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Racers/Trackday Geometry settings

10K views 11 replies 9 participants last post by  wrx_02 
#1 ·
Mostly with the forks...

Do you change your fork height for track days or racing?
The forks in stock settings look pretty tall in the tripple tree.

With certain tires are you guys changing geometry much? if so what combination?

I plan on using Pirellis SC, SP and superbike Pros.

I was depating on slapping on a 200/55 SC rear I have for now, then go back to 180/60 SC after the next TD.

I am trying to get her set up decent b4 the first ride.

I took her on a short test ride and was surprised how stiff the stock suspension was (set at full hardest) 245lbs my weight :(


 

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#5 ·
Ok, I kinda figured it might need to go down some. Its stock forks and 2011.

I heard someone else tell me the forks need to change for track duty...but they never told me where lol...or how much in what directions and since I knew the bike was put together by an amateur I wanted to set her up for the track.
 
#4 ·
I picked the bike up in February.
It sat outside in some dudes back yard since summer 2013.
Ive done most of the rebuild on it, but I am a Kawasaki person and not sure where the forks are suppose to be set up to.

It was crashed 2 times b4 I got it and they replaced the stock clip ons with after market and i can tell the person who painted and put the bike together did not know what he was doing.

Im 245 lbs so I just cranked the preload all the way stiff, but in testing the bike its too stiff, and I do plan on getting my sag set and I can fine tune it myself, but I was wondering if guys who predominantly run there bikes on the track change the fork height ?

example:
On all my zx10Rs I generally raise the forks tubes 5mm, while most zuki 750 owners push the fork tubes down 5mm below the top tipple clamp.
 
#6 ·
Ok i found the geometry settings i was told....

forks have 9mm showing
shock is shimmed 5mm to 9mm

Do anyone on the track run this geometry set up?
 
#9 ·
This is the ever on-going struggle for a lot of people. I don't understand what's so secretive about geometry, but I've asked multiple times on WERA and seem to get half answers or people asking additional unrelated questions. These people know their stuff, but for some reason, they aren't keen on handing out baseline numbers.

First off: You don't measure front geometry by how much fork is stick through the top of the triples. Depending on what's in your forks, they are going to be different length. The correct way to measure is by putting the bike on a pin style front stand, and measuring from the top of the lower triple tree to the center of the axle. When measuring the rear, you take the length between each eye holes in the shock.

Each tire is different and will effect geometry different. Will you feel the difference? Unless you're a seasoned expert level racer, probably not. For example, the Dunlop GPA-Pro rear tire is taller than the Pirelli SC rear tire, so you would take that into consideration if you're comparing your setup with someone else's.

Your geometry is going to depend on the track. Are you setting your bike up to be fast in the long sweeping corners? Or are you setting your bike up to fast in the tight, technical sections of the track? This matters. If you are setting it up for the faster, long corners, then you want a more stable geometry setup. If you're setting it up for tight technical sections, you may want the bike to turn quicker, so you lower the front end.

I setup my 08 for the fast sections of the race track, and do my best to muscle it through the tight sections. Here's the baseline I started with: 525mm for the front and 293mm for the rear. Wheel base extended as far back as possible. Stock gearing, or 15/43. What I found to be important is that its easy to mask suspension issues by softening things up, but by doing so, you're sacrificing corner enter, or exit. So, it's important to have the correct spring rates in your shock and forks, and to setup the preload properly so that the spring stiffness is accurate. From there its just dialing in the rebound and compression.

Hope this helps you with a starting point.
 
#10 · (Edited)
you lost me at "200/55" on a 600 ;)

up in till just a few years ago, world superstock was still running 180/55, and wss riders had the choice between 180/55 and 190/55 . the 180/60 pirelli is only slightly bigger than 190/55's but still designed for a 5.5" r6 wheel. but a 200/55 is just too much tire for a 600, and will be harder to ride, slower to turn, and just silly in general.

and the reluctance to give geometry #'s isn't so much it's a secret, but it totally depends on the fork setup, where the fork bottoms, oil height, and a dozen or so other things. same with the shock. sure 292-297 is common, but you are trying to squeeze a 200 rear tire on the bike, so that makes lots of other stuff irrelevant. then add your 245lb rider weight, and it's just hard to say "this will work".
The 2008-current comes with 10mm of tube showing above the clamp, and a shim above a stock shock and 180/55 tire. put a 190/55 on there, and remove the shim. pretty simple.. ? but to expand on that is very tough, as many are running cartridge inserts in the forks, aftermarket shocks, and the like.
Axle position just depends too. there is no magic position. Some setups may like the axle forward, some back.
 
#11 ·
From my limited experience I've learned a lot. The biggest thing I learned is to take what other racers tell you with a grain of salt, unless they happen to be the fastest in the club and are the type of person that's happy to share what they know. At my club, there's only a few people I would actually trust for reliable info. Then you also have to remember that a lot of setup is totally personal preference and pace related. Some bikes have built engines, and can run different gearing due to more power. My honest opinion is ask and learn as much as you can, then use your best judgement as to the direction you want to go and you will slowly learn through trial and error.

The faster you go, the more compression you might want in the front end. If you go too slow on a stiff set up, the bike might feel skittish, but if your pushing hard enough to load everything up, then that firm setup will feel just right. It really just all depends. The temperature can affect a lot too.

I noticed a huge difference in handling switching to pirellis this year and I've consistently been faster right out of hot pit lane. The tires inspire so much more confidence than the dunlops imo.
 
#12 ·
I am running 294mm on the shock, that includes a shim.
As for the fork I am not sure. I have a ohlins 25mm cartridge so I know my fork length is far greater than yours. I have the top of the triple lined up with the 2nd notch from the cap, on the fork. I believe this will be the setup we continue to run based on the last event. I just started riding this bike so this is a good starting point for me.
 
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