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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Tracking, Autocrossing, Dragstrip, Driving Techniques > Front tires feel like they're floating



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      04-25-2008, 10:24 AM   #1
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Front tires feel like they're floating

I also posted this in the wheel and tires section

I just got general UHP's on the rear of my new rims 275/30/19 and I kept my 235/35/19 old tires (Hankook Ventus) on the front.
I noticed that when I take a high speed sweeping curve, it feels like my front tires float or my car is not as stable as it was when I was running 265/30/19's on the rear (Hankook)
I know that the Generals are sticking because on a tight corner, my rear end would slip out, but with the UHP's I grip and don't get traction control warnings.

Would tire widths cause the floating feeling? Do I need to change out my front tires for 245/35/19's?
What if I just lower my air pressure? I haven't tried it yet and I don't know what they inflated it to (forgot to check)
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      04-25-2008, 10:29 AM   #2
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New tires dont grip well...they are probably pushing...(wheel turns..car still goes straight). They just need to wear down a bit. You could try to INCREASE the pressure in the rear.
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      04-25-2008, 12:24 PM   #3
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Quote:
Originally Posted by S4to335 View Post
New tires dont grip well...they are probably pushing...(wheel turns..car still goes straight). They just need to wear down a bit. You could try to INCREASE the pressure in the rear.
So if I understand this correctly my two rear tires are causing my front two tires to slide? My two front tires are older (swapped).

Would it make sense to lower the pressure in the front and raise the pressures in the rear?
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      04-25-2008, 12:59 PM   #4
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In the first place..I would not have two different tire types on the front as compared to the rear. However, since you are already stuck...if the car is pushing..you should raise the pressure in the rear to compensate. You could also lower the front pressures.

In the future..dont get different tires on the car..it just creates problems. The new tires get burned off much quickly than if you just bought four new ones.
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      04-25-2008, 01:18 PM   #5
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Thanks I'll try it out.
Yeah I wasn't expecting to replace any tires since they're still fairly new but with camber issues, I had no choice in the rear, as well as having a nail in the sidewall with a slow leak.
I may just pop for a new set of UHP's up front. I figured as long as both tires up front were the same, i'd be okay.
At least they're both the same up front and not two different tires up front
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      04-25-2008, 03:11 PM   #6
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You can also get that floating feeling if the car need aligment.
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      04-26-2008, 12:46 PM   #7
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So I adjusted the air pressures yesterday then took a nice long trip to Reno.
Set the fronts to 32 and the rears to 36
Car tramlines like crazy with the new tires
Suspension doesn't feel as solid as it did with my old aftermarket rims/tires. Could it be due to increased offset/wider rear tires?

When taking some of the twisties, I noticed a lot more wallowing in the turns. Car wasn't planted flat like it used to be.

I'm going to schedule an appt to get suspension put in and alignment done hopefully on Sunday but a lot of shops are closed on Sundays (why IS that?)
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      04-26-2008, 10:27 PM   #8
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New tires do that..you will have more grip with the old tires..than with new. One time I put on brand new Dunlop SP9000s...and went on track..and it felt like I was on blades of grass while on track. Kinda scary actually.
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      05-01-2008, 11:46 AM   #9
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Okay for an update:
I got my front two tires replaced and the car drives noticeably better however there is still some slight wallowing.
I'm thinking that an alignment will fix it

Bad news was the the tire shop dinged up a rim in the process...
they tried to say it was like that when I got in even though the paint was still flaking off from the area. Good thing the manager knew I just bought those wheels and had them installed a few days ago.

He ended up ordering me a new rim. We'll see how it goes
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      05-01-2008, 12:06 PM   #10
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Quote:
Originally Posted by BzsBimmer View Post
Okay for an update:
I got my front two tires replaced and the car drives noticeably better however there is still some slight wallowing.
I'm thinking that an alignment will fix it

Bad news was the the tire shop dinged up a rim in the process...
they tried to say it was like that when I got in even though the paint was still flaking off from the area. Good thing the manager knew I just bought those wheels and had them installed a few days ago.

He ended up ordering me a new rim. We'll see how it goes
You are probably feeling a bit of understeer also because you went with a wider rear tire and kept the same width front. Your rears have more grip because of the larger tire and will tend to push you through the turn or understeer. You would have to upsize the fronts to 245s to balance out the grip.
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      05-01-2008, 12:40 PM   #11
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Quote:
Originally Posted by AW325xi View Post
You are probably feeling a bit of understeer also because you went with a wider rear tire and kept the same width front. Your rears have more grip because of the larger tire and will tend to push you through the turn or understeer. You would have to upsize the fronts to 245s to balance out the grip.
Well I ordered the larger rears after some input on the forum thinking that a bit of understeer was a good thing?

So if I wanted a more neutral/balanced handling ride, I should have stayed with 265's in the rear and 235's in the front?
I specifically didn't get 245's up front because some people claimed to have turning issues with the wider tires
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      05-01-2008, 01:29 PM   #12
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Quote:
Originally Posted by BzsBimmer View Post
Well I ordered the larger rears after some input on the forum thinking that a bit of understeer was a good thing?

So if I wanted a more neutral/balanced handling ride, I should have stayed with 265's in the rear and 235's in the front?
I specifically didn't get 245's up front because some people claimed to have turning issues with the wider tires
Yes, if you wanted a more neutral/balanced handling ride, you should have stayed with the 235/265 combo.
I think the turning issues may be with cars that are lowered and agressive offsets. The shop that's doing my suspension set-up runs 255's up front on the track. I don't know the offset he's running though.
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      05-07-2008, 08:41 PM   #13
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Well here's my latest update.
Had dealer align my car back to "specs" after I got the matched tires up front.
Even without the alignment and matched tires up front, it felt so much better.
Lesson learned

With the alignment, car feels a bit better but I haven't had the chance to open it up yet so the jury's still out on this one.

In any case, although my wallet may not thank you guys, I do!

Now I just need to get my suspension done and another alignment
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