clutch for a bike?

[Zipperhead]

"My trike puts the drive to whatever wheel is turning the slowest - so if one slips (as on snow f'rinstance) it just transfers to the other."

And when one lifts e.g. off road ALL the drive goes to the one in the air! First (and only) longish ride I did on my Rogers my CTC "friends" - accidentally I'm sure - led me along a bumpy track. They rode along the one-wheel width groove while my two driven wheels were bouncing along 6" higher than the front...

Er, no. The drive goes to whichever wheel is going the slowest. If I'm being stupid I can ride along with one back wheel in the air, pedalling away happily and the driven wheel is the one on the ground.

Obviously, being such a salad dodger I don't do that, 'cause it's a bit of a strain on everything.  

Edited to add: Of course anybody who goes off road on a trike is probably on first name terms with the staff at the local funny farm. It's scary enough on roads!

[Euan Uzami]

Why would that be better than 50" fixed, 70" free?

'cos descending the Horseshoe Pass, or Ventoux on 50" fixed would be agony.  Or just very slow.

I figured most riding would be done fixed - when you get tired, or it gets hilly, the freewheel would come into it's own.

  yeah but that's why you'd have the 70" freewheel ...   ...surely?
climb it on the 50" fixed, then when you get to the top, put it in freewheel mode and coast down the other side. bliss.
Or do you see enforced spinning as an important advantage of fixed, rather than just better climbing due to lack of deadspot?

you can spin out on 53x12 (certainly the south side into llangollen) on the horseshoe pass so you might as well just get into an aero tuck position.

[Greenbank]

If you're just going to be freewheeling on the descents then it doesn't matter what sized gear freewheel you put on it.

70" fixed for the majority of it, with the intention of climbing and descending using that same gear.

The 50" freewheel would only be deployed if you were tired enough that you couldn't climb or descend using the 70" gear. I've climbed Ventoux with a 40" lowest gear (39x26) so a 50" gear wouldn't be too hard for someone used to pushing a 70" gear up big lumps.

Intending on starting out climbing in 50" fixed isn't in the spirit of things.

[mrcharly-YHT]

My trike puts the drive to whatever wheel is turning the slowest - so if one slips (as on snow f'rinstance) it just transfers to the other.

Interesting, that's the exact opposite of how most diffs work.  What trike are you riding?

What's it like cornering? Do you have to back off on the pedalling?

[Zipperhead]

My trike puts the drive to whatever wheel is turning the slowest - so if one slips (as on snow f'rinstance) it just transfers to the other.

Interesting, that's the exact opposite of how most diffs work.  What trike are you riding?

What's it like cornering? Do you have to back off on the pedalling?

It's a Longstaff, but it doesn't have a diff it has two freewheels, one for each rear wheel (which is why it behaves in an opposite manner to a diff). Cornering is no problem, well no more of a problem that on any trike  , the only time I notice it is if I try and turn *really* tightly at low speed when pedalling gets very hard.

[Zoidburg]

My trike puts the drive to whatever wheel is turning the slowest - so if one slips (as on snow f'rinstance) it just transfers to the other.

Interesting, that's the exact opposite of how most diffs work.  What trike are you riding?

What's it like cornering? Do you have to back off on the pedalling?

It's a Longstaff, but it doesn't have a diff it has two freewheels, one for each rear wheel (which is why it behaves in an opposite manner to a diff). Cornering is no problem, well no more of a problem that on any trike  , the only time I notice it is if I try and turn *really* tightly at low speed when pedalling gets very hard.

I have had a go on Gordy's and it has the same arangement

Without seeing one its hard to get your head around the arangement but it is quite simply a metal tube linking two freehub bodies both facing the same way.

[Euan Uzami]

If you're just going to be freewheeling on the descents then it doesn't matter what sized gear freewheel you put on it.

70" fixed for the majority of it, with the intention of climbing and descending using that same gear.

The 50" freewheel would only be deployed if you were tired enough that you couldn't climb or descend using the 70" gear. I've climbed Ventoux with a 40" lowest gear (39x26) so a 50" gear wouldn't be too hard for someone used to pushing a 70" gear up big lumps.

Good point... although for the 70" freewheel i was thinking of your common or garden pedally descents.

However, another mechanical point is that if you could engineer a hub to be able to switch gear AND switch from freewheel to fixed, on the fly, might it not be the case that you would have all 4 combinations, i.e. 50" fixed, 50" free, 70" fixed, 70" free?
 I don't know how the switching between 50"/70" would work on fixed, it might be dangerous, and I'm not sure the necessary gubbins (thinking along the lines of a rohloff) would fit into the hub as well as the clutch assembly, but if you could do it, then you might have all the options.

Intending on starting out climbing in 50" fixed isn't in the spirit of things.

  that's just the typical bloody minded psychology of a fixed rider  

the whole point of this "invention" is to cheat...  

[clarion]

I don't do things in 'the spirit'.  I want an easy life

[rogerzilla]

Technically, all bikes except fixies have clutches, since a freewheel is a unidirectional clutch.  Sturmey-Archer 3 speeds have three clutches (two freewheels and a sliding dog clutch to select the gears).