Trailing Arms

[Van-go]

I’m to the point where I need to buy or build trailing arms.
Planning to run a 14in coil over.
I’ve seen a bunch of different options and want to be sure I invest in something that will work and will last.
My chassis is set up for the typical 2-5/8in joint on the rear lower.
I do not want the arms to have a bend in them and lose ground clearance. I like TMR & busted knuckle’s arms.
Busted knuckle uses DOM with a Uniball inside which has a width of like 3-7/8. They used to have a different design that used a normal 2-5/8 uniball. Not sure why they changed it. They also use a 1.5in heim at the axle side to allow for more articulation.

BKOR Ultimate Trailing Arms

PLEASE, NOTE THE ORIGINAL YOUTUBE VIDEO SHOWS 1.75" HEIMS. THESE HAVE BEEN DISCONTINUED. This kit includes and 1.50" heims, and these have plenty of BEEF. These are the ULTIMATE Trailing arms. The MASSIVE D.O.M. housing houses a 1.25" uniball with spacers to allow a 1" bolt. Each side of the...

bustedknuckleoffroad.com

TMR is very similar but they use a 1.25in heim so I am worried they will bind when flexed.

Competition Trailing Arms - DIY Kit

With over a decade of experience building DIY Trailing Arm Kits we're pleased to announce the latest generation of competition trailing arms! What makes TMR Customs Competition Trailing Arms the best kit on the market? High clearance! Bent, low clearance arms are a thing of the past! Proprietary...

www.tmrcustoms.com

Been looking at Bomber fab chassis and I am not sure what they have going on. Looks small.

School me on what works and help me decide which direction to go.

 

[drkelly]

@Bebop

 

[Van-go]

@Bebop

Yeah he’s got the old style busted knuckle ones. From what I’ve seen they re-designed them since Jake made his video explaining trailing arms.

 

[Bebop]

There's tons of variables.
If you can fit Jake's new arms, they're better than the old ones IMO.
The old BKOR ones are the current TMR offering, except with the smaller heims. If you have them setup right, they won't bind.

Bomber's trail chassis arms are awesome, but only work for lightweight cars and requires heat treated chromoly as a material to hold up. Very cool, very light, heavy in man hours to build, expensive and not easy for everyone to put together nicely.

Otherwise, you could look into BFR and Goatbuilt offerings with their square systems, which are good too.

As a general statement, trailing arms are amazing and I won't have another rig without them if I can.

I'm going to sell my current arms at some point. Trying to go with something different, closer to the Bomber race arms. If you're interested and not in a hurry, I could make you a deal on my take offs. By not in a hurry we're talking 6 months to a year. I'll have some shocks for sale too.

 

[shawn]

Busted knuckle uses DON with a Uniball inside which has a width of like 3-7/8. They used to have a different design that used a normal 2-5/8 uniball. Not sure why they changed it.

I'll bet $5 it's because the narrow joint didn't do a good job of preventing the arm from rolling, and probably didn't last very long. A wider joint will have less force on the rubber at the outside.

 

[Bebop]

I'll bet $5 it's because the narrow joint didn't do a good job of preventing the arm from rolling, and probably didn't last very long. A wider joint will have less force on the rubber at the outside.

Not only, but there is some truth to that.
The new BKOR design has a "return to center" function the OG/TMR design doesn't have.

In terms of longevity, I replace the delrin bushings (not rubber, that makes a difference) every year. Cost is $5 and definitely not a deal breaker.

 

[drkelly]

I just went to the BKOR website to look at their latest trailing arms, and this popped up. Dang.

BKOR's trailing arms do sound like the BEEF!

 

[Van-go]

There's tons of variables.
If you can fit Jake's new arms, they're better than the old ones IMO.
The old BKOR ones are the current TMR offering, except with the smaller heims. If you have them setup right, they won't bind.

Bomber's trail chassis arms are awesome, but only work for lightweight cars and requires heat treated chromoly as a material to hold up. Very cool, very light, heavy in man hours to build, expensive and not easy for everyone to put together nicely.

Otherwise, you could look into BFR and Goatbuilt offerings with their square systems, which are good too.

As a general statement, trailing arms are amazing and I won't have another rig without them if I can.

I'm going to sell my current arms at some point. Trying to go with something different, closer to the Bomber race arms. If you're interested and not in a hurry, I could make you a deal on my take offs. By not in a hurry we're talking 6 months to a year. I'll have some shocks for sale too.

Man, I would love to take you up on that offer. I want to get some arms sooner, but I’ve been dragging ass for so long, your timeline may work out fine.
This is what I’m working with. It’s the goat built subframe. Wouldn’t be too hard to modify it to be wider on the frame side mount.

As far as square goes, I’m not opposed to it, but I like the idea of keeping the arm flat for clearance. Not a huge fan of how bulky they are and how it’s nearly impossible to change where your shocks mount to adjust travel.

 

[Van-go]

I just went to the BKOR website to look at their latest trailing arms, and this popped up. Dang.

View attachment 359103


BKOR's trailing arms do sound like the BEEF!

