Suspension Experts: What’s Needed for 37s?

Sulley

Suspension and geometry are still somewhat of a mystery to me. There are about as many opinions out there as there are Broncos, but I am hoping to get some expert advice on what is needed specifically to upsize my 35 Sasquatch stock wheels to 37s, without sacrificing off-road capability or safety. I’m not driving a mall crawler, but I also don’t want a bunch of unnecessary upgrades to turn my low-speed Badlands off roader into some kind of desert racer.

If someone came to you and said they’d like 37s, and to retain the same capability off road, what would you tell them? Coilovers? UCAs? Beefier ties? How much extra travel does one need (20%?) Why would I want a zone lift vs. another option? Is there any reason not to continue using the stock wheels? Thanks for your expert replies.

This is a difficult question because there are so many companies and lift components out there. Here is a video by Vaughn Gittin Jr & Loren Healy that covers basics and these cats have lots of seat time behind the Bronco.

Thanks, that was surprisingly helpful.

So let’s say I want to do this in stages, first stage being front and rear 2.5 coil overs… but kept 35s on. Would this change my geometry at all? Or would the ties and UCA have the same geometry as before? I think what they were saying is the geometry stays the same until you change tire size.

Yes, coilovers will change the geometry especially in ball joints & tie rods. The higher you go and more travel & articulation the steeper the angles of the steering components. Thats why they recommend replacing the UCAs.

Sulley

So let’s say I want to do this in stages, first stage being front and rear 2.5 coil overs… but kept 35s on. Would this change my geometry at all? Or would the ties and UCA have the same geometry as before? I think what they were saying is the geometry stays the same until you change tire size.

We are not experts in this department fyi.

I've seen some with 37s and no suspension modifications, likely on sas models. No updates from them so not sure how it worked out in the long run.

We had 2.5 coilovers dialed to 3inch suspension lift on beefy 37s + UCA and Rear track bar on our 2021 BL MT 4door. Between all of our mods and the way the bronco is designed i.e. massive lower control arms etc. it really drove fantastic at any speed up to 102mph when ours hit the speed limiter here in the desert back in 2021. If you are thinking coilovers and 37s just add UCA and rear track bar. Good to go. Then you will have a decent set up for any situation that isn't too extreme or costly.

PS-I would also upgrade your tie rods, steering rack and bell housing with the stage 3 broncbuster kit. Then you can go anywhere you normally offroad without fear of something breaking because you added 37s etc.

Also, I forgot to add that UCAs will give you camber & caster adjustment along with replacing the ball joint with a uni joint for added strength and stress limits. I think they recommend UCAs for anything above 2” lift.

You can add a body lift and 37 but the only clearance you gain would be the difference between 35 and 37, but you can retain the Broncos original geometry. Once you start changing UCAs you will change the amount of droop in your suspension (articulation down) that is what seems to really affect the tie rods and CV joints. But going with the Broncbuster steering upgrade is a good way to help avoid issues with a coil over suspension lift with new UCAs. I have been vacillating between a lift and 37 or just leaving it stock. My brother lifted his and added 37 and hated it so much he just traded it in, he said it ruined the Bronco experience. Now this is just his opinion but that gave me reason to pause. I know there are several companies out there that are working on stuff that have a year + with the Bronco Broncbuster is one of them. He wheels that Bronco hard, so parts are very well tested.

Yeah, no interest in a body lift. Coilovers sound like the way to go. Sounds like Fox 25s + UCA + Bronco Buster bushings + tie rod upgrades would get me there. Why would I need a rear track bar?

Have not yet found a kit or UCA that would let me keep stock wheels with their backspace and offset.

Also keep in mind that when you mash the throttle and your wheels are taking a lot of lateral load like pushing against the side wall that is when the Tie rods usually snap. if you modulate the throttle and really just crawl you will save a lot of wear and tear on the steering components. I still think just keeping an extra set of tie rods is a really good option. if you beef up the tie rod then you are moving all that force up the steering system and that is where the steering racks have been breaking. there are folks making upgraded racks but that is more expensive than a few tie rods and an alignment. you can even use the BroncBuster tie rod support for a trail fix so that is an option to just keep those in the back and use them as needed. or if you a wheeling with a buddy/buddies someone might have them and you can borrow those to get you off the trail if you happen to snap one.

What I don't understand is why the Camberg kit won't work with stock wheels; is it just that the geometry exceeds what the UCAs can handle? If that's the case, why does nobody publish tech specs like this for their UCAs?

Anyone have experience with this Eibach kit? It looks interesting, they claim it's designed to add lift but work with the existing control arms...

https://eibach.com/us/c-939-product-releases-2021-2022-ford-bronco.html

Sulley

What I don't understand is why the Camberg kit won't work with stock wheels; is it just that the geometry exceeds what the UCAs can handle? If that's the case, why does nobody publish tech specs like this for their UCAs?

It is probably more for clearance between the wheel and the UCAs. But I'm not sure

Sulley

Anyone have experience with this Eibach kit? It looks interesting, they claim it's designed to add lift but work with the existing control arms...

https://eibach.com/us/c-939-product-releases-2021-2022-ford-bronco.html

Hmm I never going to say never but if you don't replace the UCAs you will limit your lift it will max out the articulation of the UCAs. and you will not have any more droop in your suspension. it should keep you from over stressing your tie rods but it will move that stress to other components like the ball joints and such.
But I will let others chime in that know More than me.

If you have a badlands or sas, these work really well. I added them but I'm not bumping up to 37s yet, going to burn through my 33s first.

Cheep, easy to install option that gets the job done. All you need after the install is a slight realignment.

tstarks

If you have a badlands or sas, these work really well. I added them but I'm not bumping up to 37s yet, going to burn through my 33s first.

Cheep, easy to install option that gets the job done. All you need after the install is a slight realignment.

That video that was posted does a good job explaining the dangers of this.

So I’ve looked at Eibachs, Icons (which appear to have a number of design issues they’ve had to provide hacks for), and others. Landed on a Fox coil over set, need to settle on a pair of UCAs that support 5.5” backspace.

Sulley

So I’ve looked at Eibachs, Icons (which appear to have a number of design issues they’ve had to provide hacks for), and others. Landed on a Fox coil over set, need to settle on a pair of UCAs that support 5.5” backspace.

Fox is a good choice they have been working with ford for a while with the raptors and HOSS 3.0 they have a lot of the bugs worked out already.

I just did a Zone 3" that actually lifts front 3" and rear 2" to remove rake. This is a SAS Badlands. The kit comes with great upper control arms. I put Black Rhino Abrams 17s with 0 offset and wrapped them in 37" Nitto Ridge Grapplers. No rub at all even when locked right or left. I also did the Broncbuster bushing and housing along with JKS stirring sleeves for safety. The Bronc runs great, drives great. I love it. I also did the Ford Performance tune that really helped with power, shifting, and adjusted the system for my 37s. My speedometer is right on. It cost more than I wanted to spend but I am so glad I did it.

Sulley

So let’s say I want to do this in stages, first stage being front and rear 2.5 coil overs… but kept 35s on. Would this change my geometry at all? Or would the ties and UCA have the same geometry as before? I think what they were saying is the geometry stays the same until you change tire size.

I did the ICON 2.5-3 coil over an left my 35"and have been wheeling it to see how it has been doing. After seeing the performance I am leaning towards leaving the 35". Performance is amazing. My truck is a wildtrak but I do wheel it in Moab.