17" vs 18"

[Scott]

That is all back to front.

 

Next I go drag racing I’ll be sure to run some Corsa 145 – 60 R 14’s then and see how the tiny footprint helps me get traction off then line.

 

Who drives Supra’s in the snow anyway?

 

I’m not talking about snow climbing, where talking about out right grip and handling,

 

FACT skinny tires do not cut it, I really don’t think people like Ferrari have been getting it wrong all these years!

 

Are you reading anyones replies? Its like talking to a brick wall.

 

Ok, firstly i said in the wet and in the snow. Yes if you want to get good traction in the dry larger tyres are better and give more of a footprint hence the reason for big bloody tyres, not big bloody wheels.

 

Jesus, you claim to know about drag racing yet you seem to have absolutely no clue about the reason for big TYRES.

[JustGav]

Right so you admit that a bigger surface area will give you more traction thanks.

 

At not one point did I debate the effects of weather, however that’s all people talk about on here?

 

More width and a softer compound tyre equals more grip that is simple physics.

 

And wider equals tram-lining as well... you can not at any stage simply just focus on a single aspect of suspension/traction, you logic of wider is better isn't true AT ALL...once you go wider you have increased the fulcrum point of that section of the suspension and instantly the geometry of the suspension has changed and the fulcrum points for the rest of the configuration are WAY out of wack.

 

Why do F1 cars put wider tyres on, BECASE THEY CAN and they can adjust suitably for it. You can't adjust a supra's suspension to suit 305 tyres sufficiently.

[RobSheffield]

Jesus, you claim to know about drag racing yet you seem to have absolutely no clue about the reason for big TYRES.

 

Drives an NA, previous experience FTO and computer games

[Scott]

Drives an NA, previous experience FTO and computer games

 

Ahh, bingo!

 

I don't drag race and i don't claim to be an expert in anything to do with drag racing or tyres. What i can say is that i have read some very interesting debates on different car forums regarding tyre sizes, wheel sizes, suspension geometry setup etc etc etc. Over the years i have took note of certain aspects as they make perfect sense and i understand what the EXPERTS are saying when they explain it. I cannot give every professional term but i can assure you, there are no drag racers running a sidewall of 35% on 19's

[JustGav]

Drag racing tyres are a VERY soft grip compound, usually with a large sidewall to allow winding up of the tyre.

[Scott]

Drag racing tyres are a VERY soft grip compound, usually with a large sidewall to allow winding up of the tyre.

 

Yup and i'm sure they have a lot less pressure in them to increase the footprint.

[RobSheffield]

there are no drag racers running a sidewall of 35% on 19's

 

I saw one, once

 

Didnt go very well for him!

[JustGav]

For those 'keyboard' draggers, I'd happily take a traction test on my stock offset 17's against a set of 20" alloys even in the NA over 1/8th mile

 

In fact, anyone up for it, Oct 04th, I'll be there

[Scott]

An actual professional? I've seen folks up at crail during run what ya brung etc but i've never seen anyone who knows what they are doing being so silly during competitions etc.

 

Serves him right

 

Sorry Gav that was aimed at Rob.

[NeoMagic]

Drives an N/A because I cannot afford to purchase a TT.

 

Nothing wrong with an FTO, ever driven one?

 

Don’t play computer games.

 

Anything else you want to slate me on?

 

To all, I am listening to you, but your points of physics are relatively useless when you talk about geometry.

 

Please explain to me how your geometry will be affected by moving up in inch in size and a few millimetres in width, especially when you normally come down in profile size thus keep the same rolling radius.

[RobSheffield]

An actual professional? I've seen folks up at crail during run what ya brung etc but i've never seen anyone who knows what they are doing being so silly during competitions etc.

 

Serves him right

 

Nah just some guy giving it a try at one of the Santa pod Japshow days iirc.

[NeoMagic]

And for drag racing, you do have a thicker sidewall and a wider footprint we all know that its common knowledge.

