Rim size difference

[Tako]

Just a newbie question about rim sizes.

Is it true that the smaller rim size u hav, more acceleration you'll get? becos u would cover road faster with each rev.

[SLOWEGG]

Its the weight difference between sizes.

[b18c_crx]

i know the bigger u go the your speedo stuffs up like if ur speedo says 60 ur actually going 63 or some think like that but not sure bout going smaller makes u go faster, maybe coz its lighter?

[Zdster]

i know the bigger u go the your speedo stuffs up like if ur speedo says 60 ur actually going 63 or some think like that but not sure bout going smaller makes u go faster, maybe coz its lighter?

That is plane incorrect.

Changes in wheel and tyre sizes can effect your speedometer so have a look at programs like this (http://www.miata.net/garage/tirecalc.html) however if you choose the correct setup you can within the same sort of reading as your stock wheels.

Furthermore, just because you increase the size of your wheels does not mean that your speedo reading will increase (in fact it is quite possible that it can read less rather than more).

[Zdster]

Its the weight difference between sizes.

:thumbsup:

Read here for more info. The wheels dont have to be smaller to see acceleration differences just lighter:
http://www.tirerack.com/wheels/tech/techpage.jsp?techid=108

[Muzz]

Good work zdster
There are 2 ways to increase acceleration with the wheels you choose.

1. Lighter weight of rim and tyre combo, this will reduce the rotational inertia of the driveline, and reduce vehicle weight.

2. Smaller outside diameter of the rim tyre combo, this will be equivalent to usind a higher final drive gear ratio. When the OD of your chosen tyre changes from stock, your speedo will need correcting.

The best bet is to keep the OD of the rim/tyre combo pretty much the same as stock, if not smaller, if performance is desired.
Smaller rims, with thicker profile tyres to keep the OD equal, will generally reduce the weight of the whole wheel.