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Dodgy handling/ poor setup
johnnybizzle1986 - 2/5/14 at 01:13 PM

Hi guys,

Took my CBR1000 roadster out at the weekend for the first time this year, and the handling wasn't great. Just had its first MOT.

Got the car running sweet last year, but after a few track day and advice from others I have tweeked about with a few things, but now on the road it just not right.

Here goes ... straight line speed 60mph plus the car is constanly wandering so correcting it, but the steering wheel seems to have abit of play before the car reacts, just a bit vague, there is no loose suspension parts, im guessing too much toe in?


any advice

Regards Jon

Smoking Frog - 2/5/14 at 01:37 PM

No expert but would also say get the toe checked. it sounds to me like you have toe out.

19sac65 - 2/5/14 at 03:30 PM

Yep
Racers love loads of toe out , gives better turn in
at the expense of being vague in a straight line
I think mine had been set up for track as both front and rears were toed out loads
It was horrible on the road
Set it
with a little toe in and its much better

Dingz - 2/5/14 at 04:33 PM

What tyre pressures are you running?

Ivan - 2/5/14 at 05:06 PM

Have you checked bump steer?

britishtrident - 2/5/14 at 05:52 PM

Tyre pressures first then, check dampers aren't too hard, then toe settings, toe-out at front is just unnerving, toe-out at the rear can be lethal.

Sam_68 - 2/5/14 at 06:14 PM

quote:
Originally posted by johnnybizzle1986
Got the car running sweet last year ...I have tweeked about with a few things, but now on the road it just not right.


What, exactly, have you 'tweeked about' with?

Perhaps if you started with a bit of un-tweeking?

johnnybizzle1986 - 5/5/14 at 05:14 PM

Thanks for the responses, sorry for the late response, ive been at stoneleigh

Running 22psi in toyo proxes on the road, dampers are stiff as, front wheels are toe in, front end lowered 12mm, castor is (by eye) pretty neautral

Im going to try, winding back the shocks first, then try abit less toe in, i think there is too much, what should it be?

Regards jon

Sam_68 - 5/5/14 at 05:42 PM

quote:
Originally posted by johnnybizzle1986...front end lowered 12mm, castor is (by eye) pretty neutral


Although 12mm isn't much, remember that putting a nose-down rake on the car effectively reduces castor, which will reduce self-centring on the steering. As Ivan suggests, lowering the front may have taken suspension movement into a range where bump steer has started to become significant, so worth checking that, too.

Try it with just a touch of toe in (say 1.0mm per side), if you think you have too much, though as others have said 'constant wandering' sounds more like what you'd expect from toe out.

britishtrident - 5/5/14 at 06:05 PM

quote:
Originally posted by johnnybizzle1986
Thanks for the responses, sorry for the late response, ive been at stoneleigh

Running 22psi in toyo proxes on the road, dampers are stiff as, front wheels are toe in, front end lowered 12mm, castor is (by eye) pretty neautral

Im going to try, winding back the shocks first, then try abit less toe in, i think there is too much, what should it be?

Regards jon


The shock absorbers should be set at the soft end of the range, if you set the dampers hard the suspension becomes over damped which prevents the wheels following the road surface. Running the dampers too hard is very good way to find yourself hitting the scenery in the blink of an eye.

Toe-in within reason won't make the car unstable but toe-out will.

[Edited on 5/5/14 by britishtrident]

Sam_68 - 5/5/14 at 06:16 PM

quote:
Originally posted by britishtrident...if you set the dampers hard the suspension becomes over damped which prevents the wheels following the road surface. Running the dampers too hard is very good way to find yourself hitting the scenery in the blink of an eye.


Shouldn't make the car 'wander' constantly, though: that sounds more geometric?

40inches - 5/5/14 at 08:57 PM

Try lowering the tyre pressures, I dropped mine from 20psi to 16psi, it really does make a difference