[fluider]

Might be a stupid question I'm going to ask, so potentially excuse me.

I wonder why free-coaster BMX hubs did not spread into the full-suspension MTB? Anti-squat characteristics of rear suspension would remain unchanged however pedal-kickback effect of chain lengthening should be canceled. Yes, there would be some increase in size and weight of the hub but the mentioned advantage might be very interesting. Or am I missing some important fact?
What do you think about it?

 

[MrPlow]

wouldn't they be too fragile on their threads and also not engage quick enough?
( I know the concept but have never ridden one)

 

[jonKranked]

you sacrifice engagement, and some reliability (the kids I know with freehubs rebuild them more frequently than those without). But more importantly, the disengagement is not quick enough to offset pedal kickback, or to provide any real advantage. All the freehubs I've ever ridden had to be manually disengaged via a small pedal back-stroke.

 

[fluider]

wouldn't they be too fragile on their threads and also not engage quick enough?
( I know the concept but have never ridden one)

Slower engagement might be the issue. However I think there are enough quality designers and/or engineers able to design new standard for a durable product.

 

[jonKranked]

Slower engagement might be the issue. However I think there are enough quality designers and/or engineers able to design new standard for a durable product.

The real issue is that there's no tangible benefit to downhilllers; its a solution looking for a problem to solve. For bmx and street riders, yes, there are benefits (but also shortfalls) as a lot of them regularly ride fakie. When was the last time a downhiller needed to ride fakie?

 

[P.T.W]

Anti-squat characteristics of rear suspension would remain unchanged however pedal-kickback effect of chain lengthening should be canceled.

Iv just had a quick think an i could be wrong(its late an im tired), but i dont think a freecoaster would cancel pedal kickback an this is caused by the BB to rear axle distance lengthening. Hence "chain pull" the hub would pick this up as the same as pedaling an engage the clutch.
Like i said i could be wrong tho

 

[fluider]

Yes, BB-to-rear axle distance change is the cause of chain pull. Here, the rear wheel is virtually rotating backward. However with the standard freewheel mechanism; rear wheel rotating backward forces sprocket to rotate backward, too. The sprocket with wheel are the fixed end and crankarms are (always) free end. Hence, the missing chain length must be taken from the chainring.

But if we "un-lock" the sprocket from the rear wheel; sprocket doesn't rotate with wheel, missing chain length might be taken from the sprocket. Sprocket would become more free than crankarms because of rider's feet pushing against the crankarms. This is how I think about it.

 

[P.T.W]

Yes, BB-to-rear axle distance change is the cause of chain pull. Here, the rear wheel is virtually rotating backward. However with the standard freewheel mechanism; rear wheel rotating backward forces sprocket to rotate backward, too. The sprocket with wheel are the fixed end and crankarms are (always) free end. Hence, the missing chain length must be taken from the chainring.

But if we "un-lock" the sprocket from the rear wheel; sprocket doesn't rotate with wheel, missing chain length might be taken from the sprocket. Sprocket would become more free than crankarms because of rider's feet pushing against the crankarms. This is how I think about it.

Under compression the top run of the chain lengthens and something has to give...if your cranks don't move backwards your sprocket has to rotate forward to "feed" the top run,thus engaging the freecoaster.
My understanding is that freecoasters engage when the sprocket is doing the "driving" an disengage when the wheel is "driving"(in either direction).
Seems to me now that the engage/disengage action would also be quite variable due to changes in gearing sizes/ratios.
If you combine this with the suspension cycling,a chain bouncing round, wheel rpms rapidly changing and a changing bb to axle distance, you would have a freecoaster that doesnt know whether its coming or going.

 

[jonKranked]

My understanding is that freecoasters engage when the sprocket is doing the "driving" an disengage when the wheel is "driving".

Not really. All the freecoasters I've ridden you have to disengage with a small backpedal; most of them (when properly set up) don't disengage when you stop pedaling.

