Wheel Width

[InterCooL]

hey guys

got an r33 gtst with stock looking rims, except the rears are 7.5" wide, fronts 6.5" (as pointed out by the tyre shop)

i've getting some bad understeer on the track. will this drastically change if i upgrade to wider front (and rear) wheels? or am i better off putting $1000 into swaybars / subframe alignment / camber etc?

cheers

[battery]

tyre's is what i'd look at first

Edited September 9, 2008 by battery

[InterCooL]

yeah. i got good tyres

[nfi]

I would first look at getting the swaybars as you can then change the characteristics of the chassis and they will make the biggest difference as they will also reduce body roll.

When money permits I would go as wide as you can with wheels ie. 8.5 front, 9.5 rear.

[nisskid]

id be looking around for some cheap 2nd hand wheels, maybe a few hundred $$ worth, go at least 16" diameter and something up around at least 8". when i say cheap i dont mean tempe specials, i mean good lightish brand name wheels, just cheap in price (whether it be due to looks, gutter rash etc). chuck some decent wide tyres on them and upgrade the sway bars.

[nisskid]

yeah. i got good tyres

what size? cant imagine ud get much over 225's on 6.5", even then they would be flopping around something stupid on the track.

[battery]

yeah. i got good tyres

what tyres have you got mate?

[battery]

heres a question

just say you are running a 235/45/17 on a 9" and a 7.5" rim would you notice a difference between the two?

[InterCooL]

i was actually wondering if anyone could say if and why the stock rims are bad for track use

[nisskid]

i was actually wondering if anyone could say if and why the stock rims are bad for track use

stock rims are thin, u cant fit as large tyres on them, its basically that simple.

for track use u have to remember the tyres are being put under higher force, so if u put wide tyres on thin wheels, ull have the tyres flopping around all over the place as there is less strength holding the sidewalls upright. if u have a wider rim and put a same size tyre on, the walls will be sit nice and vertical or slightly pulled in which keeps the sidewalls more rigid which obviously transfers to more responsive steering.

although then there is the issue of unsprung weight, but tbh i think thats less of an issue.

[nisskid]

heres a question

just say you are running a 235/45/17 on a 9" and a 7.5" rim would you notice a difference between the two?

yes, big difference. the 9" will have more rigid sidewalls and movement of the tread will transfer more directly into the wheel and in turn the steering. this can mean u get tracking where the wheel follows the road more, not great for highway driving but great for steering response.

[InterCooL]

i guess the theory of wider wheels / tyres is pretty simple. but can anyone quantify the difference (perhaps when they have upgraded to wider wheels)?

as in, have people felt there was a WORLD of difference in turn in ability when they have gone from 215 to 245 front tyres (for example)?

just like this thread (except this one is all about swaybars);

http://www.skylinesaustralia.com/forums/In...rs-t235329.html

[nisskid]

the only way to really know is by doing it urself and getting a feel for it urself.

[InterCooL]

yeah you're right

i guess if i think about it logically, its going to be $1600 - $2000 for some rims and OK rubber

full swaybars are going to be $500ish

so the wheels option is going to cost about 4 times more than swaybars. will it give 4 times the benefits? i doubt it... (but could be wrong)

[nisskid]

what tyres are u running now?

[InterCooL]

toyo t1r's

however they are 225's up front which are a little too wide. i could take them off and put 205's to reduce sidewall flex, but i'd loose contact area.

would i notice a huge improvement by downsizing tyres, or would it be better off investing the $400+ on tyres into swaybars? argh....

[nisskid]

swaybars are ur best bet, but as i said u dont have to spend big $$ on rims, just buy smart. something like this:

http://hardtuned.net/forums/index.php?showtopic=333667

there are much better examples around obviously, and if need be u can just buy 2 pairs if they are dirt cheap.

quality rims, decent width, and if u buy well u could probably get away with a similar set for less than $400.

but yeh, go the sway bars first.

[InterCooL]

hmm is it legal to have mismatched rims on the street?

[pkmike]

would i notice a huge improvement by downsizing tyres, or would it be better off investing the $400+ on tyres into swaybars? argh....

Tyre profile would be far more noticeable than changing tyre size on your rim. That said, swaybars will make a significant difference. By themselves, they will improve the cornering ability of your car noticeably, but once you've stiffened up the roll rate through tightening adjustable swaybars, you can back off your dampers and enjoy the benefits of better roadholding mid-corner as your shocks can now do a better job of absorbing bumps, rather than being set hard to stop body-roll.

Swaybars are my suggestion.

[nisskid]

hmm is it legal to have mismatched rims on the street?

there are no ADR's requiring the wheels to match front and rear.

saying that u are only allowed to go 1" wider and increase the track by 26mm (13mm each side), so pretty sure legally your limit is a 18x7.5 +27. those rims i showed u are legal besides being 1/2" over width, but no cop should be able to tell what width they are. in other words if u get defected for them, u were gonna get defected for them regardless of whether they were legal or not as the officer cannot tell what size they are from the outside (unless the size is stamped on the outside of the disk).