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Who likes Crank-drives?

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Did they have nice big fat chains on or just the usual "wears out in 5 minutes' skinny derailleur type?!
Did they have nice big fat chains on or just the usual "wears out in 5 minutes' skinny derailleur type?!

I didn't look too close. There were so many of them, that some of them are bound to be good

Lots to look forward to:cool:, hope they keep price down

They will be, we're bringing in a crank drive bike that'll sell for 50p.

They will be, we're bringing in a crank drive bike that'll sell for 50p.

 

Aye but will it go over 25.1 mph?

They will be, we're bringing in a crank drive bike that'll sell for 50p.

 

Any e-bike will sell at 50p.

 

But will you sell it for that? ;)

crank drive bikes will always be more expensive than hub bikes.

If you can sell a crank drive for 50p then someone will sell the hub equivalent for 45p.

They will be, we're bringing in a crank drive bike that'll sell for 50p.

 

50p per minute to charge a battery for three to four hours is quite a costly task.

 

MS.

I am a newbie but wouldnt the speed and power of these drives wear a chainset out very fast ?
I am a newbie but wouldnt the speed and power of these drives wear a chainset out very fast ?

Interesting comment.. I have done 1500 miles on the original chain with only a small amount of stretch /wear (using the park chain wear tool). I expected it to wear out quickly given the extra strain it's exposed to.

I suppose its how hard you push it trex i wouldnt like the idea of the chain breaking and causing damage
not so much as breaking but more a case of stretching and wearing. The rear sprockets, especially the smallest sprocket (12 teeth) gets used a lot on flat roads. Average expected lifespan is 1,500 miles for 1% chain stretch. The cost of replacing chain and freewheel is about £15-£20 for Woosh CDs, about £30-£40 for German bikes.

My CD chain lasted about 700 miles. Rear sprocket also pretty worn. There are a couple of chain manufacturers who produce CD specific chains and seem to promise good life. I plan on checking one of them out this summer.

 

However as explained above, replacing them fairly often won't break the bank. It just came as a shock to me!

 

I've also taken to riding in slightly lower gears a lot of the time. I reckon this might put less strain on the transmission? Any views on this strategy anyone?

I've also taken to riding in slightly lower gears a lot of the time. I reckon this might put less strain on the transmission? Any views on this strategy anyone?

 

Doing that is more a matter of less strain on you. There's no difference for the chain since, assuming a single chainwheel, for a given performance it's transmitting the same force at the same linear chain speed

 

On a hub gear bike it actually increases the strain on the hub gear due to increasing the torque in lower gears.

 

Fortunately you have a derailleur gear bike, so any torque increase at the rear sprocket is compensated by the increased size of a lower gear rear sprocket, the load spread over more teeth.

I reckon the pressure on the teeth is responsible for the wear. Consequently, if presented with a choice between say gear No 5 or No6 on a 5% hill, I tend to choose No5 - the chain runs faster, but less pressure on the sprocket. I believe the choice results in less chain stretch and perhaps fewer shiftings
But as said Trex, the chain isn't running faster for a given road speed, assuming a single chainwheel as on the CD. It's just running on a larger rear sprocket which turns more slowly.
I reckon the pressure on the teeth is responsible for the wear. Consequently, if presented with a choice between say gear No 5 or No6 on a 5% hill, I tend to choose No5 - the chain runs faster, but less pressure on the sprocket. I believe the choice results in less chain stretch and perhaps fewer shiftings

 

I think that's right because isn't the motor having an easier time and therefore not having to produce as much power?

may be not but it feels like it does. Your TCM is very much like my BBS01, the faster the motor runs, the higher the yield up to about 75 RPM so the motor produces plenty of power up to that point then it starts to be less productive but somehow, because it sounds sweeter when it runs faster, it seems to have an easier time but if you look at the ground speed, it produces more power when it runs faster.
I think that's right because isn't the motor having an easier time and therefore not having to produce as much power?

 

Not really, for a given performance the power onto the road has to be the same, so the input has to be the same.

 

It's the power and torque difference again. The same speed chain runs on a larger rear sprocket so spreads the load over more teeth, so would seem to produce less wear.

 

But the torque in a lower gear is greater so the pressure on the teeth is increased, and because the larger sprocket is turning slower, the chain roller pressure on a tooth is for longer.

 

Ergo there is no gain in wear terms.

.

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