Tire width and wet traction....

[MTMike]

I'm going to be purchasing new tires for my Camaro this month, and I've chosen the Kumho ECSTA Supra 712's. http://www.tirerack.com/tires/kumho/ku_712.jsp

I've chosen these becuase they have well above par wet and dry traciton ratings, and the looks of the tread design suggest excellent water chanelling. The tires I have on there now hydroplaned SOO bad in even a tiny bit of water.... so it's important to me to have good wet traction capabilites. Plus, they're a great tire for the $92 they (the 255/50/16's) cost. I want to go with the 255's becuase they keep the stock tire diameter better than the 245's, and they dont' make the 712's in anything in the 215 - 235 range.

Now, my question is, is what is YOUR experience with a tires width and wet traction? Wider better? Narrower?

I know for a fact, from much experience, that a narrower tire does better in ice and snow, because there's more pounds per square inch of normal force between the tire surface and the ice/snow. My dad has 33"X9.5" tires on his truck, and he goes up our driveway in 2wd with no problem, when I struggle in 4wd with my 12.5" wide tires.

He is convinced, that wet (and dry) traction is the same way, but I'm not so easily convinced. He is a very smart man; a highly tallented engineer, and a very mechanically and physics-inclined. He does make logical sense, as to why more pounds-per-square-inch of tire surface to the road, the higher the frictional force will be, and therefore, the better the grip in stopping and accelerating, but I'm leaning more towards the fact that the tread design has more to do with how the water's chaneled than the tire width. Crappy tread in a 215 size is going to hydroplane more than a 255 in a good tread.

This is relating only to street use, I know it's a totally different story at the track when the tires are heated up.

Should I find a good 215 tire and be sure, or should I risk it and potentially sacrifice wet performance by giving the 255 Kumho's a try?

-Mike

[ February 03, 2002: Message edited by: MTMike ]</p>

[DominusEtDeusNatus]

In the snow or rain you want a thin tire so less water/snow gets under it and you have more force pushing the tire down. Notice the rain tires have huge grooves in the middle, so it's like 2 very thin tires next to each other. Very little contact area. Performance tires have a huge contact area cause you need all the grip and on corners it helps also as there is more rubber.

For winter 215, for summer 245+.

[Dominic]

I will try to answer your question the best way that I can.

From what I've heard so far, the Kumho 712s are some of the best tires for dry/wet use on the planet, and they suck horribly for any kind of snow use.

As far as straight line traction is concerned, a wider tire will not necessarily give you more grip since the grip factor is determined by the coefficient of friction - and nothing else. A wider tire simply spreads the weight out more, but the larger tire patch compensates for this, so its really about the same "physically speaking."

However, a wider tire does provide many advantages over a smaller tire. For one thing, a wider tire is far superior to a narrower tire under lateral acceleration circumstances (hard cornering). With a wider tire you also have the ability to average out road conditions better because with a wider patch area, one little puddle of water might not cover the entire tire's area, so some of the tire will remain dry and will give you good traction - this is why wider tires are better for drag racing in the rear [img]smile.gif[/img] .

Now, narrower tires do offer advantages, but they're not seen as quickly as the advantages of a wider tire. In snow, a narrow tire is not always good because it has a tendancy to sink in the snow. If the snow is less than 10" deep then it'll sink to the ground and you'll have traction, otherwise you'll get stuck [img]smile.gif[/img] . Wider bigger tires are better on ice, with very low psi, so that they conform to the surface better. Everything is a tradeoff pretty much :/.

When radials were first invented they didn't have very good tread patterns, so the narrower tires would be less resistant to hydroplaning. Many of the older people still go by this, and on a B rated tire it is probably true. The Kumho is a new design however, and is rated AA (stopping distance on wet surfaces) even in a P275/40 form... Very impressive tire.

Going from a P235/55 to a P245/50 tire did nothing but HELP my dry traction tremedously, and the tread pattern was so much better that I feel as though I have god's feet in the rain. I think Kumhos are a good choice - but don't run them in the snow.

[img]graemlins/fluffy.gif[/img]

[MTMike]

<blockquote>quote:</font><hr>Originally posted by TheCardinal:
Wider bigger tires are better on ice, with very low psi, so that they conform to the surface better. <hr></blockquote>

First off, I have to disagree with you on that. Trust me, from experience, on packed snow and ice, a wider tire sucks big time, and a narrower tire, of the same tread pattern will perform noticably better.

As for the Kumhos. I dont run the car in the snow, therefore the snow performance of the tires is not important. What I need the tires for, is superb, all around, every-non-snowy-day performance, in rain and on dry pavement. The highways suck up here, and are rutted, so when we get a heavy rain, puddles form on the highway, so I need a tire that is excellent in channeling water.

Dom, did you notice any difference in your speedometer by going to the 245/50s from the 235/55's? There's about a 1" diameter difference between those tires (the 245's are 1" smaller). The 255/50's will insignificantly bigger than the 235/55's I'm replacing now.

Thanks for the input, guys! Keep it coming.....

-Mike [img]graemlins/fluffy.gif[/img]

[Wolfy]

I got a question really quick when I get new tires I want to get a good size, now i know every body has their own oppinions, and here is mine. i have those damn 235/55 and yeah there great, but I want something cooler. I like the lower side wall look, but i don't want to give up my rims, cuz i love those and their 16". but at the same time i don't want a lot of empty space in the fender, and I don't have the money to spend on springs and all that. What size do you recomend. like 255/50, or what I really like a wide tire too.

