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Old 10-28-2017, 07:48 PM   #31
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What rear tire?
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Old 10-29-2017, 12:02 AM   #32
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Pirelli sc2 180/55. The new DOT V2 tire.
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Old 10-29-2017, 06:44 AM   #33
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Pirelli sc2 180/55. The new DOT V2 tire.
That explains a lot.

Toss that turd and get the 180/60. Just about everyone using the numbers you are using is using the 180/60 (or taller), and it's MUCH taller than the 180/55, not just a tiny bit. Nobody I know of is even using the 180/55.

The 180/60 is taller and has a much better contact patch. A lot of guys are even using the 200/60 Pirelli or the 200/55 Dunlop, both of which are close to the same size and even taller than the 180/60.

PS: $5 says your problems disappear when that tire is swapped out.

You coming to Laguna with Keigwins? I can probably bring a 180/60 mounted on a rim for you to try. I have two sets of rims.
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Old 10-29-2017, 12:44 PM   #34
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Sorry, I got mixed up - this last four days I've been running the new rear 180/60, I forgot that Daredevil got me on the new one when I changed it over. Pirelli does have a 190 rear now in the DOT, should I give that a shot? These are almost toast anyway...

I'd like to come to Laguna but I doubt this bike will pass sound with an M4 slipon on the right side. Also generally outside of my budget... if I can pick up a cheap last minute ticket I may give it a shot.

It's weird that the bike has so little rear sag since I think this spring is pretty close for me... There is a lot of threads showing above the hydraulic preload on the ohlins shock (su647). Wonder if the collar is just set really low. Ohlins gave me a spec for coil length with zero preload but not the amount showing above the collar.

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Old 10-29-2017, 02:50 PM   #35
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Sorry, I got mixed up - this last four days I've been running the new rear 180/60, I forgot that Daredevil got me on the new one when I changed it over. Pirelli does have a 190 rear now in the DOT, should I give that a shot? These are almost toast anyway...

I'd like to come to Laguna but I doubt this bike will pass sound with an M4 slipon on the right side. Also generally outside of my budget... if I can pick up a cheap last minute ticket I may give it a shot.

It's weird that the bike has so little rear sag since I think this spring is pretty close for me... There is a lot of threads showing above the hydraulic preload on the ohlins shock (su647). Wonder if the collar is just set really low. Ohlins gave me a spec for coil length with zero preload but not the amount showing above the collar.
The 180/60 is about the same diameter as the 190 DOT, it's almost as big as the 200. Sounds like you are good
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Old 10-29-2017, 05:10 PM   #36
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big rear tires seem to require tons of front ride-height. the tire height pitches the bike forward and takes away swingarm angle, making the bike not finish corners. adding more shock length steepens the forks too much, removing front stability and causing the tire to tuck easily. so the answer is tons of fork length to get the stability and swingarm angle back. some bikes need shock length too, others dont.

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In order:

1. I was implying raising the whole bike, not just the front - I was under the impression this would make the bike transition easier from side to side

2. I couldn't adjust the rear ride height because I don't have two of those super thin 24mm wrenches. So I dropped the front instead, since my goal this weekend was to experiment - how else am I going to find out what's wrong?

3. I went to 4 turns (of 14) from full out on the front. Tuner backed it off to 2 turns. Felt fine, not bottoming (zip tie about 3/4cm from bottom of stanchion).

4. Rear has no preload. Tuner claims its still way too stiff, and it needs more sag. I can't remember the number he gave me but it was apparently less than ideal, he said that might be screwing with the whole bike. It sort of chops at high lean angles and he said that's why. Racetech and the GSXR forums seem to say 100 N rear spring is pretty close to spot on but he would rather back it off to a 95.

5. Thill East. Mostly turn 1 and 8 I felt it the most that it was boaty. It wasn't unrideable but it was really hard to turn in and vague.

6. I played with it, it felt better with more brakes to the apex for sure now with less compression in the front it was better. I think one leg was all the way closed (!) so that probably explains why it wouldn't pack down for me on the brakes previously.

6 cont'd. If you wanted some reading, there's a great thread from an AMA racer here that outlines his and east coast suspension guru Thermosman's experimentation on this bike's setup.