[JustGav]

Please explain to me how your geometry will be affected by moving up in inch in size and a few millimetres in width, especially when you normally come down in profile size thus keep the same rolling radius.

 

Do you understand the following phrases;

suspension kinematics, sprung weight, unsprung weight, sidewall deflection and elasticity?

[JustGav]

And for drag racing, you do have a thicker sidewall and a wider footprint we all know that its common knowledge.

 

Okay, so why do you have a thicker sidewall? please explain...

[RobSheffield]

To all, I am listening to you, but your points of physics are relatively useless when you talk about geometry.

 

 

Please explain to me how your geometry will be affected by moving up in inch in size and a few millimetres in width, especially when you normally come down in profile size thus keep the same rolling radius.

 

You have been a member about a month and now you are telling people who have been there and done that how you are right and they are wrong?!

 

I ran 19s with 315s on, on this countries roads they offered no more grip than 18s and 285s would, on track maybe - IF id checked the geo and got it as close to stock as possible.

 

You harp on about Ferraris and F1 cars, yet fail to understand that they are built and designed to run larger wheels so it is no issue.

[NeoMagic]

Do you understand the following phrases;

suspension kinematics, sprung weight, unsprung weight, sidewall deflection and elasticity?

 

Yes, and I’m not stupid I can see exactly what your trying to do, just because there is a consensus on this forum, doesn’t mean its right.

 

I am not claiming to be the fountain of knowledge, but when you have a car the weighs 1600kgs and puts out 350 RWHP or more traction is essential.

 

Light weight wheels like TE37’s with a decent sidewall and width with a decent suspension setup will go ALONG way in helping put that power down on the road!

[RobSheffield]

Yes, and I’m not stupid I can see exactly what your trying to do, just because there is a consensus on this forum, doesn’t mean its right.

 

I am not claiming to be the fountain of knowledge, but when you have a car the weighs 1600kgs and puts out 350 RWHP or more traction is essential.

 

Light weight wheels like TE37’s with a decent sidewall and width with a decent suspension setup will go ALONG way in helping put that power down on the road!

 

Not on the road, at least not in this country.

 

Maybe on track.

[Scott]

Drives an N/A because I cannot afford to purchase a TT.

 

Nothing wrong with an FTO, ever driven one?

 

Don’t play computer games.

 

Anything else you want to slate me on?

 

To all, I am listening to you, but your points of physics are relatively useless when you talk about geometry.

 

Please explain to me how your geometry will be affected by moving up in inch in size and a few millimetres in width, especially when you normally come down in profile size thus keep the same rolling radius.

 

 

Ok i'll try to explain it the way i understand it.

 

If you take a 17" with stock tyres. Measure the sidewall thickness. It will be around 3" as far as i know. If you move up to 19" and keep the same rolling radius your sidewall will drop to 2".

 

Straight line grip:

 

If you keep your tyres at the same pressure there will be less flex in the 19's as there is less air to compress. Therefor when the weight is on the tyres it won't flatten out as much giving less of a footprint. This is where you need to widen the tyres to increase the footprint. You can only go so far though with the width of the tyres and the amount you make up in width usually won't cover the amount you lose over the radius.

 

Cornering:

 

Because your sidewall would be smaller when you corner there will be less lean allowed on the tyre and therefor the tyre is likely to lift off the road during heavy cornering giving less grip. Again the only way to increase this is to make the tyre wider but again you won't be able to keep up with the ratios.

 

Think about cornering like this \__\ the shorter the \ the less lean you will get before breaking traction. The more the sidewall flexes the longer the tread on the tyre will stay square to the road and the more grip you will get.

 

Drive:

 

Because there is less sidewall there is less dampening through the tyres causing more noise and bumps are exagerated a lot more.

