Why do JBA UCAs fit with 255/85/16s on my stock TRD OR wheels

On the JBA site Marlin says 4.5” backspaced wheels are necessary to use these wheels with this tire size. But I threw on my test fit tire wheel combo and it looks like there’s at least 1.25” clearance between the arm and tire. And unless I’m measuring wrong, these have 5 1/8” BS.

Am I overlooking something? I haven’t driven the truck yet as I need to bolt the other side up. But with three corners of the vehicle’s weight on wheels and tires, and the DS front on a jack stand, there seems to be plenty of clearance...

 

Try asking here.

https://www.tacomaworld.com/threads...-and-suspension-mega-thread-bs-thread.364484/

I think stock Trd OR wheels have a backspace of 4.7ish.

That's what I came up with using this formula.

Wheel width /2 + backspace + 1/4 in.

7in wide wheel and 25mm backspace.

I think I'm correct but not 100% sure.

I'm going to get some JBAs and was wondering if I'll need spacers for 255.

 

The tires might hit the uca when the tire is turned all the way. Although with a 255mm wide tire you may be okay. The JBA arms don't seem to have as much clearance as other aftermarket arms.

 

I measured the backspacing last week. I put a straight edge across the back of the wheel and measured up to it from the mounting surface and it was 5 1/8”

 

OP - Please show us some pics and let us know how it turns out. I'm actually not surprised. JBA is probably being conservative because different wheel designs can vary in terms of where they will cause interference despite similar specs.

 

I’ll do that later today.

On a side note, I over tightened the ball joint bolts (the four that fasten the bolt to the arm) and snapped one. I was thinking of replacing them with stainless steel but maybe that’s a bad idea? Should these be grade 5? I forget how to read the lines on the bolt head. There are three. I’m going to start a new thread with this question as well.

 

Three lines is grade 5, yes. https://www.nutsandbolts.com/v1-bolt-grade-markings.html

Stick with the same grade, it what the manufacturer designed for in terms of tension and shear strengths as well as stretch, etc. You should be safe with using stainless in the same grade in this application.

 

This^^^
The tires will likely rub at the front of the UCA when turned all the way.

 

OP, how did the JBA's work out on stock wheels? I am wanting to go this route with 255's as well.

 

Skinny 33 should not hit anything.

 

Nice, thanks

 

How did this work out? Curious minds want to know?

 

I was looking at the JBA UCA’s but I had questions about fitment.

I’m running 255/85r16s on ‘19 trd pro wheels w/ 1.25” spidertrax.

Are these jba’s going to fit or am I going to create a headache for myself?

(More of a headache lol)

 

I think you’ll be alright having the spacers.