1975 Sky Blue Schwinn Sports Tourer

[momo608]

Probably the coolest looking Schwinn crankset ever. I'm doing a 73 I think, that has that crankset. The inner ring is rather worn so I'm going to replace it with a Takagi 41 tooth 130 mm BCD. It's on the way to me so I hope it works. I'm debating if I will cut out the addition spokes on the Takagi to make it look stock. I'll have to see it first.

http://www.ebay.com/itm/351621392343?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

 

[Metacortex]

The inner ring is rather worn so I'm going to replace it with a Takagi 41 tooth 130 mm BCD. It's on the way to me so I hope it works.

Unfortunately that ring will not work. The Nervar cranksets had a unique 128mm BCD 40T inner ring. Those rings are very hard to find individually.

The even more rare version of this crankset used by Schwinn on the early to mid-'71 Sports Tourer had a 90mm BCD inner ring with only 36T:

 

[momo608]

well that sucks! I did measure it but that requires some eyeballing. I guess I need to get my eye ball calibrated. Thanks for the bad news I guess! Unfortunately not the first time I had parts coming that I knew were wrong before they got here.

 

[Schwinn499]

Here are some pics I snapped while tinkering yesterday.

The middle saddle is the one that was on it with two saddles off of 77 and 78 Superiors that I now have B15s on.

 

[momo608]

Were these cranksets anodized? Mine sure looks like it wasn't.

I have been spoiled on most of my bike projects so far, found NOS chainrings or the steel ones I had all looked very good as far as wear. I did a google search on worn chainrings. What I have looks pretty good compared to what I'm seeing as examples of worn chainrings. A excellent 40t chainring for this is going to be hard to find. I wonder if it was a Schwinn only size?

 

[Metacortex]

Were these cranksets anodized? Mine sure looks like it wasn't.

They were not anodized and as such can be polished up very easily.

A excellent 40t chainring for this is going to be hard to find. I wonder if it was a Schwinn only size?

That same crankset (less the "Schwinn only" inner guard) was available from Nervar and was also used on other makes and models, You can see the Nervar catalog page for that crankset here: http://www.velo-pages.com/main.php?g2_itemId=5844

From the catalog page you can see that the inner ring was available with 38 to 48 teeth (Schwinn and many others used 40T) and the outer ring was available with 46 to 54 teeth (Schwinn used 54T, most others used 50 or 52T).

 

[Eric Amlie]

Thanks for that catalog link Metacortex.
I have a Nervar Star crankset that I've been looking for a 50t ring to replace the 52t that's on it now. All that I've seen on Ebay are 52t rings so I was beginning to think that that's all that were available. Now I know that a 50t was available. I will keep looking.

 

[momo608]

Thanks for that catalog link Metacortex.
I have a Nervar Star crankset that I've been looking for a 50t ring to replace the 52t that's on it now. All that I've seen on Ebay are 52t rings so I was beginning to think that that's all that were available. Now I know that a 50t was available. I will keep looking.

We're kind of stuck on the chainring size so they look right with the guards. You wouldn't think a one or two teeth difference would change the size much but it does.

 

[Metacortex]

We're kind of stuck on the chainring size so they look right with the guards. You wouldn't think a one or two teeth difference would change the size much but it does.

Very true. One option is to simply eliminate the guards. Schwinn deleted the outer guard on the '76-'78 Superior. The inner guards can be replaced by spacers as found on the standard (non-Schwinn) Nervar cranksets. With the guards deleted any of the available size inner and outer chainrings could be used.

However if the guards are desired then there is some flexibility since the guards were built in two sizes. The Schwinn-only inner guards were produced in versions for 36T (1971) and 40T (1972-'78) chainrings, and the outer guards were produced in 52T and 54T versions:

Unfortunately the guards might be harder to find than the chainrings!

 

[momo608]

Good advice, but it kind of ruins the best looking crankset ever thing. Those guards are what makes it. I have a 42t coming, I'll put up a photo of it in place when I get it.