What gears do you actually use?

[Straylight]

Pretty sure I couldn't change mine because of the Torque sensor mounting but I've not looked closely.

I've a mega-range rear set, is it possible to change top gear only or does one have to change the whole set?

Terry

Well here'sthe rub, if you have a rear hub motor then as Flecc says the wheel will only take a screw on 'freewheel', and they come as a complete, unadaptable set, and the smallest sprocket available to my knowlege, is 13 tooth (Shimano did make a version of the megarange freewheel that went down to 11tooth, but it's been sadly discontinued - spent days scouring the internet looking for one, to no avail ), so no real advantage. Otherwise you may well have a cassette, which is a more widely used system, and offers more choice and flexibility.

It's a pity that cassettes are unavailable for hub motors though, as I'd have thought that if the power cable came out of the other side of the motor, it would indeed be possiblle to have a narrower spindle on the gear side. This would of course require a redesign (slight) of the motor, and in particular its spindle, but you never know - maybe one day...

 

[Wooky]

Well here'sthe rub, if you have a rear hub motor then as Flecc says the wheel will only take a screw on 'freewheel', and they come as a complete, unadaptable set, and the smallest sprocket available to my knowlege, is 13 tooth (Shimano did make a version of the megarange freewheel that went down to 11tooth, but it's been sadly discontinued - spent days scouring the internet looking for one, to no avail ), so no real advantage. Otherwise you may well have a cassette, which is a more widely used system, and offers more choice and flexibility.

I have a rear hub motor with a 14 -34 Shimano Megarange, I'm guessing a 13 is not going to make much difference.

Terry

 

[torrent99]

It's a pity that cassettes are unavailable for hub motors though, as I'd have thought that if the power cable came out of the other side of the motor, it would indeed be possiblle to have a narrower spindle on the gear side. This would of course require a redesign (slight) of the motor, and in particular its spindle, but you never know - maybe one day...

Interesting you should say that as I saw a thread on ES the other day featuring a Suzhou Bafang hub that had the power cable coming out of a plate on the side of the hub rather than through the axle. This should allow solid, stronger axle than the current hollow ones.

 

[Straylight]

Wooky,

I didn't think so, when considering my options, hence the new chainring. I found this page very handy though:Sheldon Brown's Bicycle Gear Calculator

In fact, the entire website is a goldmine of information

 

[Straylight]

Interesting you should say that as I saw a thread on ES the other day featuring a Suzhou Bafang hub that had the power cable coming out of a plate on the side of the hub rather than through the axle. This should allow solid, stronger axle than the current hollow ones.

Wow, how does that work? I'd have thought the cable would need to exit through the centre of the hub - got a link?

 

[Wooky]

You say torque sensor but it sounds like you have a pedelec sensor and a hub motor, if I'm wrong then so is the info below probably.

It is a torque sensor on the Rush Trek bikes, and looks fairly integrated with the gear assembly, Here's some not very clear pics as I'm at work with only an iPhone and poor lighting!

On the other hand why would they re-invent the wheel and make a custom chainring?


MobileMe Gallery

Terry

 

[Wooky]

Wooky,

I didn't think so, when considering my options, hence the new chainring. I found this page very handy though:Sheldon Brown's Bicycle Gear Calculator

In fact, the entire website is a goldmine of information

Thanks for the link, i'll look at that later when I get some spare time and see if I can begin to understand it!

Terry

 

[flecc]

I'd have thought that if the power cable came out of the other side of the motor, it would indeed be possiblle to have a narrower spindle on the gear side. This would of course require a redesign (slight) of the motor, and in particular its spindle, but you never know - maybe one day...

This won't happen since it's not very practical. The cable comes out of the drive side because that's the open side of the rotor from where the cables emerge from the rotor. For service replacement of Hall sensors it's the best and simplest arrangement. In addition, the opposite internal rotor drive side has to have the orbital gears support frame anchored to the spindle strongly enough to take the entire motor torque so maximum spindle strength is desirable there.
.

 

[flecc]

Interesting you should say that as I saw a thread on ES the other day featuring a Suzhou Bafang hub that had the power cable coming out of a plate on the side of the hub rather than through the axle. This should allow solid, stronger axle than the current hollow ones.

This requires a static side plate and means the hub must rotate on a very large diameter bearing on the periphery of the side plate. The Heinzmann motor's very old design is like this. However, it's a potentially noisy and very heavy arrangement, noisy because the large diameter of the ball bearing race means very high bearing speeds, heavy because the hub shell and side plate need to be much more thick and rigid than usual to provide a completely stable large diameter bearing structure between side plate and hubshell. There are also waterproofing and lubrication complications.
.

 

[frank9755]

This won't happen since it's not very practical. The cable comes out of the drive side because that's the open side of the rotor from where the cables emerge from the rotor. For service replacement of Hall sensors it's the best and simplest arrangement. In addition, the opposite internal rotor drive side has to have the orbital gears support frame anchored to the spindle strongly enough to take the entire motor torque so maximum spindle strength is desirable there.
.

