drenner43

I also posted this one in the OEM forum and it should have been here, sorry!

Alright so I'm a little confused. My jeep has 33's. I know with just the tires I can change the speedo gear to correct the speedo and odometer. BUT, if I regear to 4.56's along with the 33's, will this correct my speedometer and odometer or will I still need a speedo gear? Thanks

TheNerd

Check the chart:

http://go.jeep-xj.info/HowtoSpeedoGears.htm

Its not real likely. Generally when you re-gear OR get a different tire size you need to get a new speedo gear.

EVILXJ

My 33s only threw off my speedo 1-2mph but i still want to change the gear. They are only $30-40

drenner43

Awesome, thanks guys. So I shouldn't need a new gear when I change to 4.56's. Appreciate the help.

TheNerd

What? You didn't look at the chart did you. Stock Jeeps generally have a 28 or 29" tire (i believe) and 3.55 gears. That means you have a 34 or 35 tooth gear. If you look at the cart and match 33" tires with 4.56 gears, you get a 39 tooth gear. 39!=34/35. Technically, you never need to change the speedo gear unless you want an accurate reading. If you DO want an accurate reading with 33"/4.56, then (again, according to the chart) you need a 39-tooth gear.

Finally, when you have the wrong speedo gear in, your reading is off by a percentage, not by static numbers (i.e. it could be 1-2mph at around 15mph, but 3-4 at 30mph and 6-7 at 60mph....etc)

DrShaggford

x2^^
When your speedo is off it is off by a percentage not by mph. My 33s thow me off by 20%!! that means every 10 miles I drive I have really gone 12.

freegdr

junk yards can be a cheap place to fing them