How wide is too wide?

[Smokey228]

Anyone know of a wheel aligner with race experience on the north shore of sydney?

Reason i started this thread, was that someone had mentioned, they had a 225 on a 6.5" rim. They than went to a 205 or a 215 and saw increased handling.

If the tires are of equal quality and they share, respectively, the same contact patches to the ground and sidewall stiffnes, than why would a narrower one give better traction and handling?

Cheers,
Jase

[Kyosho]

If it's on the same rim.
The original tyre may have been too large for the rim, allow the tyre to "float" across the rim.

Much like what happens when your tyres start going flat.

[oldeskewltoy]

Also they may look like the Mk2 supra pattern but I assure you they came from a soarer

Not sure about other markets... but Only one year availability.....1985 USA Supra Type "L" only. In the USA the Mr II Supra came as a sports models, type "S", and a luxury sports model type "L". The type "S" cars came with the fender flairs, the "L" type didn't have them

[Soarer21]

If it's on the same rim.
The original tyre may have been too large for the rim, allow the tyre to "float" across the rim.

Much like what happens when your tyres start going flat.

^ ^ ^

Exactly what Kyosho said...
225 tyre on rear of JZX90 as standard fitment uses a 7.5in rim
I'd use a minimum 8in myself
Fitting it to a 6.5in rim will result in poor performance, exactly as per Kyosho's statement and example

[IN 05 NT]

jasey,

on my old rims i was running 225/50/16 on 8.5" rear, front was 205/50/16 on a 7.5" fronts..
(that was a good setup, never had understeer problems)

new rims are 17x8 and will be running 235/45 (generic rubbish brand) rear and 215/40 fronts will be falken azenis RT615's...

drifters say stretched tyres are better as there is no sidewall flex, but have not seen any hard eveidence that proves that they are better (eg, fater lap times...)

[Soarer21]

jasey,

on my old rims i was running 225/50/16 on 8.5" rear, front was 205/50/16 on a 7.5" fronts..
(that was a good setup, never had understeer problems)

new rims are 17x8 and will be running 235/45 (generic rubbish brand) rear and 215/40 fronts will be falken azenis RT615's...

drifters say stretched tyres are better as there is no sidewall flex, but have not seen any hard eveidence that proves that they are better (eg, fater lap times...)

There is a point where too large a rim for a given tyre will produce less grip
It also increases likelihood of the tyre popping the bead
Drifters do it for several reasons
-allows fat rims to clear guards
-cheaper tyres in a smaller size
-reduces grip
-it looks "fulli sik bro"

There are advantages and dis-advantages to lots of different setups.
V8's don't want to go to 18in tyres because the current setup allows better straight-line grip then if they went to a lower sidewall and an 18in rim. They run an odd sized tyre in the world-wide scheme of things, and changing to an 18 would allow a cheaper tyre however drive would be compromised. BTCC cars run a small sidewall because they usually only have around 350hp to play with compared to 650hp in the V8s so traction is "less" of an issue and they can take advantage of the lower profiles cornering ability.

If you check the tyre manufacturers recommended rim/tyre guides and select a rim width at the upper end of their range, or a tyre at the narrower end of a rim width allowance if you already have rims then you'll get best results.

[allencr]

First

...I read in the classic celica thread, that one of the guys saw better handling with a 6.5" or 7" with 225s than they did in a 8" with same tires....

Then

...someone had mentioned, they had a 225 on a 6.5" rim. They than went to a 205 or a 215 and saw increased handling.

Which is it? I'm pretty sure that the first was misquoted, or complete BS from them.
There is less sidewall flex/compliance, nothing special and nothing that isn't easily felt & observable & tested out. Higher pressure and/or lower aspect ratio/profile lessen the affect.

I saw an old interview with Jim Hall(Chaparral), and he said it was tough stopping the tire engineers from developing & supplying him with wider tires because of what they saw on his car - tires that 'looked' too small. He appreciated it, but after the 2nd set of rims to handle their wider tires, they were going to go even larger yet, until being stopped. I think he knew what worked.

Edited poor grammer, to attribute BS to them, not Smokey228!

[Stefan]

Also they may look like the Mk2 supra pattern but I assure you they came from a soarer

No, they also came on some L-types in the US and I believe some Celica XXs too.

[Negative Boost]

Not sure about other markets... but Only one year availability.....1985 USA Supra Type "L" only. In the USA the Mr II Supra came as a sports models, type "S", and a luxury sports model type "L". The type "S" cars came with the fender flairs, the "L" type didn't have them

Its P (performance) type and L type...
http://forums.celicasupra.com/showthread.php?t=7599
Sorry to get off topic.

[Smokey228]

First

Originally Posted by Smokey228
...I read in the classic celica thread, that one of the guys saw better handling with a 6.5" or 7" with 225s than they did in a 8" with same tires....

Then

Originally Posted by Smokey228
...someone had mentioned, they had a 225 on a 6.5" rim. They than went to a 205 or a 215 and saw increased handling.

Which is it? I'm pretty sure that the first was misquoted, or complete BS.
There is less sidewall flex/compliance, nothing special and nothing that isn't easily felt & observable & tested out. Higher pressure and/or lower aspect ratio/profile lessen the affect.

I saw an old interview with Jim Hall(Chaparral), and he said it was tough stopping the tire engineers from developing & supplying him with wider tires because of what they saw on his car - tires that 'looked' too small. He appreciated it, but after the 2nd set of rims to handle their wider tires, they were going to go even larger yet, until being stopped. I think he knew what worked.

Geez man, thats anal! I may have written it wrong. But if you must find out so badly as to quote me and call me a liar, check the classic celica thread...

Ill do a direct quote if it really bothers you that much though!

8in rims will not fit under a stock 22 without some kind of body work perferably flares.
l ran a 6 and 7in wheels with 235x50x13 on a 23 and l didn't do any body work. Mind you it handle heaps better on the 6in rims than the 7in.

So he ran 235s on a 6" and again on a 7" and he said that it handled better on a 6"...

Cheers,
Jase

EDIT: Okay, i was quite inaccurate, but its the right direction... It actually contradicts alot of what you guys have said though



PPS EDIT: I just read now that the cars suspension was setup with a 6" Wide rim, and when he went to the 7" it 'felt different'... So i spose thats not exactly a good reference.