Interestingly the Tongxin rear wheel motor has the wires coming out on the left (non-drive) side. This obviously keeps them clear of the chain and gears. I had wondered why others didn't do it this way.

 

[frank9755]

I have a rear hub motor with a 14 -34 Shimano Megarange, I'm guessing a 13 is not going to make much difference.

Terry

It would give you one extra gear at the top end. If your current set-up is fine certainly not worth doing but if its slightly undergeared, then it might be just what you want.

I'm actually looking out for a 13T to replace the 14 that is on my wife's bike!

 

[flecc]

Interestingly the Tongxin rear wheel motor has the wires coming out on the left (non-drive) side. This obviously keeps them clear of the chain and gears. I had wondered why others didn't do it this way.

It's very different internally Frank, and more complex with a two piece spindle and the roller drive.

The normal hub motors with orbital gears don't suit that as I described. You can see the cable exit slot in the spindle with feeds direct to the windings and Hall sensors here. Leading the cables out the other side would leave nearly all the spindle hollow and weak and give less strong anchorage for the orbital gear frame onto the spindle:

 

[frank9755]

I'm going to be an renegade here and say that I love the first on the Megarange! It's the only thing that gets me and the 2 year old (who weighs as much as a 3 year old) up the final 100yds of Highgate Hill. It'd be nice to have a 1.5gear though as the difference between 1 and 2 can be a bit too big at times.

In fact, Steve, assuming you haven't changed the chainring on the Wisper, that 34T megarange gear on a the 52T chainring will give you exactly the same bottom gear as Mussels' modified set-up, which I believe is a 28 rear and 42 chainring - therefore you're not actually disagreeing at all!

Depending on tyre size, they both give a bottom gear of around 39" - which isn't a particularly low bottom gear (the one I was riding at the weekend has a megarange (34) and a 28T inner ring giving me a low of 22" (700c wheel) which was a joy to use on a 1 in 5 hill). Therefore, unless you put a smaller chainring on, I would hang on to the megarange on the Wisper.

 

[Wooky]

It would give you one extra gear at the top end. If your current set-up is fine certainly not worth doing but if its slightly undergeared, then it might be just what you want.

I'm actually looking out for a 13T to replace the 14 that is on my wife's bike!

Have you an idea on price for one of these, also what description am I looking for to fit a rear hub motor wheel? I see the 34 - 11 listed in the States as Nexave and Deore whatever that means and mines a 7, some of those are 8's.


Terry

 

[frank9755]

You just need a screw-on freewheel. Spa Cycles have a Shimano one for £20 here
The Sun Race ones may show up cheaper elsewhere (eg eBay)

NB I'm talking about 13-34s, the 11-34s don't seem to be available anywhere. Make sure you don't get a cassette - some of those you've seen may be.

 

[musicbooks]

Agattu- No sprocket modifications-used for steep hill climb commutes

1 = never, 2 = very occassionally, when setting off from steep incline, 3= occassionally, when setting off from slight incline, 4 = when feeling lazy on the hills, 5 = most used gear on steep hill commute, 6 = sometimes on slight inclines and 7 = on flat



Conclusion - under-geared

bw
musicbooks

 

[flecc]

Agattu- No sprocket modifications-used for steep hill climb commutes

1 = never, 2 = very occassionally, when setting off from steep incline, 3= occassionally, when setting off from slight incline, 4 = when feeling lazy on the hills, 5 = most used gear on steep hill commute, 6 = sometimes on slight inclines and 7 = on flat

Conclusion - under-geared

bw
musicbooks

The consequence of complying with the 15 mph limit on a drive through the gears bike. Fine with a three speed hub gear which was what was used on all early Panasonic system bikes, their own and the Lafree Twist Lite, therefore giving a usable bottom gear, but adding 7 and 8 speed hub gears has stretched the gear range down to well below usability for most.
.

 

[torrent99]

In fact, Steve, assuming you haven't changed the chainring on the Wisper, that 34T .

Well I haven't changed the megarange, but yes I have changed the chainring. It's now a 32T with 110mm cranks! Did someone say something about hamsters ??

 

[torrent99]

In fact, Steve, assuming you haven't changed the chainring on the Wisper, that 34T .

Well I haven't changed the megarange, but yes I have changed the chainring. It's now a 32T with 110mm cranks! Did someone say something about hamsters ??

The consequence of this for the Wisper is that (when my knee doesn't hurt too much) when I actually pedal it's almost perfectly geared. I use 1st going up the steepest bit of Highgate Hill, 7th on the flat with full throttle to give about 17-18mph, and 2-6 for various grades of incline. All it needs is 1.5th!

 

[frank9755]

That gives you something like a 24" gear - almost as low as mine! Just what you need for tackling hills without taxing your knees.