Hot Rods TT and AA rails

Hey guys,

I’ve seen lots of cars over the years using AA and TT frame rails with model A cross members and the rear trimmed and modified to be a hot rod frame that has a similar profile to a 32 frame rail.

What I’m curious of and can’t seem to find is if the rails have the same profile? Are the frame rails basically the same?

Looking at photos online they look similar, the T might be shorter after the rear most cross member but there seem to be multiple wheel bases available for the big trucks so maybe I’m just seeing different wheel bases and not comparing apples to apples?

the TT frame all together is clearly narrower and more parallel just like the T as compared to the A/AA but if your just using the rails that wouldn’t matter.

anyhow figured someone here may have some first hand knowledge they could share

thanks in advance

 

Here’s a shot of @NoSurf coupe on AA rails and a bump to the top @MrModelT maybe you have some incite to this?

 

Because they use the same sheet metal, wishbone(close, anyway), spring mounts, front crossmember, & steering, the AA & the A frames have the same linear dimensions, a least back to the transmission crossmember, although the material is heavier & the depth of the frame is greater in the AA. The back of the AA frame can be modified to fit whatever suspension/body style/wheelbase you're using, & probably wouldn't need to be "boxed" to be strong enough for almost any modern motor combination.

 

The frame of the TT cab and frame I bought a number of years back and cut the frame up because it was so twisted from a wreck that it wasn't usable had a frame that was freaking heavy. I'd say if guys are actually using those rails they are because they are seriously stout along with having a decent profile from the side. I was over twice as strong as I am now and I could barely lift the rear spring to stick in in the back of my truck to haul it for scrap. Sections of the rail weren't light either.

 

Didn’t get notifications that you guy had replied!

yes! They are mega stout with beefy rails and they have a nice looking side profile that is taller than a standard A or T.

im curious if the front section of the frame rail has the same dimensions regardless of tt or aa or if they are really close?

my main reason for asking is if they are more or less the same in the front section that a hot rod would use it opens up the year range of possible donors by quite a lot

 

The front frame would be the same although the front crossmember may need to be changed out to a passenger car one.


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I built a low slung T on TT rails (which now just sits in parts in storage). They are shaped like 32s, sort-of, with no reveal (obviously) and they're really heavy duty. The TT rails are different than AA rails.

 

@-Brent- any chance you have a clear photo of the rail from the side in your archives?

I can find side shots of AA rails easier and figured then I could just post a side by side comparison and we wild all know how close they are to each other in shape etc.

 

Here's some shots of an AA and BB frame combined. It took some work but the two together made for a pretty neat side profile. They were cast offs and scrap pieces, I was unemployed so we made a good time out of it......







This little Farts 17 now and workin' on his own stuff.

 

Best I can do, right now. This is after it was chopped up, shortened, modified for A running gear, etc. That taper of the TT rails is one of my favorites but it's so dang heavy. Not as heavy as my current A chassis... but it's no little T lightweight.

I should get this roller mocked together, again.