Question pertain to tire size and drag racing

Onefast99gsx · 09-07-2005

Hi guys- Like the title says, I have a question regarding tire size. My car is gonna make it to the track at least once here soon regardless of gas prices. I want to run my stock 17" GSX Wheels. 2 of the wheels came with a 215/45 profile and the other 2 were 215/50. You wouldn't think that would be much but it's noticeably different when you set the 2 side by side. Would I be better to run the taller tires in front or back? Or does it not even matter?

Thanks.

**JET** · 09-07-2005

You are running them on a GSX? Do you realize that you are frying your VC and transfer case every time you drive the car? AWD's should have the same sized tires all the way around. If it is a GST, then run the taller ones in the front.

Onefast99gsx · 09-07-2005

Yes, a GSX. No i didn't actually run them "yet". My 19's are still on it till i decide to race it. Actually I have all (45) profiles for it but one of them had cracking sidewalls. When i bought it he gave me 2 spare tires that were the (50's). Because of the one sidewall i put the (50) on to replace that bad one. So the way it sits now (3) 45's (1) 50. I was gonna take another 45 off just so it would have a matching mate. I don't really want to buy 1 tire.

You think this is a no-no the way it sits now hah?

Thanks.

rk4g63 · 09-07-2005

I've usually seen same size tires on a AWD. I think it messes up the way the power is distributed to the wheels.

**Goat Blower** · 09-07-2005

The only thing you'll damage is the VC, and I've yet to even see one damaged.

I've run slightly different size tires on an AWD, no problems that I ever saw. Just put 5-8 more psi in the 215/45 than the 215/50's.

Onefast99gsx · 09-07-2005

Thanks guys. It wouldn't be for all time use. I have my 19's which are a 35 profile for everyday show use. I just wanted to run the stock wheels for a race. Maybe 5 runs or so.

The air pressure trick is a great idea. I can understand the idea why it would be hard on it though. The 45's would make a complete revolution before the 50's would thus fighting one another.

**JET** · 09-07-2005

I disagree that the VC is the only thing that will be stessed more. The VC locks up as the fluid heats up. You are running different sized tires, which rotate at different rates. That causes the VC to heat up and it tries to lock at 50/50 because it thinks the tires are spinning. As it tries to lock where is this extra stress going? It is going to go to the center diff and the T-case.

Why take the chance of messing something up? If you are going to have one mismatched tire, put it on the front unless you have a non-lsd car. I don't recommend doing it though. Will it kill parts immediately? Probably not, but it will wear your parts faster.

Onefast99gsx · 09-08-2005

Thanks Jet for that detailed explanation. It's more in depth that i thought. I will keep that in mind. I will keep my eyes open for a 45 tire meanwhile. I have a few weeks to possibly come across one cheap. Tread doesn't have to be the greatest as the other 3 aren't either. Ebay has numerous ones but they want a fortune for shipping.

**Shane@DBPerformance** · 09-08-2005

I have driven AWD DSMs with different tires on the front and back with a welded VC in the car and the car jumps all over the place. It makes the car feel very fast with it hopping all over the place, but it is hard to control.

slowbubblecar · 09-08-2005

I think it would be better to get a set of tires that are all worn the same also.

Onefast99gsx · 09-08-2005

Thanks you two. Well my VC is not welded. Tranny is completely stock. It's either run with 3 (45) profile tires and 1 (50) or run my 215/35 19's and i think the 19's would be very bad to run and there is barely a sidewall.

**Kracka** · 09-08-2005

I'd run your 19's at the track long before I ran mismatched tires on an AWD car. Not a good idea...I'm with JET on this one.

Onefast99gsx · 09-08-2005

Well if i do run the 19's then i don't have to do anything because they are already on the car. :-) Thanks for your input on this.

**Goat Blower** · 09-09-2005

The VC would try to lock, but it doesn't lock completely, it's always going to slip a bit. Besides, you're talking about a very small difference here. If it was as bad as you guys think, everybody that ever had a low tire would've blown their VC.