Just wondering if there is a chart available for re-gearing / tire size guidelines.
I would like to basically move up to 35" tires and change gears accordingly so that my speedometer/RPM stays approx. the same. I still do a lot of highway driving and don't want to sacrifice too much mpg by going too steep in gear ratio. I was thing that 4.88 would be enough, but a chart would be real helpful.

Thanks

 

We have online calculator, all you have to do is plug the numbers in!!!!!

http://www.currieenterprises.com/ces...lculators.aspx

 

Thanks David.. That will come in handy..

 

Im also considering new gears mainly to get the speedo accurate.

In my opinion going from 32's to 35's doesn't affect performance enough to justify a regear. I'm also running the 4.10's currently (07 Tow package)
If you go by the chart then you would want a 4.48, I've never seen that ratio but have seen 4.56's although they are not availible for the JK as far as I know. So you are basically stuck with 4.88's which would bump up your RPM over what you were on stock 32's.

If you had 30's stock then the 4.88's would be about perfect for 35's, so my initial thought was to do that then go to the dealer and have them adjust my stock tire size to 30". I know you can have them adjust it for up to 32" tires so I assume they can lower it as well. That should make the speedo pretty damn close.

However, if you look at the cost of a regear......
4.88 JK gears + overhaul Kit from http://www.northridge4x4.com/proddet...GEARS-OVERHAUL = $699.95 + install from a compitent mechanic will probably be another $200 or more.

Hypertech Max Energy Programmer from http://www.northridge4x4.com/proddet...=HYPERTECH-MAX = $379.99 Can probably install yourself

For even less you could get the ACCU PRO Speedometer and Odometer Calibrator - Jeep JK Wrangler $199.95
or the Superlift TruSpeed Speed Sensor Recalibrator for $189.95


I think I'll will go with the programmer, it cost only a little over half the price plus will bump up performace some.

Now if I could just get a 4.1 or lower TC for a decent price id be lovin life.

 

So with my set up 32" stock Duelers and 3.73 gears according to Davids converter I get 4.08 ratio for 35" tires, so I'm thinking I'll hold off on gears to see how things work out. Changing from 3.73 to 4.11 is not a big enough jump to warrant that kind of money. As you say a re-programmer may be the best option there.

 

Personally, I think there is a significant diff between 3.73 and a 4.11. I hve 4.10 and have driven the 3.73 with all things else pretty much the same. It was noticeable. My thoughts are if you go 35s or larger with anything under 4.10 it just isnt enough. Even that is questionable.... again, in my very humble opinion.

 

It tell me to go to 4.10s with 37s yeah that would out me back to stock but I also look at it this way if you got a rig that came stock with a high gearing from the factory you are better off going off of a lower gear ratio offered for that same rig. Basicaly my 3.21 number can go right out the window and I am basing my info off of the 4.10s

 

yeah I should have mentioned that I currently have the 4.10's and was basing my calcs on those.

You guy's with the 3.73's and especially the 3.21's should consider the regear a little more. I've never driven another JK but the 4.10's seem to be about right for 35's, 3.73's are probably good for the stock 32's, but not much more.

 

thought this might help

 

got a few stupid newb questions: is the 1:1 the only ratio I need to worry about or do I also need to worry about my overdrive ratio with new gears? I have an 08 X with auto, 3.73. I'm noticing some of the rpm's are higher with the new gears than stock, I thought they were supposed to be about the same? Does 100 rpm make that big a difference in power (I know it makes a difference in gas)?

Clay