Suspension Bump steer NOT helped with new poly bushings.

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Apr 1, 2010 | 07:30 PM

#26

gawannamini

5th Gear

Joined: Mar 2009

Posts: 835

Likes: 5

From: Atlanta, GA

Quote:

Originally Posted by Headlands

Today I tried adjusting the pressure of my tires. I experimented with a few settings and settled on 35 psi for all four. It does make a noticeable positive difference, indeed! It feels a touch sloppier on the curves, but barely noticeable, and the tradeoff in not feeling like someone else is taking control of my steering wheel is worth it in spades.

Hard for me to imagine why MINI recommends 38 psi -- even only 3 psi less makes the car much easier to deal with.

This car has been a great learning experience in many different ways. Unfortunately, the driver's course I tried to sign up for at Willow Springs next weekend is full, but I'm looking forward to taking a class at some point and learning even more.

For what it is worth, my local dealer, Global Imports, actually told us in the MINI 101 reception that they recommend 36 psig for second gen MINI on all four wheels. That's what I run mine at. I have Michelin Pilot Sport A/S Plus non run flat tires and don't notice trammlining. I do have torque steer on acceleration.

There is also a patch in a curve on a road that I drive frequently that extends all the way across the lane (they installed a water line across the road). If I hit this patch with any power the car will hop to the outside. Not sure what this is called.

Apr 1, 2010 | 07:59 PM

#27

dubyas

1st Gear

Joined: Oct 2009

Posts: 25

Likes: 0

From: Tempe, AZ

Gawanna, your experience is torque steer, Torque steer is inherent on all front wheel drive vehicles with transverse mounted engines.

Last edited by dubyas; Apr 1, 2010 at 08:21 PM.

Apr 4, 2010 | 01:18 PM

#28

tvrgeek

5th Gear

Joined: Jun 2009

Posts: 663

Likes: 12

From: Maryland

Quote:

Originally Posted by countryboyshane

I think he is a bit overly optimistic. The engine bushings help torque steer more than anything not bump steer. I have a Mini-madness poly bushing for my lower engine mount. It definitely helped in the torque steer department!

How is it for harshness? I am guessing all this torque steer talk is how it becomes a real handfull at wide open launch. All you "kids" don't know what torque steer really is. Mu Sonnet would rip the wheel from your hands in reverse. You had to drive with a constant bias on the wheel just cursing. Let go,m it would U-turn on you. THAT's torque steer! At least the Mini goes straight.

Of course, bump steer is a geometry issue. It has to do with the relationship of the rack, differences of steering arms etc. I recommend the old Fred Punn book How To Make Your Car Handle as he has excellent pictures. Then you can see why everyone who changes the ride height complains about bump steer. The problem is caused by not understanding what you are changing. A strut suspension will ALWAYS have bump steer unless you ran the steering arms of the top bearing. The manyfactures attempt to minimize it at standard ride height.

Apr 4, 2010 | 04:46 PM

#29

cmt52663

6th Gear

Joined: Jun 2006

Posts: 4,166

Likes: 401

https://www.northamericanmotoring.co..._knuckle_2.jpg

Apr 5, 2010 | 03:47 PM

#30

tvrgeek

5th Gear

Joined: Jun 2009

Posts: 663

Likes: 12

From: Maryland

Interesting. No steering arms shown. There is still no way to maintain exact proportions of steering arm lengths with respect to the virtual arm lengths as you are still following the strut. You will still have some bump steer. Zero bump steer is only possible with paralell arms. Not a usual configuration. One only hopes the OEM did their best so it is not too bad.