 

This is very very hard to explain without drawings etc so i hope it gives a little bit of insight. As i have already said, this is how i understand it and i know none of the techincal terms

[JustGav]

Yes, and I’m not stupid I can see exactly what your trying to do, just because there is a consensus on this forum, doesn’t mean its right.

 

 

And what I am I trying to do then?

 

All I'm doing is stating opinoins which I can back with facts

[Scott]

Light weight wheels like TE37’s with a decent sidewall and width with a decent suspension setup will go ALONG way in helping put that power down on the road!

 

You cannot have 19" alloys with a decent sidewall thickness. Well, i'll change that.. you can but you would need to modify your car extensively or raise it like a 4x4.

[NeoMagic]

 

 

 

You have been a member about a month and now you are telling people who have been there and done that how you are right and they are wrong?!

 

I ran 19s with 315s on, on this countries roads they offered no more grip than 18s and 285s would, on track maybe - IF id checked the geo and got it as close to stock as possible.

 

You harp on about Ferraris and F1 cars, yet fail to understand that they are built and designed to run larger wheels so it is no issue.

 

I fail to see, what length of service as you seem to regard it as has to do with anything.

There are limits to everything, and simply sticking 305’s on the rear isn’t going to help agreed.

 

For one that isn’t a practical size anyway, but I don’t need to go into specifics.

 

Yes a Ferrari or an F1 car is designed and built to run that sort of width tyre, but that in itself says it all, Supra’s are very customisable cars there are plenty of suspension components and extras you can buy to suit your needs.

 

My point is YOU CAN run WIDER wheels and WILL see a noticeable difference in grip its all about choosing the right parts and setting things up to accommodate correctly! Not that I feel you will notice any difference between 17’s or 18’s anyway.

[JustGav]

Ok i'll try to explain it the way i understand it.

 

If you take a 17" with stock tyres. Measure the sidewall thickness. It will be around 3" as far as i know. If you move up to 19" and keep the same rolling radius your sidewall will drop to 2".

 

Straight line grip:

 

If you keep your tyres at the same pressure there will be less flex in the 19's as there is less air to compress. Therefor when the weight is on the tyres it won't flatten out as much giving less of a footprint. This is where you need to widen the tyres to increase the footprint. You can only go so far though with the width of the tyres and the amount you make up in width usually won't cover the amount you lose over the radius.

 

Cornering:

 

Because your sidewall would be smaller when you corner there will be less lean allowed on the tyre and therefor the tyre is likely to lift off the road during heavy cornering giving less grip. Again the only way to increase this is to make the tyre wider but again you won't be able to keep up with the ratios.

 

Think about cornering like this \__\ the shorter the \ the less lean you will get before breaking traction. The more the sidewall flexes the longer the tread on the tyre will stay square to the road and the more grip you will get.

 

Drive:

 

Because there is less sidewall there is less dampening through the tyres causing more noise and bumps are exagerated a lot more.

 

This is very very hard to explain without drawings etc so i hope it gives a little bit of insight. As i have already said, this is how i understand it and i know none of the techincal terms

 

The force is strong in this one...

[RobSheffield]

I fail to see, what length of service as you seem to regard it as has to do with anything.

There are limits to everything, and simply sticking 305’s on the rear isn’t going to help agreed.

 

For one that isn’t a practical size anyway, but I don’t need to go into specifics.

 

Yes a Ferrari or an F1 car is designed and built to run that sort of width tyre, but that in itself says it all, Supra’s are very customisable cars there are plenty of suspension components and extras you can buy to suit your needs.

 

My point is YOU CAN run WIDER wheels and WILL see a noticeable difference in grip its all about choosing the right parts and setting things up to accommodate correctly! Not that I feel you will notice any difference between 17’s or 18’s anyway.

 

I give up...

[NeoMagic]

Scotster, good post!

 

And you are correct in your thinking.

[NeoMagic]

I give up...

 

Good, because I’m bored of your single minded bullshit anyway!