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FREE Suspension Setup advice from an expert
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Thanks for that, looks like my gearing swingarm length is spot on a@ 545 15/41 106L. My question was how many mm's does the swing arm height alter at the axle for every mm of shock length change. I was going to work it out mathematically but my high school knowledge of 1st and 2nd class levers is sketchy! I might need to purchase or fabricate a ride height tool
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Oh yea, fortunately or unfortunately, the tire has been picked. RCII 200/55. The 60 is not for a year at a min.
This is with an inch of adjustment with a Sato adjustable link. Interesting! I see now why ride height is so important not to change when you change something else.
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Hey, Roadracerx, I ride a base V4 and changed the Sachs shock for a DU468 , on the delivered setup sheet with the shock is the lenght 310 +4/-2 mm. I read here length of more then 315 mm, is that still OK then? Is there enough thread left ? I'm 196 lbs with gear, the spring is a 100N (original 95N) now. The spring preload is 12mm (setup datasheet) , is this with the hydraulic preload adjuster set too '0' turns and is each turn corresponding with 1mm extra preload? I have an issue with the static sag in the rear, even with the preload at '0' turns, I get a free sag of 9mm and a static sag of 28mm total, that's the max, is my springrate too high then (ordered the shock with the 100N). V4 is dedicated trackbike , I'm a just a trackday guy (expert level). Tires: Pirelli superbike SC2 and SC1 depending on tracktemp. Pressure out of the warmers F: 32-33psi and R: 24-25psi.
Last one, how do you see the difference between cold teare and hot teare and how too solve it?
Last one, how do you see the difference between cold teare and hot teare and how too solve it?
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@rikkie07 which size tire SC Pirelli? 315 mm is the correct length for the OEM shock with Ohlins OEM fork. What is the length of your fork from the bottom of the lower triple clamp to the center of the axle? 2 turns on the hydraulic adjuster is equal to 1 mm preload. What spring number is on the shock? If you have fixed rearsets put the bike so there is no weight on the rear and measure the length of the spring. If your spring is a 21041 which has a 160 mm free length then if your preload is at 12 mm (which is fine), typical range is 10-16 mm, then your installed spring length should measure 148 mm. Do no go past the notch on the bottom of the shock for ride height adjustment as there is a minimum number of threads that must be "inside" the shock to keep its integrity. Typically you will need 10-15 mm of bike sag and 28-30 rider sag so you are pretty close. Are you saying that you have backed off the preload adjuster until it stops and you are at 9 mm bike and 28 mm rider sag? Do you have a shock compressor device? If so, you can readjust the preload adjuster 2 mm closer to the body, re-install the spring with a minimum of 10 mm preload between measured free length and installed length and then add 1 or 2 turns on the preload adjuster. This will give you about 11 mm of total preload and probably get you right where you want to be. Tire tear is a long convo. Let's get the other questions answered first. Pics help for me to tell the difference between hold and cold tear....but basically you have too little or too much air pressure in the tire....are you using warmers? If so have you checked with a digital thermometer to see what temp they are getting??? Are you running them in the highest (hottest) setting? Have you checked your air gauge against at least 2 others to see if it is accurate?
OK thanks, Roadracerx,
Tiresize: F: 120/70 en R: 200/60.
For the front: My fork is the original Showa BPF with 6 turns of preload (standard 4). Lenght from the fork (static)= 378mm. Comp: 2.5T en Reb: 1.5T
For the rear:The reason why I changed to the DU468 and the harder spring is that with the Sachs I had issues accellerating out of corners, with 6 turns of preload this was a lot better but then I didn't have any free sag anymore and the static sag was 20mm, so I lost on braking. So I concluded I needed a harder spring. The Ohlins I ordered from my suspension guy was setup with 12mm preload and had intiallly 3 turns on the hydraulic adjuster. With 2T for 1mm preload this means that with '0' turns I would still have 10.5mm, so this looks OK for me. Spring= 21040-34/100, free length= 160mm. I don't have a shock compressor device.
