kroozer 

Good morning, bikers. I just bought a 1971 Schwinn Super Sport for my son, and this will be his first road bike (what a clever way to feed my vintage habit). I’m planning to put the original steel Schwinn parts into storage, and replace them with alloy parts. The seat post appears to be steel, so I want to get an alloy post. Would anyone know what the diameter would be? (the bike hasn't arrived yet) Also, does anyone have any experience with the BMX US-to-European bottom bracket converters? Thanks.

Scooper

Schwinn part number 58 806. Seat Post 9" long, 1 1/16" O.D. chrome.

1/16" = 1.587 mm

25.4 mm + 1.587 mm = 26.987 mm

So, you could try 27.0 mm, and if that's too big, go with 26.9 mm.

Nothing's simple.

Scooper

As far as the one-piece Ashtabula crank conversion is concerned, Pastor Bob did that conversion with his Super Sport, "Sporty"...

He's probably preaching his sermon about now, but will likely chime in when he sees this.

Fissile

I own a fillet brazed Schwinn Superior, which is the same as the SS except the it has a threaded bb, forged dropouts with integral derailleur hanger.

The correct seat post for this bike 26.8mm I know because I bought a vintage Campy seat post in that size and it fits properly. Admittedly, this is no longer an easy size to find. My advice is to try eBay, that's where I bought my Campy seat post -- NOS from a seller in Italy.

Scooper

I agree; if 26.8 mm isn't easy to find, 26.9 mm is damn near impossible to find. Googling 26.8 seatpost, I got enough hits so you should be able to find one fairly easily.

pastorbobnlnh 

Sermon is done. And I have a break before heading to my youth program later. 26.8 is the correct size. Sporty wears a SR Custom Campy copy supporting a Brooks Professional.


The crank conversion begins with an adapter made by FMF or Truvativ, which is bolted into the over sized BB shell. Then it is hit and miss finding the correct length cartridge BB (I've never found a traditional BB which works in the adapter) to fit your crankset to the Super Sport frame. BB width is very dependent on the crankset, the the way the stays spread from the BB shell, and whether you plan to use a double or triple. Sporty has a 119mm Phil BB and runs a triple.

nlerner

+1 on 26.8mm. That's what my '71 Super Sport takes.

Neal

kroozer 

Thanks for the info, guys, I'll start the search for a 26.8. I just bought a BMX BB adapter from Asylum, and once I actually get the bike I'll start looking around for other parts. The bike will be for general use, so I'll probably get a double crank. I imagine I'll need to switch pedals also. Actually, I plan to switch out the entire drivetrain, to 70's era Suntour and SR. By the way, how much does an all-alloy Super Sport weigh? How do the frames themselves compare with lugeed chrome-moly frames? I got the bike because I think the fillet-brazed chrome-moly frames are pretty cool, but they deserve some lighter parts.

Scooper

The Sports Tourer and Super Sport fillet brazed frames are made with straight gauge (not butted) chromoly tubing, so they'll weigh a few ounces more than a lugged chromoly frame with double-butted tubing. The benefits of the straight gauge tubing (very dent resistant, super strong to carry all but the heaviest riders with ease) outweigh the slight weight penalty IMHO.

Pastor Bob thinks Sporty weighs 27-28 pounds with the alloy components including the triple chainring. Pastor Bob also removed the kickstand, which is surprisingly heavy.

You're right; they're pretty cool.

nlerner

My Super Sports w/ 27" alloy wheels, set up as a 5-speed, Truvativ adapter and 3-piece crankset, no kickstand, aluminum alloy seatpost, stem, and bars, and steel fenders weighs about 28 lbs.

Neal

67tony 

My newly acquired '73 SS, frame and fork only, weighs about 10 lbs.

I stripped it down and used a weight watchers food scale:

Kickstand 13 3/8 lbs. (380g)
Handlebars 12 1/4 lbs. (347g)
Stem & small bolt 7 3/4 lbs. (220g)
Cammed stem bolt 3 lbs. (85g)
Two brakes 7 5/8 lbs. (216g)
Seat post 5 5/8 lbs. (160g)
Seat post clamp 2 5/8 lbs. (74g)
Original crank (heavier than heck!)

jjhabbs 

If your trying to lighten up a supersport you may as well start with a new bicycle..LOL

Chrome Molly

25 lbs (excluding the tool bag), with the leather seat. Descends like it's on a luge run.

