ford 9'' ratios

[MikeB]

im in the process of building a 9'' for my yj, my original plan was to run 4.88's but the closest ratio for the 9'' is 4.86, ive seen guys running 4.86 in the rear with 4.88's up front so obviously it can be done but am i setting my self up for disaster 10 or 15k down the road?

 

[DAFFY]

I'm new here at the forums, but had my 68 cj for 20+ years now.
I"ve got a 9 in mine.
Let me tell you a little story.
When I first got the 9 I had 4.11's installed. I had a hell of a time finding matching gears for the front dana27 (never did find any). THe jeepers jamboree was coming up quick and still no luck. I ended up runing rubicon with 4.11's in back and 4.88 up front. That lil ol 27 held up no problem, even when we went from dirt to granite, the tires just sliped and caught some folk's attention, but it got me through. I would unlock the hubs if we were going to be on rock or dry dirt for a spell.

I ended up putting 488s (486?, been so long now) in the back after we got back, which was the better ration anywayz with my 33 tires.

I've heard of folks running what you're asking about without problems, Just don't lock up the front on the dry street, and you shouldn't have any issues. (just my 2 cents)

PS, I"ve since torn into the transfer case, front diff, and hubs and din't find anything wrong or signs of excessive wear.

 

[Bounty__Hunter]

4.88 and 4.86 is fine, not enough of a difference to notice or harm anything.