Tires size

I have a 2000 GL that I want to start modifying. I'm going to start with rims and shocks. I believe the standard tire size for the vehicle is 15 in. What's the risks I take if I upped them to 17 in? I heard the Odometer and Speedometer will be inaccurate.

[justinusaf]

Originally posted by BigJon34@Mar 24 2004, 04:35 AM
I heard the Odometer and Speedometer will be inaccurate.

try this link
Tire/ wheel size calculator...

This is a thread already on the site. I think that going from 15 to 17 in wheels only affects the speedo by 2 mph or so.

[Naich]

to keep the outside diameter close to the same, you will want 17" tires that have much less sidewall than stock. This has advantages and disadvantages. First, because there is less rubber in the sidewall, some of the "cusion" that results will be gone. You will feel the road more... more jolts from small imperfections in the pavement, and you will need to pay more attention to advoiding pot holes, because less sidewall also means you can bend your rims easier.

[Redog]

I heard that if you take the largest stock size wheel and plus size that one your cool

ex: largest stock wheel on the alero is 16, plus size 1 is 17

Many people around here have gone to 18's with no problem. But like Naich said, you need to keep the outer diameter as close to stock as possible. Soooo:

225-45-17 will work as will 235-45-17.
225-40-18 will work if you want to go up to an 18.

But be warned... less sidwall means that HUGE gap between the wheel and fender will look even bigger, so you should lower it to make it look right.

[Naich]

235/40/18 also works

My speedo should be off by around 4 mph at 60, but it actually correct there because when I originally did my gauges to install the import intelligence stickers back in the day, I put it back on a smidge too low.

Whatabout the Odometer? More or less?

[Naich]

well, honestly, I guess the odometer would read less with bigger tires. Your car will be moving furhter than the computer will think... and all those centimeters will eventually add up.

[Oldsman]

our speedo is set with 25" diameter tires.

so as long as you stay close to 25" diameter everything will be fine even odometer.

if you up to 26" you will be off 3 mph.

[johny_boy32]

alright mathematicians...if you have 205/40/17 tires...how fast would you really be going if the speedo said 60 mph?

[Oldsman]

you would actually be going 56 mph

[johny_boy32]

thanks olds

[johny_boy32]

another quick ?....will this size tire work good;
205/40/R17? to small/big or just right?

205/40/R17? to small/big or just right?

If it were me I would go with something a little wider like a 215 or 225.

[johny_boy32]

thanks for the imput...i will take this into consideration.

A couple of other points.

1) if you get tire/wheel combos with a larger outside diameter your speedo will read slow (of course) but your odometer will also go slower, so when your car actually has 100,000 miles on it, the odometer could read just 90,000. If you want to be a bit dishonest that is.

2) you will effectively be raising your final drive ratio, that means slower acceleration but higher top speed.