Wisper 905 rear wheel/rim.

[Farmerjim]

Hi, I've been riding a Wisper 905 for a few years now, it was 2nd hand when I got it so I guess it's about 10 -12 years old. Recently I noticed that the rim has started to break up. Its where the brake blocks have been rubbing. [My fault entirely, the wheel buckled and I didn't get it true enough.]
The Bafang motor is fine but , as I say, it's getting on. I think my best way forward is to replace the whole wheel. [26"]
Has anyone any pointers as to what might be a suitable replacement and who to buy one from?
Thanks for looking !

 

[Amoto65]

Best bet is get in touch with Wisper they are always very helpful, David is usually hovering about this forum so he may answer your query.

 

[Farmerjim]

Best bet is get in touch with Wisper they are always very helpful, David is usually hovering about this forum so he may answer your query.

Thanks for the swift reply.
I've already spoken to someone at Wisper but they're talking of around £360 for a new assembly which, given the age and condition of my bike , is an uneconomic repair. There are so many 26" 36volt conversion kits around in the £120 -£160 bracket , I thought perhaps that might be an answer?

 

[Kwozzymodo]

Can you mount the motor in a new wheel rim - a full wheel build isn’t going to cost more than £100 with all the parts, rim, spokes, nipples - probably less than that.

 

[Nealh]

New rim 36h £15-20.
Spokes Sapim Strong £20.
LBS to lace and true £50 -£75.

 

[Nealh]

Thanks for the swift reply.
I've already spoken to someone at Wisper but they're talking of around £360 for a new assembly which, given the age and condition of my bike , is an uneconomic repair. There are so many 26" 36volt conversion kits around in the £120 -£160 bracket , I thought perhaps that might be an answer?

The cheap kits you talk of will D/D hubs or real cheap gutless geared hubs , stick with Bafang you have and have it rebuilt.

 

[Farmerjim]

Thanks very much for the advice. I think a rebuild is going to be the best option, hadn't got round to thinking about that. I'll contact local bike shops.

 

[Amoto65]

In view of the price I agree a rebuild sounds best.

 

[sjpt]

If you have time for an educational experience build the motor onto a new rim yourself. You might not do as good a job as the local bike shop (though with some LBS's that may not be as true as it should be) and it will take you much longer, but it will be very satisfying and give you confidence for better truing etc in future.

 

[Woosh]

May be worth considering a new motor wheel, cost: £150-£220 depending on the motor.

 

[Andy-Mat]

If you have time for an educational experience build the motor onto a new rim yourself. You might not do as good a job as the local bike shop (though with some LBS's that may not be as true as it should be) and it will take you much longer, but it will be very satisfying and give you confidence for better truing etc in future.

That is the best idea I have seen here, and I was just going to suggest it, but you got there first!
That way he saves a few $$$ and learns something very important!
I have trued up a few wheels over the years, but never rebuilt one, I am TOTALLY JEALOUS!
regards
Andy

 

[Nealh]

I watched a couple of tutorials and did some reading a few years ago, first go was on an old wheel. I dismantled it completely then relaced and trued it a few times, with each wheel build you be come more proficient. It looks tricky but if you follow step by step guides using the pause button on vids lacing a wheel becomes easy, the hard part is having patience and initially having an hour or two to quietly go about truing.
For spoke length's.

Spoke length calculator for wheelbuilders

Take a look at the NEW 2023 calculator. The best spoke length calculator just got better!

www.wheelpro.co.uk

A couple of very good lacing vid's.
The first one is my favourite one .

 

[Farmerjim]

I watched a couple of tutorials and did some reading a few years ago, first go was on an old wheel. I dismantled it completely then relaced and trued it a few times, with each wheel build you be come more proficient. It looks tricky but if you follow step by step guides using the pause button on vids lacing a wheel becomes easy, the hard part is having patience and initially having an hour or two to quietly go about truing.
For spoke length's.

Spoke length calculator for wheelbuilders

Take a look at the NEW 2023 calculator. The best spoke length calculator just got better!

www.wheelpro.co.uk

A couple of very good lacing vid's.
The first one is my favourite one .

Thanks for the links to the vids and advice. Looks like a learning curve but at least it's a new skill!

 

[Sturmey]

A quick and economical way (using old spokes) to replace rim is the following.
1. Be sure that replacement rim is same inside rim diameter as old rim, then spokes will fit.(ERD and Rim height of cross section will also approx be the same).
2. Loosing all the spokes gradually.
3.Tape new rim to old rim with the valve holes adjacent.
4.Change over the spokes one by one, starting at the ones nearest the new rim and leave loose. I usually do them in nines.
5.Tighten spokes gradually and evenly, starting on drive/freewheel side, and true wheel in normal way.

However, if broken spokes have been an issue, I have had good results replacing the 13g spokes on the non-drive side of rear hub with more flexible and lighter (and cheaper) 14g spokes.

 

[Farmerjim]

A quick and economical way (using old spokes) to replace rim is the following.
1. Be sure that replacement rim is same inside rim diameter (ERD) as old rim, then spokes will fit.(Rim height of cross section the same).
2. Loosing all the spokes gradually.
3.Tape new rim to old rim with the valve holes adjacent.
4.Change over the spokes one by one, starting at the ones nearest the new rim and leave loose.
5.Tighten spokes gradually and evenly, starting on drive/freewheel side, and true wheel in normal way.

However, if broken spokes have been an issue, I have had good results replacing the 13g spokes on the non-drive side of rear hub with more flexible and lighter (and cheaper) 14g spokes.

Thanks for the tips, that seems a logical way to do it.

 

[sjpt]

A lot of people say 14g spokes are more break-resistant than 13g because of their greater flexibility. The mix Sturmey suggests is a good compromise; Spa cycles build quite a few wheels that way. I think it would be a false economy to reuse spokes from a wheel that age that has already had problems; it also limits your choice of rim.

 

[Nealh]

A skill for the ebike diyer I think a must to learn and have ago at.
A truing stand isn't totally necessary as and old bike can be chopped up to utilise the drops outs to make one or simply use your current bike as a truing stand.

 

[Sturmey]

PS There are advantages to using the existing spokes, e.g. The have become pretensioned from use and will have (hopefully) curved nicely around hub eyelets. Hopefully the spokes wont be corroded and will open without damage to spoke or nipple. New spokes have to bed in and need to be retensioned and may not be as good a fit as original spoke.
Getting a replacement rim can be tricky. I have used ordinary 36 hole double walled rims but had to widen the spoke nipple holes with a drill. In some instances, the bike may have matching front and back 13g spoked wheels, so an option is to cannibalize the front wheel, taking the rim off and using it on the back motor wheel. The front wheel can be replaced with an ordinary wheel. (Good option if you have plenty of bike spares).

 

[Nealh]

I use 14g on double walled rims and not yet had to open anything up they all fit through nicely.

A tip :
Thread the nipple from the top a couple of turns on to a spoke to insert it in the hole, its a pain if you let one slip into the rim void.

 

[Chainring]

Yes, I've watched that video by the Australian bird and built a couple of wheels. She's very good. As someone else said, you are more in touch with something you have built yourself. Lots of lubrication both ends of the spokes is important, so they can move without snapping. SJS cycles are good, and Taylor Wheels in Germany. I built my current back wheel with a rim from my original Santana. I know you are not supposed to use old rims, but it's done 14000 miles now. Have a go!