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Bmx Question


ben.richardson

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If it freewheels forwards and backwards, how does one pedal? Is there a way to engage it?

Basically your pedaling along, and then to disengage the hub (enable it to freewheel backwards) you do a slight backwards pedal. It's not disengaged so you do your trick, roll along real far backwards :P, and then it's time to engage it again. To do this you simply put in a small crank, it will be like having no chain on for about 1/8th of a turn (called the 'slack') and then it will be engaged and give resistance and pedal as normal.

On most freecoaster hubs this 'slack' can be adjusted. Although you may wonder why someone would ever chose a larger slack, it means that they dont assidentally engage the hub as easily- particularly when doing tricks such as a hop in the rollback. This would obviously flip them onto their back and if it's a high speed rollback could be very nasty :).

I have a KHE Geisha Street Freecoaster which is sort of leading the market and i love it to bits! I just snapped the axle but a new, redesigned and stronger axle is coming out in a few months so hopefully that should sort out the problem.

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Yeah it's because they run a freecoaster, works on a clutch kind of system which disengages when you roll back.

yep. all the ones i have used have been commpletely crap though

Weren't you running a Geisha street? haha scrap that, too late.

Edited by huck_it
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take you chain off. thatll let you roll backwards without pedalling ;)

Dont do this!

If your used to going backwards with a chain and backpedaling, then keep the chain on otherwise you will think you still have a chain, try to spin it round with pedal pressure and absolutly annihilate your knee on the stem. Hurts, ALOT! haha

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Dont do this!

If your used to going backwards with a chain and backpedaling, then keep the chain on otherwise you will think you still have a chain, try to spin it round with pedal pressure and absolutly annihilate your knee on the stem. Hurts, ALOT! haha

i rememebr trying to sidehop over a bench without a chain. I knew it wasn't there and had been riding without one for an hour. Still pedalled. f**ked myself. Tried again, f**ked myself, tried again, f**ked myself, tried again did it! yay! What a tool!

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so do they work like a centrifugal clutch like a mini moto? the turning force of you pedaling causes the "clutch" to expand out and push against some sort of drum inside the hub but when your not pedaling it doesn't expand, so it doesn't engage.

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If anyones spotted this in any Aaron Chase videos (I know I did) then he's able to roll backwards without pedaling, yet runs gears, because he uses a smoothed off toothless gear on his cassette, so that when you change into that gear, the chain just slides freely around it, and upon changing back to any other gear you get full, normal engagement. Tis the way forward for geared street! I mean, why not, who really needs all 9 gears! :D

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so do they work like a centrifugal clutch like a mini moto? the turning force of you pedaling causes the "clutch" to expand out and push against some sort of drum inside the hub but when your not pedaling it doesn't expand, so it doesn't engage.

sort of but not quite.

it's a clutch system but not centrifugal.

basically there's a big lump on a thread - when you pedal forwards the lump rolls up the thread and connects with the hubshell which gives you the engagement. when you roll back the lump shoots the other way down the thread and disengages with the hubshell

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sort of but not quite.

it's a clutch system but not centrifugal.

basically there's a big lump on a thread - when you pedal forwards the lump rolls up the thread and connects with the hubshell which gives you the engagement. when you roll back the lump shoots the other way down the thread and disengages with the hubshell

Ah I see......... no wait I don't.... confused :S

Davey

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They are actually really simple to understand once you've seen the guts of one. But check out this webpage, it should help explain it all a little better: free-coaster.com

"The driver will have a screw shape coming off of it into the hub. And the clutch will have it on the inside, so that when you turn the driver, the clutch will move in toward the diver.

But what if the clutch just moves forward with the driver(you might ask)? Well, that is the work of the resistance. In most coasters this resistance is created by a spring running along the axle. The spring will prevent the clutch from moving forward easily with the driver, so the threads on the driver will pull the clutch in toward itself."

I feel stupid, but that makes no sense, think I need to disect one. Back in the village I grew up in there was this kid who did flatland and he had one and at the time we were all like "oooooohh" because we were all still riding trials on Raleigh Max bikes with cantilevers!

Davey

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I feel stupid, but that makes no sense, think I need to disect one. Back in the village I grew up in there was this kid who did flatland and he had one and at the time we were all like "oooooohh" because we were all still riding trials on Raleigh Max bikes with cantilevers!

Davey

Basically what it's saying is that the driver has an external thread, and the clutch is threaded on the inside, so when you turn the cranks forward (thus turning the driver) it causes the clutch to wind up the thread on the driver until it enagages again.

Then the other paragraph is explaining how they stop the clutch from moving without the driver. So with the Freecoaster i have (KHE Geisha), the clutch sits on top of two bearings which are seated on either side of the centre spindle, and these bearings have a spring between them, so they push outwards, so when the clutch sits on them it makes it harder for it to slip off, so they create resistance.

Try check out this bit: exploded diagrams

Edited by huck_it
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Try check out this bit: exploded diagrams

Weyhey, now I get it, when you pedal it turns the driver and the thread on the driver draws the clutch across to engage it, then when you roll back you back pedal a little to disengage it and voila you're free coasting!

Pictures make everything easy to understand (Y)

Davey

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Yeah, basically. If I'm going for a properly fast rollback, as in I'm pedalling pretty much as fast as I can go, I'll usually pedal round so my right foot goes right to the bottom of the pedal stroke, then bring it up to the normal right foot forward position, just so I know I've got full slack. You just stop thinking about it generally though after a while, just 'cos it becomes quite natural.

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So if your going along and you want to change your footing position for a trick so you pedal backwards to get it right, will that disengage the freewheel or whatever.

It will disengage the clutch for the free coaster but you'll be freewheeling forward so wont notice anything, accept there will be a little extra slack when you go to pedal again, I think.

Davey

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It will disengage the clutch for the free coaster but you'll be freewheeling forward so wont notice anything, accept there will be a little extra slack when you go to pedal again, I think.

Davey

Pretty much spot-on. It's usually how I disengage mine to go for a trick, like just normally I usually pedal a little bit past where I need to be, then back pedal a bit. Works fine (Y)

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