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Goofy Tire size question

Michael Long
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Michael Long Member

Michael Long

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Posted

Hello all:

 

TL;DR: can I reprogram computer to accept different diameter front tires than rear?

 

I've got a 99 986, 5 speed manual (not sure if it will matter), and 17" twist wheels. I had thought about doing this on a car for a long time, and finally did: I got tires with a size higher aspect in rear and a size lower in front (normal is 205 50 front, I did 205 45, and in rear 255 45 instead of 40). The thought behind this was improved steering without sacrificing ride.

 

Well, this wasn't the best idea, as you probably know. The issue that started after I left the tire shop and ever since is that when I press in the clutch over 30 mph, revs hang or increase to around 3-4k. This is a failsafe because of the ABS sensors reading differently and the computer being angry with me... if I shut off the traction control, the issue vanishes. My question:

 

Can I reprogram anything to accept the differing diameter tires? Or do I just need to hang my head in shame and buy matching diameter to my rears? I REALLY like the steering feel, but the rev hanging isn't something I wanna live with. And leaving the TC on sounds like a good idea.

 

Thanks for any help and for reading this far.

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