Comp: 14 en Reb: 12. The shock lenght is 310mm accordingly to the setup datasheet, should I change this then? My earlier bikes were 1199 and 1299 but this V4 in my opinion is very sensitive for every riderinput and chassissetup is more critical but when you get it wright , man it's fun! I try too setup my bikes as 'soft' as possible because I think the better the suspension works the lesser the tire has too work.
Thanks in advance for your detailed info.
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@rikkie07 where is the bike and rider sag for the front AND rear rn? what is the bike doing that you don't like? You have lowered the rear with the 200/60 tire by over 5 mm vs stock 200/60 SP V3. Have you changed gearing? Did you change stock ride height on fork? It is not clear what you mean by "length of fork (static)".
Front: bikesag: 28mm/rider sag: 38mm. Rear: bikesag: 9mm/ ridersag: 26mm. Gearing is original. Fork ride height is original. Length of fork (378mm) is what you asked (bottom lower triple clamp till center of axle) without rider. Last year at Catalunya was my first trackday with the V4 (suspension F and R original) and on the straight the bike was weaving like a snake sometimes it got so bad I had to close the throttle . You can see a video if you want, search for 'V4 catalunya' on youtube and the first one should be mine (onboard racing). A lot other guys with V4 had the same issue so it has something to do with basic geometry. Because it was my first trackdays I didn't won't to change to much I only had this in Catalunya, the other circuits I ride don't have that long straights.
Do I need to change the shocklenght to compensate for the reartire? Would 2mm more shock lenght be OK?
I would like some more frontend feel so I'm more confident to attack the corners and I always lose on cornerexit but that can be due to me I think i'm to careful with the throttle.
Normally I would be back in Catalunya in march but due to Corona everything was cancelled.
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@rikkie07 the weave is a geometry problem that was addressed on the V4R with the adjustable swingarm pivot. We need a little more bike and rider sag from the rear, remove preload to get to 28-30 mm of rider sag, and I would recommend that you switch to the new Pirelli 125/70 and 200/65 slicks so the rear isn't low. What do you mean you "loose on corner exit"? Is the bike running wide?
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@rikkie07 so you bought a stack of tires for the season and the rears are 200/60 Pirellis, right? What year is your base V4? You said your shock has a max length of 314 mm so if you have 10 mm bike and 30 mm rider sag from the rear and 25 mm bike and 40 mm rider sag from the fork and the fork length is stock and your shock is currently at 310 mm eye to eye and your rear tire has 4 mm less radius then we need to compensate for that. Measure the stock shock length eye-to-eye, I believe it is 310 mm. The linkage has about a 2:1 ratio so lengthen your Ohlins shock from 310 to 312 mm. The bike should steer much better and stop running wide.
Yes, that's right. Build end 2018, modelyear 2019. I will change the shocklenght to 312mm and give you some feedback as soon as the tracks open again.
I now have the DP trackfairing from the R model (with the wings), do you think due too the downforce at high speeds I should compensate this with more preload or maybe more oil in the fork?
Thanks for the advice,
I now have the DP trackfairing from the R model (with the wings), do you think due too the downforce at high speeds I should compensate this with more preload or maybe more oil in the fork?
Thanks for the advice,
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@rikkie07 you are likely going to have to go up a spring rate or replace the fork insert with an Ohlins FKR and go up one spring rate from normal. We need to get the bike working WITHOUT the added downforce FIRST so leave the wings off for now...they do work.
For example, 185 lbs rider w/o gear (me), I will run a pair of 10.0 N/m on a NIX30 fork but a 9.5 N/m pair on an FKR because the compression valving technology needs less spring force to resist bottoming but the V4R, which has FKR on the compression side, is running 10's.
For example, 185 lbs rider w/o gear (me), I will run a pair of 10.0 N/m on a NIX30 fork but a 9.5 N/m pair on an FKR because the compression valving technology needs less spring force to resist bottoming but the V4R, which has FKR on the compression side, is running 10's.
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Ok thanks, I will do that. I checked my original shock (Sachs) and the shocklenght is 311mm, then I saw that my suspension guy wrote this number on the back of the shockreservoir, i hadn't noticed that. So it's possible that he already set the Ohlinsshock to 311mm, but I still have to compensate for the tire diameter so I'll go to 313mm. When I would go to 314mm shocklenght is that better or worse regarding handling of the bike?
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