kos11-12

Smaller tires on bigger rims, does it work on our road / track cars...!?

Here is what Michelin says....

¬We have found the smaller-tire + wide-rim combination, with its accompanying “high-tension” inflated shape,
can be more efficient:
¬More direct yaw response Decreased “phase lag”
between steering wheel input and vehicle turn-in
¬Less “overshoot” at corner exit Less of a tendency
to “wiggle” at corner exit (thus upsetting the car) when you roll back into the throttle
¬Can result in decreased negative camber requirements,
thus increasing braking and accelerating efficiency
¬Can improve vehicle response to air pressure tuning
*
http://www.google.co.uk/url?sa=t&sou...h6-trPZ7IbMOhA

Thanks to alexjc4 for posting this info....
*

jimq

thats what they do on the ricer cars around here. They all seem to think a fart can muffler and goofy looking skinny tires on wide wheels make them a race car

kos11-12

Well yes, Porsche or Micheline can come up with some non sens !!

Still ....Thinking : front 225 on 8 1/2 & rear 255 on 10 ....18's

sml

255 on a 10" rear will have that teen-age stretched look.

even 265 on 10" had a bit of a trendy 'stretch' appearance.

i think you really some proper data on the original michelin data. i have read similar and do not disagree, however I think the concept is more like ... do not use 295 on a 10" ... 265 will be better .... it's not about the narrowet tyre and maximum stretch.

next thing is you'll be doing this ...

kos11-12

This wheel is for a car with flashing blue lights underneath.....

I run 8 1/2 with 225 & 10 with 265 (18) at the moment and it's find , the fronts looked more stretched than the back.... But absolutely find and not over the top ...
I thought the 255 will be ok on 10 but you may have a point, the perfect size for 265 may well be 9 1/2 , so 10 is just about right, the perfect stretch would be about 1/2" ...!?
I am ordering new OZ Allegeritas so thinking of the best choice ....

Babalouie

I think it's one of those "it depends..." questions

Years ago, I had a fwd car, and I put 215 tyres on the front and 205 tyres at the back. The 215s were more like a "true" 220 in terms of theit actual size tho (and the manufacturer spec sheet confirmed the same). So the front tyres were noticeably wider.

Both ends were mounted on 6.5in wheels (the 215s did look a little baggy on the narrow rims) and to my surprise, there was less understeer with the 205 tyres at the front.

moacur

I run 225/40 on my 9" fronts and 285/30 on my 11" rears. Car looks the biz and handles like it is on rails

kos11-12

225 on 9 & 285/30 lower profil .... You are probably on the limit ....
Yours is a wide body ? Could you post your alignment numbers ...
Thanks !

I think I will go for 8 1-2 with 225, 10 with 265.... and later see if 255 will fit ,

sml

https://rennlist.com/forums/wheel-an...ta-hlt-se.html

are you going for the 8.5ET53 for the front?

i still think my 235 on the 8ET50 was pretty close to perfect on the front .. wont you get a fair bit of rubbing on the inside with 8.5ET53?

kos11-12

Hi SML,

I have at the moment 8 1/2 ET 52 with 225 and no rubbing, I have stops at the steering so no rubbing inside .....

I wish they do the 9 1/2 5x 130 ET 43 on normal titanium rims, I will ask this morning I have to hurry to change my order I put last Friday ....stressing...

sml

good luck with the decision ... i spent ages trying to work it out a while back .. and also did a last minute change of mind! lol

Geoffrey

Michelin is ablsolutely correct and on the race cars it does make a difference in how the spring in the sidewall feels. On my RSR, I run a 10" front with a 24/640/18 Michelin Slick (240mm short profile, maybe a 50) and the rears are a 12" with a 27/680/18 (270mm but a tall profile, maybe a 70). These are the widest rims that the tire will fit on and it does make a difference.

kos11-12

thanks for confirming Geoffrey !!

is it over the top for a track/road car.... !?
best may be to go smaller & lighter rims (8 & 9) and pull them out as much as possible, with recommended manufacture tires size...!?

Geoffrey

Realistically, for a street car, as long as the tire fits well on the rim, I wouldn't worry about it much. For instance, a 225 will work on a Cup 1 7", 7.5", 8" wheel. I much prefer the look on a 7.5 and 8" wheel. If you put that same tire on a 8.5" wheel, the edge of the wheel will be the first thing to hit the ground if you set it down. I personally would rather have the tire hit the ground first so as not to damage the wheel edge.

You can probably tell a difference in handling when the tire is put on a narrow wheel, for instance the stock cup 1s vs the Mille Miglia replicas which are wider. The latter do provide better grip and confidence. And personally I think the tire looks much better.

kos11-12

thanks Geoffrey

decision taken;

8 X 18 ET 50 with existing 225
9 X 18 ET 43 with existing 265, and may fit 255 at later stage when those will be worn !....