Speedo gear change necessary?

[gw204]

Getting ready to go to 235/75/15s on my '00 XJ 4x4. It came stock w/ 225/75/15s. Will I need to change the speedo gear after geting the new tires?

Thanks.

Brian

 

[AZ Jeff]

This question can be answered easily--how much TALLER will your new tires be, compared to the old ones, calculated as a percentage of the old tire size.

If it's more than a 5 percent, plan on getting a new speedo gear.

 

[Tucker]

235 vs. 225 ... not significant enough of a difference to change speedo gear.

 

[gw204]

Going from 225 Goodyear Wrangler RTSs (28.3" diameter) to 235 BFG All-Terrain T/A KOs (29" diameter). A little over 3% taller.

Thanks guys.

Brian

 

[martin]

GW,

The 88 XJ service manual I have for my XJ has a speedo gear chart. If you have the automoatic with the starndard gearing - 3.54 - then you are just fine. My XJ uses a 33 tooth gear for both tire sizes

Martin

 

[Eagle]

I've run my 2000 through a couple of those radar trailers some police departments are using now. With stock 225/75 tires, my speedo reads faster than actual speed. Moving up to 235 would probably make the speedo just about correct.

Go for it.