 

[P.T.W]

Cheers.....ive never ridden one,just going of what ive read.
That sounds even worse for a mtb aplication now

 

[fluider]

You're right PTW. It seems freecoaster would bring more mess than advantages.

 

[jonKranked]

Cheers.....ive never ridden one,just going of what ive read.
That sounds even worse for a mtb aplication now

I DO believe that you can set it up so that it will disengage when you stop pedaling, but the clutch mechanism will be so loose that it drastically affects how long it takes for it to re-engage when you start pedaling again. I messed around with a friends once, and we set it up super loose like this, and it was taking about a nearly quarter of a complete crank stroke (I'd estimate at least ~70°~80° of rotation) before it re-engaged.

 

[P.T.W]

You're right PTW. It seems freecoaster would bring more mess than advantages.

I hope I'm right...its 1am here an i should be asleep, so the ol brains a lil cloudy.
You should do some snooping round an look into the rear hub that the CVT Hondas had when they 1st appeared. Apparently the CVT would self destruct if the bike was rolled backward etc, so honda came up with a hub that sounds like a glorified freecoaster.

 

[jonKranked]

I think I'm right...its 1am here an i should be asleep, so the ol brains a lil cloudy.
You should do some snooping round an look into the rear hub that the CVT Hondas had when they 1st appeared. Apparently the CVT would self destruct if the bike was rolled backward etc, so honda came up with a hub that sounds like a glorified freecoaster.

Which gen of their transmission? I would guess the early ones? From what I heard 2nd or 3rd gen on was basically DIAB (derailler in a box).

 

[P.T.W]

The very 1st ones that had the linkage driven CVT transmission.
Ok not the very early prototypes,they had transmissions very similar to a motorbike...but the very 1st gen that the g/cross team used.
Ive seen a cpl of patent drawings of the CVT box an hub, but cant remember where....to tell the truth i wouldn't be surprised if the whole CVT thing was either never used in anger or just a big cloud of smoke to steer jo public away from what was really a very simple thing.

 

[FarkinRyan]

Not really. All the freecoasters I've ridden you have to disengage with a small backpedal; most of them (when properly set up) don't disengage when you stop pedaling.

Not true. A properly set-up and maintained KHE Geisha/Reverse will disengage instantaneously in pretty much every situation. Only time they don't is when they're brand new in my experience.

 

[demo 9]

I have a geisha MTB freecoaster and it EATS bearings, to the point that i just stopped changing them. i get about 30-40 minutes to a bearing

 

[jonKranked]

Not true. A properly set-up and maintained KHE Geisha/Reverse will disengage instantaneously in pretty much every situation. Only time they don't is when they're brand new in my experience.

Ah, that is not one I have had any experience with (as I hinted at in my post, my description was based on the ones I have used).

 

[FarkinRyan]

Yeah I figured that, jus' sayin' For the record; no one has used them on a duallie because it is a bad idea and would mean extra maintenance.

Demo 9 - Unless you weigh like 300 pounds that shouldn't be happening; something, somewhere is bent and in the only other Geisha I've seen that chewed through bearings like that it turned out to be the dropouts of the frame.

 

[Bicyclist]

Why not just run a rub with 2pt engagement?

 

[jonKranked]

Why not just run a rub with 2pt engagement?

Why bother with gears and chains at all?

 

[w00dy]

I have a geisha MTB freecoaster and it EATS bearings, to the point that i just stopped changing them. i get about 30-40 minutes to a bearing

Good god, you need to have that looked at. I have been on one for a couple of years with no issues.

To the original poster; Do you have problems with pedal kickback? If you're rolling forward with any amount of speed it should hardly be noticeable.

 

[demo 9]

Yeah I figured that, jus' sayin' For the record; no one has used them on a duallie because it is a bad idea and would mean extra maintenance.

Demo 9 - Unless you weigh like 300 pounds that shouldn't be happening; something, somewhere is bent and in the only other Geisha I've seen that chewed through bearings like that it turned out to be the dropouts of the frame.

How would it be the dropouts?how would i know? (i only ask because its a custom made frame)