Well I was very pleased with my overhaul of Crichton’s internally geared hub a couple of weeks ago, but you may remember I said I didn’t have time for a test ride. Last weekend I did have time, and the simple fact is I cocked up! The stickiness of the pawls that was originally the problem was fixed alright, but I put them back in the wrong way round. As such, I still only had top gear, middle, and neutral. The pawls (on the left of the picture below) were simply facing the wrong way to engage with the ratchet in the hub casing, but since I had already cleaned and oiled everything, this time I only had to be careful to keep everything clean, so it only took half an hour. I did make doubly sure I’d got it the right way round this time! Again, no time for a test ride but I’m pretty sure it’s working now. I also took the opportunity to add some tension to the rear spokes, which seemed a little on the floppy side.
Anyway, last weekend was taken up with wheelbuilding, having collected all the necessaries from the bike shop:
Two Ryde Sputnik 700 x 19 rims (one 32 hole, the other 36), front spokes, rear spokes, small brass washers for the rear wheel, nipples, my two hubs and my red spoke key. I don’t intend to take you through the process of wheelbuilding, because Sheldon Brown’s guide is so much better than I could do. There are a couple of things to watch out for, however.
Firstly, you need to understand that in the end you want the spokes either side of the valve hole to be parallel, rather than crossed. This has no effect on wheel strength but will quite definitely make it easier to get access to your tyre’s valve when inflating!
Above is the finished front wheel, shown in the front fork with a nice old Sakae quick release. You’ll see every other spoke either goes into or comes out of the hub. The ones going in (with the bend of the spoke inside the flange) need to be done first. You probably could do it the other way round, but it would be unnecessarily complicated.
Apparently a really good wheelbuilder pays attention to small details, such as lining up the hub logo with the valve hole:
That doesn’t just happen, it takes a little advance thought! I was really pleased with this. I tried to get the front hub the same, failed, tried again, but again no dice. It just doesn’t seem possible with this hub, sadly.
For cross-3 wheels your outer spokes are threaded through the inner spokes for strength, each spoke goes over one, over the second, then under the third. Over, over, under. Over, over, under. Repeat until done. I find wheelbuilding becomes easier with knowledge of your 2, 3 and 4 times table, as well as either 8 (for 32 spokes) or 9 (36 spokes).
And here are my lovely new wheels:
After all the spokes are in, but before adding any tension, I give the wheels a good look over to check there are no mistakes. If there are, it’s a pretty simple process to strip it down and do it again – no damage done.
When adding tension you need to gradually tense up all parts of the wheel gradually, so you give it the best chance of coming out reasonably true. A nice neat trick is to tighten every third spoke. If the number of spokes doesn’t divide exactly by three (40, 32, 28, etc) you can add tension to every third spoke and by the time you’ve gone round the wheel three times you will have hit every spoke. For 36 (or 24) spoke wheels you need to remember to skip an extra spoke each time round, or you’ll tighten just the same 12 spokes, while the other 24 stay slack.
So I’ve tightened the wheels up a bit and done some rudimentary trueing so they’re not completely awful. I’ve submitted them for marking, I.e. I’ve taken them to the shop to be trued and tensioned properly. It certainly feels like getting my homework marked, and I seem to have managed another A+ if the look on the resident wheelbuilder’s face was anything to go by…