Wheel hop - what more can I do?

[Dr. Supra]

38-40
Just whatever the computer yells at me to do.

Thats way too high. At highest i run mine at 32 and lowest for grip 20

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[FLtrackdays]

That’s way too much. Try 32-34 psi

I like to start with that on track & bleed as the day goes on, to maintain that lower pressure hot. In town, like he’s doing, I run 36 psi cold and she does just fine.

 

[vlad]

That’s way too much. Try 32-34 psi

The sticker in the door asks for 38 PSI. What’re the pros and cons of 38 vs 32?

 

[Thraxbert]

Better traction, lower gas mileage.

 

[Funkjaw]

I suppose lowering the tire pressure could in fact help with wheel hop as it will soften the sidewall up a little bit. I'll air em down a few PSI and report back.

 

[exe36m3]

His rear toe has side-to side variation of 0.02 degrees. I would bet real money that if the alignment tech were to roll the car off and back on, there's a good chance to it would register as dead-on. and yours would come back as misaligned again.

Conceded, for F and G series BMWs, the rear end toe likes to unadjust itself on the fly for stock suspensions.

What's your take on his front toe though? Wouldn't the snowplow settings (12/14 vs 0 or .05) essentially exacerbate the behavior of the rear of the car?

In defense of my post, I was reacting to how funky the alignment settings for toe were with all the fun parts the OP already installed. The tech should have done a better job matching numbers. If the numbers fresh off the rack were all matching and clean, then move onto the parts.

However@Funkjaw, I apologize as I mistook your post as being one from our more ahem, "younger" members (new to cars, never had school autoshop, etc.). Reading your short reply and your experiences, I see you have probably exhausted all other avenues and moved onto parts.

And the latter is no fun! Best wishes on finding a solution!

 

[stormgreysupra]

Have you played around with tire pressure? Lowering the pressure made a noticeable difference for me.

 

[Tsuki8]

The Z4 has had that since inception. Not new, easy to get.

It's not to the diff, it bolts to the bottom of the battery box.

Huh, irrelevant to forum but you and me.
330e has a similar brace that the 330i/M340i doesnt have.

 

[MisterSkiz]

38-40
Just whatever the computer yells at me to do.

whoa...seems way too high - i'd have have double check but I think OEM tire/wheel is like 33psi?

 

[SupraYYJ]

38-40
Just whatever the computer yells at me to do.

whoa...seems way too high - i'd have have double check but I think OEM tire/wheel is like 33psi?

I run 34 psi. Door says 38 psi.

 

[razorlab]

Doesn't surprise me one bit that you have wheel hop/traction issues when running your tires that high.

On track (turny track) I aim for 32-33psi hot and go out with 25-26psi.

 

[kern417]

Fundamentally wheel hop is caused by slop in the rear. So if you already have all solid bushings/bracing, then I agree it's something else.

I also agree that more traction is kind of a band-aid. If the wheels spin, it should spin straight.

On top of your wheel alignment, maybe also double check that your wheel/tire setup isn't out of balance or worn unevenly. Also, make sure traction control is off when you're judging it because the abs will do a lot of wonky things, especially in low grip scenarios like cold/wet pavement.

 

[TBK]

Doesn't surprise me one bit that you have wheel hop/traction issues when running your tires that high.

On track (turny track) I aim for 32-33psi hot and go out with 25-26psi.

Isn't 32-33 on the high (edit: i meant low!) side for cars that weigh as much as ours?

This is from trackdays.ie, but also mirrors most of what i've come across online about this. Appreciate any advice you're willing to share about this, because i've been struggling while trying to get this right.

 

[lucky phil]

Isn't 32-33 on the high side for cars that weigh as much as ours?

This is from trackdays.ie, but also mirrors most of what i've come across online about this. Appreciate any advice you're willing to share about this, because i've been struggling while trying to get this right.

You've confused me. @razorlab said he's aiming for 32-33 psi hot (on track) which is LOWER not higher according to your chart for a 1700kg car?

 

[licklobster]

You've confused me. @razorlab said he's aiming for 32-33 psi hot (on track) which is LOWER not higher according to your chart for a 1700kg car?

the gr supra is 1540kg with a full tank of gas, all oe equipment, and zero weight reduction.

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