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TooManyFords
02-24-2006, 08:07 AM
As some of you know, I'm going "extreme" on tires and wheels. What I need to know is just how far out of spec I can go with tire diameter between the front and rear tires before something on the car complains. I don't have traction control and god knows the rear tires would probably appreciate if I'd quit mashing the loud pedal so much, but will the antilock system cry foul?

If my math is correct, the ratio is about 1.047% larger diameter rears than factory. Just how big can this number get before the antilock ruins my day? If it is out of spec, what specifically happens and is there a workaround in the PCM I can fix with SCT ProRacer?

I want to get these rims sent in for widening but I'd better dot the i's and cross the t's on the exact tire to order so I know how wide to make them.

Thanks guys!

john

SergntMac
02-24-2006, 10:58 AM
I believe you have the math down correctly. As far as the ABS, it will throw a dash light, that disappears when you restart the car. It will not affect the operation of the car, like TC does. I've driven over 100 miles with the ABS light on, no problems.

magindat
02-24-2006, 11:22 AM
All I've ever heard from tire techs to my collision expert friend is 7% or less different than stock to keep from triggering abs problems. The ratio front/rear has never been mentioned. Of course, tire size will have to be accounted for in the PCM for speedo and odo.

My rears are about 1/2" taller diameter than factory and have given me no trouble at all.

magindat
02-24-2006, 11:27 AM
Oh yeah, when does the work begin? :eek:

TooManyFords
02-24-2006, 11:31 AM
It begins a week from today. We'll probably move the cars around during this next week in preparation. Now I have to find that triple-nickle plating thread...

Cheers!

john

Zack
02-24-2006, 11:31 AM
http://www.mercurymarauder.net/showcase/files/4/0/4/TCoff.bmp
You can fudge the numbers in the software with revs per mile and the axle ratio.
With enought tweaking, Im sure you could have an accurate speedometer, shifting and no abs light condition.

magindat
02-24-2006, 12:06 PM
I have a 'catapult'. Give me all your 'riches' or I'll launch a 'big rock' at your head?!:shake:

When 'catapults' are outlawed, then only outlaws will have 'catapults'?!:shake:

That's why I'm packing a trebuchet. No, I'm not happy to see you!:up:

Dragcity
02-24-2006, 09:00 PM
1.054 is my vote for max varience. The biggest I think will fit are equivilant to 265/70-16 in the rear, which I think is 29.7"