Ok, i was riding in the car with a good friend of mine, and she mentioned something about changing the size of your rims messing up ur spedometer... it sounds completley stupid but i gotta ask because i put 17' rims on my '95 neon. just wondering

 

It does mess up your speedometer. The larger the rim, the longer it takes to rotate....your stock rims rotate about a half turn faster then your 17's, which means your actually going faster then your speedometer reads......your car was setup to read the 14-15in rim that came with it......go to a dealer/mechanic and have them adjust your speedometer.....

Changing rim sizes can throw your speedometer off from 1mph to 15mph....the most average case is 3-6mph.....so while your riding around thinkin your doing 55mph, you may be doing 61mph.....and then your gonna be wondering why those flashing lights in the rearview are after you.....[:@]

 

Rim size is not actually what matters. It is the overall diameter or circumference of the tire. So it might be possible to have a 17" rim with the same overall diameter tire, then your speedo would still be correct. You would have to compare the specs between your old tires and the new ones.

 

Sorta what he said ^ you need to measure your old wheel with the tire on it from top to bottom, then you need to find a low enough profile tire for your new wheel to make that measurement the same, the wheel size doesnt really matter, just the tires you put on it

 

Tire diameter matters. Rim size doesn't.

 

Rim size does infact matter.....if you go from a 15in wheel to a 20in wheel....i doubt very much you could in fact find a tire that will let you match up with that same said 15in wheel.

However, the overall tire diameter does mean more then rim size. If you can get a 17" rim with tire to be the same height as a 15" rim with tire.....then you wont have to do anything.

That said, not everyone is going to go thru the process of checking their tire diameters nor does everyone have the kind of cash to fork out for some of these low profile tires......it is simply easier and cheaper to have your speedometer adjusted for the average person.......

For the record, I never said that rim size was ALL that mattered....simply that changing rim sizes affects your car....because most people will not even think about checking tire sizes, rim sizes, speedometer issues, etc.....

 

hey, thanks alot guys, all of that helps alot, ill do the measuring tomorrow, if everything doesnt add up then ill take it to the dealer.... what if i got a digital outboard speedo??? would i have to do anything then, i was thinking about getting one anyway before the rims question..... just curious again???

 

It does not matter, you have to match the tires and rims. If you don't it will mess up the spedo. As long as the outside diameter of the tire is the same you will be fine.

 

Crash - aftermarket speedo's are not remarkably expensive, maybe $100-125 for the gauge, should use the stock sender. Problem is you can't run the stock unit and the aftermarket unit (and the signal to the PCM) at the same time, so you might run into problems later if you try to sell the car (odometer error). Rather than go to the dealer, just calculate the diameter using the measurements on the sidewall. If you need help, there are plenty of on-line sites that will spit out the info based on what you put in. Or just post here... As long as you aren't way outside the stock size, there's no point in trying to recalibrate the speedometer, which I've never heard of being done on a Neon... I have my cluster apart right now, and there's no adjusting pot anywhere on it...

East Side - I can't find the words...