do the gear ratios have to be the same or different?

PHROX · Post by **PHROX** » Tue May 11, 2004 7:12 am

For front and rear I mean? does the transfer case feed the two out and a 1 to one ratio or does the front spin slower or faster? Just wondering, I have 5.13 in the rear right now and I was just going to do 5.13 in the front to but I an wondering which gear ratio would be correct. would 5.13 work or would it have to be higher or lower or what? itss an 87 bronco running a d44 in the front and a ford 9" in the back, has the stock 2.9. and I am hoping to run 38"s. if any of that matters. if you guys could help me that would be great. sure I could check it myself, but I figure one of you guys knows it already so it would be easyer to just ask you guys.

DBrown · Post by **DBrown** » Tue May 11, 2004 7:27 am

yes, the front and back has to match. I have heard of people running 3.50's and 3.55's with no problems but I wouldn't push it if you don't have to. a 5.13 is probably about right for 38's.

PHROX · Post by **PHROX** » Wed May 12, 2004 5:24 am

ok, I was just making sure that I didnt need like a 4.10 in front to match the 5.13 in back because the transfer case feeds it at a different rate.

Happy_Jack · Post by **Happy_Jack** » Thu May 13, 2004 9:41 am

The only reason to run different ratio ring and pinions is if you were going with two different tire sizes. Some mud bogger's did this at one time on rigs that only ran in competition. Seem to remember they would run the front a little faster. For some reason certian axle combinations will be off slightly. Like 4.09 in one end and 4.11 in the other. Like DBrown said this is acceptable but try to stay as close as you can get if you are running the same size tire front and back.

Post by **Nobody** » Thu May 13, 2004 10:03 am

The mud boggers wanted their fronts to spin a little faster so their steering would be more responsive. That's my understanding anyway.

I think up to a 2% difference is acceptable. I bet the difference between a new and used tire is more than that. Heck new tires probably vary that much.

But as others have said, you want matching ratios otherwise your transfer case will probably explode.