vonfilm 

I have been trying to decide on a theme for a build up of my 1987? 58cm Schwinn Super Sport frame and forks. After a lot of contemplation I think I would like to experience the "magic carpet ride" of fat tires on 650b rims. I want to feel "like rolling on fast clouds".

I know the Super Sport has no eyelets for fenders, but it seldom rains around here anyway. Does anyone know if i could go up to the Grand Bois Hetres tires with this frame and fork? If not, how wide could I go?

nlerner

Time to do some measuring:

From Ed Braley's article on 650B conversions: "The widest part of a 650x38B tire is located 320mm from the axle center."

Check that point on your rear triangle and your front fork and see how wide you can go. There are several good 38mm 650B tires on the market, as well as the 42mm Hetre.

Neal

ColonelJLloyd 

I'm not familiar with the '87 model, but when I had an '81 Super Sport in the stand last summer I kept thinking to myself how it seemed to be a great candidate for a 650B conversion.

tugrul

I don't think a 1987 Super Sport would appreciate 650Bs

Iowegian

I just fit a 650B wheel into my 87 Schwinn SS frame and it looks like a tight fit between the chainstays. I didn't have a tire on there but I'd guess the max size that would fit would be 28 or possibly 32. If you put the wheel back farther in the dropouts you might get a bit more room but probably not much.

frantik

while we're talking about 1987 super sports.. were they made by panasonic?

tugrul

They don't have a serial number stamped into the front of the lower head lug, so I don't believe they are Panasonic made.

frantik

so they're made in the usa? or taiwan? (want to add this to my ad for the 87 SS frame, assuming not made in taiwan )

tugrul

There is speculation the Tenax frames were made in the Greenville, Mississippi plant.

rccardr 

...although at least some of them came with Made in Japan labels on the seat tube down by the Tenax sticker. Flimsy, came off right away...perhaps intentionally?

ColonelJLloyd 

My 1988 model Tenax-tubed Voyageur was built in Japan.

gabewill

I can't stress this enough. The Rivendell site has a good list of things to look for. Tire clearance, Brake reach, and bottom bracket drop are all important. This will change the handling, as geometric trail will be increased and fatter, softer tires will feel different. I was going to convert a Trek 420, but, the 75mm of BB drop on that frame would mean using 165 cranks. Also, would've had to buy extra extra long reach brakes. No Thanks!!

However, it's worth Measuring just to see what your options are. Good luck!

that_guy_zach

From what I understand, If its got the serial on the headtube its built by Panasonic. If not it was US built. This is for the Tenax frames though since I have never seen anything about Giant ( Taiwan ) building Tenax bikes.

illwafer

here's a dude that converted a 1982:
https://www.flickr.com/photos/olliean...th/4909045379/

vonfilm 

That 82 is certainly a beautiful Super Sport. The frame is different at least in the fact that it has eyelets for fenders. i don't know if it varies in other areas.

noglider 

Wow, that article Neal cited is fantastic. I now see why someone would want to do this. Until now, I was skeptical.

Now I want to measure all of my frames to find the best candidate.

Oregon Southpaw

I was pretty skeptical about 650b conversions, and fat tires in general, until I rode a sweet fat-frank equipped bike the other day. Now I'm looking at my 81 Voyageur with inquisitive eyes...

mudboy

I just wish there were some good but inexpensive 650b rims more widely available, such as the Weinmann ZAC19's. The least expensive 650b rims I have been able to find are the VO ones at $50 per rim.

Pete

noglider 

Agreed! And the tires aren't cheap, either. So it better work out well. It's a big investment. It may require purchasing new spokes, brake calipers, fenders, etc.

southpawboston

Yeah, I was skeptical as well, until I did my first conversion... wow, what a difference a fat, fast tire makes in terms of ride quality!

But as others have said, measure, measure, measure! The whole point of converting is to be able to ride really fat tires without altering the height or geometry of the bike significantly. Switching from 700x25 to 650x42 results in the bike that's only 2mm lower than before the conversion.

nlerner

You can still get the Zac19s--32-hole in silver for $24.93 each:

https://store.icyclesusa.com/rim-wein...50b-p2051.aspx

Neal

noglider 

Neal, you're really tempting me now!

vonfilm 

I measured approximately 320 mm from the middle of the rear dropouts and wrapped masking tape so that it's rear edge is at that 320mm position. I then took pieces of business card that were 41mm and 44.45mm(1.75") wide and placed them as far as they would go up the chainstays. It would appear to me that I would have room for at least 38mm wide tires. I had read that the Grand Bois Hetre's measure 40 mm at their widest. Maybe they would work if the axle was all the way back in the dropouts.

photo by vonfilm, on Flickr

photo by vonfilm, on Flickr

photo by vonfilm, on Flickr

photo by vonfilm, on Flickr

nlerner

I think you'll be cutting it close with the Hetres. Mine measure 41mm on Rigida Sphinx rims, and even only a couple of mm on each side is awfully tight. There are lots of fine 38mm 650B tires, including:

Pacenti Pari-Moto
Soma B-Line
Panaracer Col de la vie
Schwalbe Marathon

Neal

noglider 

Read the rest of that article.