Hi,

My GPS just failed the chilean roadworthiness test because of one deformed tire, and I'm a little strapped for cash. I was hoping to replace the two front tires with 205/50/17, as they are both quite worn, and leave the rear 205/45/17 (stock) for another month or so in order to spread out the financial hurt.

For anybody who is curious, I want to change from the stock size in order to smooth out the crashing ride on rough south american roads (which have already cost me two trips to the alloy repair man)

Is this going to wreak havoc on ASR and ABS? I imagine that having different tires across an axel would cause problems but what about different sizes up front vs in the back?

Thanks!

Although its not recommended for safety issues and excess tyre wear, running a 45 profile and a 50 profile on the same axel is unlikely to to cause issues with onboard computer errors as its not much different to having a worn and a fresh tyre on.

However I know many people (including myself) that run different profiles on alternate axels. i.e. 205/40/17 on the front and 45 on the rear.

Thanks!

http://www.alloywheels.com/TyreCalc.asp

This will give you the effect on speedo accuracy.

On the Lotus, for the very same reason, I went from 215/50/15 to
225/50/15. The only must, as above, keep the same saize on both side of the axel.