7. the tuner's sheet he just emailed me said the rear sag was 20mm. I will try to remeasure myself because every resource I've found online says that this is the right spring for my weight.
1. ahh. sounds like u are 6-8mm away from max front ride height right now. so u can add 3-4mm of shock length and not need extenders. its prob worth trying there before spending the $$ on extenders.

2. the GSXR all use a shim under the top clevis, correct? a lot of racers dont bother changing the shock length. they set it at their minimum, then swap shims. that way your changes are accurate, u dont need to mess w/ funny wrenches, you dont round the shock nuts, and u dont burn your hands. it takes an extra 3min on the R6 to swap shims.

3. its funny you are running so little external preload. i think before i had assumed the shop that worked on it would have cut the preload spacer so that the adjuster was near the middle of the range. prob didnt happen that way. i think we also agreed previously that your fork springs are too stiff. lots of things still to sort out w/ the front end. a spring w/ very little preload has some interesting side-effects, so its prob a good idea to measure if/when u swap springs.

4. i hope not. "no preload" is bad news bears. springs arent linear w/ no preload. if u have an Ohlins, theres a topout spring in there and u need preload to deal w/ that too. dont listen to Racetech. their springrate calculator is way off for every racer i know. and who knows about yahoos on a forum . change the springs so u can stop "wasting" trackdays on an ill handling bike.

5. both of those turns are easy to get into completely off the brakes. so your dynamic ride height is taller and the bars are difficult to turn. but thats how setup works. we very often sacrifice one corner to make up time in the other 14 turns.

6. in a normal braking zone, where u brake for at least 1sec with the bike upright, compression damping has very little effect on the fork position. the shorter the braking zone, the more effect it has. damping controls the speed of fork movement, springrate/preload/oil height controls the position of it. any overlap btw those 2 concepts all depends on time/duration of the input to the suspension. i fully expected u to say the bike was better on the brakes, because the front is/was taller. the brakes lower the ride-height, reduces trail, shortens wheelbase, and lets the bike turn easier. can u use that to go faster? (u should def say yes )

6 contd. IMO, the main reason why racers run shit tons of fork length is because theres plenty of time to be made up on the brakes. modern tires can support A LOT of brake pressure all the way to the apex. 40% brake pressure with a knee on the ground is borderline normal. getting off the brakes before turn-in is slow obviously. so the front end is statically very long and they control front ride-height w/ the brakes. u arent riding like that... yet. so the setup that works for an AMA pro might not work well for u. i just rode a 2016 Graves R6 last weekend for one session. the front end was practically immobile at fast A group pace when i was hardly using the brakes. but as i started to use my racing markers and brake harder, it was money. there is some discussion to be had about how to setup a bike for a rider thats learning... set it up how fast guys use it, then hope u learn to ride like that. or set it up best for u now and hope that u realize when it needs to be adjusted. hmm.

7. see above for online calculators - they are shit. if u want the best suspension experience, find a tuner that has personal experience setting this bike up for racing. not just building parts and sending it out. literally working at the track w/ a racer. then get them to watch u ride and pay them for their recommendations. normally, i dont care one bit about sag. but u arent in range so we'll use it. and its telling us u need a new spring. also, def verify how much installed preload u have. measure the spring length now w/ the rear tire off the ground and get back to us.
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Old 10-29-2017, 10:24 PM   #37
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big rear tires seem to require tons of front ride-height. the tire height pitches the bike forward and takes away swingarm angle, making the bike not finish corners. adding more shock length steepens the forks too much, removing front stability and causing the tire to tuck easily. so the answer is tons of fork length to get the stability and swingarm angle back. some bikes need shock length too, others dont.

1. ahh. sounds like u are 6-8mm away from max front ride height right now. so u can add 3-4mm of shock length and not need extenders. its prob worth trying there before spending the $$ on extenders.

2. the GSXR all use a shim under the top clevis, correct? a lot of racers dont bother changing the shock length. they set it at their minimum, then swap shims. that way your changes are accurate, u dont need to mess w/ funny wrenches, you dont round the shock nuts, and u dont burn your hands. it takes an extra 3min on the R6 to swap shims.

