[Yamatokh]

Hi all

Not sure if it's just my car or if its the nature of Z4 factory setting, I found my car has a resistance to turn in under speed. If compare to the F22 2 series I have owned before, I feel the 2 series has an easier turn in feel than the Z4.

I have not push my Z4 M40i anywhere near it's limit, so cannot comment it's behavior in that area. But from daily driving, I found it difficult to make a 90 degree turn at speed of 70-80km/h. Is it normal? Should I have my wheel alignment checked?

If this under-steer feeling is due to the factory setting, what can I do to make the turn-in easier?

Thanks in advance for your advise.

[TAZ007]

I can say that the M40 has some slight understeer at higher cornering speeds. As far as your more moderate speed, I have not experienced any understeer.

Your comparison with your F22 might have something to do with it though. I will say that my 2015 F23 cornered different as the driver is closer to the front than the G29. What you may be going thru is learning the differences of the G29 over your previous cars. Get some more wheel time. I will add that it is similar to my 1980 Vette only the G29 is alot tighter in the suspension.

[chilort]

1) check to be sure the shipping spacers have been removed.
2) get the alignment checked. Lots of the Supra folks report out of spec alignments from the factory. Plan on getting mine checked soon (holidays have interfered with fun car time).

[CJ421]

Yamatokh Turn-in resistance is different than understeer. Turn-in resistance is what you describe, the car hesitating to turn in. BMWs have negative front toe from the factory, which helps with high-speed (highway) stability, but makes them less responsive to turning. If you want easier turn-in, get your car aligned with minimally negative or neutral front toe.

Understeer - the front traction giving up before the rear i.e., the car plowing into turns - is caused by the driver. Factory cars are set up to understeer for safety reasons, so the car won't spin during emergency maneuvering. Changing tires is really the only way to change the car's physics/grip.

chilort The Z4 has the same problem with factory alignment, see my before and after alignment results here.

Charles

[Yamatokh]

Originally Posted by chilort

1) check to be sure the shipping spacers have been removed.
2) get the alignment checked. Lots of the Supra folks report out of spec alignments from the factory. Plan on getting mine checked soon (holidays have interfered with fun car time).

Is there such a spacer existed? I have never heard of it, but it make sense as they don't want the wheels to turn during the transportation.

Do you by any chance have a picture of such spacer or know where they would have installed it?

I have driving my for almost 6000km, it's hard to imagine if there is a spacer there that's not removed.

Thanks for the advise on the alignment. I will check it out.

[COKen]

Originally Posted by Yamatokh

Is there such a spacer existed? I have never heard of it, but it make sense as they don't want the wheels to turn during the transportation.

Do you by any chance have a picture of such spacer or know where they would have installed it?

I have driving my for almost 6000km, it's hard to imagine if there is a spacer there that's not removed.

Thanks for the advise on the alignment. I will check it out.

As it turns out, you can purchase a shipping spacer ($3.90 US). It goes on the shock.



The link below is where I found the photo. They also have an explanation about how the spacer works.
https://www.turnermotorsport.com/p-5...uine-bmw-part/

[Yamatokh]

Originally Posted by CJ421

Yamatokh Turn-in resistance is different than understeer. Turn-in resistance is what you describe, the car hesitating to turn in. BMWs have negative front toe from the factory, which helps with high-speed (highway) stability, but makes them less responsive to turning. If you want easier turn-in, get your car aligned with minimally negative or neutral front toe.

Understeer - the front traction giving up before the rear i.e., the car plowing into turns - is caused by the driver. Factory cars are set up to understeer for safety reasons, so the car won't spin during emergency maneuvering. Changing tires is really the only way to change the car's physics/grip.

chilort The Z4 has the same problem with factory alignment, see my before and after alignment results here.

Charles

Hi CJ421

Thanks a lot for your great explanation on the steering resistance and understeer. I think I have felt both. Other than feeling the resistance of turns, I was often surprised by the line of path in a turn, where the line are often wider than I expected. Not sure if it's the understeer or not? However, the line seems more predictable during lower speed turns or U-turn.

If I would like an easier turn in feel, I presume I should follow your suggestion by reduce negative toe in? From your alignment sheet, your front toe shows 0.11 and 0.10 degrees, are those positive toe or negative toe? Is that the factory standard for the toe?

Thanks a lot for your further advise.

[Yamatokh]

Originally Posted by COKen

As it turns out, you can purchase a shipping spacer ($3.90 US). It goes on the shock.



The link below is where I found the photo. They also have an explanation about how the spacer works.
https://www.turnermotorsport.com/p-5...uine-bmw-part/

Interesting to know! Thanks!

Learning something new everyday!

While my ride is not harsh, I will check it out, just in case.

Thanks for the heads up.

[CJ421]

Originally Posted by Yamatokh

Hi CJ421

Thanks a lot for your great explanation on the steering resistance and understeer. I think I have felt both. Other than feeling the resistance of turns, I was often surprised by the line of path in a turn, where the line are often wider than I expected. Not sure if it's the understeer or not? However, the line seems more predictable during lower speed turns or U-turn.

If I would like an easier turn in feel, I presume I should follow your suggestion by reduce negative toe in? From your alignment sheet, your front toe shows 0.11 and 0.10 degrees, are those positive toe or negative toe? Is that the factory standard for the toe?

Thanks a lot for your further advise.

Negative toe is also called toe-in; the fronts of the front wheels are closer than the backs. That is why toe-in is more stable at high speed, because the tires are trying to "reach" each other. It improves stability and reduces the car's tendency to tramline i.e., follow the road surface.

Your toe would read 0.00 degrees if it was zerod out. The wheels will be pointed exactly straight ahead. That will ease turn-in. The alignment shop should be able to do that.

Maybe drive the car more, see if you get used to the handling? I think the factory alignment is excellent for general use. If I was doing road-course events, I would get zero toe. But for highway driving, toe-in is best.

Charles