5-speed downtube shifter

[ericonabike]

I have an old steel bike that I inherited from my brother - it's got nice lugs, thin fork and stays, a boss on the fork for the front light and an oiler for the bottom bracket [cute!]. It also has the original cottered cranks and 27 inch wheels. It has a five speed cassette, but at present I'm running it as a single speed by using cog no. 3 - a nice pub bike! It has a boss on the down tube for a shifter, but no other bosses at all - none for the rear brake cable and none for the gear cable. I'm thinking of getting it back to 5 speed, using bits in the garage, but the lack of bosses confuses me.

I assume that originally the gear cable was enclosed in the outer throughout, and attached by clips to the frame. Seems very friction-heavy, but maybe that's how they were? The boss for the gear lever though is round, rather than square. What kind of gear lever would have fitted it? the ones I have go on a square boss and have bare cable leading from them, for use with a brazed on cable stop on the chainstay.

[531colin]

It was the done thing to have Campag clips ....the brake cable ran along the top tube in outer all the way, the gear cable was bare and ran on top of the BB in a clip-on "tunnel".
Does the gear lever boss have 2 flats at the top?

[ericonabike]

Cheers Colin - curious way to have done it? Clips ruin paint! But no, the boss on downtube is round as a hound. no flats nowhere. It does have a bolt screwed into it, with a flat head about 2cm diameter, milled edge and with, oddly, BENELUX embossed on it. I'd assumed this was a blanking bolt put in by someone to cover the raw edge of the boss, but perhaps not?

[cycleruk]

You could fit one of these under the BB:-
http://www.sjscycles.co.uk/club-tour-bo ... -prod8628/

This one would need a tapped hole to secure but I have seen some that just use a plastic "plug" instead of a bolt.
Is there a cable stop on the chainstay?

Some systems had an inner and outer all the way from the shifter to the derailleur. The "stops" were integral with the shifter and derailleur.

[ericonabike]

No stops on chainstay nor anywhere else. It seems a particular type of downtube shifter is called for, with integral stop, then?

[PT1029]

Yes, gear lever mounting hardware (back plate) will need to have an outer cable stop on it to run an outer cable down the down tube all the way to the back gear. That's how it was done in them days.
If the bolt has Benelux on it, I'm trawling my early meories here, but there used to be Italinan bosses (lever, not Mafia), French bosses and English. For quite some years, Italian boses have become the standard, thus you may have trouble finding a lever to fit the boss. Certianly don't loose the Benelux bolt.
Worst case is a bolt on down tube lever. If the lever had no outer cable stop, you could fit a bolt on (inner) cable guide just above the BB shell, and a bolt on outer cable stop on the chainstay just infront of the RH drop out. That's how it was done in them days less a few years.
As frames have had brazed on cable stops for years, these bolt on stops aren't always easy to get hold of.

[531colin]

Campag bolt on fixes....http://compare.ebay.co.uk/like/290939978839?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&_lwgsi=y&cbt=y&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=63
brake cable clips, with outer
chainstay cable (outer) stop
BB cable tunnels

Benelux = Cyclo gear company, but all their levers I have seen wanted a square boss at the base of the lever.

[BigG]

Your Benelux gear lever boss will almost certainly be threaded 5/16" BSF whereas all modern levers are M5. Because there is little strain on the thread, you could probably get away with retapping it to M5, but a more sensibe option would be to fit a band-on lever just above (i.e. towards the headset) the present boss. My old Freddie Grubb which dates back to the 1960s has no braze-ons of any kind except a Campag rear drop out. it works fine with clamp-on parts all of which are currently readily available on ebay.

[ericonabike]

Thanks all. Gives the frame a bit of provenance, which is good. I suspect searching for an original shifter may be a fool's errand, and so a band-on one looks to be the answer. And can be supplied from my parts bin!

[thirdcrank]

The type of rear mech you eventually fit will also govern the type of lever you need.

A lot of deraileurs from that time had a fixed arm with the cage mounted on a rod, wrapped in in spring. Pulling the lever pulled the rod closer to the arm to select the higher gears, while the spring took it into the lower gears, and if the cable was badly adjusted or snapped, the cage tended to end up in the spokes.

Anyway, the lever for that type of mech had a much larger pulley than the parallelogram types which superceded them. It was about the size of an old ha'penny or a modern 2p. A modern lever won't pull enough cable OTOH, if only an old lever will fit, it will work a modern mech but pulling the lever half a millimetre will pull so much cable it will change 2-3 gears.

[Brucey]

Your Benelux gear lever boss will almost certainly be threaded 5/16" BSF whereas all modern levers are M5. Because there is little strain on the thread, you could probably get away with retapping it to M5....

5/16" is a tad large, no?

3/16" I'd believe....but BSW not BSF

BTW huret and simplex used the BSW thread -or something very close to it- for many years, and used bosses that looked round, but often had a location on the base where it wasn't quite round. Often their band-one levers could be disassembled and used on the braze-on bosses.

You can fit modified friction levers (and even some index ones) to old style-bosses, provided you use the correct screw in the boss. With a little modification you can make a shimano one fit I think.

cheers

[BigG]

Your Benelux gear lever boss will almost certainly be threaded 5/16" BSF whereas all modern levers are M5. Because there is little strain on the thread, you could probably get away with retapping it to M5....

5/16" is a tad large, no?

3/16" I'd believe....but BSW not BSF

BTW huret and simplex used the BSW thread -or something very close to it- for many years, and used bosses that looked round, but often had a location on the base where it wasn't quite round. Often their band-one levers could be disassembled and used on the braze-on bosses.

You can fit modified friction levers (and even some index ones) to old style-bosses, provided you use the correct screw in the boss. With a little modification you can make a shimano one fit I think.

cheers

You are probably right. The 5/16" was a slip of the keyboard. The BSF was as I remember it, but I think that a Whitworth thread was more likely.
Stirring my rather fallible memory, I drilled my old bosses out (8 mm I think) when I fitted my first parallelogram gear (Suntour VXGT) and araldited in M5 thread inserts. I no longer have the frame, but confirm that this was simple to do and worked very well.