3. its funny you are running so little external preload. i think before i had assumed the shop that worked on it would have cut the preload spacer so that the adjuster was near the middle of the range. prob didnt happen that way. i think we also agreed previously that your fork springs are too stiff. lots of things still to sort out w/ the front end. a spring w/ very little preload has some interesting side-effects, so its prob a good idea to measure if/when u swap springs.

4. i hope not. "no preload" is bad news bears. springs arent linear w/ no preload. if u have an Ohlins, theres a topout spring in there and u need preload to deal w/ that too. dont listen to Racetech. their springrate calculator is way off for every racer i know. and who knows about yahoos on a forum . change the springs so u can stop "wasting" trackdays on an ill handling bike.

5. both of those turns are easy to get into completely off the brakes. so your dynamic ride height is taller and the bars are difficult to turn. but thats how setup works. we very often sacrifice one corner to make up time in the other 14 turns.

6. in a normal braking zone, where u brake for at least 1sec with the bike upright, compression damping has very little effect on the fork position. the shorter the braking zone, the more effect it has. damping controls the speed of fork movement, springrate/preload/oil height controls the position of it. any overlap btw those 2 concepts all depends on time/duration of the input to the suspension. i fully expected u to say the bike was better on the brakes, because the front is/was taller. the brakes lower the ride-height, reduces trail, shortens wheelbase, and lets the bike turn easier. can u use that to go faster? (u should def say yes )

6 contd. IMO, the main reason why racers run shit tons of fork length is because theres plenty of time to be made up on the brakes. modern tires can support A LOT of brake pressure all the way to the apex. 40% brake pressure with a knee on the ground is borderline normal. getting off the brakes before turn-in is slow obviously. so the front end is statically very long and they control front ride-height w/ the brakes. u arent riding like that... yet. so the setup that works for an AMA pro might not work well for u. i just rode a 2016 Graves R6 last weekend for one session. the front end was practically immobile at fast A group pace when i was hardly using the brakes. but as i started to use my racing markers and brake harder, it was money. there is some discussion to be had about how to setup a bike for a rider thats learning... set it up how fast guys use it, then hope u learn to ride like that. or set it up best for u now and hope that u realize when it needs to be adjusted. hmm.

7. see above for online calculators - they are shit. if u want the best suspension experience, find a tuner that has personal experience setting this bike up for racing. not just building parts and sending it out. literally working at the track w/ a racer. then get them to watch u ride and pay them for their recommendations. normally, i dont care one bit about sag. but u arent in range so we'll use it. and its telling us u need a new spring. also, def verify how much installed preload u have. measure the spring length now w/ the rear tire off the ground and get back to us.
1) Let me be clear, the rear is right now around 320mm eye to eye as set by Daredevil on a motion pro jig. That's already 4-5mm over the length of the stock shock. You're correct in that I'm about 2-3mm fork showing over the top of the triple so I could in theory drop it another 8mm or so.

I did get a line on a used set of GP fork caps that are 15mm so I'll be installing those this winter so I can do some more experimentation next year.

2) I think you need to pull the tank up to get at it, which is kind of annoying. I got a couple 24mm standard wrenches I'm going to grind down for this off ebay. But shims are more exact you're right, I could just bring a set of those to the track and some jack stands.

3) I was fine running it at 4 clicks, it felt alright under braking and I'm honestly getting more used to the stiffer front end. The tuner said lets back it off, the sag was 33mm at 4 turns, it's 38 with two. I'd prefer it less stiff though for sure, if I can find fork springs for halfway cheap.

The issue was the compression valve in one leg was ALL THE WAY closed before this weekend. Meaning it would not pack down, at all. Some tuner's oversight I guess...

4) "no preload" meaning the hydraulic preload is 0/14 clicks. That doesn't mean no preload, Ohlins has quite a bit of preload on the spring just based on where the collar sits (and I checked it just now, it's to spec, the collar hasn't been moved from factory) it's around 11-12mm.

Rider sag is currently 21mm on the rear according to the tuner which is way too low. He said it's topping out at full lean and that's what's causing chopping. I just got a 525lb (92.5N) spring and I'll put that on, should be a little closer to the mark.

