Estimating pneumatic trail
Estimating pneumatic trail
(OP)
Is there a simple way to estimate the peak pneumatic trail of a tyre? I need to calculate some likely peak steering forces without any tyre data.
I can estimate the contact patch length, would e.g. taking the trail to be 75% of the way along the patch length be OK?
Thanks, Ian
I can estimate the contact patch length, would e.g. taking the trail to be 75% of the way along the patch length be OK?
Thanks, Ian





RE: Estimating pneumatic trail
Have you got any tire data for a similar tire? Mz/Fy is the trail.
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Estimating pneumatic trail
Max P-Trail is load, pressure, rim width and tire structure dependent. If its an existing tire, the tire manufacturer can get you scrub torque values or P-trail from routine slip/load/camber tests.
RE: Estimating pneumatic trail
I can estimate the expected Fy from expected car performance. Using the current amount of steering trail suggests the steering wheel force will be too high for driver comfort. We can reduce steering trail by up to 20mm (easy), or we could go for power assistance (not so easy), but without knowing the pneumatic trail I'm unsure that the 20mm reduction would have enough of an effect.
Regards, Ian
RE: Estimating pneumatic trail
It'll make the car feel less linear which is bad for a road-car.
There are other effects, those are the biggies (IMNVHO)
Cheers
Greg Locock
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.