Staggered tires and understeer

Correct me if I am wrong here -

A lot of people seem to add wheels and tires that are larger in the rear than the front to cars that came stock with all four wheels and tires of the same size. I see this often with two brands I have owned - BMWs and RWD Lexuses. It seems to be if you take a non-sports package 330 and add the staggered wheel and tire combo without doing anything else to it, it would take the moderate stock understeer and turn it into serious understeer. Yeah, it would look cool. I get that.

I have a GS400 as my family car. The popular upgrade seems to be going from the stock 235/45/17 package to a 245/35/19s in front and 275/30/19s in the rear. It seems like this would kill the handling balance. I was thinking I might just slightly upgrade to 245/40/18s all round. What do you all think?

Otto_Maddox wrote: What do you all think?

I think that's why Porsche went to such extreme stagger with the 911 Turbo.

My 750Li came with 19" wheels with 245/45 up front and 275/40 in back. It handled pretty neutrally at the 2 autocrosses I ran this summer. Interestingly the stock 18" wheels have a non-staggered setup, but perhaps the bigger sidewalls help the balance somehow? I've got 18s with snows mounted and the ride is remarkably better but a lot of that is likely due to the nature of the snow tires vs. the summer tires on the 19s as much as it is to the difference in sidewall height.

For your car, if it's a pure family cruiser I wouldn't go bigger than 18s unless you have really smooth roads.

The 911 also has extreme weight distribution. Manufactures may also do this to promote understeer, it's a safety issue. Then again, it puts the bigger tire where the power is.

Pontiac did a stagger thing on a FWD car a while ago,only the bigger tires were on front.

The 911 Turbo went with super fat rear tires because of a combination of a lot of weight on the rear tires and a lot of power going through the rear tires.

For a GS400, not having the rear weight bias of the 911, big rear tires would only be for acceleration traction and would likely increase understeer (I am assuming rear wheel drive and front weight bias without checking).

I am not sure people are getting my point. Of course a 911 uses staggered wheels and tires. It makes sense to do so, same with a lot of cars. I am asking if it makes sense to switched to staggered wheels and tires if your factory setup uses equally sized wheels and tires. My inclination is that doing so would worsen handling.

Yes it would. But if you are going to the grocery store or commuting on the highway I don't see it as a big deal.

If the car doesn't have Staggered rims, like 7" wide in front 8" wide in back, I would run the same size tires front and rear for tire rotations ease of replacement etc.

My E36 M3 has the staggered wheel setup. (they switched to this in 96 IIRC) I'm pretty sure BMW did it to add a bit of understeer to the pretty neutral handling 95 M3 for safety's sake.

When I go to the track I run same size tires/ rims all around. Around town I like the looks of the staggered setup, and you only notice the understeer as you approach the limit which rarely happens on public roads.

Put 275s all around

Like Joe said - a lot of M3 guys delete staggered setup to improve their handling. I don't think that doing the opposite would improve your car unless you had also added a lot more horsepower to your rwd car and had become traction limited out back.

a lot of 240 drift guys have discovered that rocking JDM tyte stagger with 9 or 10" rear rims makes their car understeer...

But in drifting, you can make just about anything drift with the proper technique so its not that big of an issue.

I really doubt the contact patch size of a 245 versus a 265 (or whatever the typical stagger is) really makes THAT big a difference.

I went from staggered to non staggered here.

225/45R18 F 245/40R18 R
to
275/35R18 all around.

I could've gone with wider rears, but the 350Z's just got great balance like that.

Going from 205/55/16 all around to 205/55/16 rear and 215/55/16 front completely eliminated the understeer on my Accord.

I always wondered how wider in the front of a FWD would work

In reply to mad_machine:

I know bigger/wider front tires help FWD dragsters, but I'm just as puzzled as to how they would help with cornering.

2002maniac wrote: Put 275s all around

That's what I run

The Alfa SZ ES30 runs staggered tires, and it is the best handling of the cars built on that platform. The gtv6 and milano use the same platform and have major understeer. Im not sure of the ES30 would handle better with big front tires or not though, there arent enough around anyone has tried that i dont think.

I will admit.. staggered looks better... but if I was after looks, I would not own an NG900 saab or a BMW 318ti

Well let look at Micro-ride height changes by tire diameter. Large on the back will. 1) raise rear roll center. 2) take caster out of the front. 3) change coner weight distribution.

Micro changes but changes none the less. Sometimes those little thing add up to good other not so good.

44

The big tires go where the weight and/or power are.

When I read "stagger", I thought of the oval track practice of using different diameter tire/wheel combinations on each side of the car, to bias the handling toward one side..

We referred to using different sizes front and rear as "big-and-littles"

Remember that a lot of cars came with the same size all around for logistic reasons, not necessarily for optimized handling. It's cheaper to stock one size versus two and reduces the chances of a mistake on the assembly line. In older cars, it also simplified full-size spare tire issues.

I chose to use the same size all around on my Valiant for much the same reasons.

xci_ed6 wrote: Going from 205/55/16 all around to 205/55/16 rear and 215/55/16 front completely eliminated the understeer on my Accord.

lolololololololol

Made me laugh out loud at work.

An example of an OEM implenting this strategy is with Honda "taming" the handling of the s2000. a big part of that "upgrade" was going with staggered wheels/tires.

There are a bunch of variables in the equation (F/R distribution, power level, sway bar stiffness, spring rates, etc.), but I like having some serious rubber up front, even in a RWD car. The front tires take a beating in braking and cornering, so having a lot of rubber up front will definitely help within reason. I remember someone racing AI or AIX was experimenting with larger tires up front to get some more grip and less understeer out of their Mustang. It looked wrong, but IIRC, it did improve the handling.

For daily driving duties the change would probably be less noticeable, but on a track or auto-x situation I think it would be more apparent.

andrave wrote: An example of an OEM implenting this strategy is with Honda "taming" the handling of the s2000. a big part of that "upgrade" was going with staggered wheels/tires.

I probably should have added, it was not the only change, just the final change. I did not want to install a different anti-roll bar, so I tried something cheaper, and it worked.