Lightweight rear hub kit

[guerney]

Buy a decent spoke wrench/key, I prefer to use spokey single size type to suit the nipple size I'm using but there are also 6 way spoke keys.

A couple of wheel lacing utube vids I quite like.

lacing a 3x bike rim - Search Videos

www.bing.com

The ancient and wise (also crafty and shameless ripoff merchant) 93 year old bike Yoda (he knows everything - a genuine fountain of bike knowledge, but sells you cr*p which lasts 5 minutes, if it works at all [for repeat purchase purposes {his family have been in the bike biz for over 100 years, so this approach must work}]) who owns my local bike shop, or rather his young stressed out overworked assistant... wanted £25 to true a wheel - and I would have paid that gladly, if it were not for a 3 day wait THREE FREAKING DAYS!!! "Only Bike Yoda is capable of such a feat", he said "And if the wheel is very warped, he charges an extra £15 per additional hour!" he added in awe. So... I learned to true wheels myself by watching Youtube videos like that one. I discovered that the multi-size spoke wrenches comprehensively chew brass spokes, but well made single size spoke wrenches as nealh says, is the best way to maintain spoke nipple shape while making adjustments. Loosening slightly, after tightening helps take out the twist in the spoke - brass is self-lubricating (to an extent, the twisted spoke will right itself with use), but it's good to take out the twist so you don't have to adjust spokes all over again after riding the bike. Also it's easy to overtighten a spoke accidentally, which sets that and/or other spokes (or spoke nipples) on the road to breakage... which is when my trick of plucking the spokes and listening to the pitch they produce comes in handy - it's just like tuning guitar strings (which I'm much more familiar with) - just make sure you pluck each spoke at the same location, exactly halfway along it's length: wildly overtightened spokes become glaringly obvious. Hey, it works for me! My new wheels now are perfectly true and tuneful. They should have been straight when bought, but they weren't quite exactly perfectly straight - close but not close enough! Anyway, it's well worth learning. I might have to build my next pair of wheels, as good quality replacements for my (very old) bike and chosen tyre width are becoming quite rare.

 

[Jodel]

The wheel building / measurement videos on the Grin web site are also very good. Not as comprehensive as Roger Musson's wheelbuilding book (well worth buying IHMO) but a good guide.

In my (limited) experience if you get the spoke lengths correct, the wheel build itself is actually quite straightforward. Take your time and get all your measurements correct - especially the ERD - before you order your spokes.

I used the Grin spoke length calculator and it gave results which were absolutely spot-on. I also agree with the advice given earlier in the thread to buy a decent spoke key - it makes life a lot easier.

If you work methodically, I would expect your home built wheel to be much better than any machine built version. Plus, it is very satisfying to build a wheel from scratch.

 

[Malcolm]

Thanks for the video suggestions guys. Watched them all. The Grin Tech video is especially useful as it recommends no more than a single-cross lacing pattern because of the larger diameter of hub motors. I'm looking forward to having a go at this.

 

[Nealh]

One has to be careful with the grin advise as it is american and often they only use larger powered D/D hubs.
The akm100/128 and similar size hubs can all use 2X in a larger wheel format like 26" or over, other wise 1X in small wheel format. The more crosses one can lace then the stronger more stable the wheel build, but this is dependant on the nipple angle.

 

[Jodel]

Malcolm, by all means use the Grin calculator but bear in mind nealh's comments about the much larger flange diameter that is common in motors used in North America. I don't don't know what size the flanges are on your motor, but if they are small, then a twin cross pattern may well be more suitable if you can maintain a decent nipple angle at the rim.

Off the top of my head, Sapim Polyax nipples allow a maximum angle of around 9 degrees, but less than this is better.

 

[Malcolm]

I checked the calculator for both lacing patterns. Single cross gives a nipple angle of 5 degrees, and double cross gives 9 degrees, so I think I'll stick with single.

 

[Malcolm]

Spent a couple of hours this afternoon reading about spokes and nipples. Too much choice...
Checked the existing front wheel and it has 14g/15g double-butted spokes. I'm thinking that plain 14g should be fine for the rear wheel I'm going to build. Is there any advantage in using double-butted other than saving a few grams?

 

[Jodel]

Single-butted Sapim Strong spokes are quite well regarded for use in hub motors as the flange spoke holes are normally larger than 'normal' hubs. I have them in my Shengyi rear hub motor and use Sapim spoke washers at the hub end too. Double-butted spokes would probably not give you any real-world advantage over single-butted for a hub motor.

 

[Malcolm]

Thank you Jodel, that's good to know. I was wondering about adding some spoke washers. I guess I'll have to wait until my hub and rim arrive so I can double-check hole sizes and effective rim diameter before ordering spokes. I'm itching to get started now.

 

[Nealh]

I have never used a spoke washer on a hub motor.

 

[Jodel]

The reason I used washers was that the spoke holes in my hub are 3.3mm and even with Sapim Strong spokes, it looked like there would be a (minor) risk of 'bottle capping' due to the angle the spokes took up.

