearend to see if it gets too tight. This would be very difficult unless you,
1) Have a very heavy friend that can sit on your bike, or
2) Take the rear shock out or disconnect the lower eye or something to allow you to easily lift the swingarm without that resulting in compressing the spring. My chain was not seeming too loose when I rode it.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
08 May 2001 09:35 |
Chain Adjustment: Stock Specs Must Be Checked w/Increased Ride Height!
Jess, I completely agree with your chain adjustment critique. Here is how I plan to do this with out the fat friend. I’m going to set up two mounting points perpendicular to the line of the bike on my garage floor. With the bike on its rear stand, loosen the rear pinch bolt just enough so that there is some drag and adjust the eccentric so that the chain is obviously too tight. Then I’ll attach the straps to the rear sub-frame and ratchet down the bike until the front sprocket, swing arm pivot, and rear sprocket were all in a line. Then I’ll check that there is 8-10mm of up and down movement at the center of the chain. Then torque pinch bolt to spec. Once finished, I’ll check the chain according to the standard adjustment procedure, recording the amount of new free play in the manual so that I can adjust it properly in the future with out strapping it to the floor again.
Not yet convinced about the rear shock movement speeding up. I agree that the movement becomes progressively harder as the swing arm moves up and that the lower eye does not follow a pure arc upward. This movement in the stock linkage is what makes it progressively harder. I’m just not convinced that there is enough rearward movement. I’m going to take another look at this tonight. The boys at Attack told me their linkage slows the rate. Given the Attack linkage is different, but both move the lower eye forward, and I’m still leaning towards a slower shock movement. And like you, if I’m wrong, O’ well. As long as all feels right out on the track hitting bumps at the apex.
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Martin Sweet
Chico, California,
USA
Posts: 429
Daytona T595 (97-98)
08 May 2001 11:38 |
Damn. I used to have an awesome (but simple) four bar linkage analysis program for my PC. Unfortunately, I gave away the PC and forgot to download the program.... That is exactly what we need in this case, as linkage rear suspensions are classic four bar linkages. This makes it a whole lot more complex than the simple one pivot scissor exercise we're playing with. If I get a minute, I'll surf around and try to find a shareware version.
Brad - Please share your results of the "new" chain adjust spec.
Thanks!
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
08 May 2001 13:24 |
Definitely will share numbers.
I have SolidWorks software at home and could work the four bar linkage solution out on that. Just don't think I have the time at the moment.
In the simple scissors example if the shock eyes are attached at equal distances from the pivot point then they will travel in the same radius. If the bottom eye is further from the pivot point it will travel in a radius that is that distance further from the pivot point, but still in a circular arc. If, the bottom eye is allowed to shift towards the rear while moving upward it will travel a path that increases in radius. By moving the lower eye forward along the dog bone, the eye will still move in a path that increases in radius, just less so and therefore slows the rate of compression. Now I'm working this out in my head from memory of the triumph linkage, so this is the best I can come up with on a slow day at work.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
08 May 2001 20:28 |
I played alot with my linkage with the bottom of the shock disconnected, trying to determine how much I could move the rear dog bone hole forward. It really does work quite similar to my scissors example. I had the lower shock eye disconnected and I reconnected the two links with the pivot bolt. Try it and see if you see what I saw. How's that for a sentence?
I too am very interested to know what your new chain adjustment spec is. I agree totally with your method. That is a good way to do it.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
09 May 2001 08:35 |
Chain Adjustment
I'll be stopping by Home Depression ... ehm ... Depot, on the way home tonight to pick up a masonry bit, fixings, and a couple of large eye bolts tonight. I'll post results when finished. It could take a while. I have to look out for my 2 and half year old at the same time.
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Homertrix
South Bucks,
United Kingdom
Posts: 8,721
Premier Member
Daytona T595 (97-98)
09 May 2001 12:30 |
Sounds like a recipe for disaster!
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
09 May 2001 14:29 |
Nah!
Stuart, what are you worried about?
