Clearence for 31's

Ask technical questions about your Ford Bronco II here. Technical write-ups on your axle swaps, engine swaps, chop tops, etc. are encouraged.
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stevenf
Posts: 96
Joined: Sat Mar 08, 2008 11:32 am

Clearence for 31's

Post by stevenf »

I am going to call tomorrow about insureing my Bronco II again because I absolutely hate how ugly my 97 Jimmy is. The Jimmy has brand new 31's right now and I would like to put them on the bronco for a weekend toy. What size lift do I need?
Also, Right now the BII gets about 12-13mpg. What will I be looking at with these tires?
One more thing. What cheap gearing would you go with? Right now its got 28" tires and barely moves.
vabronconut
Posts: 268
Joined: Thu Mar 20, 2008 4:04 am
Location: CENTREVILLE, VA

Re: Clearence for 31's

Post by vabronconut »

as for the lift i have no idea

but for the gears i would look for either 3.73 or 4.10's

4wheelparts.com has a chart which is somewhat accurate. it gives tire size vs gear and the resulting rpm's. if i was doing a gear swap i probably would do the 4.10's as down the road i would not be able to resist doing more lift and bigger tires. the 4.10s with 31's wil give you a lot of torque and might actually help in gas milage because the engine will not be working so hard to keep the speed.

a good swap from what i get from other members is the explorer axles. the front dana 35 is supposed to be unbelievably easy and the rear you would need to flip the spring perches. these axles are a dime a dozen in the bone yard so they are really cheap. probably get front and back for somewhere around $300-400. versus new ring and pinions at $150 a pop, plus carriers or lockers for anything above 3.92, plus bearing install kits $65 a piece, plus labor $150 - 200 a axle for the set up.

the explores also came with trac loc's which is like a locker.

last thing is the explorer runs a 8.8 which there is a better aftermarket for and is ALLOT stonger than the 7.5

all this is my opinion only, and i can't help but go to far when building my own stuff, so you may want to disregard this
87 bronco II 93 5.0 HO, NP435, 44 sas
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skfury440
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Re: Clearence for 31's

Post by skfury440 »

The D-35 swap is a direct bolt in you only have to modify your driveshaft if you've got stock lift. There's a point (I think 4'' suspension) that makes this equal so you won't have to modify anything if you have a lift. The D-35 you just unbolt hub to hub and bolt it back in, you can have a TTB front on the ground in about an hour. Takes a little longer to put it back (obviously because of weight reasons) but you can run 33's afterwards with it and not worry about it, then you just need the lifts to run the tires.
'86 BII
'64 Tbird 428P.I. Full Restoration
'66 Sport Fury 383 4-Speed Car
Texas4x4
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Joined: Mon Aug 11, 2008 2:37 pm

Re: Clearence for 31's

Post by Texas4x4 »

31's will fit under stock bronco 2 suspension if you have not lost much height due to sag.
stevenf
Posts: 96
Joined: Sat Mar 08, 2008 11:32 am

Re: Clearence for 31's

Post by stevenf »

How well do you think the stock axles(with 4.10's) would hold up to 31" tires and a 302 swap?
vabronconut
Posts: 268
Joined: Thu Mar 20, 2008 4:04 am
Location: CENTREVILLE, VA

Re: Clearence for 31's

Post by vabronconut »

stevenf wrote:How well do you think the stock axles(with 4.10's) would hold up to 31" tires and a 302 swap?
are you asking how will the bronco ii stock axles work with 302 and 4.10's or stock explorer axles?

the bii axle's will not hold very well with a v-8 the rear end is too small unless you have a 8.8" rear found in the 89 and 90 models. if you have the 8.8 it is nearly if not the same strength as the 9" for what your wanting.

the explorer has the 8.8 and had 4.10's from the factory in some of the explorer's. it is a very good rear end and will hold up t0 302 without a problem. the explorer axle also has the 31 spline axles which are stronger than the stock early bronco 28 spline. the front axles are another story. the dana 35 from the explorer holds up better than the factory bii. and for light to moderate wheeling it should do the job for you just fine. if you get a wild hair up your ass and feel like doing some harder climbing and what not this axle would not do very well. with 31's or up to 33's you should be good though.

hope this helps and this is just my opinion.
87 bronco II 93 5.0 HO, NP435, 44 sas
88budget4X4
Posts: 27
Joined: Sat Jun 14, 2008 10:54 am

Re: Clearence for 31's

Post by 88budget4X4 »

Texas4x4 wrote:31's will fit under stock bronco 2 suspension if you have not lost much height due to sag.

but if its for a weekend trail toy he may be taking off the sway bars and then he will be rubbing in the back.

i had 31's with no sway bars and didnt rub with a 3'' lift... went to 33's and rubbed on the rear frame rails when the rear axle was way twisted crawling a rock or somthing
stevenf
Posts: 96
Joined: Sat Mar 08, 2008 11:32 am

Re: Clearence for 31's

Post by stevenf »

you went to 33's on 3" of lift?
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