[cjperformance]

I know about the wire harness relocate needed w 305/35/20 on the rear, but I've got 285/30/20 on the front.

Ive heard that much of a mismatch COULD cause issues w/ ESC, so is anyone running this combo, and are any issues seen?

What size are you running in front if you are running the 305/35/20 in back?

I'm basically running the 1LE config now on 10" and 11" wide rims. I want to run a 305/35/20 DR in back but not if its going to hork things up and make me swap fronts with a different size.

[arpad_m]

Your 1LE sized fronts are 3.6% shorter than stock, while these 305/35s are 2.9% taller, which makes for a total 6.5% front-to-rear skew compared to stock. While I never tried such extreme deviations, from what I saw in the forums over the years, ~3-3.3% total is the max you can have without ABS and Stabilitrak issues and MILs. I don't think you'll get away with such a difference, even considering how non-uniform these sizes are across manufacturers.

To suggest one option, I am currently running 285/35/20 in the front and 305/35/20 in the rear on my MRC 2SS with stock 1LE wheels, so more sidewall on both ends instead of only in the rear. This config works fine, no errors whatsoever and it even improves the ride slightly, but there is a little bit of rubbing at full left lock on the driver side front.

[cjperformance]

I was thinking the same thing about the mismatch. The 285/30/20 are already really close to the strut. No rubbing there I guess with the 285/35/20?

I might just wait for 305/30/20 DRs to become available again. I found the 35s, but not the 30s...

[arpad_m]

Originally Posted by cjperformance

I was thinking the same thing about the mismatch. The 285/30/20 are already really close to the strut. No rubbing there I guess with the 285/35/20?

No, it's okay, this setup still clears the MRC strut perch on both sides. The gap is arguably very small, but it doesn't matter since they move together.

The only thing is a very slight wheel well liner rub at full lock, barely visible, but I think next time I'll just go back to stock 30s (main reason for going with 35s in the first place is this was a great deal).

[cjperformance]

Lol, screw it. "Tired" of waiting for 305/30/20 NT555R2 to come back in stock, and I don't want to replace my fronts again to work with the 35. The fronts are practically new, and my car aint gonna hook on the NT05s when the weather gets cooler. They barely do now.

So, I just ordered some 305/45/17's which are very close to stock height. I'll pick out some 17" wheels that won't look stupid all mismatched... because of course the wheels I have are discontinued. Anyway, I'll just drive around on the street with those until I can find 305/30/20 NT555R2s for the street. I should hook at full power at the track right

I don't drive this car daily or anything. I have a truck for that.

[Colin101234]

Sorry to rehash a old thread but I need some opinions. I'm currently running 305/35/20 (28 offset, 11 inch wheel) in rear, but In the front I have a 245/40/20 (9in wheel, 20 offset) I'm having an issue with T/C coming on randomly. Any suggestions what to put my front at where it wont rub? I considered a 265/40/20 but looking at the numbers it will definitely rub. The current setup is a 2.5% difference, 28.4 in rear and 27.7 front diameter.

[arpad_m]

Originally Posted by Colin101234

Sorry to rehash a old thread but I need some opinions. I'm currently running 305/35/20 (28 offset, 11 inch wheel) in rear, but In the front I have a 245/40/20 (9in wheel, 20 offset) I'm having an issue with T/C coming on randomly. Any suggestions what to put my front at where it wont rub? I considered a 265/40/20 but looking at the numbers it will definitely rub. The current setup is a 2.5% difference, 28.4 in rear and 27.7 front diameter.

The computer is glitching because the actual difference it sees is 2.9%, which is very close to the (empirical) maximum of 3%, and--depending on conditions--the tires may veer across the threshold occasionally.

The way to calculate the difference is not by comparing front and rear diameters but by adding up the magnitudes of your rear and front deviation from stock, because the computer expects the stock rear to front height ratio and has a ~3% built-in tolerance fo deviations.

Your fronts are essentialy stock (0% difference, wheel width does not matter here), while your rears are 2.9% taller than stock, which adds up to 2.9%. If you increase your front height, you'll eat away some of that 2.9%, transitioning back into the safe zone.

As a counterexample, if you reduced your front height by, say, mistakenly going to 285/30/30 1LE wheels and tires that are 3.6% shorter while keeping the same rears, you'd grow that difference to 2.9 + 3.6 = 6.5%, and you'd have even worse drivability problems.

So, you have two very good options IMO:

1) aka "the cheap way": get 255/40/20 tires for the same front wheels, which will resolve your ABS/Stabilitrak issues and cause no rubbing, or

2) aka "the deluxe way": get proper 10" front wheels and wrap them in 285/35/20 tires, which will give you amazing front grip and 1.2g+ cornering ability, assuming you get quality tires of course. The only downside will be a tiny bit of rubbing on the driver side at full left lock, but it will only destroy the wheel well liner if you go completely bonkers for several years.

[Colin101234]

Well, not exactly the rears were tuned in with HPtuners set to a 28 circumference. So the computer isn't exactly looking for the original tire size, I'm more or less referring to matching the diameter of the front and rear closer. Although when coding it in with hptuners it does not ask front or rear it just asks the gear ratio and tire circumference but not specific to front or rear. The issue actually got worse when I had GPI tune in the larger circumference tire.

[KingLT1]

I ran that setup for years with no issue.