Wisper 905 rear wheel/rim.

[Kwozzymodo]

Also, check to ensure that all the spoke threads are completely in the nipples before starting the truing process. You should be able to tighten individual spokes by hand and check this by rubbing a thumbnail across the spoke and nipple, before moving onto a spoke key.

Take it slow, as others have suggested. You are working on eliminating lateral movement of the rim, making sure the rim stays round and checking dishing (dishing ensures the wheel sits centrally in the frame). It’s an iterative process. So do a bit of each, until the rim gets close to true. If you can end up with 0.5mm lateral and vertical movement, that is a pretty good effort!

If you are going to turn wheelbuilding into a habit, a truing stand is a good investment.

 

[Sturmey]

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

I agree. What I have noticed about the 14g spokes (on my wheels) is that (because they are more flexible), they wrap themselves snugly around the hub flange leaving no air gap and no room for movement. When I look at my 13g spokes. there is nearly always an air gap at the hub flange, which I think is the source of movement and fatigue, and (imo) causes breakage at this end. (Not a problem on front wheels)

 

[Woosh]

There are additional difficulties with relacing a rear motorwheel with rim brakes:

1. The new rim needs to have the same circumference and width
2. the rim needs to be machined for rim brakes
3. you need to dish the wheel correctly. The length of the spokes on the drive side is a little shorter than the non drive side.
4. you need to tension the spokes correctly. In this regard, 14 gauge spokes are easier to work with because they are more flexible and usually more tensile.
5. The truing needs to be more precise so that the braking works perfectly.

I only relace rear motorwheels as the last resort.
From my experience, the computer driven spoke machines performs much better than humans in new motorwheels.
Don't forget that if you replace only the old rim, the new rim may outlast the motor.

 

[Andy-Mat]

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!

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.

If the OP decides to do it himself, he should make a few good clear photos before taking the old rim off.....
Andy

 

[Chainring]

Also, bear in mind that nothing is final! If it doesn't go as you expected, slacken it all off and start again. (and again). You'll feel you have accomplished something when it's back in the bike.

 

[Chris M]

I re-rimmed a rear wheel many years ago on a manual bike. It took a while to get it done but it worked well for years. Surprisingly it me gave no trouble at all . It's now somewhere in Africa with the rest of the bike.

 

[Farmerjim]

Thanks for all the helpful advice guys.
The problem now has become acute as the rim gave out with a bang today on my morning ride!
So I need to order a 26" 36 hole rim to fit a 26 x 1.95 tyre and some new spokes. They measure 220mm from rim to hub, does that sound about right? Also I'm unsure as to which rim I should get i.e. I'm a little confused as to the shape [I know it's round ] but the rim type would it be 559-18?

 

[Kwozzymodo]

559 equates to 26”. The width, 18, depends on the type of tyre you want to use - off the top of my head, an 18 rim should take from a 28 to a 40-42 width tyre. So, if you are running an mtb tyre, look for something wider.

 

[Farmerjim]

Well the wheel's off the bike now. I'm not sure I have the confidence to relace it myself as I've never even done a normal wheel. I'll run it into a couple of LBSs tomorrow and get some quotes.
Thanks again for the advice

 

[Woosh]

if you are stuck, you can send it to me, I'll fix it for you.

 

[Farmerjim]

if you are stuck, you can send it to me, I'll fix it for you.

Cheers Woosh! Afraid you're the wrong end of the country for me but thanks anyway.