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
09 May 2001 18:11 |
let me know also
I was trying to do a similar thing tonight with a fat brother on the back of the bike but he just aint fat enough. Don't really have time to undo the linkage to test but now see why my chain was slack. Have adjusted it to about 45mm for the moment.
Is 10mm slack the correct measurement for the swing arm in line or an estimate? I don't want to set mine too tight as this will restrict the suspension.
Can someone with their linkage still standard confirm the chain slack when all is in line?
As for the spring issue I am a bit lost on that one without having a look and head scratch at the same time. To confuse matters though, my free to static sag dropped from 5mm to 3mm but with me on it changed from 32mm to 35mm (this was before I changed the compression damping). Unless of course my girlfriends reluctance to buy me any dougnuts lately has affected the issue!
All I can say is the bike certainly rides better now, not just steers better but feels more rooted to the tarmac thru the bends.
As an aside, with regard to suspension settings (Prior to this mod also). I have found that the compression damping advised in the performance Bike article the wrong way to go, for British roads any way. It absorbs the bumps much better wound out to 1.5 at the front and now 1.5 at the rear. This ride height change has now removed what traces of from end patter were still there.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
10 May 2001 09:25 |
Compressing Suspension Very Tricky
Well Stuart, it's not disastrous, but it ain't easy either. I had the seats and rear bodywork, gas tank and high pipe off, with the pinch bolt loosened. Plan A: I had the bike on the Pit Bull rear stand. I attached straps to the tabs that stick up at the center of the sub-frame. I suspected they may not be strong enough and sure enough they started to splay out as the load increased.
Plan B: Reposition bike and attach straps to each other and drape them over the very end of the sub-frame with a piece of cardboard in between. The bike was still on the Pit Bull, which allowed for movement of the eccentric under load. The problem is that the stock linkage is VERY progressive. The more the spring is compressed the less leverage the linkage gives you. I was told it was 175% progressive. I'm not clear about how the 175% value is calculated. Only that the bigger the number the more progressive. I believe Superbike's and GP's are as low as 6%. 175% is unbelievably high and is probably the major impediment to better one-up handling for the Dayto. I was able to compress the suspension close to in line, but the load on my ratchet straps was getting way too high for comfort. I did learn that 45mm of chain movement with 12mm increase in shock height is not enough. The chain was getting pretty taught the closer the front sprocket, pivot point, and rear sprocket got to being in line. Mind you, having all three in line is getting close to full compression of the shock spring.
I will attempt Plan C tonight: Bike on rear stand, lift bike from below with hydraulic floor jack, taking care not to damage delicate bits, like the oil filter. Disconnect bottom of shock and lower bike until the front sprocket, pivot point, and rear sprocket are all in line and adjust chain tension.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
10 May 2001 21:08 |
Wow - I can appreciate your effort. The easiest way may just be to drop the shock out while the rearend of the bike is supported from the ceiling. Then you could practically lift the rear wheel through its travel by hand. I built a structure on the ceiling of my garage that I could hang a come-along from. Then I just ratchet either the front or rear of my bike off the ground by lifting it by the frame. This is how I did my dogbone mod and exercised the linkage to determine what the effect would be.
Good luck and be careful!
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
11 May 2001 10:17 |
Chain Adjustment Experiment Successful
Last night I executed Plan C. However, I did not reinstall the Penske. I put the OEM Showa back on. The Penske needs to be 10mm longer then the OEM Showa when used in conjunction with Attack’s triple clamp and Rear linkage. Otherwise you will not be able to achieve the desired ride height increase of 44 to 46mm. I sent the Penske back to be modified. I’m going to go into detail about the reasons for this in another post.
