Return to the bent!

[AntonyC]

I used an Andra 40 rim and Sapim Strong spokes with head washers on a Shengyi DGW22C motor.



Grin's calculator worked a charm, I measured the rim carefully and the rest fell into place as shown. The wheel's beginning to creak and needs retensioning after 1900 miles.

 

[saneagle]

Also, I forgot to mention that I've built many wheels with offsets, and always used the same spokes for each side. You have to be more careful with the calculations if you have single-walled rims, but i always use double-walled MTB rims that have loads of space between the nipples and the tube, so it's no problem when the spoke pokes through the nipple.That also means that you can use slightly longer spokes that makes the lacing easier.

 

[Benjahmin]

I've redone the measurements and calculations and this is what it's come to:

Online Spoke Calculator for Hubmotors and Ebikes

Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...

ebikes.ca

So it looks like left spoke at 208mm and right at 206mm.
The tension ratio still looks high but< I guess, it is what it is. If it wasn't for the calculator I wouldn't have a clue about it and would just use the wheel in ignorance of spoke tension. I'm guessing that so long as all spokes on one side 'ring' the same note, then it'll work. I hope.

 

[AntonyC]

> it is what it is
...and that's ideally not a jelly, if the ratio's really high you can end up with cracks around the nipples
Have a look at my lacing

 

[Cadence]

I've redone the measurements and calculations and this is what it's come to:

Online Spoke Calculator for Hubmotors and Ebikes

Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...

ebikes.ca

So it looks like left spoke at 208mm and right at 206mm.
The tension ratio still looks high but< I guess, it is what it is. If it wasn't for the calculator I wouldn't have a clue about it and would just use the wheel in ignorance of spoke tension. I'm guessing that so long as all spokes on one side 'ring' the same note, then it'll work. I hope.

If you look at AntonyC's calculation he has left side spoke elbows in and right side out, giving a much better ratio of 35:65. I've been trying to see if I could get it any better, but I can't. Incidentally, the drawing for the AKM-128CST has the flange spoke hole diameter at 129mm - not that 1mm is likely to make much difference.
AKM-128 CST Drawing.png (1253×838) (topbikekit.com)

 

[saneagle]

If you look at AntonyC's calculation he has left side spoke elbows in and right side out, giving a much better ratio of 35:65. I've been trying to see if I could get it any better, but I can't. Incidentally, the drawing for the AKM-128CST has the flange spoke hole diameter at 129mm - not that 1mm is likely to make much difference.
AKM-128 CST Drawing.png (1253×838) (topbikekit.com)

That's right, you can reduce the offset a bit by bringing all the spoke out the same side of the spoke flanges. I've not done one like that, but it makes the lacing a bit more complicated. I think you'd have to build one side at a time - the brake side first, then the gears side otherwise you'd have to bend some of the brake side ones into all sorts of shapes to bring them to the rim.

What building sequence did you use, Antony?

 

[AntonyC]

That one sounds right.

 

[Benjahmin]

Ok, I've changed the right side elbows to out and it's bought it to 35:65.
That's the same as yours Anthony and that worked out did it?
Thanks for the help everyone, you're helping to demystify the dark art of wheel building.

Online Spoke Calculator for Hubmotors and Ebikes

Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...

ebikes.ca

 

[Benjahmin]

With the tensions now at 35:65, I can't get it any better, and as Ryan's back from holiday, I'm going to order spokes.
Going to ordr all 208 as I figure 0.9mm won't make much difference.

 

[Benjahmin]

Ryan's out of stock of black Sapim strongs, so I've ordered from Bitex Hubs UK. Hope they come through.

 

[Nealh]

Could have gone silver, S/S for a bit of bling.

 

[Benjahmin]

True but it's a black rim, motor and cassette which will show up my bright yellow cycling jacket quite nicely methinks.

 

[Benjahmin]

Me spokes have arrived and me nipples are soakin in oil. (Stopiiit!)
Realised I was short of a square driver, but I've found a red rawlplug fits nicely over the nipple top nut and passes through the inner wall of the rim.
Let the adventure begin.

 

[saneagle]

Me spokes have arrived and me nipples are soakin in oil. (Stopiiit!)
Realised I was short of a square driver, but I've found a red rawlplug fits nicely over the nipple top nut and passes through the inner wall of the rim.
Let the adventure begin.

I screw a spoke a few turns into the top of the nipple, poke it into the hole, then twiist the poking through part of the nipple with my fingers to screw it onto the wheel spoke and screw it off the spoke that poked it through. I only have to do that with the second 18 spokes because the first 18 all reach through the rim so that you can screw on the nipple easily.

 

[Benjahmin]

I am immensely chuffed to have built my first, apparently, concentric and true wheel and just to proove that it happened:

And here it is on the scratch built truing stand in concentricity mode, 'cos ya can't really turn a bent on it's back !:


Of course it's only now that I realise I haven't yet ordered a tyre, tube, rim tape or cassette.
So to the interweb it is and get the wallet out - again.
Thanks to everyone who helped this process along. Hey, it's not such a dark art afterall.

 

[saneagle]

Nice stand. That's the way to do it. No need to spend loads of money. I don't like the set-square though - it makes it look like you took too much care to get it right.

 

[Benjahmin]

Thought I was dead clever ordering tyre,tube, rim tape and cassette all from one supplier so avoiding delivery charges - forgot the bloody disc didn't I.

 

[Benjahmin]

Wheel's now finished.
Here's a picture of it alongside the one that's come out:

Out of curiosity I weighed them both. The DD wheel is 8Kg+, the geared hub wheel is 5Kg.

Not being able to upend the bent, I made a scratch workstand. It did mean that I was fighting gravity putting the wheel in. There was some filing needed (previous motor was not fully seated)so, with all the fiddling, it took about an hour to get it in first time. 'Twas then I found the caliper fould the motor by about 2mm. An hour round trip to the lbs got me a 180mm disc and adaptor. Wewnt in fine second time around with one washer inside the frame to give disc alignment.
Wiring next - pictures will follow.

 

[Benjahmin]

Here's the bike on the stand in lash up mode:


The observant may spot that I've used 'girly' Wago 221 connectors - they're only temporary - honest.
So far it's working on throttle but not pas. Because I have a KT-V12L sensor the c1 needs to be set to 07. Currently struggling to follow the instructions, is there an easy hack/fix for the lcd3 ?

 

[saneagle]

All that spaghetti is making me feel hungry.
KT-V12L PAS!!??? You guys and your sado-massichism. If only you posted a complete shopping list, I might have seen it. Oh well, eventually someone will be able to get one working and tell the rest how to do it - hopefully you. Good luck to you and all who sail in you.