Tire width vs Brake Balance

[HellPhish89]

When one is using a staggered set of tire widths, would changing brake balance be advantageous?

IOW, with more of a difference between front and rear widths, would one want more braking to be done by the rear tires to take advantage of the extra tire?

I ask because I often see staggered widths and even I am going to be using a rear tire almost a full inch wider than the front. I dont think it would be given weight transfer and weight distribution however; the added contact patch makes me wonder if accounting for it would help maximize braking ability. I searched around a bit but havent found anything specifically referring to this.

[Schwartz Performance]

There's a lot more to it than what you've illustrated. For instance, the spring rates, weight and distribution, the tires, etc.
An adjustable proportioning valve is recommended to fine tune the brakes, which would probably answer your question anyway..

-Dale

[HellPhish89]

There's a lot more to it than what you've illustrated. For instance, the spring rates, weight and distribution, the tires, etc.
An adjustable proportioning valve is recommended to fine tune the brakes, which would probably answer your question anyway..

-Dale

i realize that. even mentioned it :).

assuming i have the springs right, the corner weights as good as they can be, etc... would somehow proportioning brake balance adjustments on the added rear tire contact patch be something worth looking into?

[SSLance]

I had stock 225/60/15s all the way around on my car when I first put the rear disc brake package on it. Under hard braking it would lock the rear tires up before the fronts. Not long after I switched to 275/40/17s on the rear and 245/40/17s on the front and the rear locking up first stopped due to the extra traction of the wider rear tires. So yes your theory works.

Like Dale says though, there is much more involved in it than that. Just recently I upgraded the front brakes and changed my tire setup once again to 275/40/17s all the way around. Not knowing exactly how the car would react I left the rear brakes alone for now and have driven and competed the car for a month or so. There is no sign of the rears locking up first so my next step is to upgrade the pads in the rear...if that overshoots and they start making too much brake force I'll have to either install a proportioning valve or step back on the pad CoF to even it back out again.

Take into consideration that I've also optimized the spring rate and shock valving for the best grip the car can achieve without loosing traction.

[HellPhish89]

I had stock 225/60/15s all the way around on my car when I first put the rear disc brake package on it. Under hard braking it would lock the rear tires up before the fronts. Not long after I switched to 275/40/17s on the rear and 245/40/17s on the front and the rear locking up first stopped due to the extra traction of the wider rear tires. So yes your theory works.

Like Dale says though, there is much more involved in it than that. Just recently I upgraded the front brakes and changed my tire setup once again to 275/40/17s all the way around. Not knowing exactly how the car would react I left the rear brakes alone for now and have driven and competed the car for a month or so. There is no sign of the rears locking up first so my next step is to upgrade the pads in the rear...if that overshoots and they start making too much brake force I'll have to either install a proportioning valve or step back on the pad CoF to even it back out again.

Take into consideration that I've also optimized the spring rate and shock valving for the best grip the car can achieve without loosing traction.
youre car is pretty close to a 'control' for this. im going with the assumption of an optimized setup. the variables in chassis, springs, shocks, rotating weight, etc would be too much to get an accurate answer otherwise.

the next question would be: how much of the braking duty do you think you could have put on the rears given the roughly 1 inch per side difference in width compared to the front? ie: change from 60%front with the old tire size to 55% with the wider tires?

i have found a couple physics models relating to traction and traction budget but nothing that includes tire width. i have an idea how i can figure out a ratio of sorts but i need to find the right model.