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instant engagement hubs


ogre

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Very different design to the bearing clutch hubs, but I don't think they'll stand up to it either.

I'd love to be proven wrong and will be keeping a close eye on them, but I'd wager they won't be able to hack it.

Not too fussed about the immediacy of engagement - more interested in the lack of noise.

Would be a dream come true if I could have a silent hub.

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Hm... I find the sound of an Echo TR freewheel/Hope Trials hub soothing. I wouldn't want it to be silent at all. :) The instant engagement on the other side...

Drives me insane, slightly dreading the Jitsie freewheel I'm getting as they're supposed to be the loudest you can get. Saying that though at least I know it's working, with a silent hub I'd be scared of putting the power down too hard.

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Drives me insane, slightly dreading the Jitsie freewheel I'm getting as they're supposed to be the loudest you can get. Saying that though at least I know it's working, with a silent hub I'd be scared of putting the power down too hard.

Did you say Shimano? :D

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Ah sprag clutches, identical to the starter clutch on 99% of motorbikes.

Ask the owner of a big single, high torque (read open class supermoto/enduro bike) engine bike how long the starter clutch lasts? Mine completely gave up the ghost after about 7000 miles, it had been slipping for 4000 or so of those miles. I'll stick with my king thanks :)

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Ah sprag clutches, identical to the starter clutch on 99% of motorbikes.

Ask the owner of a big single, high torque (read open class supermoto/enduro bike) engine bike how long the starter clutch lasts? Mine completely gave up the ghost after about 7000 miles, it had been slipping for 4000 or so of those miles. I'll stick with my king thanks :)

No moto or bicycle conponent in world will be 100% reliable or failure feel for 100% of it's riding lifetime, but if it provides better performance reliability than the nearest competitor (let's say a Chris King or Hope PRO2), then give it a chance to prove itself. Is Steath the same as this

Stealth-Hub-Histroy-3-600x400.jpg

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Same as the 'anti reverse bearing' on a decent spinning reel. I envisage the hubshell being cracked by the force of the cams.

A sprag clutch is similar to a roller clutch, but instead of allowing each piece to roll freely, the cam shaped pieces lock into place when rolled in the opposite direction. Free wheel and the cams barely brush the inner surface of the hub shell, held down by the spring, but pedal and the cams lock into place instantly where ever they are. The other crucial difference is that according to my engineering friends who know a lot more about this stuff than I do, the more torque you place on a roller clutch, the more force is exerted on the hub shell. The sprag doesn’t work in this way, which should mean the absence of cracked hub shells and much lighter overall weight.
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But as the cam lobes wear it starts to slip, what kills them in motorbikes is the shock loading from trying to bounce a 100mm piston over 12-13:1 compression ratio. I personally can't see them lasting in trials, being a friction device compared to a positive mechanical lock.

edit:@ Rusevelt, the design works and is generally pretty reliable, however under certain loads it fails much quicker - in my example turning over a large bore, high compression engine puts such shock loading on the clutch that it soon starts slipping. This is a pretty good analogy for the forces imparted by trials riding.

Edited by forteh
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I'm not entirely convinced by this design. Like adam quite rightly mentions, the design looks like it would naturally try and break the outer race. Which if the outer race is pressed into a hub shell, it's new hub time if it breaks. It's probably ok for xc useage and BMX racing, but nothing more

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The forces have to go somewhere though...

Looks like a sprag does try and 'explode' the outer race to me - unless they are using something totally different. Even then the torque has to go into either radial or axial force.

image003.gif

Just remember seeing this prototype on Crewkerz facebook.

1924819_610765612344201_1448135868_n.jpg

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