I like the fact that the frame is almost impossible to flex when climbing, grinding, etc. I've thought of making a cross bike out of one of these due to the geometry and great ride.

With the aluminum fork, the frame fork/headset was a bit under 9 lbs. The rest of the setup is an additional 16 lbs. With really light weight components, I could see getting the bike down to 23 lbs, but that might not mesh too well with the old school looks...

top506

26.8 Is what my current projects takes.
As soon as the graphics arrive from JR will I have something to show you folks!

Top

Fahrenheit531 

Resurrecting a zombie with new and, because we're talking old Schwinns here, conflicting information for future seat post researchers.

I just replaced the post on my '72 Super Sport. The 26.8 I bought based on this thread was too big. I exchanged it for a 26.4, and that worked out.
So either my old SS has .4mm of ancient grime inside the seat tube which throws these numbers off, or something changed for 1972.

Ahhhh, Schwinn. Nothing's ever easy, is it?

wrk101

+10 Nothing is easy on early Schwinns. By the 1980s, they did tend to get their act together.

What was the size of the existing post? Check out the gap on the backside of the seat tube at the clamp area. I find a lot of distorted seat tube tops where PO used too small of a post and clamped the crap out of it to "fit". I had a bike recently with a 25.4mm post where the bike should have had a 26.8mm. Needless to say, that took a while to straighten out.

I have also had bikes where PO forced in too large a seat post and POUNDED it in to fit. What a disaster.

Fahrenheit531 

The existing post was too small, but unmarked. At the bike co-op, when I took back the 26.8 along with the one I'd pulled, we figured that one to be on the small side of 26.0, and yes, the gap was certainly closed up a bit to accommodate the smaller tube. I expanded it to normal before trying to get the 26.8 in, but no dice... that would have required the "pounding in" described above, and while I do take some liberties with the old Schwinns, that would clearly be over the line.

Thing is, even the 26.4 was a tight fit. Took a bit of effort to get it in, rather than the smooth slide I normally expect. I wonder if 26.4 is the "just will fit" size, while 26.2 is the correct one? Either way, the 26.8 wasn't gonna happen.

Edit Re: 1980s: They didn't get their act together... the Japanese factories did!

Metacortex

Just to clarify this the stock seat post on the fillet-brazed '60s and '70s Schwinns (Superior, Sports Tourer and Super Sport) is 26.8mm nominal, however in actual use there are slight variations. I just measured no less than 7 original posts using digital calipers and they ranged from 26.75 to 26.95mm in diameter, with most being around 26.85. I test fit several original posts into a couple of bare Super Sport frames and they fit perfectly. I also test fit an XLC brand alloy 26.8mm post (which actually measured 26.75mm) and it fit slightly more loosely in the frame than the stock posts.

Mr IGH

Somebody installed too small of a post, then torqued it down and bent the tube in at the seatpost slilt. Use a screwdriver to open it back up and it'll be a 26.8mm.

Fahrenheit531 

Did that. Described it in #17 . Not 26.8, I assure you.

daf1009

As I am about to restore a Super Sport, this thread leads me to dread! Oh gosh...what am I jumping on**********

zazenzach

as others have eluded to, your seat tube is damaged. keep an eye out for cracking etc in the future. I have a '72 in cool yellow that im working on right now, bought a 26.8 uno seatpost from velo orange and it fits perfectly.

all super sports frames from mid '71 on are identical, so there should be zero variations. i also believe the 60s super sports use the exact same tubing, so the seatpost sizing should be identical there too. every thread i have ever seen suggests a 26.8 works for them.


its not really a big deal. there is some funkiness like the headset being BMX spec, needing to use a smaller diameter stem, and the necessity of finding a clamp on cable guide if youre gonna use a newer front derailleur. luckily all this stuff is available on ebay.

Fahrenheit531 

Huh. Mebbe I'll get a 26.8 and rubber mallet that sucker in there. Straighten things out.

wrk101

+10 The SS makes a good project. Not much special sizing wise, and an endless quantity of vintage Schwinn parts out there. You should enjoy this project.

Mr IGH

I assure you, it's 26.8mm, look closer...post some pictures...one thing it certain, it's not 26.2 or 26.4....