5)

6) Yes I overbrake beforehand - this year has been so focused on setup I tried to spend a few sessions in the afternoon on Sunday ignoring the bike and just focusing on braking markers and pushing it a little bit. Of course trail braking feels better, particularly into 6, 9, 10, 12 - I understand the physics and I feel it as well for sure. I should be braking slower and later.

Cont - this is interesting, but isn't the travel the same regardless of the height of the bike? Or is it just when the whole thing is higher cornering with the brakes is more effective? More of an academic question I suppose but still interesting. I was led to believe the goal of a taller bike overall was a) to ease full lean to full lean transitions, b) give more clearance for dragging parts and c) increase swingarm angle (related).

7) There's basically no free sag on the bike atm. on the sidestand it's 136-138mm long. The spring off the shock is 148mm long. A softer one is going in as I said.
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Old 10-30-2017, 04:43 AM   #38
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IMHO you need about 6mm more length on the shock, or 6mm shims. Yes, you have to pull the tank, undo the large nut, and drop the shock, (at the linkage) it's a PITA. Really easy on the 1000, but a PITA on the 600/750.

That closed valve wasn't helping things.
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Old 10-30-2017, 11:30 AM   #39
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1. ill defer to afm199 on the shock length u need.

2. the shims i use on the R6 are slotted. they just slide in. remove seat (2 bolts), lift the tank (3 bolts), loosen the shock nut, lift up on footpegs and slide in shim, put everything back. i guess that doesnt work for your GSXR, oh well.

3. i still dont care about sag . all the way closed on compression doesnt mean the fork doesnt move. the oil still flows past the shim stack for all fork velocities and u might have a bleed hole in the valve body. and only one leg, psh jk. ya im sure riding that sucked, esp if u werent pushing that hard on the brakes.

4. 11-12mm preload is great. a good range for preload on almost any shock is 8-16mm total preload. obviously, putting the adjuster so that full soft is at 11mm ruins your ability to get down to 8mm. the tuner saying "no preload" threw me off, an odd thing to say. dont forget, preload has nothing to do w/ spring stiffness as well.

i dont know what u mean by "chopping". can u explain?

6 cont'd. the travel isnt the same on most pro setup bikes, at least on the ones ive seen. a good tuner can use an aftermarket fork cart to extend the travel by 10-20mm. the extra travel allows for a wider range of useable springrates before hard braking causes bottoming. this in turn moves the dynamic ride-height around a lot, for better or worse. ive heard the whole reason GSXRs "need" extenders for race pace is because the fork bushings only allow for 10mm extension (or something) and u still gotta go higher.

but rly, that part ^ doesnt matter much for your actual question. say uve found some dynamic* ride-height, some ideal fork position, that allows the bike to turn as good as possible on the brakes... but now u want to brake harder. u must add fork height, add preload, or increase springrate to maintain that ideal position given the stronger input. the same goes for midcorner too. faster riders load the suspension more w/ higher corner speeds, so they might run a taller static ride-height to deal with it. im sure u can think about how all this relates to my prev paragraph for #6 w/ compromises and pace.

funny thing... RaceTech recommends .875 fork springs for me and "roadracing". with the stock fork travel, i can bottom .925 in any hard braking zone. so why the hell would they recommend .875!?!?!. however, that Graves bike i rode 2 weekends ago had the longest R6 forks ive ever seen, 8mm longer than my extended forks. they had .90s and i couldnt bottom them. midcorner grip felt good too.

7. heres the manual for your shock. its interesting that they recommend 14mm installed out of the box. sounds like the adjuster is setup to allow ~10mm at minimum. its all making sense now. https://www.ohlins.com/app/uploads/w...3/MI_SU647.pdf

*i say "dynamic" because u are riding the bike when u need this ride-height. its not static ride-height when the bike is on a stand.
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Old 10-30-2017, 12:54 PM   #40
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Quote:
Originally Posted by stangmx13 View Post
1. ill defer to afm199 on the shock length u need.

