Front Wheel Width

I've seen pictures of FWD cars at the strip with wider front wheels than the rear. Does anyone here run a setup like this? I have never seen it mentioned around these parts.
I assume it's largely advantageous for traction, launch, etc.. so why isn't everyone about this? Can't an inch or 2 be added to the wheel width without jutting from the side of the car?

Well, it's actually a good idea in a lot of ways, and not so good in some other ways. Depends on what you want out of the car. Performance-wise there are a lot of good things that come with wider tires on the front wheels of a front-drive car. From a practical angle, it can be a little frustrating for some folks.

1st thing: forget about rotating your tires using conventional means. You'll need to have the tires remounted to all 4 wheels every 8k miles. If you do a lot of driving, that is going to get expensive. Most tire shops won't do that sort of thing for free, especially if you have a custom set up. For what it's worth, this is just not practical for racing unless you have a big budget for multiple sets of tires on 2 rim sizes.

Just finding a shop that will work with you on the wider-up-front idea could be difficult. In order to do it, you may have to bring them the wheels off the car and mount them yourself at home, or play dumb and have the wide ones mounted in rear, then change them later. Why should they care what wheels go where? Simply put, your safely. Tire guys know that the best traction needs to be in the rear - even for FWD - because oversteer is dangerous. I once fought with a shop about putting the tires with the most tread up front. They insisted the better tread should go in back, because it ensures the front end will come out first if you lose control. Smart from a liability standpoint. Since adding 2" of tread to the front wheels will increase grip to those wheels, it's an effective way to encourage oversteer. They probably won't support the idea.

Fuel economy will take a hit. Increasing unsprung rotating mass to your front wheels means more energy is needed to accelerate and brake from speed. More contact creates added rolling resistance. Even the frontal area of the wider tire creates aero drag. It's actually quite significant, and one reason you see such narrow tires on economy cars.

Finally, wider tires up front might look goofy, and could pose some logistical challenges. When you see cars at the strip with wide front slicks, they often have a completely different set of wheels for the front vs. rear. The fronts usually offset out rather than in (so there is no steering rub). That's an odd look on the street. To get a good looking set-up, you'll need to find a rim that's available in different widths and offsets, and you'll need to mix & match them, getting it right on the first try, which is not the easiest to do. The front wheel/tire combo should have minimal or no wheel rub when steering or compressing the suspension, and the rears should have an offset that has a consistent appearance. Experimenting here could get expensive.

Having said all that, performance can significantly improve from the idea of wider rubber up front. Obviously, you will have greater traction for straight line acceleration. Less obvious is the tendency to decrease understeer, which is abundant in a front heavy FWD car like the Riv. One practical benefit is longer tread life up front, which is definately a plus considering the drive wheels usually wear quickest. An almost unknown benefit of wider fronts is decreased torque steer, which GM discovered when they crammed a FWD V8 in the Grand Prix GXP a few years back, as well as the Impala SS. Sending 300 HP to the front wheels creates significant torque steer issues. The solution? Wider tires up front. Read about it here:

http://www.caranddriver.com/reviews/pontiac-grand-prix-gxp-road-test

I and a few others have played with wider front tires and/or slicks, but for all of us it's a track-only setup. You don't want to run different size tires on these cars IMO.

What about wider tires all the way around?
If stock is: 225/60-16
Would a 235 or 245 60-16 be of any benefit?

Yep. You'll increase lateral grip in the corners. One of the easiest ways to improve handling for any car.

charlieRobinson wrote:

What about wider tires all the way around?
If stock is: 225/60-16
Would a 235 or 245 60-16 be of any benefit?

The overall height of the tire increases also. This has an effect on your overall gear ratio, and speedometer calibration. The stock tire is 26.6" tall. A P235/60R-16 would be 27.1" tall, and a P245/60R-16 would be 27.6" tall. Not sure if you can fix the speedo error by reprogramming the PCM, but a taller tire numerically decreases your gear ratio.

Larry is correct, however the difference is small. But over thousands of miles it will add up on the OD. You can also use a lower profile to compensate for the difference in dia (55 instead of 60 is perfect for 245). Otherwise tuning the PCM is the only way to cheat and get it exactly right. You can even fine tune for differences in tire pressure.

Link to wheel, tire, bolt pattern, bore info: https://rivperformance.editboard.com/t454-wheel-tire-lug-bolt-pattern-center-bore-info

I'm running bigger wheels all around with larger tires on the front most of the year. My impression is that it can help significantly in performance driving but I'd almost say the type and condition of tire is still more important. The tire dimension is just going to be something you play with based off what you can mount on the rim you have. Because of the shape of the riv, I think you can get away with more staggering without really noticing too much visually because nothings really parallel.


That's my winter tire (stock 225/60/16) next to my summer front (275/40/18)
Going from one to the other, you have to relearn how to drive the car just about.

Agreed. I just swapped on my 225/60/16 winters from 245/45/18 summers and what a huge difference. Codith, do your your 275s rub when turning? I think mine rub just a tad at full lock when parking. Maybe your greater offset helps there.

