Tire Clearance for stuffing 37-40's with under 4" lift need some input

[79INA69]

I'm in the build process for my 69 Bronco and need some advice on how much rear fender modification to do. My current set up is 400m,C6,NP203/205,FWD44, FW9". This has left me with a 22" rear shaft requiring me to lower the ride height to help with the rear driveshaft angle. I have a rear 4 link that is very similar to the JD rear 4 link kit using WH stock front coils. I set my ride height with spare tire, 23gal gas and hard top at 8" frame to axle. With no springs I can squat the rear and sit it on 4" bumpstops with clearance everywhere. The problem is when articulating the outer edge of the tire is hitting sheet metal all the way up to the tub structure with 6" of axle to frame clearance. I know having narrow frame rails is part of the problem, but I need to find a compromise of a min. of 3" compress while still keeping my 37s out of the sheetmetal (also wanted to run 37-40 skinnys) but at this point 37s is fine. Ideally I want 4" compress, so please anyone show me your inner rear fender mods, filler neck relocation you did you make this work. Note I am running rear seat and gas tank behind axle. Thanks

 

[Apogee]

How much have you stretched the wheelbase by pushing back the rear axle, if at all? You could really benefit from a Tru Hi-9 differential given your drive train configuration.

I'm a little behind you, but figuring out how to fit 37's with F150 axles and 3.5" SL plus 2" BL. The BL helps a lot, and not just with tire clearance...everything else clearance as well. I might be able to drop it to 1", but I'm not sure it's worth the effort at this point. I just want to drive it again before my kids are in college. That said, I was planning on moving my bumpstops to the top of the spring plates (still leafs), pushing them out a bit to help with just such tire/body interference issues.

 

[79INA69]

So I have stretched the front 2" and the rear maybe 4-5". I still have the factory rear cross member in tact and have 3/8 -1/2" clearance from the member to the upper link bracket. I'm piecing together a 35spline HI9, 14b outers and TG housing to roll under after I have this up and running with real world testing. Currently has a Currie HP8.8. Any how, I'm ok with bringing flares up to the body line and modding the inner tubs, didn't want to relocate filler neck, but that's minor at this point. Stretching the WB anymore to the rear will be down the rabbit hole of cutting up cross member, gas tank, losing rear seat. I do have the 1" poly body mounts and bumper is set nice to that. I also would like to get wheelin' as this has already been 5 yr process going half an hour at a time, haha. What I'm after is the maximum compression distance possible at this low lift. Ideally 4". I'm thinking I can raise my rear tubs up 3 inches and stretch them back 4 and I might be good as it gets. My front looks like I need to move the 4x4x2 box forward 2" and I should clear the TRO

 

[JSmall]

I’m running close to the same setup. Rear stretch 3”, front stretch 3”, 3” suspension lift, 1” body lift, 38” tire, full width 44 and 9”, 6” up travel, tubed front clip, extended rear inner fenders...

 

[JSmall]

I’m running a backseat and gas tank in the stock location. You can see the rear inner fenders that I made and the location of my filler neck in these photos.

 

[nvrstuk]

Check out Jaromy's build for answers to most of what you thinking of building...

I'm stuffing 40"s with 2 1/2" susp lift and 6" uptravel.

http://classicbroncos.com/forums/sho...d.php?t=278607

 

[BanditBronco]

Depending on what 23 gallon tank you have that can make a difference also. I am not sure how you guys are getting over 2" of rear stretch using a 23 gallon tank, I am within 1/2" from my non body lift tank, you gain an inch of clearance on body lift tanks because they don't have the front lip that rests under the cross member. I didn't have to hard of a time stuffing 37's with 3.5" susp. and 1" body lift but I am only 1" back and will be able to keep stock filler neck location and no wheel well mods.

