I have now laced quite a few 16" and 20" wheels. I always use the spoke pro calc on line after I purchased his book as well.

 

http://www.wheelpro.co.uk/spokecalc/

 

All my small wheels with front motor hubs are now laced radial which is sufficient, easy and strong. They also look great

 

I would not use radial on larger front wheels. In practice for my small front wheel radial builds I have to take about 1-2mm off the measurement given in the online spoke calc.

 

As stated Keyde motor dimensions do vary. I have a black and a silver one which measure both 92mm and 90mm flange diameters. The early versions of these hub also had different measurements. All my narrow Tongxin motor measurements have been consistent. The safest bet is to never order your spokes until after you have the motor in your hand!

 

Rim wise you should be ok but again for rims you have not used before its better to have it in you hand before you order the spokes.

 

Wheel building skill takes a while to master. Its not hard and I would always encourage people to have a go if they feel like minded. However, it does take a while and a few builds to develop the skills to get consistent results and your spoke measurements spot on.

 

Regards

 

Jerry

Edited January 14, 201412 yr by jerrysimon

I should add that I by no means consider myself an all round wheel builder, having only ever built two larger front wheels and only a few smaller rear hub wheels. I do however feel confident that I can consistently build a good front motor hub wheel in the smaller 16/20" size.

Edited January 14, 201412 yr by jerrysimon

Jerry, does the book worth it? Isn't it the same to read sheldon brown articles?

I used both when I was first learning to build my own wheels.

 

There are lots of resources on the web including loads of good videos though.

 

Regards

 

Jerry

Strange. Just trying to move this on an re-did the calculator and got a slightly different result:

Complete wheel data

Hub: q85, front

Left flange ⌀: 108 mm

Right flange ⌀: 108 mm

Centre to left: 20 mm

Centre to right: 20 mm

Spoke hole ⌀: 3 mm

Rim: Sun CR18

ERD ⌀: 340 mm

OSB: 0 mm

Size:

Tension for 36 spokes

CrossesSpoke length leftSpoke lenght rightTension ratio L/R

0116.2116.2100%

1120.8120.8100%

2133.2133.2100%

3150.3150.3100%

4168.9168.9100%

 

Jerry so if I go for radial would you recommend knocking off 1.5mm (from the 116.2)?

Edited January 19, 201412 yr by Joneser

The nipples from the wheel laced by bmsbattery always get loose. I tighten them and 5mn after they get loose again.

 

Any idea why?

You haven't done them tight enough.

Really? I was thinking to maybe put some loctite

Ok, I contacter the spokes seller, he gave me another site to test the spokes length:

http://www.wheelpro.co.uk/spokecalc/

 

I have new measure now.

 

It does look like the measure you gave me d8veh. How many cross pattern should I choose?

I'd use one-cross on short spokes like that.

Thanks D8veh. You're the most helpful chap I've met

I've finally found back this initial thread, but now I'm trying to lace a rear BPM2 on a 26" spare bike.

 

My rim ERD calculation shows about 517mm hole to hole:

 

By adding 10mm, I can expect the ERD to be about 530mm??

 

 

So calculation would be the following:

 

With 108mm flange diameter and 19mm left flange distance and 15mm right flange distance.

 

So at 1 cross pattern, I should buy 182.6mm left spokes and 182.2mm right spokes.

 

Is that alright as calculation? And what's the best place to buy these spokes?

 

Thanks

10mm added to the inside diameter is too much. Add 5mm to get the approximate ERD.

so about 525 erd? and other data from the bpm should be correct too? I need to get some spokes now

There's a couple of mistakes in your calculations.

I'd use a ERD of 517 +5mm = 522mm

The circle diameter of the spoke holes is 168mm, not 180mm. 180mm is the diameter of the edge of the flange.

For a high-torque motor like the BPM, I'd use a 2-cross pattern.

 

When I put these results into my spoke calculator, it gives the length as 203.5mm for 2-cross and 184mm for one-cross. 203.3 and 203.8 if I add in the 4.75mm off-set to the centr of the hub.

ok thanks for the correction.

 

4.75mm off-set to the center of the hub is to cater for the freewheel? And it should be the same number for any bike?

 

Or shall I place the motor to the bike and measure distance to bike center before ordering spokes?

Ok I'm almost there, here's the calculator:

 

I'm thinking to get these BMX spokes with 1X pattern at 184mm:

http://www.ebay.co.uk/itm/36-Halo-BMX-Spokes-Black-or-Silver-Stainless-with-Nipples-/111215652834?pt=UK_sportsleisure_cycling_bikeparts_SR&var=&hash=item19e4f82fe2

 

Everything's good and fine?

14g might be a bit thin for a BPM motor. I've mostly used 13g - sometimes 12g. The problem is that you can't find them on Ebay. You have to get them from a spoke maker and then they become expensive.

 

BMSBattery have 12g in 184mm, but you have to order something else to get the shipping cost down. 40 spokes = $8 plus postage.

OK thanks, I'm checking with bmsbattery then