Changing Wisper gearing.

[allen-uk]

How big a job, and how effective would it be to change the rear cogs on a 905?

I want a higher top gear, so could this be achieved by playing with the cog sizes? 1, 2, and 3 are okay. 4 and 5 seem very close together, so 5, 6 and 7 could be reduced a tooth or two.

Can you make up your own cog block (don't know if that's the right term), or do they come in pre-set sets?

Is this a daft idea? Would my local bike shop (good people, old and experienced) be able to handle it, if it ISN'T a daft idea?


Allen.

 

[flecc]

Cassettes on sport bikes usually come as blocks with a couple of interchangeable small higher gear sprockets, but rear motors have to use multi-sprocket freewheels instead which come as fixed sets. These sometimes come with one or two small interchangeable sprockets but they are the devil to swap. Choice of these freewheels is very restricted and they are often difficult to source.

You will probably have to remove any connector from the motor cable since these don't usually go through the freewheel centre hole, refitting the connector afterwards.

To remove the freewheel you need a suitable socket or tube spanner, a freewheel removal tool (not a cassette removal tool) and a chain wrench to grip the cluster while you undo the centre nut. A set of these are in the photo below, but you'd probably need a long socket or tube spanner to clear the spindle length on the 905's motor:

 

[Mussels]

You'll need a special freewheel remover as the hole in common ones is too small to go over the spindle, search on here as suitable ones are documented.
You can't get a much smaller sprocket on there, it will be a minimal difference, I know because I did it to my 905. Don't make the same mistake as me and fit a different brand freewheel as the sprocket gaps weren't quite the right size and it never worked correctly.
The alternative is to fit a larger chainring to raise all the gears, I wanted the opposite and reduced it. I also changed the Megarange for a 14-32 freewheel as I found the big megarange gap made bottom gear useless.

 

[Old Timer]

Change the front chain ring, not sure if it is a single on your bike but you could look into maybe fitting a double or a triple. Thinking about it, the seat tube might be in the wrong place for a front changer so you would be left with just upping the size of just the single chain ring which wouldn`t be too hard to do and as long as you don`t jump up too high then your lower gears will still get you up most hills. In general the gearing on E bikes is far too low when you consider the motor is doing more than 50% of the work.

On one of my bikes that only had a single front chainring(48T) and the seat tube wasn`t in the right place to fit a changer then I fitted a new double chain ring with a 52 and 48. the thinking was that if I ever came to a hill that I couldn`t get a low enough gear to get me up using the 52 then I would pull over and change to the smaller ring by hand in an emergency. I have never needed to revert to the smaller chainring and I`m 65 and as you know I`m recovering from a mild heart attack and have dodgy knees

 

[allen-uk]

Afraid not, OldTimer, not on a Wisper 905 anyway. It was my first solution, too, but I'm told that the seat post and additional hardware at the base of the battery mean that there's no room for a conventional front ring changer.

(Q: are there any UNconventional changers that would work?)

So if the answer to that is no there aren't, then you're right, upping the front ring is the only way. Trouble is, although gear no.1 is dismissed as a 'granny' gear I wouldn't want to lose it entirely, as there are still some hills when I DO drop down to 2, then for the last few yards, gratefully into 1. Not pretty, but it stops me stopping...

Allen.

 

[flecc]

(Q: are there any UNconventional changers that would work?)

Afraid not, we've gone into this before and there are no changer solutions known.

there are still some hills when I DO drop down to 2, then for the last few yards, gratefully into 1. Not pretty, but it stops me stopping...

Old Timer just fits a second motor to deal with this!
.

 

[flecc]

If money is no object, a Schlumpf two speed bottom bracket is an answer which gets round the chainring changer problem.

Schlumpf Innovations
.

 

[allen-uk]

Money isn't MUCH of an object, but that £400 puts me off, even though it looks like an amazing device.

No, it's going to be the front chainring, on a suck-it-and-see basis, I think.


A

 

[Mussels]

I spent ages trying to improve the gear range of my 905, the solution in the end was to sell it and buy a 906 Alpino.

Money isn't MUCH of an object, but that £400 puts me off, even though it looks like an amazing device.

No, it's going to be the front chainring, on a suck-it-and-see basis, I think.


A

 

[Wisper Bikes]

Hi Allen

We do have larger chain wheels in stock that will raise all the gears. I personally am more comfortable with a 48 or even 52 tooth chain wheel than a 44.

Regards

David

 

[Old Timer]

Hi Allen

We do have larger chain wheels in stock that will raise all the gears. I personally am more comfortable with a 48 or even 52 tooth chain wheel than a 44.

Regards

David

David

Would your cranks allow him to fit two rings at once? even if he has to manually change by hand when needed?

I remember when I was young(15-16) I had a double front chainring set up and the mech broke and I was so fit I could actually reach down when riding to change the chain over by hand Now I can`t even do up my shoe laces without getting out of breath

 

[Old Timer]

Old Timer just fits a second motor to deal with this!
.[/quote]

Naughty I know but on my rather heavy Powertrek, that thumb throttle on the left hand bar end always makes me grin

 

[Mussels]

David

Would your cranks allow him to fit two rings at once? even if he has to manually change by hand when needed?

I remember when I was young(15-16) I had a double front chainring set up and the mech broke and I was so fit I could actually reach down when riding to change the chain over by hand Now I can`t even do up my shoe laces without getting out of breath

I was able to fit two chainrings on my 905, I put a bash guard on the outside instead,
When your mech broke was the cage intact and movable or did the chain stay in place without it?

 

[Old Timer]

I was able to fit two chainrings on my 905, I put a bash guard on the outside instead,
When your mech broke was the cage intact and movable or did the chain stay in place without it?

It was 50 years ago so can`t remember but my powertrek has a double ring and never had a changer( frame like a Wisper) and the chain stays on either ring when put their.(I can`t change it going along though

 

[Wisper Bikes]

I was able to fit two chainrings on my 905, I put a bash guard on the outside instead,
When your mech broke was the cage intact and movable or did the chain stay in place without it?

Well done Andrew, we have not been able to achieve this because of the controller casing.

Regards

David

 

[Mussels]

It was 50 years ago so can`t remember but my powertrek has a double ring and never had a changer( frame like a Wisper) and the chain stays on either ring when put their.(I can`t change it going along though

I just remembered I did try running two chainrings myself but the chain kept on falling onto the inner one, I though about fabricating a cage but couldn't think of a good way to keep it in position.

Well done Andrew, we have not been able to achieve this because of the controller casing.

Regards

David

Are you thinking of the ones with the sprockets to stop the chain coming off the chainring? I couldn't make that work because the controller casing pushed the sprockets out. The one I successfully fitted was to replace the chain guard that came on the original chainring and to stop the teeth biting my leg if I had an accident. It was a simple one like this.

If I had removed the bash ring and fitted the chainring on the outside then I may have got the chainguide to fit with the controller, I didn't try as I like my right leg and wanted to keep the guard.