Bicycle Mechanics - Thinking outside the box

Greetings from the far side. I have been gradually learning about bicycle maintenance for the past couple of years by asking questions here, reading Sheldon Brown's web pages and hanging out in a couple of local shops.

I have recently felt the urge to learn more after a very successful re-gearing of my road bike. What I am thinking now is that solely for the purpose of learning more, I would like to take at least one of two older bikes I have and upgrade to newer components. I will likely be using some take-offs from things I have done to my roadie and some that friends have graciously offered up.

Some of the questions I anticipate having are:

what new parts/components can be installed on a bike like my 1971 Raleigh Grand Prix? or a mid 70s Schwinn Varsity?

can the old 10-speeds be converted to more gears? if so, how far can one take that? 18? 21? more?

can newer crank sets be installed on 70s era bikes? what's the limit; double ring or triple?

I'm sure there will be many more questions as I go, but those will get me started. Keep in mind I'm only doing this as an exercise in learning how to work on bikes; not to build some superbike. That siad, I will be using what-ever parts I can get free or dirt cheap. If something doesn't work I'll back out and try something else. :twitchy:

Some problems with bikes that old:

The original 5-speed rear dropout spacing was 120 mm. When standard 6 and 7-speeds were developed the spacing was increased to 126 mm and for 8-speed and up road bikes went to 130 mm and MTB's to 135 mm. Your old frames are likely 120 mm and will have to be "cold set" (aka bent) to accept wider hubs with out a struggle. Typically cold setting a 126 mm frame to 130 is considered easy, 120 to 130 not so much.

Your Raleigh had proprietary bottom bracket and fork steerer threading and won't accept the far more common "English" threaded bottom brackets and headsets. There are modern bottom bracket cups made to fit that threading by Phil Wood but they are very expensive.

I'm not sure about your Schwinn but if it has an Ashtabula crank, there are adapters that will convert it to take an modern bottom bracket. BTW, here are a couple of articles on the history of those early Varsities: http://sheldonbrown.com/varsity.html
http://www.cyclesportandfitness.com/the_varsity.htm

Finally, your Raleigh probably had 27" wheels and modern 700c wheels may not align with your current brakes if the pad adjustment range (4 mm lower) isn't sufficient.

I'm sure there are other mis-matches i haven't mentioned but these are the ones that came to mind.

Alrighty: great start then. I'll probably keep a compilation of notes so once sufficient and appropriate parts are gathered I will have some direction.

The note about width of rear dropout spacing has me wondering if there are narrower hubs available that might allow for more cogs in a rear cassette with minmal cold setting.

thanks.

A 120 dropout spread is good for building a wheel around an internal gear hub,
and you resolve the 27>700c rim diameter reduction , by combining a Drum brake in the hub as well..

can make for a good city/winter bike.

You could also build one of them into a single speed. SS's are simple and elegant to ride. My old UO8-peugeot SS conversion remains my favorite ride. You'll still learn about chain lines and gear-inches without taking on a cold set of the rear drops.

I just measured the rear dropout spreads; the Raleigh with 5spd RC is 120.6mm and the Felt F80 with 9spd RC is 127mm. That said, we are are only talking about slightly over 1/8" per side. Is it that difficult to spread that much without doing damage to the frame? I'm not arguing but asking, because I don't know.

And since you're thinking about other projects besides those old steel frames, remember you cannot cold set aluminum or carbon. Only steel can stand up to a cold set (...never considered titanium, tho)

I just measured the rear dropout spreads; the Raleigh with 5spd RC is 120.6mm and the Felt F80 with 9spd RC is 127mm.
The Raleigh is nominally 120 mm as above. What "speed" is the Felt now? It is either 7-speed or may have been made during the transition from 7 to 8+ speed hubs and the spacing was a compromise between 126 and 130 and would take both. Usually that would have been 128 mm though.


The note about width of rear dropout spacing has me wondering if there are narrower hubs available that might allow for more cogs in a rear cassette with minmal cold setting.
It is physically possible to cram an 8/9/10-speed freehub body onto a 126 mm hub but it leads to excessive wheel dish and a potentially weaker wheel. One of the major reasons for the increase in hub width as the number of cogs (and cluster width) went up was to keep the dish within reasonable limits.

The Felt is a 2005 year model 27-spd F80. (of course I'm not changing the Felt--just using it for reference) The 120.6mm of the Raleigh leads me to think a 7spd cassette may be possible with very little effort. How difficult would it be to add a granny ring up front? That would then make the 10spd into a 21.

7 speed cassettes are old gear, and not well supported by spares, anymore.
better to use a freewheel hub then.. you can still source 7 speed freewheels.

Hybrid, a 5 speed IGH, + a chain tensioner, front derailleur, and 2 or 3 chainrings
would be an interesting project.

Keep in mind, long term durability and/or replacement parts are not a high priority here; I'm just using this odd-ball project to learn more about working on bikes. This build might only see a hundred miles a year if my brothers come to visit and are energetic enough to want to go ride. The youngest of them turns 60 this year.

If you want to up grade it, dont be to ambitious. A 7 speed would be reasonable. The bottom bracket could be replaced using press fitted cartridge Bottom brackets. They are sealed, like a typical square taper, they just press in. They are commonly used if the bottom bracket shell is stripped.
Friction shifters will work, you could get some indexed gear on ebay.

A 120 dropout spread is good for building a wheel around an internal gear hub,
and you resolve the 27>700c rim diameter reduction , by combining a Drum brake in the hub as well..

can make for a good city/winter bike.

+1000

Give it a few more gears via IGH...and while you're at it, go drum brake, or drum brake plus generator. Why not increase the "utility" while you're at it?

=8-)

You didn't say what the spacing was on the Schwinn.

Does it have the 1 piece or 3 piece crank?

I've turned an old 10 speed into a 21 speed, but one needs to know what you have to see if it's worth trying.

I just measured the rear dropout spreads; the Raleigh with 5spd RC is 120.6mm and the Felt F80 with 9spd RC is 127mm. That said, we are are only talking about slightly over 1/8" per side. Is it that difficult to spread that much without doing damage to the frame? I'm not arguing but asking, because I don't know.

Hell no, it won't hurt the frame. I've straightened steel frames that were bent inches off to one side. Once everything was aligned, the bikes rode fine. Converting the Raleigh with a couple 700C "hybrid" wheels (8/9-speed, wide rims, 135mm width rear hub) is what I'd do if I wanted to be cheap... or put on an internal gear hub if I wanted to spend the money.

Here's 51 pages of upgraded older bikes to give you ideas.

http://www.bikeforums.net/showthread.php/361558-retro-roadies-old-frames-with-STI-s-or-Ergos

Dropout spread is what I imagine would be the real limiting factor, I just recently went to a 14 speed drivetrain on my 73 raleigh super course, so I'd say 21 speed is doable without blinking. Although I believe the PO did cold set the dropouts to 125.