General speedometer question
 

So, on the suggestions of another member and my wife completely agreeing with the lack of stopping power in her Alero. I went digging and found info here on the forums to swap the brake system for that of a 98 Camaro/GXP. Then I noticed I need bigger than the stock 15 wheel, while this makes us super happy and I have already picked out the set and style we want "Motegi MR7"...What is stumping me and I cannot seem to locate this on the forum either due to not knowing how to find it or it possibly not being here. How does one resolve the speedometer being off after switching to bigger wheels and tires???

you get larger diameter wheels, and the tires to fit them....

the overall diameter does not change unless you want it to. size your tires correctly... more wheel, less rubber sidewall... 25.2" overall diameter or close to it is what it is from the factory






FOR REFERENCE ONLY; NOT ALERO SPECIFIC SIZES

Thank you very much...now I know why I could not find it, common sense should have kicked in. Found a very nice wheel plus sizing site that shows all the variances I needed.

This has been my favorite over the years:
Miata.net Tire Size Calculator

Can visually see how tall/wide your choice of tire can be.

Sweet thank you, I will have to try this when I am not at work for some reason the multi billion dollar company I work for cannot seem to keep the computers updated with the right versions of Java.......

It's not just 98. You can use the front caliper and caliper bracket from a Camaro built as early as 93 or as late as 2002. The overall design didn't change, but I would just go to the parts counter and ask for the 2002 brakes unless you get them from a junkyard, then its' a different story. You can also do C5 Corvette front brakes, the main difference is that they have cooling fins and are made of a different material which makes them lighter and more solid or something to those lines.

Also, you can google "tire diameter calculator" and you can see how much your speedo will be off with bigger tires. The 3 general rules of upgrading to bigger wheels is that for every plus size the wheel goes, you have to lower the sidewall. If you want wider wheels, you have to lower the sidewall for every plus size you go wider, so if you have 225/60/16, combination and want 245s on your 16s, you have to downgrade to 50s or 45s to keep the diameter the same. Finally, be aware of your stock offset. If you have an offset of 42 on 15 inch tires, it is not the same on an 18 inch tire despite having the same offset. Take for example my Cutlass... It comes with a 16 inch rim with a 42mm offset (or 45 i dont remember). It is not the same as a 18 inch offset with 42mm and thus will hit my caliper. Interestingly enough, the Mustang's 21mm offset fits perfects if they are 18's. These are just things to be aware of, especially offset as it is often overlooked. If you can test fit the wheels, do so!

The only issue with that tire sizing logic is that the Alero doesn't follow it. I know my 225/50/16 tires where replaced with 225/45/17 and if I went 18's it would have been 225/40/18.

Not too sure about the cooling fins on the Corvette calipers, but it is possible with the Vette being a high performance car. The Vette calipers have 22% more clamping force than the Camaro counterpart. The only issue is finding the Camaro Caliper bracket by itself.

When I upgraded I bought everything from RockAuto.com. I'd rather have brand new calipers than used ones. But I had to shop around to get the ones with lowest core charge because I did not have calipers to return to Rock.

Don't let the 22% number scare you. The Camaro Calipers will stop the Alero on a dime. The first time I panic stopped with the Camaro Calipers, I went from 70-0 at a traffic light at the end of a highway. I stopped about 200 feet short of the intersection, where the stock Alero brakes would have put me thru the intersection before hitting 0.

Look up the thread "Current pics of car, as requested" I started the thread in March 2011. I'm at work and the linker isn't working