I search on ABS and tire diameter, only found one comment that there maybe problem with ABS. I am starting this thread to get more knowledge pooled together here.

I want to know if there would be a problem with the ABS system, if I use different front and rear tire size.
My little knowlege on ABS system is that it measure wheel speed, so since I use different size, Will it be messing up the ABS?

Front: 245/45/16 ~ 24.7 OD
Rear: 245/50/16 ~ 25.7 OD

These are on stock rims 16x8 on an FD.

Thanks
Reza

 

That's a good question. I beleive if you look at the sensor on each brake axle it looks for pulse sending it to the ABS. A mechanic told me at a Mazda dealer that any ABS system there has to be 90% to 100% pulse difference from any of the wheels before it turns on the ABS pump motor to pulsate the channel (wheel) that has lock condition.

So I don't think a 1"OD will effect the ABS. If anything the rears will pulse sooner during hard braking.

 

So that means I cannot do the tire combination?
Is there a way to adjust for this?

Reza

 

Can we ask why you are contemplating this odd tire sizing? Why wouldn't you just run 225/50 or 245/45 on all four rims? I don't understand.....

The only thing I can think of is you are asking about putting drag radials on the rears.

 

I am not sure myself. I just want to put bigger tire in the back.
My goal all around is to have wider tire on stock rim. Until I have enough money for 17" rims.
But the front can only take 245/45/16 but the back can have bigger tire, so the biggest is 245/50/16.

I am starting auto-x, is this good idea to have different size?

Thanks
reza

 

You are not making any sense. 245 is the width of the tire. 245/50 is not any wider than 245/45, the sidewalls are just taller. Just put 245/45 on all 4 wheels.

EDIT: Actually, if you want new tires for auto-crossing, I'd stick with 225/50s and just get very good tires. As SLeepR1 has pointed out many times, the best handling results from a properly matched tire/wheel combination. 225/50 on the stock rims may actually handle better than 245/45 because more of the tire is supported by the rim.

 

really?
I am currently on 225/50/16. The previous owner puts dunlop 8000 front and yoko A520 rear.
I feel the car to be very slipery, but that could also because I put throtle too much. I know I need to be smoother.
But I kept thinking that with wider tire, I would not be loose so much.

Everyone else here with FD runs 245s, so that is why I thought I better go with 245s street tires, and not go with race tires, until I got better handle of the car...

I am thinking of S03 or KDW or Ecsta Supra 712

Any suggestions?

Reza

 

Define what you mean by the car being slippery. Is the front sliding going into turns; is the rear end coming out on you; is the whole car just drifting? Be a little more descriptive.

For one thing, I would NEVER drive around with two completely different tire brands/models on the car. Secondly, when's the last time the car had a 4-wheel alignment? Third, what conditions are the tires in? How are the front anti-roll bar mounts? Are they cracked? There's many reasons why you may be losing traction, including too heavy of a right foot....

BTW, avoid the Kumhos like the plague. I've heard they make great racing tires but their street tires are crap. Stick with the S-03s, KDWs, SP8000s, AVS Sports.

 

****, I'd almost say keep the 225's up front and run 245's in the rear so that you have a little more predictability. Will hopefully hold your back end a little more than it is. Having the same brand tires front and rear will help too. S-03's or T1s are a good way to go. They both have good wet weather as well. Along with the KDW from what I've read.

I'd stick with 225/50 up front and go 245 in the rear if you want some more meat. Sounds like you're starting out and would want some understeer.

 

Amen on the tire advice... stick w/ 225/50 or 245/45 on the stock wheels, and the same brand for all four. Your choice on the stagger.

As far as the ABS, i wouldn't worry about it. I know of folks running A032s in 234/40/17 f and 275/40/17 rear (not optimal, but there are very few A032 sizes) with no ABS problems...