Originally Posted by
Rooney
There are certainly some here much more qualified to answer, but here's what I've learned:
The frame sets shared the same geo with the difference being the tubing. 5XX = Ishiwata, 7XX = Reynolds, 9XX = Columbus. I believe the tubing thicknesses were incredibly close, if not the same. I'd argue the greatest difference between these frames is the aesthetics of the tubing decals. This all pertains to the early TX series frames. The first number represented the tubing, the second number the style/geo of the bike, and the third signified the bike's groupset. This becomes clear as you look through the 77-81 Trek catalogs. Once you get to 82, they still adhered to that general system, but it became more nuanced as more models were added.
My comment about the 910 is solely based on the fact that I've seen far fewer 910s than 710s or 510s.
I was aware of this, but I mostly wanted to see how people liked the different tubing given the same size, geometry and builder. Basically: all other factors the same, which tubing do people like more?
I'm holding on to my 910, but I've wondered if I might prefer the ride quality of the Ishiwata or the 531. Hard to find them all in my size though, but I currently have all three in different sizes.
One last difference that does matter to me: the fork crowns. I love the nicer fork crowns on these, and I know later Ishiwata frames got the "death forks" with the unreinforced crowns. Not sure if those made it on 510s, but definitely on some 4xx and 6xxs that I've seen. Plus, they just don't look as nice without the cast "Trek" on there!