paul_huryk

My new issue of R&T comes in today - review it and found this gem on page 103...

Apparently the author of the article is telling the reader that while wider tires may (and should) improve handling, they will contribute to longer stopping distances and diminished straight line traction. He is advocating just replacing OEM sized tires with the same size in a stickier, more aggressive tire pattern instead of going wider. In some cases, doing that is the only option (and a not so bad one), but why does say BMW upsize their tires as the cars get better suspensions and brakes on the same model?

R&T is a popular magazine with a huge amount of readership, yet is publishing inconsistent information on performance oriented items and upgrades (as tires can be).

While he does have some nice visuals of tire patch (some are correct), the accuracy is wrong in spots - cars under dry conditions will brake better with wider tires compared to more narrow ones; straight line traction might not increase with wider tires - but should not decrease in 95% of the cases; and from what I have seen, wider tires are the most effective way to decrease lap times on the track (autocross and road racing).

Man do I hate new car magazines! Not only do you get skewed opinions on new cars with the paid advertising, but now you have bad information on the upgrade path possibilities.

Now if I can only find some aggressive 215-65-15 tires to replace my 275-40-17 sized ones so my car will take off and stop better...

Johnny Blaze

iTrader: (15)

NHRA Top Fuel cars will soon be switching to a 7" wide slick.



NOT!!!!!!!!!!!!

lb9 GTA

How the hell is a wider tire going to shorten the contact patch?

Eagle223usa

Good question, It looks like they are referring to "Bling sized" tire combo's. My circumference is the same on my 17's as it was on my 16's with a lot more grip... Makes no sense. I quit reading these rags (C&D, R&T etc...) when the new 5th gen's were coming out, they all seemed to talk about the "Stigma" of Camaro ownership.

Eagle223usa

And in the article right next to it, a shot at C3 Corvettes... Pompous asses. Elitist snobs. I own a Corvette, and a Corvette is a Corvette, no matter what. It would seem they are opinionated...

87350IROC

iTrader: (2)

Easy. Assuming same tire height, same air pressure, if you widen the tire it is going to lower the pressure applied on the road by the tire. Same weight on the tire but a larger contact patch = lower pressure. The lower the pressure, the less the tire will deform due to the weight on the tire. Less deformation - less contact patch length. Dragster tires are tall for forward traction, longer contact patch. I SUSPECT dragster tires are wide for thermal management.

novaderrik

sometimes, bigger isn't better. you can reach a point of diminishing returns once you start to get to the point where the car doesn't need that much rubber, and actually decrease performance due to the extra mass and friction. it's all about finding that sweet spot- and with a factory suspension on a factory car, it might just be the wheel/tire combo that they put on it from the factory..

i've heard of people picking up et and speed at the drag strip by going to a narrower tire that is the same diameter, and i've also read of road racers that increased lap times with bigger tires..

paul_huryk

Your point is important and well stated.

I know a few people who have rear engined late model 911s - of which a few put wider wheels and tires and it negatively affected the handling. In their case, the balance was thrown way off putting wider front tires to aid turn in, while the rear tires remained the same as stock. Obviously the more modern the suspension, the more "tuned" it needs to be to perform properly. Then again, new 3 series BMWs come with staggered tire sizes with the performance suspension option (they have 50:50 wt distribution) and they really increase grip when you go to a "square" tire setup of say 255 width tires all around (vs. 225/255 ones).

As far as our cars go, wider tires mean more grip - which positively affects handling and braking. It is pretty darn hard to be competitive in CMC racing on 245-50-16 tires when the competition is on 275-40-17 sized rubber - assuming equal driver talent. Most of the pro touring 1st gens run mega rubber on their cars (295/345 in some cases) with highly advanced aftermarket suspensions and turn in lap times that make brand new exotics jealous.

Too much grip (and rolling resistance) at the strip is not good - 12" slicks with 12psi are going o slow a 250hp car down compared to a 245-50-16 drag radials. Front skinnies help with mph due to their low RR nature - but are treacherous to stop or turn with.