increasing wheel size
 

Hello.
Sorry, rookie question and Im sorry if its been asked before. Im pretty new to the modifying scene so please be gentle with me.... ;o)

How much acceleration will I lose by upgrading from 15in rims to 17ins?

Also, if I decided to go through with it nonetheless, how would I go about configuring my speedo to take the added size into account.

I dont really want to go down the "low profile tyre" route. Im a sucker for ride comfort.

Thankyou for any help guys ;o)

RE: increasing wheel size
 

http://www.miata.net/garage/tirecalc.htmlGo here and see what size "low pro" tire matches the overall diameter of your stock tires. Look at 205/40/17. You'll get the hang of how to use the calculater.

RE: increasing wheel size
 

oh thats rather excellent! ;o) thankyou!

RE: increasing wheel size
 

Depends how much they weigh.

There won't be any added size, because you will have to get lower profile tires.

Too bad, see above [8D]

RE: increasing wheel size
 

dont' worry about it... everyone asks these kinds of questions when they start getting into cars... and after all, asking questions is the best way to learn ;)

Anyway, you're going to have to go with low-pros, like mxs said. Honestly, I have 17's; they're pretty uncomfortable, but they're still liveable. I've hear 16's are a ton more comfy. But anyway, don't worry about the speedo.. it'll be about 3% fast (it'll read 61.8 mph if you're going 60), but there's not much you can do about that.

And like mxs said, the acceleration loss depends on the wheels weight. Most 17's are around 17 or 18 lbs (unless we're talking Falkens... those things are heavylol(with the exception of hanabis)), compared to the 14 lb stock steelies. To be honest, unless you're racing, you aren't going to really notice the acceleration loss.

RE: increasing wheel size
 

thankyou reaper, for the understanding and the input, and thankyou all ;o) Ive been looking around your site regarding the subject and everyone seems to be preferring the 15's or 16's anyway. It never occurred to me that certain wheels would be heavier/lighter so thankyou for that.
Shopping time!!:D

RE: increasing wheel size
 

try www.edgeracing.com ... they have pretty good prices (got my 17's for like $550 with tires and shipping!)

RE: increasing wheel size
 

I wouldn't get anything that weighs over 15 lbs. You can find 16-inch Rotas that are 13.5 lbs (Slips, I believe) and 15-inchers that are 12 lbs or less. Some 17-inch wheels weigh 20 lbs or more and yes, you WILL feel the pain, not only because the tire profile will be too low, but also because the extra unsprung weight will contribute to the kidney-pounding ride. I think light 16s are a good compromise, but the 12-lb 15s are tempting, since you will be gaining acceleration and a silkier ride without losing too much autocross handling.

RE: increasing wheel size
 

^ it's not the extra weight that translates to a crappy ride; it's the short, stiff sidewalls of the low-profile tires you have to use with larger wheels that kills the ride quality.