Cycling UK Forum

Found this when giving the bike shed a deep clean (much easier now that the 5 bikes and 3 trikes have been reduced to an e-bike and a Spa Audax with too many memories).

No idea how or when I acquired it. It's stamped Cone Lock Pat appl.

I presume it dates back to when the first cotterless cranks came on the market. I wonder if these got that far.

Don't remember those.
I remember Gnutti cranks which seated on a spline on the axle, I think the cranks themselves were tubular steel, and I vaguely remember the TA Criterium cranks here https://hilarystone.com/cranksets.html which are a curious blend of cottered and cotterless, to our modern mind.

531colin wrote: ↑22 Jan 2024, 10:24pm Don't remember those.
I remember Gnutti cranks which seated on a spline on the axle, I think the cranks themselves were tubular steel, and I vaguely remember the TA Criterium cranks here https://hilarystone.com/cranksets.html which are a curious blend of cottered and cotterless, to our modern mind.

In what way are the TA Criterium cranks cotterless? I don't understand, they just look cottered to me.

I would say the drive torque is taken by the 90 degree angled interface of the crank and axle (like a quarter of a square ) and the tiny cotters (if thats the right term) are only there to wedge the assembly up tight. ....instead of using a tapered axle/crank interface.

I think Gnutti must have been a tapered spline, which sounds like a nightmare to make accurately!

531colin wrote: ↑22 Jan 2024, 11:04pm I would say the drive torque is taken by the 90 degree angled interface of the crank and axle (like a quarter of a square ) and the tiny cotters (if thats the right term) are only there to wedge the assembly up tight. ....instead of using a tapered axle/crank interface.

I think Gnutti must have been a tapered spline, which sounds like a nightmare to make accurately!

I'm not aware that Gnutti cranks had a tapered spline.
Never owned them myself but a chap in my club had them. He was very happy with them but a lot of people had problems.
My clubmate was of the belief that if the crank loosened and wasn't dealt with in short order the crank spline was damaged and the whole became useless.
They were being sold off cheap around the end of the fifties.
Basically a good idea if the correct materials were chosen.

Back in the early 1960s I had an Olmo bike with a Gnutti cotterless chainset. It had a three arm drive side crank and I'm pretty sure the splines were tapered. My cousin made me a special tool to remove the cranks.

531colin wrote: ↑22 Jan 2024, 11:04pm I would say the drive torque is taken by the 90 degree angled interface of the crank and axle (like a quarter of a square ) and the tiny cotters (if thats the right term) are only there to wedge the assembly up tight. ....instead of using a tapered axle/crank interface.

So, approximately speaking, it was a cotter pin in form but not in function? Ta!

Bmblbzzz wrote: ↑23 Jan 2024, 12:33pm

531colin wrote: ↑22 Jan 2024, 11:04pm I would say the drive torque is taken by the 90 degree angled interface of the crank and axle (like a quarter of a square ) and the tiny cotters (if thats the right term) are only there to wedge the assembly up tight. ....instead of using a tapered axle/crank interface.

So, approximately speaking, it was a cotter pin in form but not in function? Ta!

In a conventional cottered chainset, the cotter pins are the only thing that transmits torque, because everything else is round.
I think that TA set transmits torque via the odd quarter-square thing, with a cotter wedging the assembly up nice and tight.
Makes a square taper look like a really good plan!

Just my thoughts, I have never had one to bits!

Norman H wrote: ↑23 Jan 2024, 12:26pm Back in the early 1960s I had an Olmo bike with a Gnutti cotterless chainset. It had a three arm drive side crank and I'm pretty sure the splines were tapered. My cousin made me a special tool to remove the cranks.

ANTONISH wrote: ↑23 Jan 2024, 9:55am .............I'm not aware that Gnutti cranks had a tapered spline.
Never owned them myself but a chap in my club had them. He was very happy with them but a lot of people had problems.
My clubmate was of the belief that if the crank loosened and wasn't dealt with in short order the crank spline was damaged and the whole became useless..........

I don't see how they could have been tight on the axle without a taper?

Below seems to show an original extractor?

Doesn't a square taper sound nice and simple!

1952 Gnutti by bagheerabe, on Flickr

====================================================
I recognised the image of that TA "Criterium" crankset from some ancient recess of my memory but I didn't remember what it was called.

There is some info on Classic Lightweights which I thought was collated by couple of regular contributors to this forum

https://www.classiclightweights.co.uk/c ... ta-cranks/

Grandad wrote: ↑22 Jan 2024, 8:42pm Found this when giving the bike shed a deep clean (much easier now that the 5 bikes and 3 trikes have been reduced to an e-bike and a Spa Audax with too many memories).

No idea how or when I acquired it. It's stamped Cone Lock Pat appl.

I presume it dates back to when the first cotterless cranks came on the market. I wonder if these got that far.
........

I can see the conical bit, which presumably tightens the axle/crank interface....a bit like a quill stem expander.
How is torque transmitted? I guess the axle/crank interface isn't completely round ?

The BB ispindle - described in the Classic Lightweights link I think as"kite-shaped" is rather like a Kraft cheese slice - a sort of triangle with two straight sides and the third curved, which is where those fasteners bite

thirdcrank wrote: ↑23 Jan 2024, 4:05pm The BB ispindle - described in the Classic Lightweights link I think as"kite-shaped" is rather like a Kraft cheese slice - a sort of triangle with two straight sides and the third curved, which is where those fasteners bite

Thats the TA one, TC.....I can't see how the "cone lock" one works?

531colin wrote: ↑23 Jan 2024, 5:33pm

thirdcrank wrote: ↑23 Jan 2024, 4:05pm The BB ispindle - described in the Classic Lightweights link I think as"kite-shaped" is rather like a Kraft cheese slice - a sort of triangle with two straight sides and the third curved, which is where those fasteners bite

Thats the TA one, TC.....I can't see how the "cone lock" one works?

My misunderstanding about which one you were querying

531colin wrote: ↑23 Jan 2024, 5:33pm
Thats the TA one, TC.....I can't see how the "cone lock" one works?

From the photograph it looks as though the BB axle has two parallel flats.