General Category > Freewheeling
Helicomatic hub
robgul:
I've just bought an early Peugeot Triathlon bike and on taking the back wheel off found it to have a Helicomatic hub ... with a strange splined freewheel.
I can't understand how it all works with the lock ring etc, but that doesn't matter as I have some other wheels to rebuild the bike.
Sheldon has some harsh words to say about them ....
Just thought I'd share that with you - 40 years+ of messing with bikes and I've never seen anything like it before.
Rob
... oh, what do you reckon it would sell for on eBay ? ;D
Zoidburg:
The heliomatc works thus
The hub body is a fore runner of the cassette system we now know and love/hate(delete acordingly)
Its like an ordinary screw on hub with bearings in the same place, onto that is fixed a splined body that the freewheel goes on, the difference being from a cassette is that the splines are very fine and run in a helical pattern like the rifling of a gun barrel
You slide the freewheel over the splines and then use the knurled lockring to lock it in place, forward pressure on the drive train pushes the freewheel down against hub body ensuring a that the freewhhel stays put and doesnt attempt to come off on its own
The upside of this design is that the freewheel locking its self into the hub body under drive means that the lock ring will hold the freewheel in place safely with little more than finger tightening of the lock ring, this makes them very easy to change in the field with out any major tools
Sadly the whole system is a bit fragile as all the splines are too fine and the moving parts on too small a scale for them to be robust and reliable
If you upscaled it it would work very well indeed
Edit - They are a doddle to remove, just use a mole grip on the lock ring, you dont need a lot of pressure, its easy to see how it works once you take it to bits
robgul:
--- Quote from: Zoidburg on 23 December, 2008, 06:09:35 pm ---The heliomatc works thus
The hub body is a fore runner of the cassette system we now know and love/hate(delete acordingly)
Its like an ordinary screw on hub with bearings in the same place, onto that is fixed a splined body that the freewheel goes on, the difference being from a cassette is that the splines are very fine and run in a helical pattern like the rifling of a gun barrel
You slide the freewheel over the splines and then use the knurled lockring to lock it in place, forward pressure on the drive train pushes the freewheel down against hub body ensuring a that the freewhhel stays put and doesnt attempt to come off on its own
The upside of this design is that the freewheel locking its self into the hub body under drive means that the lock ring will hold the freewheel in place safely with little more than finger tightening of the lock ring, this makes them very easy to change in the field with out any major tools
Sadly the whole system is a bit fragile as all the splines are too fine and the moving parts on too small a scale for them to be robust and reliable
If you upscaled it it would work very well indeed
Edit - They are a doddle to remove, just use a mole grip on the lock ring, you dont need a lot of pressure, its easy to see how it works once you take it to bits
--- End quote ---
Indeed - I have the freewheel block off now .... you can see why it's so fragile ... the "splines" are very fine ... in fact they look slightly chewed on the one I have..... perhaps I can recycle the rather reasonable, low mileage by the look of it, rim.
Rob
Zoidburg:
I am a wee bit sad for knowing exactly how one works :-[
And how to take it to bits :'(
LittleWheelsandBig:
Helicomatic bearings are a little odd also.
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