Mine don't rub far as I know about. What's the difference in offset? I don't remember what mine is

On the other side of bigger tires, what do you guys think about slightly skinnier tires? I just bought a set of 215s because they were on rims i liked and a very good deal...How significant of a performance decrease do you think i might see in cornering/straight line performance? The tires are Falken ZIEX ZE912

i always thought some fatties up front and some skinnies in the rear would make for some oversteering fun. Still considering a set up like this. I just want to see how my Riv handles after I do sway bars and install the springs. That will influence how I configure my wheels and tires when the time comes.

ETA late summer early fall for wheels and tires.

I would really like to do 235s or 245s up front and 225s in the rear. Nothing drastic, just enough to be able to hook a little better.

Sir Psycho Sexy wrote:

I would really like to do 235s or 245s up front and 225s in the rear. Nothing drastic, just enough to be able to hook a little better.

I'm running 245/45/ZR17 all the way around with no issues at all. I'm actually thinking about going wider....Funny though, with the wider tires, you're going to get road crown pull. It was a little difficult to get used to.

I noticed the crown pull with 245s, like Abaddon mentioned. Especially sensitive on uneven patched roads. That's one part about wide tires I never considered before making the switch. I also notice this with OEM tires to a lesser extent - especially when riding over steel grates on an incline, like a drawbridge for example.

So would you all still recommend the wider tire even with the crown pull?

charlieRobinson wrote:

So would you all still recommend the wider tire even with the crown pull?

If your goal is better handling and traction, then absolutely

Abaddon wrote:

charlieRobinson wrote:

So would you all still recommend the wider tire even with the crown pull?

If your goal is better handling and traction, then absolutely

Scott, what is your opinion on a wider tire up front and a stock or smaller tire in the rear?

charlieRobinson wrote:

Scott, what is your opinion on a wider tire up front and a stock or smaller tire in the rear?

Well, I don't much see what the point would be. The Riv needs all the handling help it can get. It's heavy, and it's mushy. With my suspension mods, there's been times where I've hit a hard corner quite fast, and the ass end kicks out. It's controllable, but I think with bigger tires in the front and smaller in the rear, not only would it look funny, but it would make that problem worse.
Plus, the tires on the car are too narrow as it is.

I have my stockers on right now. A set of Sumitomo's on the front, and Goodyear Integrity in the rear. The Sumi's can handle the corners being on the front. The Integrity's just fold under the rim.

Would 245s fit on the same rims that 215s are on? I dont remember, but i think the kid told me they are 6.5 inch rims when i bought them...

Yes, but the sidewalls will be proud of the rims, max protection from curb rash. 215s would be stretched, so rim is exposed - little or no protection from curb rash.

al wrote:

]Well, I don't much see what the point would be. The Riv needs all the handling help it can get. It's heavy, and it's mushy. With my suspension mods, there's been times where I've hit a hard corner quite fast, and the ass end kicks out. It's controllable, but I think with bigger tires in the front and smaller in the rear, not only would it look funny, but it would make that problem worse.
Plus, the tires on the car are too narrow as it is.

I have my stockers on right now. A set of Sumitomo's on the front, and Goodyear Integrity in the rear. The Sumi's can handle the corners being on the front. The Integrity's just fold under the rim.

The point is, some folks will always be looking for oversteer in a nose heavy FWD car, and don't mind sacrificing overall handling to get it. The type of oversteer we all want is power oversteer - on the throttle out of a corner. Easy in a RWD car with more weight up front. For our car it's near impossible to do, and if you get there, the car will also also demonstrate "lift-off" oversteer - the type when the rear kicks out as the front end loads in a turn. By the very nature of our car's design, we will almost always have lift-off oversteer before power oversteer.

It's fine to increase the front tire widths for more grip, but I question narrowing the rear tires to lose grip, because the overall cornering performance of the car becomes compromised. The back end slides out sooner than the OEM design.

My approach has always been to increase width to ALL tires, decrease front weight, add rear weight, stiffen sway bars front AND rear. This increases the entire car's grip threshold, even if it does still understeer most of the time. I've noticed sometimes it will sometimes plow into corners, other times will kick out the rear end. Sometimes it's near completely neutral sliding, especially when wet or icy. Like any car, a lot depends on how you load the car's suspension when you approach and enter the corner. I can understeer, oversteer, or stick it just by choosing to take the apex early or late, how the brakes are applied, and by how quickly I flick the wheel. The driver is a key component to the car's suspension!

215's???? Who has 215's on the Riv??? Stock tire size is 225/60/R16. No reason whatsoever to put 215's on it.

I hope it's a typo...

It's for those into "stretching" tires. Popular trend with VW owners. I actually ran 215-45/R18s for a little while after I got my wheels (7.5" wide). It was free rubber, so I used it.

I bought a set of rims, and the tires that are on them are 215s. I knew it was skinnier than stock, but i figured i could either get away with it for a while or sell them and get the tires i wanted. I dont know what he had the wheels on.