Agreed. A new batch of hubs was just produced - they are made in batches of 300. We’ll look at this for the next generation but that won’t be for quite a while.
On the frames, KH frames can’t get any thinner on the inside face and still maintain the standard bearing spacing. All I can do is try to control manufacturing quality on the weld bead, which can vary slightly in thickness. Before now this never mattered.
I had to shave off the inside face quite a bit on my KH36. It actually was not the weld that was rubbing. I did a first pass at shaving it down, and it would still rub intermittently. I did notice that there is some play in the bearing holders, so I think the wheel would shift to make it rub or not. I shaved more off, and now it doesn’t seem to rub anymore. I do hear a faint grinding sound from behind the dust cover on one side of the hub now. The cover on the other side had actually come off the hub from the rubbing, and I had a lot of grease leak out onto the frame (and my pants while riding around the plantsite at work). I put a little grease back in and put the cover back in place. It seems to be staying on for now.
I have a new hub with the dust shields and a 2011 KH 26 frame. I did not need to remove any material, clearance is tight, but I have had zero rub.
That said, it is mighty tight down there (0.5mm clearance per side) so if I ever developed any wobble or side to side play in the hub, it would rub for sure.
I’d like to see a 125mm spacing, a disc brake that is spindle or hub mounted, an option for a 25% step down or up, let’s see, uhhhh, yeah, that’ll do it for now
At last I have got My old (266) hub back this week after waiting almost all year! One of my Hub bearing’s sezied up two days before Karapoti Classic this year I unsezied it and over lubed the hub to race (ride).
I think that the slow speed of fixing/repairing is too slow and I have Sold my Triton (with repaired and up dated Hub) 26" to a Very fast Unicyclist so it’s going to a good home.
BUT this will be the Last Schlumpf Hub for me?
I’ll be building up a Design I have been working with the crankarms/hub not made SO wide I’ll be working around 80 to 90mm wide hub bearing set up. A custom saddle (a Bike Saddle with a Handle) 3 or 4 speed and quick change wheel bearing set up.
Unicycle design’s need up dating for the long ride’s that more People are riding, i.e. 50km’s +
See you out on the Tracks
PeteG…
bouin-bouin, I respect your expertise on the subject, but I don’t think your number is correct. I’m not going into the internals of the hub, number of teeth on the cogs etc. I just focus on observations about revolutions. I just checked with my KH/Schlumpf 29", bought in July this year.
If your numbers are correct, then if the cranks turn 16 full revolutions, the wheel should turn exactly 25 full revolutions. This is an easy check on your number. But if I try this, the wheel does NOT turn a whole number of revolutions, in fact it does about 24 and three quarter turns.
However, if I turn the cranks 11 full revolutions, the wheel does exactly 17 full revolutions. I did multiples of 11 just to be more accurate, and the wheel keeps doing exactly 17 revolutions. So 17/11 must be the true in/out ratio of the KH/Schlumpf in high gear.
This holds for the latest batch of hubs, and also for quite early hubs. I used to own hub number 00000006 (have sold it this summer). When I just had it, I measured the ratio also to be 17/11.
Thanks for the link - I vaguely remember that discussion. Can we be sure that those photos are of actual production KH/Schlumpf unicycle hubs? If so, it is an interesting puzzle how to get to 17/11. I cannot fully fathom if this is impossible or not. But I’ll eat my hat if the ratio of my hub is not exactly 17/11.
Hugo presented recently photos from the inside on the last production batch. I asked him if it is possible to receive them in high quality, this should help a lot to check is any change on cogs
The photos I posted for sure are not from the latest batch.
Under the assumption of planets with 15 teeth there is exactly one possible configuration resulting in a 17/11 ratio (solving the equation 11n = 6n + 2*15). That is a sun wheel with 36 teeth and an annulus with 66 teeth.
There was one photo I posted and the quality does not allow to count any theeth Also the other photos won’t help - and it wasn’t me who took the other pictures.
As far as I understood Florian, the gear ratio has never changed since he started to build these hubs.
Anyway, the planet gear needs to match with ring gear and sun gear; so ring gear primitive radius is the sum of sun gear and planet gear primitive radius
So ring gear teeth = 2 x planet gear teeth + sun gear teeth
66 cannot be seen on the photos mentionned in the link
Let me offer a new theory: from the first picture I posted before, a sun gear with 31 teeth seems reasonable. With that the annulus would turn out to have 62 teeth (planets with 14 teeth given), resulting in a gear ratio of 48/31, which is pretty close to 17/11. So after 11 revolutions of the cranks, the wheel would have performed 17.03 revolutions. That derivation of 0.03 is something that can easily be overseen.
BTW, I am still waiting for a response from Florian Schlumpf. He for sure should be able to answer that question.
Forget about that theory. I just did a spin test with 2 different hubs (M0502 and M0360). In both cases 17/11 looks perfect (even after 22 crank rotations), 25/16 is close but not more, and 48/31 is close as it’s close to 17/11, but after 31 crank rotations a clear derivation of the wheel position of about 1/10th rotation could be observed.
Schlumpf hub ratio is 17/11 (1 + 36/66 = 1.5454) as said by Florian and others
it’s based on : ring gear 66 teeth (and not 64 as I estimated) / planet gear : 14 / sun gear : 36
for that, Florian is using a special teeth machining (offset of cogs) to allow cogs meshing because impossible with standard machining as 36 + 2x14 = 64 and not 66 !
and this is also compatible with 6 planets (condition is : ring gear teeth + sun gear teeth)/ number of satellites = integer number --> 36+66/6=17)