2. the shims i use on the R6 are slotted. they just slide in. remove seat (2 bolts), lift the tank (3 bolts), loosen the shock nut, lift up on footpegs and slide in shim, put everything back. i guess that doesnt work for your GSXR, oh well.

3. i still dont care about sag . all the way closed on compression doesnt mean the fork doesnt move. the oil still flows past the shim stack for all fork velocities and u might have a bleed hole in the valve body. and only one leg, psh jk. ya im sure riding that sucked, esp if u werent pushing that hard on the brakes.

4. 11-12mm preload is great. a good range for preload on almost any shock is 8-16mm total preload. obviously, putting the adjuster so that full soft is at 11mm ruins your ability to get down to 8mm. the tuner saying "no preload" threw me off, an odd thing to say. dont forget, preload has nothing to do w/ spring stiffness as well.

i dont know what u mean by "chopping". can u explain?

6 cont'd. the travel isnt the same on most pro setup bikes, at least on the ones ive seen. a good tuner can use an aftermarket fork cart to extend the travel by 10-20mm. the extra travel allows for a wider range of useable springrates before hard braking causes bottoming. this in turn moves the dynamic ride-height around a lot, for better or worse. ive heard the whole reason GSXRs "need" extenders for race pace is because the fork bushings only allow for 10mm extension (or something) and u still gotta go higher.

but rly, that part ^ doesnt matter much for your actual question. say uve found some dynamic* ride-height, some ideal fork position, that allows the bike to turn as good as possible on the brakes... but now u want to brake harder. u must add fork height, add preload, or increase springrate to maintain that ideal position given the stronger input. the same goes for midcorner too. faster riders load the suspension more w/ higher corner speeds, so they might run a taller dynamic ride-height to deal with it. im sure u can think about how all this relates to my prev paragraph for #6 w/ compromises and pace.

funny thing... RaceTech recommends .875 fork springs for me and "roadracing". with the stock fork travel, i can bottom .925 in any hard braking zone. so why the hell would they recommend .875!?!?!. however, that Graves bike i rode 2 weekends ago had the longest R6 forks ive ever seen, 8mm longer than my extended forks. they had .90s and i couldnt bottom them. midcorner grip felt good too.

7. heres the manual for your shock. its interesting that they recommend 14mm installed out of the box. sounds like the adjuster is setup to allow ~10mm at minimum. its all making sense now. https://www.ohlins.com/app/uploads/w...3/MI_SU647.pdf

*i say "dynamic" because u are riding the bike when u need this ride-height. its not static ride-height when the bike is on a stand.
yep the slotted ones don't slide in neatly, the clevis bolt is inaccessible to slide in, shrouded.

Yep, the bushing only allows about 10mm extension internally, then you run out of bushing. I've done that by shortening top out springs.

Good remarks all in all.
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Old 10-31-2017, 01:53 PM   #41
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1. ill defer to afm199 on the shock length u need.

3. i still dont care about sag . all the way closed on compression doesnt mean the fork doesnt move. the oil still flows past the shim stack for all fork velocities and u might have a bleed hole in the valve body. and only one leg, psh jk. ya im sure riding that sucked, esp if u werent pushing that hard on the brakes.

4. 11-12mm preload is great. a good range for preload on almost any shock is 8-16mm total preload. obviously, putting the adjuster so that full soft is at 11mm ruins your ability to get down to 8mm. the tuner saying "no preload" threw me off, an odd thing to say. dont forget, preload has nothing to do w/ spring stiffness as well.

i dont know what u mean by "chopping". can u explain?

6 cont'd. the travel isnt the same on most pro setup bikes, at least on the ones ive seen. a good tuner can use an aftermarket fork cart to extend the travel by 10-20mm. the extra travel allows for a wider range of useable springrates before hard braking causes bottoming. this in turn moves the dynamic ride-height around a lot, for better or worse. ive heard the whole reason GSXRs "need" extenders for race pace is because the fork bushings only allow for 10mm extension (or something) and u still gotta go higher.