[Black_V6]

i'll give some 1st hand advice....
i got these exact tires...and i LOVE them! great all around traction! they blow away my old bfg's! although there may be better specifically desinged tires out there, these give you the best of both worlds!

i got more pics of the tread in my sig if ya wanna look!

[DominusEtDeusNatus]

<blockquote>quote:</font><hr>Originally posted by MTMike:


First off, I have to disagree with you on that. Trust me, from experience, on packed snow and ice, a wider tire sucks big time, and a narrower tire, of the same tread pattern will perform noticably better.

As for the Kumhos. I dont run the car in the snow, therefore the snow performance of the tires is not important. What I need the tires for, is superb, all around, every-non-snowy-day performance, in rain and on dry pavement. The highways suck up here, and are rutted, so when we get a heavy rain, puddles form on the highway, so I need a tire that is excellent in channeling water.

Dom, did you notice any difference in your speedometer by going to the 245/50s from the 235/55's? There's about a 1" diameter difference between those tires (the 245's are 1" smaller). The 255/50's will insignificantly bigger than the 235/55's I'm replacing now.

Thanks for the input, guys! Keep it coming.....

-Mike [img]graemlins/fluffy.gif[/img] <hr></blockquote>


Mike, I can't tell a difference. I know the speedo will be off, but without any instruments, it's so hard to tell. I don't care much either. I have 235s on the front and 245s on the rear now just cause I got a good deal on them. I'll probably buy 255s next time.

I agree with that a narrower tire is always better in snow. If you're driving in such deep snow that the tire sinks in further, then you're out of your mind driving in such deep snow to begin with.

[John D.]

I went from 235's (Kelly brand) to 255's (Kumho) and there was a HUGE difference in my wet weather traction. My car grips sooo much better now. It is no doubt due to the width and design of the tire.

I agree with you Mike on the tread design theory. You can put extremely wide tires on a car, but it you can't channel the water out of the way you might as well put skis on it.

[MTMike]

<blockquote>quote:</font><hr>Originally posted by Dom:
Mike, I can't tell a difference. I know the speedo will be off, but without any instruments, it's so hard to tell. I don't care much either. I have 235s on the front and 245s on the rear now just cause I got a good deal on them. I'll probably buy 255s next time.

I agree with that a narrower tire is always better in snow. If you're driving in such deep snow that the tire sinks in further, then you're out of your mind driving in such deep snow to begin with.<hr></blockquote>

Whoops.. I didn't notice that you and TheCardinal (both Dom's) had replied... that was directed towards TheCardinal, but you answered it for me too. Thanks.

<blockquote>quote:</font><hr>Originally posted by Black_V6:
i got more pics of the tread in my sig if ya wanna look!<hr></blockquote>

The link doesn't work :(

I will probably go with the 255's... in spite of my father's warnings against it. Maybe I'll prove him wrong for the first time ever.

Anyone else???

-Mike

[ February 04, 2002: Message edited by: MTMike ]</p>

[MTMike]

<blockquote>quote:</font><hr>Originally posted by Wolfy:
I got a question really quick when I get new tires I want to get a good size, now i know every body has their own oppinions, and here is mine. i have those damn 235/55 and yeah there great, but I want something cooler. I like the lower side wall look, but i don't want to give up my rims, cuz i love those and their 16". but at the same time i don't want a lot of empty space in the fender, and I don't have the money to spend on springs and all that. What size do you recomend. like 255/50, or what I really like a wide tire too.<hr></blockquote>


The only way to get thin (small aspect ratio) and keep the stock tire/wheel diameter, is to go with a bigger (17 or 18" wheel) If you put really thin tires ona 16" wheel, it'd be alot smaller than the stock diameter.

[Jp]

I have 255's on mine now (kumhos) and as bald as they are now they still give fairly decent wet traction

when i first got them i'd floor it while it was raining and depending on how much water was on the road, sometimes i wouldn't even spin

the only downside is i went from being able to peel out easily on the stock tires to not being able to peel out at all with the kumhos =(

i guess that's a good thing tho

only downside is i got 35k miles out of them and now i need to buy more tires =(

[Night Rider]

I also noticed an immense improvement in wet & dry handling when i upgraded from the stock crappy 235-55r16 goodyear gsa's to 245-50tr16 bridgestone potenza RE910's.

The goodyears would hydroplane bad. With these new bridgestones, i fell like i'm driving on glue even in the rain.

Though i think my speedo is off, but not by much, maybe 1 or 2 mph. I can tell when i pass by one of those "watch your speed" monitors every so often.

But mike, have you considered the bridgestone RE950's: http://www.tirerack.com/tires/bridgestone/bs_re950.jsp i plan on getting them next. Based on the custom surveys they rate higher in dry/wet handling, w/ longer thread life warranty. Just fyi. although they do cost more.

[ February 16, 2002: Message edited by: Night Rider ]</p>

[shortdog273]

I never had the chance to experience my Kumhos in the snow, because I always put my factory wheels back on during the winter.

[chas]

its not so much width as void ratio and just plain tire design that determines how a tire will perform in the wet and snow.

for instance a bald tire is great for dry traction but water and snow get trapped under the tire and lifts it from the surface. snow tires have a high void ratio. performance tires tend to have a lower void ratio so that you are getting more rubber on the pavement at the cost of all weather traction.

[CamaroMan]

About the width question: My 275's SUCK in the rain. If you live in an area with alot of rain, wider is NOT better.