Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: nick69 on August 28, 2006, 03:30:47 PM

Title: 31x10.5 tyres and speedo??
Post by: nick69 on August 28, 2006, 03:30:47 PM

Guys,

will I have to change the speedo cog when putting 31x10.5 tyres on my standard TJ??

Thanks
Nick

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Post by: Mike Pavelin on August 28, 2006, 04:03:47 PM

Check your speedo with a GPS and see. They read 5-10 percent high as standard so you might get away with it.

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Post by: nick69 on August 28, 2006, 04:27:02 PM

I dont have GPS :(

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Post by: Manda on August 28, 2006, 05:06:18 PM

From what I can gather you can't actually get a speedo cog which puts your speedo right for 31's. (I think the cog for 30's is the nearest) but I have been running on 31's for years wihout redoing the speedo, I just allow at least 10%. So do 26ish in a 30, 35ish in a 40 etc. Been fine so far. (Touch wood and all that.   )

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Post by: Mike Pavelin on August 28, 2006, 05:21:37 PM

My TJ speedo was spot on with 31s, about 5% over with stock tyres.

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Post by: nick69 on August 28, 2006, 05:39:01 PM

Job done then, I wont give it another thought :D

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Post by: Anonymous on August 28, 2006, 05:54:55 PM

Mine was almost spot on with 31's with the factory cog in (29 tooth)

EE

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Post by: Rikk on August 28, 2006, 06:27:36 PM

There ya go try here :-

http://www.go.jeep-xj.info/HowtoSpeedoGears.htm (http://www.go.jeep-xj.info/HowtoSpeedoGears.htm)

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Post by: MOCAJ on August 28, 2006, 07:29:36 PM

Quote from: "Mike Pavelin"

My TJ speedo was spot on with 31s, about 5% over with stock tyres.