Now for the chain adjustment. With the bike on rear stand, shock removed and the bottom bolt slipped back into the linkage (I wanted to see the path of travel the bottom eye would take) I lowered the bike until the sprockets and swing arm pivots where all in a straight line. I used a hydraulic floor jack, taking care to pad and protect the oil filter. This is very low. The rear tire is maybe an inch from touching the under tray. I strongly believe the spring would be at max compression or beyond (not possible with shock installed) when all three line up. While in this lowered position I adjusted the chain tension so that I had 10mm of movement up and down at the center of the chain, torque the pinch bolt to 55Nm. I then put the Showa back on and re-measured the chain tension. Has anybody already guessed what the measurement was? 35mm. The rear sprocket is OEM.
Since this method results in stock specs. for correct chain tension it can be used to adjust your chain after making ride height changes and/or rear sprocket changes. You could simply adjust your chain to stock specs. with OEM equipment then make modifications and leave the chain tension alone. Record new chain movement for future adjusting needs. Just don’t adjust chain to stock specs. after making these mods because you’ll have a chain that is too tight.
Jess & Martin, the path I saw the lower eye move was forward and up. Almost directly at the top eye. Moving the eye forward along the dog bone would decrease its forward and upward motion giving the swing arm more leverage against the spring. Once you made the mod did you have to increase spring compression to keep the same static and loaded sag settings?
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
11 May 2001 15:32 |
Chain Slack
You guys have been busy. Thanks to all for making the effort and sharing the results. By the sounds of it, taking the measurement for the arm in line may be going too far as I doubt even landing from a flyer would compress the setup enough to put the rear wheel that close to the undertray.
Would be a very difficult thing to judge the max compression the bike would encounter under road/track conditions.
WHAT IF,
Out of interest, could someone with a standard setup and correct chain tension- Put a jack under the rear of the engine and raise the bike so as to give the impression of a 40mm increase. Then measure the slack.
This will give us guys a safe (as far as it becoming too tight) Max for our chain slack.
We then need to decide how much we can reduce this because the shock is not likely to compress its usual amount+40mm. Especially if the action is progressive.
Although the leverage may have changed, I would be surprised if the change would make more than 5-10mm extra compression of the spring likely. We also have to take into account the the non linear arc of the swing arm, say as a guess another 10mm.
On that reckoning, if someone would jack up their standard bike (under the engine with a lift) with 35mm of slack as standard. Raise it by 20mm and check the slack perhaps this would give a ball park figure for a 40mm ride increase?
What do you think?
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
11 May 2001 15:56 |
Will Not Work w/OEM Shock In Place
Robert, the length of the Showa prevents the swing arm from opening that far. The length of the shock defines the maximum amount the rear swing arm will open.
Another benefit in changing the stock rear linkage is that the rear wheel will move through compression more easily. The rear wheel will be able to travel further through its operating range. This allows the suspension to absorb larger bumps and still keep the tire in contact with the road surface. The OEM design is a good compromise for one and two up street riding.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
11 May 2001 20:58 |
Actually, no. The difference between the free sag (unloaded) and static sag (loaded, also called race sag) measurements are less after the modification. This would indicate a higher effective spring rate caused by less leverage. This is also why Martin and I noticed that the rear end felt more firm after the mod. If the force being applied was always at a right angle to the dog bone, your leverage explanation would be correct. A simple vector analysis would show that as the angle between the drop and drag links opens to greater than 90 degrees, more and more of the pulling force of the swingarm through the drop link is being used to try to strech the links (tensile load) than to compress the shock spring. The extreme would be that when the links open to a 180 degree angle, all of the force would be streching the links and none would be compressing the shock. Moving the eye forward instantly and significantly opens the angle between the links and positions them in a reduced leverage advantage over the shock spring.
I got a little confused reading your chain slack info. Are you suggesting that I can still use the stock chain adjustment specs after the mod that I did? If you have the attack rear linkage installed I wouldn't think that you would be able to replicate my set-up. I still believe I would need more slack than stock. The manual says that the chain slack is to be adjusted with the bike on the side stand and therefore the suspension unloaded. Did you get your 35mm reading with the suspension unloaded? It is amazing how something that seems so simple at first can turn out to be so puzzling, isn't it!
Take care!