but rly, that part ^ doesnt matter much for your actual question. say uve found some dynamic* ride-height, some ideal fork position, that allows the bike to turn as good as possible on the brakes... but now u want to brake harder. u must add fork height, add preload, or increase springrate to maintain that ideal position given the stronger input. the same goes for midcorner too. faster riders load the suspension more w/ higher corner speeds, so they might run a taller dynamic ride-height to deal with it. im sure u can think about how all this relates to my prev paragraph for #6 w/ compromises and pace.

funny thing... RaceTech recommends .875 fork springs for me and "roadracing". with the stock fork travel, i can bottom .925 in any hard braking zone. so why the hell would they recommend .875!?!?!. however, that Graves bike i rode 2 weekends ago had the longest R6 forks ive ever seen, 8mm longer than my extended forks. they had .90s and i couldnt bottom them. midcorner grip felt good too.

7. heres the manual for your shock. its interesting that they recommend 14mm installed out of the box. sounds like the adjuster is setup to allow ~10mm at minimum. its all making sense now. https://www.ohlins.com/app/uploads/w...3/MI_SU647.pdf

*i say "dynamic" because u are riding the bike when u need this ride-height. its not static ride-height when the bike is on a stand.
1) I don't know how high to run it without risking tucking the front. I've heard a lot of people like ~535mm (top of bottom triple to axle center) in the front which is about +15mm or so, and 326-328mm in the rear.

3) I know you don't and I think a lot of pros don't. From what I understand it's a start point and that's about it, but just as a static measure of where the fork is in it's stroke, at least it says something without seeing it.

4,6) Good to know. I'm learning shitloads here.

By chopping I mean I can feel the rear end slip and regrip in relatively quick succession at full lean/just coming out of apex as I crack the gas. The tuner lead me to believe that it's just riding too high in the stroke, and I think a softer spring would give me some more grip. Don't know. Maybe I'm just too slow right now for the super stiff springs the fast guys are running on this bike use.

7) I have seen that - yeah it seems to come with 1cm of 'installed preload' before the hydraulic can take up about another cm.

I wonder why it says 317 for ride height and then the very tiny 6/0 mm beside it? EDIT - looks like it can only go +6mm (323mm) then. I suppose I need to find a couple shims. I think that also means I'm running closer to 319 now which is probably way lower than it should be.

Last edited by zammer; 10-31-2017 at 05:27 PM..
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Old 10-31-2017, 03:32 PM   #42
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I've run 330 plus without tucking the front. What will happen is you will have problems finishing out the corner and also spinning up the rear.
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Old 11-01-2017, 01:04 PM   #43
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i wouldnt worry too much about tucking the front due to shock length changes for a few reasons:
- changes at the opposite end have a very diminished effect. some ppl say the rule of thumb is 4 to 1. for ex, a 4mm shock length chance is comparable to a 1mm fork length change. super rough estimation, but u get the point.
- adding shock length puts more weight on the front end which is prob a good thing. most ppl tuck the front from underloading, not overloading.
- your setup is currently out of range. getting the bike more in-range is going to improve grip on both ends.
- +1 to afm199, ull notice rear end issues first

re chopping. as long as the shock isnt compressing real far and unloading while its doing slip-grip, then i agree a softer spring will prob help that condition. for that feeling, i generally try less preload first, then less shock length, then a softer spring w/ the original preload and length. the first 2 are eliminated, so ya.
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Old 11-04-2018, 10:00 PM   #44
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Originally Posted by IL8APEX View Post
One Man's Opinion: I think the fork spring rate is a bit high for your weight, unless you're absolutely killing it SuperMoto style trailing in on the brakes.

I'm 220 lbs naked and run the same spring on the same bike with caps, so my forks are probably 10-12mm or so lower in the triples than what you've got up front. Rear length sounds similar, but I would have to measure to confirm. My setup is stable on entry and neutral mid-corner to finish, enabling late brakes and early throttle.

I'm going to guess that your front spring rate is going to put your bike at a good attitude mid-corner but limiting wheel travel and making the tire work harder. Softening the rate MAY increase front grip and help you relax a bit.

-Tom


I am 185 and like the .9 springs myself.

when I tried 1.0 they were way too stiff for me
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Old 11-08-2018, 08:29 AM   #45
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My experience with the GSXR is that it likes front spring. I weigh 142 and run .9/.95.
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