Wider rear wheel/tire -handling?

[whitess]

What benefit if any does a wider rear wheel and tire than the front have for handling?
Larry.

[T-CHRGD]

On a rear wheel drive car, it allows you to power out of a corner, without losing grip.

[David Pozzi]

It's usually easier to fit a wider tire on the rear than on the front, the wider rear tire can help give you traction on acceleration. But it also can be used to carry more of the total cornering load. Ideally the wider tire would be on the front because that's where it's needed, (talking cornering load here) but an increase in rear lateral grip can be exploited by upping the rear anti-roll bar size and make the rear tires carry more of the load, thus reducing load on the front tires, which increases the car's total grip.
David

[whitess]

David,
I put on a bigger bar (from 7/8" stock to 1") in the rear so if I understand you the bar should be enough?
Larry.

[David Pozzi]

1" is very stout! A lot depends on the arm length of that bar however. If you get too stiff in the rear, the inside wheel wants to lift, also it can hurt traction on corner exit due to the inside wheel losing grip. Too soft in the rear and the inside front comes off the road.
David

[JRouche]

It's usually easier to fit a wider tire on the rear than on the front, the wider rear tire can help give you traction on acceleration. But it also can be used to carry more of the total cornering load. Ideally the wider tire would be on the front because that's where it's needed, (talking cornering load here) but an increase in rear lateral grip can be exploited by upping the rear anti-roll bar size and make the rear tires carry more of the load, thus reducing load on the front tires, which increases the car's total grip.
David

Perfect!!! Compensation for the lack of rear load. Yes, I see that. Well, plus, it just looks good. Images of the front wheel drive cars at the drags LOL Fat tires up front. Is that car driving backwards??? LOL JR

[JRouche]

1" is very stout! A lot depends on the arm length of that bar however. If you get too stiff in the rear, the inside wheel wants to lift, also it can hurt traction on corner exit due to the inside wheel losing grip. Too soft in the rear and the inside front comes off the road.
David

Great info.. But a lil outside unloading isnt bad, as long as the tire isnt off the pad for too long. A rear bar is the last part of the tuning, a tuning fork. Build the suspension to where its tight, then add bar to fine tune it. And yeah, 1" on the rear for a solid bar sounds like alot. JR

[Derek69SS]

A little bit of difference can work well, as David explained, but too much difference in size will effect how the tires heat and throw off the balance if the small fronts overheat before the big rears even start to get sticky... it can make a car very difficult to tune to its fullest if you want to do any competitive type events.

[chicane67]

...Just so that his doesn't go the wrong way in consideration of rear tire width...

There is also a thing as too much rear tire. Combined with certain differential set ups... it can down right ruin the handling of a chassis... and the resultant can be massive under-steer to snap oversteer... all within the very same corner.

I sometimes have to laugh at the thought of a 345 rear tire on a first Gen. Albeit it is mostly for looks... it however can be a daunting task to balance out the corner loading without sacrificing a handful of other things at the same time. I dont believe that you can get enough tire on the front of a stock subframe to make 335/345's worth the monies spent.

Out of experience and considering ease of the required modification to make them fit... a 275 front with a 315 rear is by far the easiest to pull off... and perform the best. Anything larger and the rear roll stiffness, roll couple and corner rate will need to be increased... pushing on the boundary of a suspension that is too stiff or compliant and on the edge of snap characteristics.

I believe that one would need to run a minimum of a 255 on the front with a 275 rear or a 275 on the front when using a 315 or a 285/295 on the front when using a 335 or anything larger on the rear... just to ease the balance issues.

[whitess]

With the 1" rear bar I've noticed a decrease in the amount of understeer. If it makes any difference the car is an '85 Monte Carlo SS.

[chicane67]

What are the current alignment settings ??

[Vegas69]

Mine handles really well with 345mm 255mm front. Of course it's street driving and some spirited runs through the winding lake roads. I can see how the fronts could over heat on the track causing under steer. Ideally I will end up with a 275mm up front and 305mm out back in a R888 or similar for track days. I really like my 345mm for looks.

[whitess]

Left / Right
0.3 / 0.5 Camber
4.5 / 5.0 Caster
0.05 /0.05 Toe
8.1 / 8.1 SAI
7.8 / 7.5 Included Angle

Front
0.3 Cross Camber
0.7 Cross Caster
0.09 Total Toe

Rear: Left / Right
-0.2 / -0.3 Camber
-0.31 / 0.09 Toe

Rear
-0.22 Total Toe
-0.20 Thrust Angle

(I wanted more Negative Camber but that's another story.)