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
14 May 2001 08:52 |
Linkage & Chain Tension
Jess & Martin: When you guys moved the shock forward on the dog-bone linkage I have been assuming you just moved the shock forward and not the drop link, using spacers in place of original hardware. Maybe I need to go back and read Martin's original post. Moving both forward would reduce the swing arms leverage. By keeping the drop link in the original position wouldn't you still gain ride height but without making the suspension even more progressive?
Jess, the 35mm measurement was taken while my bike was on the swing arm stand, chain tension at static sag. If you follow the procedure you should end up with a larger value. Besides if shock and drop link are moved forward along the dog-bone linkage I doubt you'll ever be able to achieve full spring compression. You've shortened your string.
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
15 May 2001 17:08 |
Oh Yes
Yes of course, I wasn't thinking when i suggested that if someone jacked up the back they could simulate the 40mm ride increase-you'd need 40mm static sag then! Anyway, shall have to remove my bolts and check the chain slack thru a range I think likely. My bolts were thru from the down pipe side so had to remove the headers when i first did the mod. When rushing to get it back together i went and put them thru the same side again which makes things a pain. Will have to get garage built soon as I have to keep the bike elswhere-not ideal for after dinner fiddling.
Anyway, I went out for a 250mile blast on Sunday (trying out my new Alpinestar Dyno Suit, I can actually move around the bike now) still convinced this mod is well worth it, a must in fact. I was not really happy before with the obvious pressure need to counter-steer. Just a light touch now and its away. So much easier to ride thru a series of turns. Also found reducing the rebound front and rear made notable improvements. Fiddled for ages before with settings and could find good combi but now it seems to react better to tweaks. Not sure why? I now have confidence in stock units which just didn't seem right before.
Next step a Maxton revalve and matched springs but they will have wait a bit. The dogleg mod was free and easy.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
15 May 2001 19:57 |
Brad - Yes, we moved both the shock eye and the drop link forward. I can now see why we were having a difficult time understanding each other's logic. I agree with you that if the shock (and NOT the drop link) is moved forward, there would be more leverage on the shock. To move only one forward, it would have to be moved WAY forward, because you would need room for two bolt heads next to each other. I only left a 0.75mm web of metal between the old and new holes.
Your idea is interesting though. I'll bet that the shock spring might hit the swingarm if it were moved far enough forward to allow two sets of hardware. Also, the ride height gain would have been much less if the drop link does not move with the shock. By moving the drop link forward, you have to rotate the drag link farther upward to get the two to line up. This forces the lower shock eye upward, which pushes the frame higher. This is the major factor that increases the ride height. It is identical in concept to the Jack Lilley components - just not adjustable. Ideally, one might want to run a lighter spring rate with this mod.
As far as spring compression goes, I will still have full shock travel (about 1.5" measured) with this change. The lower shock pivot will travel upward this distance before the two links become 180 degrees open, which would be the limit of upward wheel travel if the shock were removed.
For chain adjustment, I think I will just have to remove my shock and lift the swingarm the distance that it would take to bottom out the shock and then adjust the slack. Then put the shock back in and see what the slack is with the bike on the side stand. This is similar to what you did.
Is the attack linkage of a similar style, or it it a totally different approach? I'm curious.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
15 May 2001 20:03 |
Robert - I agree. The lightened steering is really worth it. The bike handles so much better now. Glad you're enjoying the mod as well. Sorry about you engineer friend's miscalculation. Sounds like it worked out alright though. Engineers make mistakes too - Martin and myself included.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
16 May 2001 09:40 |
Attack Linkage
I wish I could tell you for sure, Jess. It has been on order since the end of March. I was told I’d have it by next week. Orange County Triumph did call last week saying they have a used set that must be sold together with triple clamps and an Ohlins shock for $2,100.00US. That's only about $300.00 short of new pricing. Attack's components are $750.00 each plus $80.00 for new bearings and spacers, plus $30.00 for Triumph Tool for triple clamp cap if you don't want to use a channel lock. I already have a Penske so option was not good for me but somebody else may want to give them a ring and bargain. The spring rate on the Ohlins (intended for use with Attack linkage & 200lbs-ish rider) is 15 to 15.5kgm. I believe the OEM Showa is 13.5kgm.
