June 1, 2025Jun 1 Well there ya go. Experience wins out. Sometimes you've just gotta do it the hard way to see the easy way ! What about you try it my way and see if you get the same result or how close it is? I've never done it the proper way so I'd be interested in whether there's any difference.
June 1, 2025Jun 1 Author OK, measured it as 598 +5 = 603 against Ryans way of 602. Near enuf methinks.
June 1, 2025Jun 1 ........ Remind me is it 12 or 13 guage? I favour Sapim super strongs if I can get them. Looking at your hub in the spoke calculator you posted above, you have a large dish/offset of 9mm and a spoke tension ratio of 32:68. I would use the lighter 14 gauge rather than the heavier 12 or 13 gauge as there wont be enough tension on the disc side to properly tighten the heavier spokes if you use them.
June 1, 2025Jun 1 Author Yeh, definitely leaning towards single butted, so 13 g at the hub down to 14g for the spoke.
June 1, 2025Jun 1 OK, measured it as 598 +5 = 603 against Ryans way of 602. Near enuf methinks. Thanks for that. It's well within the boundary of measurement error. Yeh, definitely leaning towards single butted, so 13 g at the hub down to 14g for the spoke. I always use straight 14g and never had any problems. You get a better angle out of the spoke holes.
June 1, 2025Jun 1 Yeh, definitely leaning towards single butted, so 13 g at the hub down to 14g for the spoke. The picture below helps to explain why 14g at the j bend may be stronger than the thicker 13g. When the spokes are newely fitted, there is a gap at the spoke flange. With the lighter and more flexable 14g spokes, this gap disappears when the spokes are tightened and pre-stressed ( checked and re-tightened if necessary). Those stainless steel 13g j-bends spokes are very stiff and have difficulty bedding in at the j bend. This means that there is movement and eventually fatigue at the j bend. This in my view explains why the lighter 14 g spoke may give better service and why I would keep away from 13g (even butted) if possible.
June 2, 2025Jun 2 If you spoke a wheel traditionally from scratch with 13 or 12 gauge spokes, you will notice that at the beginning, there is noticeable friction between the j bend and the flange of the motor and also the angle between the nipples and the rim may look uneven. I usually stop several times when tightening the nipples, take the wheel off the truing stand, put the wheel on top of my trusty bin and push the motor up and down several times to loosen any j bend that may not sit well in the flange of the motor. I give a squeeze where two spokes cross to make sure that the nipples are also centered. Flip the wheel over and do same fir the other side. That adds 5-10 minutes to the build time but it's well worth the effort.
June 2, 2025Jun 2 Author I see what you're saying but this is taken care of by having the left side spokes (non drive side) with the bend on the inside of the flange, and the right side on the outside. Whilst reducing the triangulation of the spokes to the rim it helps to bring the tensions nearer together. Grin say that they 'recommend to anyone who will listen' that you use butted spokes with 13g at the bend and 14g at the nipple, for hub motor builds. This also allows for the flange holes of my AKM measuring a consistant 3.2mm with the calipers. We'll see, if I break any spokes I can come back and say, 'You told me so !' . I agree, it's amazing how much squeezing, bending and flexing goes on during the process. Even spokes that get bent during lacing end up pulling straight.
June 2, 2025Jun 2 It is good to use 13g at the flange and 14g at the rim but those spokes cost a lot more compared to ordinary stainless or anodised 13g for your AKM, especially if you have to buy singly at a later date.
June 2, 2025Jun 2 Author True, but what with the motor, battery and panniers full of shopping I'll be asking a lot from the spokes. Anyway they're now ordered for £31 inc. nipples and delivery. Considering I'm using a rim I've had lying around for ages, that's not too bad.
June 2, 2025Jun 2 True, but what with the motor, battery and panniers full of shopping I'll be asking a lot from the spokes. Anyway they're now ordered for £31 inc. nipples and delivery. Considering I'm using a rim I've had lying around for ages, that's not too bad. For comparison, my 14g plain stainless steel spokes cost £9.99 from Amazon. They'll be carrying my weight (100kg) + up to 10kg of shopping.
