Speedometer after changing rim size?

[Basement_Modder]

I've tried searching the site and google-ing this question, but received nothing, so a thread it shall be!

If I were to upgrade my rims from the stock 12" to 13" for ease of finding tires, how would I compensate for the un-calibrated speedometer? There HAS to be a way to make it line up again, right? People change rims all the time, so there has to be an at-home solution to this, right?

If not, can't this be compensated for by buying tires with a thinner sidewall, so the overall diameter is about the same?

Thanks!

[89newb]

depending on if you go 13" with low profile tires...the overall diameter may be the same as the stock 12" with a normal tire meaning that you might not need to change the speedometer. even without a low profile tire on the new 13" rims i would imagine it would only be off 2-3 mph and might not pose that great of a problem....i could be wrong

[Basement_Modder]

I just found an ehow article on this that had a bunch of math to do that would give you the right size for the speedometer cable gear. Apparently I need to go to ford to find one, though.

[Pu241]

Use a GPS, works a like a charm, no matter what wheels and tires I use.

[crazyrog17]

Easy tool to compare tire sizes.. no math for you to do!

http://www.miata.net/garage/tirecalc.html

Even tells you how far off your speedometer will be.

[bhazard]

165/65-13 is the size you want to keep it accurate.

[iceracerdude]

I've bookmarked this site and use it all the time, you should too!

http://www.1010tires.com/tiresizecalculator.asp

[navdoc101]

Easy tool to compare tire sizes.. no math for you to do!

http://www.miata.net/garage/tirecalc.html

Even tells you how far off your speedometer will be.

Great chart ! thanks . I love this kind of stuff, it can be used over, & over. Save in favorites. Another great one Ice, Thanks. Saved it

[htchbck]

I don't know of any other gears you can get that fit the Festiva trans... best way I know if you reeeeaally wanted to do it would be pull the plastic off your cluster, and mark where the speedo falls at 10, 20, 30, 40, 50, etc. (using a GPS) then use the marked up cluster face as a template for printing off a new gauge face (maybe scan it into a graphics program). I have printed off custom faces, as well as others on here. If you do a search for custom cluster you can find some links to it.

[crazyrog17]

That sounds like a fun modification

[htchbck]

It was. I just used the stock protege cluster as the template though, it reads pretty close with 185/60R14s