Tire rolling radius and ABS speed sensors

[pequiod]

Was looking at past posts about changes in speedometer, transmission shift point etc, by increasing tire size from OEM on upwards. Understood products can be intalled to adjust for the errors introduced by an increased tire rolling radius by interferring with electronmic sensor signals that measure the info. there seems to be fix.

But does a bigger tire affect ABS speed sensors? I see from my 2000 tlc shop manual something called an ABS sensor at each wheel. wouldn't this sensor have something to do with detecting wheel speed (based on rolling radius of the wheel) as well, and the ECM using the data in deciding how and when ABS goes off and under what conditions? if the wheel rolling radius is bigger could the ABS system is getting wrong info?

do bigger tires affect ABS operation?

 

[macneill]

Good question. Maybe I'll just take it out and see if I can lock 'em up.

 

[cruiser99]

I am sure it screws up the control algorithm gain tuning on everything that uses forward velocity input, Trans shift point, cruise control, ABS, traction control and such. The question is by how much and what conditions. 35" tire to OME is 12%. That's a lot...

 

[hoser]

No cold hard data but Discount Tire states:

"Because cars and trucks are equipped with computerized systems (ABS for example) that use feedback from tire rotation, use these guidelines to select a larger tire.

For cars stay within 3 percent of the original equipment tire height. This is up to 3/4" taller tire for larger sizes.

For pick-ups and SUVs, a 15 percent increase in tire diameter is usually acceptable. See your dealer for your vehicle's specifications."

 

[FirstToy]

I dont think it does anything to abs. larger tires are basically equivalent to driving slower right?

ABS detects *non-spinning* so larger tires wouldn't affect that. Plus the sensor is at the hub not the tire and there are 2 sensors per hub so reaction is pretty fast.

I guess you are going slightly faster for a given axle rotation but I don't see how that would affect your abs negatively (microsec. slower to react maybe?)

 

[macneill]

Yeah, but it's all offset by the looking cool factor of 33s.