60/40 Birfeild + 80 Inner

[cruisermatt]

Can a 60/40 birfeild attach to an 80-series inner axle if they are both aftermarket 30-spline versions?
Obviously this won’t work with the stock parts (27 spline/24 spline)

The only issue I could think of would be the spline length on the inners or the snap ring location not being exactly right... haven’t seen it done though.

 

[mudgudgeon]

What's your aim? 80 birf is stronger/larger than 40/60

 

[cruisermatt]

Aim is to potentially widen a 60 axle on both sides and use off the shelf 80 chromo inners with chromo 60 birfs (which will be strong enough for what I need).
I like the 60 steering knuckle enough to justify the slightly weaker birf.

Just some background on my still unanswered question.

 

[GLTHFJ60]

In theory, yes, they should work together. The spline diameter, tooth pitch, and everything should be the same. Only thing to worry about is whether or not the star gear is the same thickness on the 80 and 60 30 spline birfs, which would dictate the depth of the inner snap ring relative to the stop.

Long story short, haven't seen it done.

 

[cruisermatt]

In theory, yes, they should work together. The spline diameter, tooth pitch, and everything should be the same. Only thing to worry about is whether or not the star gear is the same thickness on the 80 and 60 30 spline birfs, which would dictate the depth of the inner snap ring relative to the stop.

Long story short, haven't seen it done.

Cool, thanks. Will post results eventually.

 

[White Stripe]

Maybe you already know this but Trail gear actually has a lot of axle shaft specs on their website. Just a quick look shows I think if I'm reading it right that a 80 series short shaft is only marginally longer than a 60 series short shaft by 3/4". The other issue possibly is the seal surface to birfield distance. They show those measures on the trail gear site too but I didn't look at it long enough to confirm this. But I would think the seal area is likely at a different point on a 80 since the birfields are bigger. I widened the short side on my fj60 housing, I wish I had widened the long side as well, but I was strapped for cash at the time. Looking back, it wouldn't have cost me much more time and labor. What's critical though I think is trussing the housing carefully without warping it. U will have a lot more housing sticking out beyond the leaf springs. Kind of fun fabrication to do in my opinion and should be a nice setup.

 

[cruisermatt]

Maybe you already know this but Trail gear actually has a lot of axle shaft specs on their website. Just a quick look shows I think if I'm reading it right that a 80 series short shaft is only marginally longer than a 60 series short shaft by 3/4". The other issue possibly is the seal surface to birfield distance. They show those measures on the trail gear site too but I didn't look at it long enough to confirm this. But I would think the seal area is likely at a different point on a 80 since the birfields are bigger. I widened the short side on my fj60 housing, I wish I had widened the long side as well, but I was strapped for cash at the time. Looking back, it wouldn't have cost me much more time and labor. What's critical though I think is trussing the housing carefully without warping it. U will have a lot more housing sticking out beyond the leaf springs. Kind of fun fabrication to do in my opinion and should be a nice setup.

Great thoughts on the seal details, hadn’t considered that at all. And no, I wasn’t aware of the axle info front TG. Thanks.

 

[White Stripe]

Trail gear has a off the shelf 30 spline shaft that works for the short side if you use the 4plus spacer. It's 120.00 bucks. If u use a 4plus on the long side I'm not sure they have a shaft in stock that would work. A custom length shaft may be needed which is a bit more expensive from trail gear but not bad.