Gear Ratio

[4x4tillidie]

i was wondering if anyone out there could help me and tell me what are the stock gear ratios on a 1986, straight 6, full size bronco

i need to know so i can change my current gear ratios from 31 inch tires to 37 inch tires

thanks [-o<

 

[avp12304]

hey dude, i'm not positive on this, but i think its 3.77, if your gonna run 37's you could go with 4.56 or even 5.11

 

[Justshootme84]

You will need to check the metal ID tag on the axles to get the actual ratio. You should have a Ford 8.8" rear on the 86 with either a 3.08:1 or 3.55:1 gear ratio. If you can't tell what you have, post the numbers from either the front or rear tag, as they will be similar if not exactly the same. I have not seen a 3.73 0r 4.10 with the 300-I6 motor, but it is remotely possible, too. It is also possible that you have a Ford 9" rear, although those are mostly in 83 and older Broncos or the 351W H.O. 84-86 models.

For 37" tires, you wil need something like a 4.88:1 ratio. With the six cylinder, you will still be struggling for power or acceleration. That's O.K. if you drive slow or travel difficult trails that need low speed with some torque. Not good for mud or towing, IMHO.