Is it possible to have too much tire?

As spring begins to break and I continue chipping away at problems with my newest VAG product, I'm beginning to plan my summer tire setup. The car is a '92 Jetta GLI 2.0 16v; with my mods and weight reduction, I'm probably around 150 crank horsepower and a little under 2400lbs. For the sake of cost I'm thinking of sticking with 15's, but the question is whether I want to run 205/50-15's on a 15x7 or 225/45-15's on a 15x8. AFAIK, 225's are about as wide as you can go on a Mk2 VW, provided your wheel offset is just about perfect. But do I really need 225's for a 2400lb, 150HP FWD sedan? Is there such a thing as too much tire? This car will probably only see a handful of HPDEs (probably not Road America because it sucks getting lapped all day). What do y'all think?

For DD, AX, or HPDE?

Basically it depends on if you can get the tires up to temp and where rotational mass exceeds the advantage.

I have seen a few rare cases for auto-x where they couldnt get the tires up to temp and were slower for it. Would happen more often for HPDE I would think.

Yes, with too much tire you can't slide around at will.

That sounds like about the weight and HP the Miata crowd tends to go 225/45.

But in reality, a 205/50 is going to be just fine. Especially if you can't get a 9" wide wheel on the car.

I've been contemplating this same question as the auto-x season approaches. 205s in front and 225s in the rear of the mr2 or 225s in the front and 245s in the rear?

Wider probably equals faster on track, but also probably makes for more darting and tramlining on the street.

Compromise is always part of the equation with tires. Whats more important?

205's will cost less, be fairly widely available, and will open your wheel choices. A number of fellow Miata drivers that I know find the 205's to be faster on a road course. I haven't bought tires in more years than I can count though, so I'm not up on the latest or greatest. Have to get some before summer though.

carbon wrote: I've been contemplating this same question as the auto-x season approaches. 205s in front and 225s in the rear of the mr2 or 225s in the front and 245s in the rear?

FYI, I hated my MR2's handling with 205s in front and 225s in back. It's much nicer on 225s at all four corners.

Mine's an SW20, so maybe that will apply to you, maybe not.

I just jumped from 205 to 225 in the Maliboo but that is 200 hp and around 3100 lbs and my 205's would start to get greasy after 4 hot laps at VIR.

If wheel weight and diameter is the same the 225 will be slightly slower top speed on a road course strait due to more rolling resistance and a larger front aerodynamic profile though if you have a suspension that can make use of the wider grippier tires you will be faster overall.

No, only too little power.

Will wrote:

carbon wrote: I've been contemplating this same question as the auto-x season approaches. 205s in front and 225s in the rear of the mr2 or 225s in the front and 245s in the rear?

FYI, I hated my MR2's handling with 205s in front and 225s in back. It's much nicer on 225s at all four corners. Mine's an SW20, so maybe that will apply to you, maybe not.

The zzw30 is balanced nicely on the setup I run, I just want to make it faster on the (autox)track.

I own and road race a Mk II Scriocco using 15X7 inch wheels with 205/50 tires. This size is fine for your car. I do plan on testing some 225/45's sometime in the future but racing a 30 minute sprint race at 10/10's is way different then a HPDE. The 205 may limit your cornering speed a bit but on a street car I think you want the front end to slip first anyway. Better to go off the track seeing what you're going to hit then backwards and not knowing. LOL!

Only when it rubs.

Appleseed wrote: Only when it rubs.

This is my rule.

And i'd rather "modify" my body with a sledgehammer to fix it than move to a smaller tire.

Anecdotally, when they were testing tires for the B-spec class, they foundthat going to a wider stickier tire lost them lap time at a certain point. They could corner better, but could apparently physically feel the extra drag on the straights. I think that's the exception to the rule though.
In practice you want to generate as much mechanical grip as possible and set up the rest of the car around that.

No.

275s. 2,300lbs. 160hp last season. Still able to slide the car when necessary.

2,100 lbs and 250hp is goal for this season.

This subject has been in GRM (the actual magazine ) a few times. It is far too car-dependent to make a blanket statement. Weight, power, suspension tuning, and application all play a factor.

I'd recommend 225s for that weight and power. I'd like to go to 225s and I have a bit less of both.

I think it depends on how much you plan on auto-xing the car. I usually follow the mantra that more rubber is always better when dodging cones, but if it's mainly a street car--- -I'd go 205.

With the smaller tire you'll have less cost, less weight, better mpg, and with an aggressive 205 tire choice-- still have plenty of grip to have fun.

The bigger tire may look cooler, but in day to day driving, I'd prefer the 205.

mazdeuce wrote: Anecdotally, when they were testing tires for the B-spec class, they foundthat going to a wider stickier tire lost them lap time at a certain point. They could corner better, but could apparently physically feel the extra drag on the straights. I think that's the exception to the rule though. In practice you want to generate as much mechanical grip as possible and set up the rest of the car around that.

more… ALMS P1 cars of several yrs ago … Acura went with a square set up … i.e. super wide on all 4 corners, as opposed to narrower fronts and wide rears … they could, and did qualify well (even some track records IIRC) … but couldn't make passes during the races .. they could out corner the Audi's, but the additional drag of the wider front tires limited their straightaway speeds enough that passes couldn't be completed

If you can't get the tires up to temperature, you probably have too much tire.

In our local 35 second autocross runs, I could not get four 9.5" slicks up to temp in my 1275lb +160lb me up to temp at all. I then went to 7" slicks. But I miss the steamroller look.

In reply to SkinnyG:

Too light to get the heat up in the 9.5's