A longer dog bone and shorter drop link might solve potential clearance problems and be ideal. I can't wait to take a close look at the Attack solution.
My free spending on the Triumph ended with this order. Some of you may remember I have another kid on the way. Well we learned that it is two on the way. O ... my ... God! (No fertility treatments & no history) After further reflection I realized in a few years I'll have my own pit crew!
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
16 May 2001 15:58 |
what do you make of this
I mailed Jack Lilly with our question of what the mod (or their adjuster) does to the shock/spring action and what they recommend regarding chain slack. I told them i had raised mine by about 40mm. Their reply is below but not sure it sounds correct?
First off, I have not found any problems with stability - even riding hard on bumpy roads.
Second, the chain slack sound hard to believe unless it is a typical racing thing to do. If as per the earlier mail, the max shock compression is 1.5 inches then surely we only need to move the swing arm up by this amount, set 10mm of slack, re-attach linkage and take the new measurement for future reference?
Let me know your thoughts guys.
Hears their reply.
"Our Race eam run 15mm/20mm ride height max, 4inches chain slack.
anyting more and it must be gettin very unstable. also the amount of chain
slack must be getting dangerous especially on bumpy roads.
Altering linkage rods does not affect the suspension setting at all. all
you may need to do is wind off the preload a bit because you have
transfered more weight to the front.
I hope this makes some sense to you .
Kind regards
Brian"
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
16 May 2001 22:20 |
Brad - Congrats on the pit crew!
Triumph has upped the rear spring rate since the Daytona first came out. The '97 had a too soft 12.2 or 12.7 kg spring. The 98 had a stiffer spring - 13.0 or 13.5 I think. In 99 or 2000, they upped it again to 14 kg. My 13.5 RT spring seemed ideal until I increased the ride height. Now it feels a bit firm. I do not mind firm though. Even in cars, I hate mushy suspension. I think your idea about making the dog bone longer and the drop link shorter is a great one. Too bad the drop link would be so difficult to modify in that manner. I guess the best way to increase ride height with the stock linkage would be to get a longer shock or to extend the upper mount lower.
Robert - Actually we need to move the swing arm up by whatever amount results in an upward movent of the rear of the dog bone of 1.5". This would be measured at the point along the dog bone where the lower shock eye pivots. The swing arm movement required would probably about 4.5 - 5 inches. The service manual's claim of 5.6" of rear wheel travel seems a bit optimistic by my observation. Otherwise, I agree with your method exactly.
Jack Lilley's information seems a bit sparse for me to make a judgement of. Off hand though, I cannot say that I agree with it. I have put about 700 miles on my bike since the mod and I have not experienced the least bit of instability. This includes hard riding and hard cornering over bumpy pavement.
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
17 May 2001 14:39 |
Jess
Your right of course about the place to measure the 1.5".
Can't imagine it resulting in 4"+ of chain slack (Or at least I hope it doesn't!)
Don't have a clue what my spring rate is as my bike is a 98 T509 to which I fitted a 955 from a sprint with modified air box which appears to give even more grunt, as tested back to back by a Triumph dealer with a standard 955S3.
I did read in BIKE mag the other month a group test which said the S3 has a longer wheel base than a Daytona but this is the first i have heard if it is true.
I think any harshness I have suffered previously was down to damping rates but would be interested to try non-progressive springs front and rear. Can you calculate the ideal rate from just your body weight?
If a spring is progressive is the rate not some kind of logarithm? Not sure how this works out.
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Robert Henry
Stoke,
United Kingdom
Posts: 53
Enthusiast
17 May 2001 14:48 |
As for unstable
As I have said, I have not noted any stability probs with the mod, perhaps a little more life in the bars but nothing more. I Once had a 88 CBR600 which would tank slap under hard acceleration over roughish roads. Not even come close to that on this.
