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upgrading to 17's what should the speedo error be ?

Posted: Sun Jun 24, 2007 12:08 am
by vibebob
I just ordered 17" rims to replace my stock 16's, about what speedo error should I expect ?can I get the dealer to set the speedo where it will register the speed correctly or would that be asking for trouble having them tinkering under the dash that, so far, doesn't have problems/rattles ?

Re: upgrading to 17's what should the speedo error be ? (vibebob)

Posted: Sun Jun 24, 2007 12:19 am
by Raven
You just have to change the aspect ratio of the tire to get the same diameter. I have 17s with 225/45/17 and the speedo is almost bang on. I think 205/50/17 is the correct size also. I'll look for the tire size calculator link.

Re: upgrading to 17's what should the speedo error be ? (Sunny)

Posted: Sun Jun 24, 2007 2:53 am
by Raven

Posted: Sun Jun 24, 2007 9:45 pm
by Sublimewind
While the tire size calculator is a good tool, it is NOT completely acurate, there is quite a varience in overall tire diameter from manufacture to manufacture.I learned this over on my Subaru site, being that my subaru has differentials front/center/rear all of our tires need to be the same size on each corner, to within a 1/4" So if we happen to destroy a tire we either buy a pair or a set, and that have to be from the same manufacture for a set, so they are close to the same size.Unless you change the overall DRASTICLY you'll be within a few MPH/KPH. Just look at plus sizing on like TireRack.com and it should give you some answers... well, along with us of course...

Posted: Mon Jun 25, 2007 3:30 am
by mistertwo
last time i checked it will only throw ur speedo off 5mph per ever 100mph.. aka you dont need to worry about it.

Re: (mistertwo)

Posted: Mon Jun 25, 2007 3:55 am
by 4X4CHICHI
Tire size, Not wheel size is what is the determining factor here.

Posted: Wed Jun 27, 2007 10:02 am
by MRCN RCE
there's also a tire size calculator stickied at the top of the w&t forum