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Tensor Cycles Darlington - chainset question

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Tensor Cycles Darlington - chainset question

Old 11-05-08, 05:06 PM
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Tensor Cycles Darlington - chainset question

I have an old (1978-80 at a guess) frame with some components that originally had the head badge "Tensor Cycles of Darlington, England", "Made in West Germany" stickers on the sides of the top tube and model name "Sport" on the down tube. I can't get to it tonight to post pictures. It was originally red metallic with black bands but has since been resprayed (by me) in purple/silver fade.

More details: It is steel, possibly high tensile and seems to be a low-end frame. The rear brake bridge is a flat plate cut in the shape of an "S", it has a fitting on the left seat stay for a lock or reflector (not present), pointed lugs, but these may be cut away plain tube sockets. Original equipment was a chromed steel "Thun" double chainring chainset with Huret zinc-plated front & rear mechs, downtube band-on double gear levers, Weinmann alloy sidepulls & levers (no hoods present), flat plate horizontal drop-outs, alloy drop bars & stem, Wrights leather saddle, plain steel seat pin, steel 27" X 1 1/4" wheels on plain nutted small flange alloy hubs. The rear derailleur cable housing runs full length from the lever to the mech.

The chainrings seem bent and are missing a spacer. The outer ring is fixed to the crank, the inner bolts inside it. It looks a bit like a Schwinn/BMX bottom bracket arrangement, where the right crank is fixed to the BB spindle with the right cup captive and the left cup has a nut on the outside of the cup around the spindleto hold the cup in place. Both cups are zinc plated thin metal and are free to rotate around the BB shell. The shell is a larger diameter than normal. There are no internal threads inside the BB shell. The left crank fits on the spindle with a cotter pin.

Since this is such an obvious cheapie, with no braze-ons to hack off, and easy to reinstate, I'm thinking of using the frame for an experimental single speed, using old parts I have lying around. However, the chainset & bottom bracket are a problem as all my other chainsets are conventional square taper alloy cotterless units.

1) Can I find a square taper axle to fit this junker?

2) is there a cheap conversion to enable me to fit a standard BB set?

3) I've thought about cutting the BB shell out of a crashed frame I have (bent top & down tubes, front impact), grinding off the lugs to fit it inside the Tensor's shell, with a good coating of epoxy and a couple of rivets to locate it. Is this likely to work, if not, why not and has anybody got a better cheap (or free) idea?

Sorry about the lack of pictures, might be a while yet. I'd appreciate your thoughts, ideas and expertise.

Best regards,
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Old 05-14-23, 04:26 AM
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I have a very sturdy 1988 Tensor 'Elite' 3 speed gents model.
Though it's a low end bike, it is well made and rides well.
They seem to be much maligned, but I've had mine over 20 years without any problems.
From what I can tell, it's as good as a similar range bike from anyone's catalogue of the period.
A proper, practical utility bike.
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Old 05-14-23, 07:16 AM
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as regards the Thun bottom bracket assembly this image shows the parts of a cottered version

most of the ones of this type found on european cycles were produced either by Thun or by Agrati

if you look closely at the non-drive side arm you may discover that what appears to be a crank cotter is actually a pinch bolt. in such design the spindle end is splined as here:

the cycle's Huret gear ensemble is likely to be the Challenger model which launched 1974:



in the U.S. readers of "a certain age" will recall the Tensor name as something associated with small high intensity reading lamps of the early 1960's, produced in a variety of models and colours.


Last edited by juvela; 05-14-23 at 07:31 AM. Reason: addition
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