Z06Vette.com - Corvette Z06 Forum - Does changing tire size confuse traction control

gandoff · 05-15-2008, 11:57 AM

The wheel rpms and the rpm ratio (front to rear) changes from the stock set-up: Has anyone experienced any unnecessary engagement of the traction control?

No Doubt · 05-15-2008, 03:13 PM

If the overall diameter of either the front or back wheel/tire varies by more than ~3% from stock then yes, it can and has been known to cause problems with traction control.

6speeder · 05-16-2008, 05:58 AM

Running 345/30-19 and 275/35-18 Nitto Invo's, or 345/35-18 and 295/35-18 Hoosier R6's, no issues. Active handling, ABS, and traction control work just like with stock sizes.

JerryL · 05-16-2008, 08:49 AM

Just keep the new sizes within 3% of the OE size you are replacing. You should have no issues.

**DennyM** · 05-16-2008, 09:00 AM

RocketSled has a handy-dandy calculator available thru his sig link.

george · 05-16-2008, 09:21 AM

Quote:

Originally Posted by gandoff

The wheel rpms and the rpm ratio (front to rear) changes from the stock set-up: Has anyone experienced any unnecessary engagement of the traction control?

I'm running a set of drag radials for trips at the strip. No issues.
335/30/18"x12" and the nitto's.

RocketSled · 05-16-2008, 05:14 PM

Quote:

Originally Posted by DennyM

RocketSled has a handy-dandy calculator available thru his sig link.

Click on the RocketSled, scroll to the bottom of the page that opens, click the link for the tire size spreadsheet. It's fairly self explanatory.

allanlaw · 05-20-2008, 09:34 AM

Quote:

Originally Posted by gandoff

The wheel rpms and the rpm ratio (front to rear) changes from the stock set-up: Has anyone experienced any unnecessary engagement of the traction control?

Running 18" wheels in the rear, I've noted that Nitto 555RII's will trip TC on occasion at speeds over 85mph; Nitto NT01's always at speeds over 50mph.

**DennyM** · 05-20-2008, 10:20 AM

Quote:

Originally Posted by allanlaw

Running 18" wheels in the rear, I've noted that Nitto 555RII's will trip TC on occasion at speeds over 85mph; Nitto NT01's always at speeds over 50mph.

What size tires front/rear on the RII's and what size NT01's ?(I assume 315/30 rear for the NT01's)
I'm running Nitto 555rII 275/40/17 in front and 305/35/18 rear and have had no issues ...

allanlaw · 05-20-2008, 10:42 AM

Quote:

Originally Posted by DennyM

What size tires front/rear on the RII's and what size NT01's ?(I assume 315/30 rear for the NT01's)
I'm running Nitto 555rII 275/40/17 in front and 305/35/18 rear and have had no issues ...

RII was 285/35/18 . . . 305/35/18, and TC tripped only a few times (hot air temp, over 85mph).

NT01 is 275/35/81 . . . 315/30/18, TC trips all the time at 50mph.

**DennyM** · 05-20-2008, 12:04 PM

OK, gotcha ... this Rocksled whiz-wheel says ...
Rear Front
295/35/18=26.13" | 265/40/17=25.35" |Delta: 0% (OEM)
305/35/18=26.41" | 285/35/18=25.85" |Delta from OEM baseline: 0.9% OK
315/30/18=25.44" | 275/35/18=25.58" |Delta: -3.6% might be too much delta (note the rears are slightly smaller than the front ...)

RocketSled · 05-20-2008, 02:30 PM

Yeah. But instead of the 315/275 combo, you could go with 315/30-18s on the back and 285/30-18s on the front, which is only a 0.2% variance. This is what I have been running for the last 3 years no problem.

Note also, the TC function is probably not "bi directional". It looks for the rear wheels to be turning faster than the fronts, but I kind of doubt it looks for the opposite. The TC system may in fact tolerate a larger variance from the OEM ratio if it's the rear tire that's getting bigger (since this makes the rear axle look like it's going slower for any given road speed) with respect to the front tire than the other way around...

4wheels · 05-20-2008, 03:27 PM

Quote:

Originally Posted by RocketSled

Yeah. But instead of the 315/275 combo, you could go with 315/30-18s on the back and 285/30-18s on the front, which is only a 0.2% variance. This is what I have been running for the last 3 years no problem.

Note also, the TC function is probably not "bi directional". It looks for the rear wheels to be turning faster than the fronts, but I kind of doubt it looks for the opposite. The TC system may in fact tolerate a larger variance from the OEM ratio if it's the rear tire that's getting bigger (since this makes the rear axle look like it's going slower for any given road speed) with respect to the front tire than the other way around...

I believe these C6s (at least the Z06's, not sure about regular C6's) have an "engine drag" monitor in the TC system, where if it sees the rears turning too slow relative to the front, they think that excessive engine braking has locked the rears & increases throttle slightly. I can't remember where I read this, but I know I heard something regarding this.

allanlaw · 05-20-2008, 04:28 PM

Quote:

Originally Posted by RocketSled

Yeah. But instead of the 315/275 combo, you could go with 315/30-18s on the back and 285/30-18s on the front, which is only a 0.2% variance. This is what I have been running for the last 3 years no problem.

I'm not sure what you're referring to, but there is no 285 available in NT01 so I'm stuck with what I've noted above. I really don't care about the TC having to stay off.