Out of interest, do you engineers know what the various geo angles are with a 40mm ride increase. Thought it would be a good comparison to say a 916, which has a damper as standard because of the "extreme" setup?
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
17 May 2001 21:05 |
I highly doubt that 4" of chain slack would be required for my set-up. I really need to check out to make sure that I am not streching my chain on big hits, but I think I'm probably O.K.
Most suspension tuners prefer straight rate springs. I am running straight rate front and rear on my bike and I like them. Contact Race-Tech for suggested spring rates. They do a good job. You can get your suggested front spring rate right off their website. For the rear you might be able to do it on the website as well.
I haven't attempted to measure my rake angle since the mod. It is working well, so I haven't really cared what it is. It would be an interesting bit of trivia though. I can still take my hands off the bars going down hill at 55 MPH with no twitch whatsoever.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
31 May 2001 13:48 |
Attack Triple Clamps & Rear Linkage On The Way!
Finally! I just got a call from Orange County Triumph and they told me the are over nighting parts today. I should have them tomorrow morning at 10:00am. This should give me enough time to bolt all together prior to this Sundays track day at Pocono. Phew! I think it'll be a half-day tomorrow.:)
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
31 May 2001 19:53 |
Great, Brad! Let us know what you think of the linkage after you ride it. I hope it works well for the price they charge.
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Bradical
Yardley, PA,
USA
Posts: 246
Daytona 955i (99-01)
13 Jun 2001 14:19 |
Attack Rear Linkage Mounted
I have had one track day with the Attack linkage and Penske shock (850lbs spring) on the bike. The track was Pocono's East course. You can see a movie clip of this track at www.teampromotion.com/picarchive/index.htm . See "One Lap on the East Course." This is a very technical and bumpy track. I had yet to mount the Attack triple clamp, which moves the forks forward, thus slowing the steering somewhat. I kept the Penske ride height at its lowest setting with the stock triple clamps on. This gave me about 20-25mm of ride height increase. The Penske is 10mm longer eye to eye then the Showa. I had also installed a 46t-rear sprocket, which forces the rear wheel to be moved to within 3-4mm of its furthest forward position and still have the chain slack adjusted properly. The combination of ride height change and shorter wheelbase noticeably quickened the steering. So much so that for the first few laps I regularly had to correct my line from inside of the apex and pick new turn-in reference points. I had set my static sag on the stiffer side and had the futune of Penske's race tech's there that day to help with my set up. Over the roughest sections of the track the bike felt much more plush. Plus, on the harsh transitions from on and off the banking I was no longer being bounced off my seat. This certainly felt better then before.
Was it worth the price? For me it was since I bought my bike used and paid less then $7,000US. I have another track day scheduled for Saturday June 23rd at Summit Point’s Jefferson Circuit. I am planning to have the triple clamps on in time and the bike geometry dialed into the “sweet numbers.” Then all I need to do is figure out how I can get to the track, fix up the house, and handle two new babies plus a toddler all at once. Any idea’s that don’t involve spending more money?
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
13 Jun 2001 16:30 |
Brad, sounds like the linkage is working well for you. I'm glad you like it. Sounds like a well engineered system, if you have gained plushness along with the quickened steering.
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Coyote
Austin, Texas,
USA
Posts: 743
Daytona T595 (97-98)
13 Jun 2001 16:31 |
Brad, sounds like the linkage is working well for you. I'm glad you like it. Sounds like a well engineered system, if you have gained plushness along with the quickened steering.
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JoHNY
Edinburgh,
United Kingdom
Posts: 45
Daytona T595 (97-98)
25 Apr 2008 10:33 |
I've done the work too. P*ss easy, took me an hour tops. Removed the link bars and stuck it in a vice and drilled to 19mm. No shock snagging and turns in to corners brilliantly. Rear a bit harder but nae bother as i adjusted the shock to make it slightly softer. Looks much better too, leans over a wee bit too much on the stand though.
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