It’s hard to stomach $1700 for 2 links. I am sure they are worth it but dang

 

[Van-go]

Here’s the goat built ones.

 

[Bebop]

Man, I would love to take you up on that offer. I want to get some arms sooner, but I’ve been dragging ass for so long, your timeline may work out fine.
This is what I’m working with. It’s the goat built subframe. Wouldn’t be too hard to modify it to be wider on the frame side mount.

View attachment 359104
As far as square goes, I’m not opposed to it, but I like the idea of keeping the arm flat for clearance. Not a huge fan of how bulky they are and how it’s nearly impossible to change where your shocks mount to adjust travel.

My current arms have a 2.63" width at the chassis. I think they should fit in the GB subframe.

It’s hard to stomach $1700 for 2 links. I am sure they are worth it but dang

Timeline-wise, I have a few cars lined up in the shop before I can get to mine so I am not in a hurry at all. Depends how bad you want a deal on these arms. They're not cheap as you found out.

 

[Bebop]

I just went to the BKOR website to look at their latest trailing arms, and this popped up. Dang.

View attachment 359103

It's actually insanely cheap for a turnkey car.

 

[Van-go]

My current arms have a 2.63" width at the chassis. I think they should fit in the GB subframe.



Timeline-wise, I have a few cars lined up in the shop before I can get to mine so I am not in a hurry at all. Depends how bad you want a deal on these arms. They're not cheap as you found out.

Yeah I almost pulled the trigger on them last year and they went up cause of the metal increases etc.
I’m tempted to just buy the joints from BKO and source metal through a buddy local.
I’ll shoot you a PM and see what we can work out.
For now, I’m starting to build my motor and build out the front half of the chassis til I decide what I need to do in the rear.

 

[MattyB4x4]

I did 2" .250 wall inch sleeved with 7075 aluminum on mine and I already have a slight bend in them on what I'd consider to be a lighter buggy - toyota, tons, leading/trailing arms. The TMR ones are beefy.

Have you considered going billet? The ones @partiallycommittedracing is making now are pure sex.

 

[UNCC-CRAWLER]

Talk to @slravene at Partially Committed Racing he will get you set up with some sweet billet trailing arms.

Partially Committed Racing

Partially Committed Racing. 1,168 likes. CNC Laser Chassis Kits and Custom Buggy Builds

www.facebook.com

 

[CLRracer]

It's actually insanely cheap for a turnkey car.

I understand what you're saying, it's just hard to imagine 85k being considered "insanely cheap" Imma just keep beating my $850 RamCharger haha.

Duane

 

[Bebop]

I understand what you're saying, it's just hard to imagine 85k being considered "insanely cheap" Imma just keep beating my $850 RamCharger haha.

Duane

I didn't say it was cheap.
I said it was cheap for what it is.

Big difference.
But you know that

 

[slravene]

Thanks for the shoutouts

We (partially committed racing) makes 7075 billet aluminum trailing arms. Custom to each need. Single shock, double shock, heim or bushing or uniball, flat or drop, designed for your rig, customized with lettering if you want. No 2 sets are the same.

 

[Van-go]

View attachment 359113Thanks for the shoutouts

We (partially committed racing) makes 7075 billet aluminum trailing arms. Custom to each need. Single shock, double shock, heim or bushing or uniball, flat or drop, designed for your rig, customized with lettering if you want. No 2 sets are the same.

That’s sexy. I may go that route after I figure out the lengths etc. Its my first real build from scratch.

 

[paradisePWoffrd]

Just for conversation purposes.... What about using something like a 2x6 box, 0.250 wall, turned on edge? Could taper the ends down to the joints. Could also window the tube for the shock mounts?

It could likely get dented, but would think the height would help it from getting bent.

 

[Van-go]

So I found some coil overs/bypasses I can grab out at KOH this year.
They are 2.0’s (ad says 2.5’s but I talked to the guy and he was off)
Will 2.0’s and bypasses be enough?

 

[Bebop]

Enough for what ?
A trail rig ? A race rig ? East Coast ? West coast ? Dairy hut run with the family ? Assault on Creampuff, wide open from the road ?

Gotta be more specific

 

[Van-go]

Enough for what ?
A trail rig ? A race rig ? East Coast ? West coast ? Dairy hut run with the family ? Assault on Creampuff, wide open from the road ?

Gotta be more specific

Haha
Definitely some cream puff assaults.
East cost trail riding and some hill killing. Maybe an occasional race.
I’ll likely stick with new 2.5’s and plan for bypasses in the future if I feel like I need them.

 

[Bebop]

Easy enough. If you build the rig, you can use 2 coilovers per corners to make the bypass mounts at the same time, since all 2,5 shocks have the same collapsed/extended length.

 

[slravene]

2.0 coil carriers and bypasses are absolutely enough for a trail rig.

2.0 coil carrier and 2.5 bypass is pretty much standard on most race cars. 2.0/2.0 is plenty.

There is a little more to it like tube placement, tube count, etc. but “generally” it holds true.