Classic & Vintage - Ishiwata vs Tange tubing

I have a 1988 Bridgestone MB-2 that I'm very fond of. I've spent way too much money upgrading it to the point where there is nothing I would change. The tubing is Ishiwata triple butted. I have enough decent parts left over from building up three mountain bikes that I can build up another frame. I wouldn't normally consider such a low end model, but I can get a 1991 MB-5 frame for $20. The frame is Tange MTB double butted. According to the Bridgestone catalog, the MB-2 weighed 28 lbs, and the MB-5 weighed 28.6 lbs. I don't think that's a significant difference, but weight isn't everything when it comes to frames. Is the Tange tubing inferior in some way besides weight to the Ishiwata tubing? Stiffness, for instance?

Somebody just bought it. Maybe posting here wasn't such a good Idea. :(

Sorry to hear the bike was bought, but I doubt that anyone here scooped you. Most of us here are more interested in road bikes, and you made no mention of where you found the bike.

It was meant as a more general question about tubing. What difference does it make if it happens to be a mountain bike frame? I'm into road bikes, too. My road bikes have Reynolds 531 frames. I was hoping to learn something about Japanese tubes.

I don't mind that the frame sold. I'll find something else. I don't have room for another bike, so I'll probably give it away after I build it.

Was it hard to figure out that it was on eBay?

For 20$, if I were curious, I would've bought it and found out. It's an old Peterson Bstone, and even the lower end of them seems to have some currency.

Both Tange and Ishiwata made some very nice tubesets. Tange best was I think Prestige, and then down in numbers 1, 2, 3 etc. Ishiwata's 022 is very nice, know from experience. I'd buy a bike built from either, tho the value is lower than comparable frames with Reynolds or Columbus.

It was meant as a more general question about tubing. What difference does it make if it happens to be a mountain bike frame? I'm into road bikes, too. My road bikes have Reynolds 531 frames. I was hoping to learn something about Japanese tubes.

I don't mind that the frame sold. I'll find something else. I don't have room for another bike, so I'll probably give it away after I build it.

Was it hard to figure out that it was on eBay?

Well, e-bay would have been on the list of places to check, but it could just as easily have been CL or a store, or a friend.

I wasn't trying to imply that people wouldn't know, or wouldn't care about your question because it was a MTB. I would have answered if I had personal experience with Vitus tubing. I meant to suggest that the odds of one of us here on the forum scooping you were low.

I don't have any experience with Vitus tubing, either. :)

This is borrowed from someone else,but 'you ride a frame, not tubing'. It's good to maybe know some basics,but mention 531,and people get all teary eyed.531 is nothing but the alloy designation for Reynolds manganese moly. It tells you nothing about the many butting configurations, let alone build quality. If it's better than hi-ten the differences usually amount to a few grams at the end of the day.