The wheel has only done a few hundred miles thus far, so I'll see how it goes.

 

[awol]

Any other tips for a novice wheel builder?

I would recommend this book for all you need to know about building wheels.

Wheel Building book for cycle wheels

Wheel Building, by Roger Musson. A complete guide to building and repairing wheels with over 90 color photos and CAD drawings.

www.wheelpro.co.uk

 

[Malcolm]

So my parts arrived from Topbikekit two weeks after placing the order, which is better than I expected considering the Covid situation in Hong Kong.

I built the wheel into a 27.5 Alex rim using Sapim Leader 14g spokes from Ryan. This was a first for me, but jobs like this are so much easier thanks to the good people on Youtube.

I wanted to keep the bike looking fairly tidy and spent a lot of time getting the cable lengths right. My wife doesn't want a throttle, so I unsoldered the bulky 9-core Julet cable from inside the controller and replaced it with a 5-core cable of the right length to feed the display. I used some EPDM rubber glazing tape I had lying around to seal the top plate and end plates of the controller

The controller itself fit neatly into one of the gaps in the rack and will be covered by panniers.

The total weight of new parts was around 3.8 kg, which brings the finished weight to a touch over 15 kg. That's quite an improvement over the old Giant Esprit, which is a real bruiser at 27 kg.

First impressions: Very smooth and quiet. Easy to ride with or without power. The PAS levels are just about right without any changes to the default settings. At one point I did try a slow U-turn on level 5 and was nearly caught out as the motor cut in halfway round the turn. I won't do that again.

Anyway, my wife's very happy with her new bike, so I'll call it a good job!

Thanks to everyone for their advice, especially Nealh for pointing me in the right direction.

 

[egroover]

very clean minimalist build, nice job, well done

 

[Nealh]

Yes a very neat little job.

 

[Malcolm]

Just a little follow-up. Discovered a feature that's not mentioned in the manual for the KT LCD4 display.

My wife came home after dark last night complaining that her hub motor was no longer working. I checked the bike in the garage and everything worked perfectly, so I took it outside for a ride and the display immediately turned off.

It turns out there's a light sensor built into the display that automatically shuts down the system when it's dark, unless you turn on the backlight/headlight option.

The bike has separate battery-operated lights, so my wife had not bothered to turn on the display backlight. I'm sure many of you already know about this feature, but just thought I'd mention it.

Otherwise, everything is working very well.

 

[kyle47]

Thank you for this excellent thread, fantastic build and lots of information for others aspiring to make a similar bike. A few questions for you:

1. Have you thought about installing the 17A version of the controller? Did you have concerns that it would overheat hence why you chose the 15A?
2. What range do you get with this battery, motor and controller? And can you specify what usage (always providing power by pedalling or full power on the motor and no pedalling)?
3. Where do you buy your wheel and spokes?
4. Are you satisfied that the controller will be protected from Water in case of rain?

Thanks!

 

[Malcolm]

Hi Kyle, glad you found it useful.

1. I didn't have any concerns about the motor overheating – just didn't need any more power. My wife likes to pedal and just uses the motor in low assist modes: level 2 mostly and occasionally level 3.

2. A comfortable 20 miles range with the 7 Ah battery at the levels mentioned above. Mostly fairly flat roads and trails with the occasional small hill.

3. The rim came from ebay and the spokes from Spokes from Ryan.

4. I used 2 mm EPDM glazing tape to replace the existing end gaskets in the controller. I also used thin strips of the same tape to seal the top cover and around any cables that did not look watertight. I've used this tape to fit my windows and not had any leaks yet

 

[Blox]

No

Hi Malcom,
Bike wheel sizes are a real mess and misleading. I'm not 100%, but I think 27.5 is the same as 28 which is 700c. I know!
It's worth a check with Woosh.
The other way is to buy a motor and lace it into a wheel yourself. Many on here have done it and it's not the nightmare you might imagine.

I've just looked at this and now I'm even more confused:

Articles about Bicycle Wheels

Articles about bicycle wheels.

www.sheldonbrown.com

Presumably you're getting 27.5 from the tyre size ? If so this may help.

27.5 =650b. 29 = 700c

 

[Blox]

I came into this with knowledge of mtb cross country racing from 1990s early 2000s. Bikes have changed! Had hardly ridden for 30+years since.
I wanted assistance not a powered bike, after research, I decided I wanted a geared rear hub motor with PAS. It had to fit in with a particular full sized folding bike that I has bought.
In the end I went for a Dillinger Premium Off Rad Kit. It’s not the cheapest but it’s a very neat solution, the geared hub back wheel motor has masses of torque, but you can still pedal it without the motor because it’s geared not direct drive. The battery controller combo is really neat and the support from the company has been very good.
The converted bike which is a hard tail urban/gravel trail mtb is great to ride. Recently did a 34mile circuit, minor road unmettaled road with 2770ft of climbing, and the battery still had life.