 

[JSmall]

Depending on what 23 gallon tank you have that can make a difference also. I am not sure how you guys are getting over 2" of rear stretch using a 23 gallon tank, I am within 1/2" from my non body lift tank, you gain an inch of clearance on body lift tanks because they don't have the front lip that rests under the cross member. I didn't have to hard of a time stuffing 37's with 3.5" susp. and 1" body lift but I am only 1" back and will be able to keep stock filler neck location and no wheel well mods.

My tank was pushed back as far as possible. I wanted to get to 100" wheelbase, but the tank got in the way. I modified the rear cross member for the upper link mount and I have about a 1/16" of clearance between my axle and tank at full stuff.

 

[BanditBronco]

My tank was pushed back as far as possible. I wanted to get to 100" wheelbase, but the tank got in the way. I modified the rear cross member for the upper link mount and I have about a 1/16" of clearance between my axle and tank at full stuff.

Damn, I didn't truss mine because it wasn't going to fit. I probably could of gotten away with it if I had a body lift tank. That is impressive you are that close and haven't had any contact.

 

[nvrstuk]

On my 100" stretch:
- I cut out and fabbed a new rear crossmember
- modified and moved my gas tank for the 4th time since new in '97. Still holds qt shy of 23gal and it does not hang down as low as new 23gal tanks which for me was critical. Like JS I'm close but 1/8" from diff. My tank is now contoured to the shape of the RuffStuff housing for more volume.
- welded in new longer wheel wells from Jaromy (thanks again JS, they are killer)
-relocated my gas filler neck
-plated my frame rails for my ORI brackets
-cut my rear qtrs even farther back to accommodate 40"s that touch the 1/4 panel body seam at stuff
-still have room for a Heep fold and tumble seat like Jaromys
-4 linked w/16" vert travel

Its all about 2 things to me...how much do you want it looking like a Bronco.
How willing are you (time and money) to design and dial in the suspension (major committment)

 

[Yeller]

I can't help with the limitations of all the bronco parts but it can s done. Mine is a full tub, gas tank behind the axle and 100" wheel base, no lift and 37's. But I have no bronco frame, or much of anything else. I. Got what I wanted, a buggy that appears to be a bronco, has the versitility of a bronco, drives like a new truck on the highway and wheels like a buggy. I get to have my cake and eat it too

JSmall and nvrstk have some phenominal builds that check all of the right boxes too;D

http://classicbroncos.com/forums/showthread.php?t=242196

 

[68rockcrawler]

I think I only ended up stretched to 98" but I had to build a new rear cross member and moved the tank back a little. I stretched the backs of the rear fenders. I'm running 3-1/2" lift and 40's. My lift is actually 2" body lift and 3-1/2" springs with the brackets moved up 2" on the frame, but I wish I had kept them lower. Mine is too low and has no uptravel.

 

[79INA69]

Thanks for all the quick replies! The one thing I would also like to see is how your rear bump stops are set up. I know the ORI has them built in. I'm having my rear tire hit at the inner upper seam where the tub meets the quarter panel double wall. I feel like I would need to raise the tubs along with a stretch to the rear. I'm not sure how much rear stretch exactly, may have overstated. Tire is hitting the filler neck though. I may mod the rear cross member too if I'm looking at this much already. I will try to get pics tonight

 

[79INA69]

 

[Yeller]

You'll need to pay for contributor status to upload pics.
http://classicbroncos.com/forums/showthread.php?t=34373

 

[nvrstuk]

Big thank you shout out again to Yeller for helping me set mine up...lots of questions and he never got tired of answering them (well, at least he didn't let on that he didn't...)

 

[Yeller]

Big thank you shout out again to Yeller for helping me set mine up...lots of questions and he never got tired of answering them (well, at least he didn't let on that he didn't...)

Awe shucks, no thanks needed, I really enjoy helping out. I've made some really good friends all across the county just answering questions and am happy/privileged to call you one too ;D

 

[nvrstuk]

Same here!! I'll be showing up on your doorstep some day!! lol

 

[Yeller]

Same here!! I'll be showing up on your doorstep some day!! lol

Be my luck I'll be standing on yours at the same time .......lol