Handy Guide To Suspension Adjustment

[Anonymous]

This appeared in Roadracing World magazine's November 2004 issue, at the end of the article: How to Go Racing, Part 12 (part of a series of articles being done by Army Of Darkness and Neighbor Of The Beast endurance teams).

Disclaimer: I have not tested any of these theories, nor do I garantee they work. Use them at your own risk. However, these are recomendations from experienced road racers, so I would venture to guess they have some idea what they're talking about. I apologize in advance for any spelling mistakes I may have made while transcribing this from the magazine.

Important: This assumes that your sag has been set.


Handy Guide to Suspension Adjustment
Reprinted without permission.

Bike turns too slow or runs wide at exits or requires significant force on handlebars:
Lower front end (usually in 3mm steps), or if you are in a hurry, remove a line or two on the preload adjuster on the front. If you lower the front, double-check the mechanical bottoming.
Raise the rear by adding ride height. Remember that on most sportbikes 3mm at the shock is about 6mm at the axle.

Bike is nervous mid-turn, particularly in fast sweepers:
Raise front end. If this makes the bike turn too slowly, try raising the rear as well.

Bike head shakes beyond acceptable limits:
Raise front end or lower back end.

Bike head shakes on deceleration:
Check/adjust steering head bearings.

Bike steers well in single turns, but steers too slowly in quick transitions (R-L-R):
Lower both ends of the bike equal amounts or lower center of gravity some other way or work out more, you big sissy.

Bike dives too much on brakes, too easily lifts rear wheel:
Add fork oil, add compression damping to forks, raise front, lower rear.

Bike's rear wheel chatters at entrance to slow turns:
Rider should slip the clutch into the turn after the downshift or buy a bike with a slipper clutch, like a ZX-6RR.

Front wheel chatters:
Add rebound damping to forks (or check to make sure you don't have too much damping) or try a different front tire.

Bike doesn't have rear grip:
Check free sag, try softer rear spring, try less low-speed compression damping, lower rear of bike, make sure the rider isn't entering the turn too slowly and trying to accelerate out too hard to make up for it, make sure the rider is hanging off the bike.

[cogsxr]

NICE POST

[Puck]

Remember to keep good fork oil in the tubes! You can try all day, but if your oil is more like water you'll be nothing but frustrated.
Sounds like a no-brainer but...

[HRCrider]

Very useful, thanks.

[Flyin Hawaiian]

good info!

[Matty]

ya that really is a good article.... then again i'd rather have a professional mess with my suspension set-up.

[RyNo24]

ya that really is a good article.... then again i'd rather have a professional mess with my suspension set-up.

Who do you recommend for this? I think I can get more handling out of my FZ1 with the proper set up.

[Devaclis]

IRDAVE!! FTW!!!!

[salsashark]

Who do you recommend for this? I think I can get more handling out of my FZ1 with the proper set up.

I had Mike @ Supertune set up my zx-14... I'm planning on having him set up the Speed Triple as well.

[stepintothepain]

raising the front really helps all around, cheapest sus. mod i know of

[racedk6]

raising the front really helps all around, cheapest sus. mod i know of


Only on your particular year make model bike. Most bikes like rear ride height being added.

Im no professional just my thoughs on looking at different bikes over the years

[irdave]

My opinion...

Some of the stuff above is ok, some not so much. YMMV.

For sure if you have questions, don't hesitate to ask...

[1BadSvt]

http://www.gostar-racing.com/information/motorcycle_suspension_set-up.htm
This really helped me alot.

[vort3xr6]

Best thing I ever did was start keeping a log of my settings. Note everything, road/track temperature, ambient temperature, tire pressure, tire tread life, preload, compression, rebound, etc.

I note what the bike is doing, make a change, and note if that helped or not. Great way to start understanding suspension.

[06R1]

My opinion...

Some of the stuff above is ok, some not so much. YMMV.

For sure if you have questions, don't hesitate to ask...

So I just switched tires on my R1 form Conti-Sports to Dunlop Q2's and to me it feels like the front tire is almost floating at highway speed. The contact patch looks like its riding where it should but the slightest tweak of the bars seems to make the front unstable. Not uncontrollable but just not planted. Any ideas? I'd be willing to bring it in and let you look at it if I can't adjust this out.

[Bueller]

Did you check your pressure? Some shops just put them back on at whatever pressure the bead set at. A guy at the track almost took his bike out with 45 psi in them.

[06R1]

Did you check your pressure? Some shops just put them back on at whatever pressure the bead set at. A guy at the track almost took his bike out with 45 psi in them.
Yeah the front is at 35psi and the rear at 34psi. It looks like the profile of the Dunlop is wider and taller than the Conti up front even though they are/were both 120/70's.

I used to run 32-34psi on my 750 and never felt this twitchy. It feels like its riding high up front or squatting in the rear. And with the rear actually being round and not beginning to flatten out in the center now maybe it was the old tires that were the problem and I just got used to it.

[koru]

I run q2's and they seem great except when i had them over inflated but other than that they were great check and make sure your front suspension is secured as in all tight and no play and check your suspension stettings they may be outa wack mate

[duelist13]

So I just switched tires on my R1 form Conti-Sports to Dunlop Q2's and to me it feels like the front tire is almost floating at highway speed. The contact patch looks like its riding where it should but the slightest tweak of the bars seems to make the front unstable. Not uncontrollable but just not planted. Any ideas? I'd be willing to bring it in and let you look at it if I can't adjust this out.

Hey 06R1, I thought the Q2s seemed a bit more aggressively profiled than the Michelin HPXs I used to use, and quite a bit more rigid and a tiny bit taller in the front. The front felt like it was "skimming" when steering while on throttle, which may be what you're describing. I found increasing rebound damping half a turn on the forks and lowering compression damping a half turn made the bike feel it was sitting on the front nicely when turning in. Steering got a little sluggish/more difficult and I had to raise the forks a little bit/increase front sag to get to a happy place, which also helped with the bike's tendency to sit up or run-wide in the corners. You might also want to look at the shock settings. I'm not an expert so take it easy if you go this route :).

Probably plenty of more knowledgeable people than me that can chime in!

[06R1]

The front felt like it was "skimming" when steering while on throttle, which may be what you're describing.
Tha't exactly what it feels like. Like the tire is skimming the pavement and not as planted. I will try the adjust ments you mentioned and see what happens.
Thanks!:up:

[Cornfed]

+1 for STM. Best money you can spend is on suspension work.

BTW, thanks Dave!

[irdave]

Just real quick as I'm getting ready to get out of town for a week of vacation... If everything was ok before you changed tires, and all you did was change tires. And everything got reassembled as it should. Then the issue is geometry. The tires are different actual diameters, so the front end geometry would be different- rake, trail, that kind of stuff.

From what you've described, I'd say chopper the bike out- raise the front a little- lower the rear.... One possible solution would be to push the fork tubes down in the triple clamps by about 5 millimeters to start- which would raise the front end of the bike. It's an easy enough thing and not so big of a change- And from what you've described...

I'm out of town until the 1st of November but if you haven't gotten it sorted by then, drop my a note... dave at STMsuspension dot dom.

[zrouth]

Best thing I ever did was start keeping a log of my settings. Note everything, road/track temperature, ambient temperature, tire pressure, tire tread life, preload, compression, rebound, etc.

I note what the bike is doing, make a change, and note if that helped or not. Great way to start understanding suspension.

best thing i've heard so far besides the main post