June 3, 2025Jun 3 Author Ouch ! I guess I've paid the price of obsessive over engineering. In my defence, for various stoopid procedural reasons, I can't use Amazon. I've tried, I'm blocked.
June 3, 2025Jun 3 I guess I've paid the price of obsessive over engineering each spoke can hold as much as 200kgs in traction force, so what gives first is not the strength of the spokes but something that caused the spoke to be loosened like the hole in the rim gets damaged or the spoke gets broken at the J bend. It is rare that spokes break in the middle. When the nipple is so loose, the spoke gets put into compression and snaps. It follows from those observations that the tension needs to be even to distribute the load evenly over many spokes, the nipples should not be too tight that may damage the holes in the rim if you hit a pothole but tight enough so they don't get loosened. I use a drop of linseed oil to help the nipples from getting loosened. Edited June 3, 2025Jun 3 by Woosh
June 3, 2025Jun 3 each spoke can hold as much as 200kgs in traction force, so what gives first is not the strength of the spokes but something that caused the spoke to be loosened like the hole in the rim gets damaged or the spoke gets broken at the J bend. It is rare that spokes break in the middle. When the nipple is so loose, the spoke gets put into compression and snaps. Failure mainly comes from metal fatigue in the elbow as a result of not enough tension in the spoke. When you put weight on the bike, the lower spokes go into compression, which puts a bending force on the elbow. 14g spokes are more elastic, so it's easier to keep them in tension all the time, which is probably why I've never seen an elbow break on one. I've seen plenty on 13g and even more (proportionally) on 12g, which is not the result that most would expect. If ever you hear spokes creaking, it because they don't have enough tension. You must solve that quickly otherwise you'll be finding broken spokes at the elbow.
June 22, 2025Jun 22 Author Finally got all the bits I needed and the time . So, in the spirit of 'show us the pictures or it didn't happen', here's the build. Motor labelled and ready to go: Build went smoothly despite some brain fog: Had to build a front wheel too with a new hub. I've really enjoyed the wheel building process, pity I waited to my seventies to learn this skill. Both wheels ready to go: I ended up having to swap the bottom bracket for one with a longer spindle to accomodate the pas. Handlebar layout took a few goes to get everything to fit. The bike fully loaded. Now a couple of questions. The reason for doing this was to end up with a fully legal bike. The motor itself is labelled. The bike isn't - yet. I know it needs to state the speed limit and also the manufacturer, but who the hell is that? AKM (the motor), Carrera or me? Does it need anything else? Second question is a set up one. The display is programmed to give walk assist throttle until pedals are turned, then it gives full speed. Great ! Only thing is full speed throttle continues after pedal rotation ceases and only reverts to walk assist when throttle is released the operated again. As I understand it to be legal it should revert to walk assist as soon a pedals stop. Anyone know the setting, the Chinglish is doing my head in?
June 22, 2025Jun 22 Author I forgot the brake switch. I used a hydraulic switch and used an old cycle computer magnet cable tied to the brake pipe. Switch is held on with doulbe sided tape, may need glue.
