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The mkiv Supra Owners Club

Wider Tyres Worse In The Wet?????


djjazzc

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Hello

 

Ive been searching on the forum regarding tyres....and i came across a thread saying that the wider the rear tyres, the worse the grip is in the wet???.

 

Is this true??

 

The reason i ask is because at present i have 245's on 19" rims. This weekend just gone i travelled from Bristol to Bracknell for the Pistonheads Sunday Service meet. It pissed down all the way and i have to say it was not pleasurable at all in the supra. I felt like i had to accelerate with an egg underneath my right foot.

 

So i want to change my tyres to 295's with new alloys as i have a set waiting for me if i want them, but now ive read that the wider your tyres are the worse it is??

 

Could someone explain please, because i thought the wider the tyre the more grip you would have.....or is it the case of the more wider the tyre is ,the more surface area is prone to aqua planning???

 

Just need confirmation please

 

Mucho gracias :D

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Physics point of view: whether or not you aquaplane is largely dependent on how much pressure the tyres exert downwards on the road surface. Using a wider tyre will lessen the pressure (i.e. same mass over a greater area), and will make aquaplaning more likely.

 

Alternatively, increasing the weight of the car will increase the pressure the tyres exert, thereby reducing the likelihood of it. For this reason, it is prudent to give lifts to fat people when it rains heavily.

 

Edit: I think there's a bit more to it than pressure, thinking about it (and reading Scott's post!). In my words, the cross-section of tyre would seem to be important. A wider tyre has a greater cross-section, gives the surface water less chance to dissipate to the sides, and hence more likely to aquaplane..... I think.

Edited by stevie_b (see edit history)
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The problem is the water. An easy way to understand it is lift on an aeroplane wing. The longer the wing is the more lift it will create. Now adpot that thinking to a tyre hitting standing water. The wider the tyre is the more surface area is hitting the water at any one time and the more "lift" created. The skinnier the tyre the less of the weight is distributed over the water.

 

245 is still pretty wide for winter driving but its about the best you are going to get. Good winter tyres would make a massive difference to your driving. You are looking for LOTS more pattern and a harder compound in the winter tyres.

 

If your planning to get new wheels anyway I would use some of it now to get some reasonable winter tyres and save the rest for when the weather gets better. That way you can have nice wide wheels/tyres for the good weather and skinny-ish tyres with good water capable tred in the winter.

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lol.....So if the wider the tyre is ,then the more chance of Aquaplaning....ok thank you.:)

So what is the prefered width of tyre that most Supra owners have on the rears??? Which width gives best results for dry and wet...what is middle of the road so to speak.

Also thinking of RLTC as i will be using the car during the winter.

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Nankang...urmmmm no...would not entertain them....had them once on my skyline ,never again.

 

I have not got that far yet Thorin....still researching what is best

 

You must have some tyres on there at the moment, if not I think I've found your problem.

 

 

The stock tyre sizes are, perhaps unsurprisingly, the best compromise.

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Thorin lol sorry .......just went outside with a torch...They are called ...Ant tyre p188....245/35/19...so basically not a branded tyre....cheapy tyres that came with the car when i collected it 2 weeks ago:blink:

 

Never heard of them. I suspect that whatever width tyre you go for, with decent rubber it'll be much better than those!

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what do i win?

 

You don,t need to go big brand for winter tyres. You will be suprised how good the medium brands are in the wet. Its all about tread. The less tread you have the harder it is to get grip so it comes down to expensive compounds. Winter grip is completely different, compound makes less of an impact. Its all about the pattern.

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Well, I'm not so sure about the statement above regarding not needing brand tyres in the winter.

If you are taking the car our when there is a risk of snow/slush, you have completely different needs for tyres than you would for normal dry/wet driving. If you do drive when its snowing DO GET REAL WINTER TYRES!

- if not driving in winter conditions and only when wet, no matter what temp (well above 0 of cause) you should just go for a good summer tyre. They will alway outperform all year/winter tyres in the dry/wet. Don't go getting extreme sports tyres like R888 or something of cause. These won't be usable in the rain. Also cheap tyres like you are running on now will result in what you are experiencing.

I've had good experiences with Goodyear Eagle F1 Assymetric compared to fx Falken tyres. They tend to stick better in the dry (no slip in 2nd at WOT) and also be better at braking in the wet. No matter what you choose, you will easily spin you tyres at anything above 3000 rpm in the wet. Below that, you should be safe with a good quality tyre like the Assymetric F1.

 

For width, stick to stockish. Wider will give you tracktion (and looks) in th dry but do you need it? At BPU levels, stock width is fine with a good tyre. If you are running a single, you might want to get other wheel for having fun in the summer.

Don't run anything larger than 18". And do make sure that your geo is set up properly as that will greatly influence your grip. Also make sure offset an so on is as close to stock as possible.

If you are going to get new wheels, I've been recommended these by Chris Wilson since they will make them specifically for the supra and very few wheels actually fit our cars properly: http://www.imagewheels.co.uk

Edited by bodilx6 (see edit history)
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I didn't say non-branded tyres? Where did you get that from? I said medium branded tyres are fine. Also the big brands you name like goodyear etc will stop nowhere near as good in the wet as say continental.

 

Winter tyres are all about driving in the rain and water dispercement, along with a bit of frost. With a supra using 245 rears it aint going to make a whole lot of difference what you have on there in the snow. Yes winter tyres will help a tiny bit, but they aint going to stop you finding the ditch if you drive over 10mph.

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Strange that on the circuit the toyo r888 is used as intermediate,

in suzuki swift cup for example...

 

R888 are a perfectly fine tyre in damp conditions, perhaps performing even better than they do in the dry especially on a heavy car like the Supra where they tend to overheat.

 

Its very wet conditions, standing water, where they start to show their grip limitations.

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Very good explanation in this article:

 

Tyres, Grip and All That...

 

Interesting excerpts:

 

the size of the contact patch of a tyre is not related to the width of the tyre - it is, in fact, proportional to the tyre pressure. What will change with the fitting of a wider tyre is the shape of the contact patch - it will get wider, but shorter longways.

 

most people will come to the conclusion that if you have "more rubber on the road" you will have increased grip. Sorry to say this folks, but to very close to 100% accuracy, the size of the contact patch is irrelevant.

 

for wet weather driving, despite what you may have heard, it is better to increase your tyre pressure, not reduce it.

Edited by spartan (see edit history)
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Eagle F1 (chevron pattern) 275's here, have had them for years...lot of wet driving over these years too. Only problem I've ever had was when the tread was down close to legal minimum...bit skittish in the wet to say the least. Obvious really, but considering the tread was legal, I was surprised at the level of squirminess.

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With a supra using 245 rears it aint going to make a whole lot of difference what you have on there in the snow. Yes winter tyres will help a tiny bit, but they aint going to stop you finding the ditch if you drive over 10mph.

 

No way. It's going to make a huge difference. Have you ever tried? Also, in most cases (if you can control you right foot) it's gonna be the fronts thats the important ones in the snow. I had winter tyres on my old Supra. That did sooooooo much of a difference compared to very good summer tyres. Even tried different brands and types over the years. There were differences but they were marginal compared to the step from summer to winter tyres.

 

If you drive your car in the snow and don't have winter tyres, you are just playing hazard with your own and other peoples lives.

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