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J Arms / 7 Open /7s


Well-Known Member
1.Searched the site and didn't find anything on JArms. Point me in the right direction if I missed a thread.

2.What is the advatage of J Arms over A arms?

3.Does it apply to a 7s or 7open truck?

Better yet, I have a toyota tacoma rolling chassi that I am building into a 7s or 7 open race truck for next year. (I hope :O) ) Only planning to run a few races, just starting out and limited budget.

What is the prefered Toyota front suspension set up for 7s? (stock gusseted lowers with custom uppers running ball joints, uni ball, ATS, Chaos, Custom, you get the idea)

What is the prefered Toyota front suspension set up for 7open?
Custom A arms running uni ball, J Arms, stock pivots (nope), center mounted lowers, ect, you get the idea.

I know, large order, but thanks for all the info. I'm trying to get a clear, educated idea of what to build. I haven't decided what rules to follow yet, 7s or 7open. But thanks to Hanna Quality in SLO, I have unlimited fab resources cause the owner is my best bro.

Erik from Deaver says he like the J Arm setup on his Yota from the BajaShop. 62s on the way from Deaver for the prerunner/chase/test truck. Thanks for all the info Erik, Jeff hooked me up, (I think)

attached a pic, thanks




- users no longer part of the rdc family -
Can I be dumb for a second and put in a useless post?

What are J-arms? I don't know much at all, I'm trying to learn, but I've never even seen an explanation of what they are. I think I've also seen them mentioned in conjunction with I-beams/radius arms?? I'm kinda confused...

David - No one of consequence.


Well-Known Member
I pulled this picture out of the skunkz on here. This is the j-arm that is on the Stewart Raceworks truggy. Mind you this is one of the top quality ones that would be out there. As far as why they use them, they give you a ton of room to mount by-pass and coil over shocks to the lower a-arm.


John Bitting

Bislam when referring to j-arm on TTB basically the radius arm is welded to the i-beam making the shape of an L of backwards J.


Well-Known Member
I think he is refering to the uper control arm of a double wish bone. But you change the shape of it to have both of the uper frame mount to the front. The advantage is this is the only way to make these arms longer (they can almost touch eachother in the midle) with out moving the moter way up or puting it in the back. So yes ther is an advantage, not sure what is legal for the classes.


- users no longer part of the rdc family -
Ok - that's what my guess was. I had seen it in reference to getting more travel, but if you bend the J-arm you hafta replace more, or something, so I had assumed that that's what it was. Thanks for clearing it up!

David - No one of consequence.


Well-Known Member
josh, i finished your springs today, they should ship out tomorrow. ill let you know tomorrow if they went out.



Well-Known Member
First read the rules of this two classes:
7 Open (Unlimited ).- You got to have the stock type front suspension on (A arms, J arms, I beams, McPherson, etc.) but can be custom made , wider, stronger, heavier, full tube, gusset. It only have to be stock type by the made but you can have also custom made your mounting points.
7S (Stock).- You must have the stock type front suspension on (A arms, J arms, I beams, McPherson, etc.), you can reinforced the suspension only but not custom made, and not altering the stock geometry of them and you must have the stock mounting points (Only reinforced).

Try read or copy the rules from the Best in the Desert Page, they have it and are practicle the same rules that SCORE.

Mexican PreRunner