I did a search on this because I DID see a link in a post on a chart that told you how much your speedo would be out if you had a differtent size tire than what was on it new.
Wow is there ever a lot of info on this site! Unfortunatly I did not see what I was looking for. I'm sure I'm not calling it by the right name or something.
Here's the deal. Sticker on drivers door says 215/75R15. I had 225 and 235's on it and have just gone back to 225s till I can get some 30s that I like. Annnnnnyway I'm driving down the highway and my speedo says 115 (about 70 mph for my american cousins) and even the transport trucks are passing me!! And they are supposed to be governed at 105!
So I need a chart to tell me how much SLOWER I seem to be going. I mean the gas milage is great but........

 

its not a chart but it will caculate just about anything you want hope it helps

 

Makes no sense. You should be going faster with larger tires.

Speedo will read slower then you are actually going.

 

borrow a GPS it will tell u correct speed

 

I'm sure it will. Ummm errr ..... Where is it?

 

Thats what my brain keeps telling me but when I think I'm really speeding and everyone including the cops are passing me like I'm parked I get confused.

 

there is more to speedo error than just tire size gearing will also affect this

 

i just put up a link yesterday for a site to do your conversion. let me think what it was.....

www.1010tires.com/calculator.asp

thats probably not it but search my name and look for hte one called tire calculator / converter, it has the link in it. it does metric also

 

sorry forgot to paste it hope this works


http://www.rocky-road.com/calculator.html

 

None of those links help and I searched your name superj and didn't find that thread.
it was a simple calculation. you typed in the stock tire size and then your new tire size and it told you how far out your speedo was.
Anyone?

 

http://www.quadratec.com/jeep_knowle...article-46.htm

Quadratec has these charts. Might they be of help?

 

Well Kinda. I wasn't really interested in changing the speedo gear yet.
just interested in how much my speedo is out of wack with the tires I'm running. I know I've seen it and it was from this site .

 

I tried the gps thing with mine...I have 31's it was almost right on the money untill about 100kph, then at 100km the gps said i was going 107km. Don't know if that helps.....

 

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

that should be it. when you put in your tire sizes, it also tells you how off it reads beneath it. mine reads 11% off going from 215/75/15 to 31s

 

OH... I know what you're looking for... I know I saw it too, just don't remember where. There's this link: http://www.800-923-jeep.com/techCorn...tors.cfm#spedo