June 22, 2025Jun 22 Motor labelled and ready to go: [ATTACH=full]63537[/ATTACH] The motor itself is labelled. The bike isn't - yet. I know it needs to state the speed limit and also the manufacturer, but who the hell is that? AKM (the motor), Carrera or me? The label on the motor looks good to me. Similar to my homemade label for my Mxus motor. As far as I'm aware a factory ebike should have a label on the frame, listing name manufacturer of bike, voltage (48v max), wattage (250 max) and max assist speed. But with conversion kits the label with this information should be on the motor, but obviously name of manufacturer should be the motor manufacturer. I'm a bit unsure if you need the max assist speed on the label of the motor, but it would do no harm to have it on there. This is mine (after several attempts). Edited June 22, 2025Jun 22 by Waspy
June 22, 2025Jun 22 Finally got all the bits I needed and the time . So, in the spirit of 'show us the pictures or it didn't happen', here's the build. Motor labelled and ready to go: [ATTACH=full]63537[/ATTACH] Build went smoothly despite some brain fog: [ATTACH=full]63538[/ATTACH] Had to build a front wheel too with a new hub. I've really enjoyed the wheel building process, pity I waited to my seventies to learn this skill. Both wheels ready to go: [ATTACH=full]63539[/ATTACH] I ended up having to swap the bottom bracket for one with a longer spindle to accomodate the pas. Handlebar layout took a few goes to get everything to fit. [ATTACH=full]63540[/ATTACH] The bike fully loaded. [ATTACH=full]63541[/ATTACH] Now a couple of questions. The reason for doing this was to end up with a fully legal bike. The motor itself is labelled. The bike isn't - yet. I know it needs to state the speed limit and also the manufacturer, but who the hell is that? AKM (the motor), Carrera or me? Does it need anything else? Second question is a set up one. The display is programmed to give walk assist throttle until pedals are turned, then it gives full speed. Great ! Only thing is full speed throttle continues after pedal rotation ceases and only reverts to walk assist when throttle is released the operated again. As I understand it to be legal it should revert to walk assist as soon a pedals stop. Anyone know the setting, the Chinglish is doing my head in? The law just says that the bike has to be marked with the maximum assisted speed. How you do it doesn't matter. From memory, the correct settings are P4=1 and C4=3. You forgot to say what it's like to ride. how does it compare with that Ezee thing you had?
June 22, 2025Jun 22 Author Haven't had chance to try it yet. All the weight is now on the rear end so not sure how it's going to feel.
June 22, 2025Jun 22 Haven't had chance to try it yet. All the weight is now on the rear end so not sure how it's going to feel. It should handle wheelie good. Why didn't you want to use a downtube battery?
June 23, 2025Jun 23 Author The rack battery has too much life left in it and I have no other use for it. Plan is to use it up then get a 48v downtube battery.
June 23, 2025Jun 23 Author Been out on a shakedown run. Firstly the steering is much lighter and the motor much quieter. Previous system was speed control and it's going to take some getting use to the lack of 'kick' at start up. I actually quite like it. It's absence means I've got to watch it pulling out of junctions as the initial acceleration just isn't the same. Main thing is hill climbing. I've just been up one of my regular longish climbs. I would keep 9-11mph in setting 3 on the old system (this setting would give me around 14mph on the flat). I was struggling to keep 8mph in setting 5, I could see the system was pulling 600-620w which is in line with me having set the max. current at 17A. I was trying to be kind to the battery, guess I'm going to have to change that. The big factor here is that I'm running a 48v motor at 36v so the lack of torque is hurting on the hills. Maybe I'll be replacing the battery sooner than I thought. Just hate the idea of ditching 2 perfectly serviceable batteries. Returning from a 6 mile ride I could feel some slight warmth in the motor, bit concerning on such a short ride and not the steepest hilss I tackle. Never felt any warmth in the big Ezee. 16mph Cut off is working well and is as subtle as can be, think I might be squeezing another 1-2 mph out of it though. Front deraileur needs some fettling. Brakes (180mm discs) are awesome.
June 23, 2025Jun 23 Author Just found that wheel size was set to 26" instead of 700c, that's part of why it all felt a bit tame. C5 now set to 9 which should give me 20A max. I think the Ezee was 20A (not sure), at least I can run in 3 or 4 with 5 for the hills - we'll see.
June 23, 2025Jun 23 Previous system was speed control and it's going to take some getting use to the lack of 'kick' at start up. I actually quite like it. It's absence means I've got to watch it pulling out of junctions as the initial acceleration just isn't the same. If you set the throttle like I said with P4 =1 and C4=3, you can use it to give instant max power when you need to pull away quickly, dash round a roundabout, through a busy junction or anything like that. That's one of the best features of the KT controllers.
June 23, 2025Jun 23 Author Yeh, checked that and it is as you say. I think the rather underwhelming performance is a mixture of wrong wheel size, 17A maximum current setting and running it at 36v, not to mention being so used (11 years) to the full power kick from the very torquey Ezee. I'll take it out again tomorrow and see how it is now it's been fettled.
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