Corbin, not only proportional on mass but also on diameter and this point is very very important for inertia. Some months ago, I calculated inertia of different wheels for a 3 gears hub project and the result is that KH 36" wheel inertia with 29" tube is 3 times 29" wheel inertia (with 2.3 WTB Stout) ! 36" tube instead of 29" tube on a 36" wheel is even 7% higher for inertia !
But I agree that on a 36" wheel, the only solution to reduce inertia is to reduce the weight as diameter is fixed ! Personally I ride a 29" tube on my 36", it’s much better but not enough according to my opinion. Light tube and tyre which were under development last summer are still not on the market. Please Roger, help us
I have a quick question for all the other schlumpf owners out there.
My number is 324 and its in a kh 26 with HS 33 brakes and 125 mm cranks and I’ve done a little over 1000km’s on it since the end of 2010 (and loving it).
The problem I’m having is that the hub seems to be getting more and more play in it.
I’ve had to move my brake pads out twice now and the wheel still hits if I try to idle or accelerate hard.
The spokes are at a good tightness, the wheel is nice and true and the hub cap is the right tightness.
Anyone seen it before, any ideas on what I can do.
Maybe I need a disk brake.
I’m trying to work out whether this is normal or not.
If its normal, I’ll try and live with it. Otherwise I need to decide if I need to send it in for repairs.
Looking forward to any help you guys can give.
Cheers
One possibility is that your frame is flexing, but that’s unlikely in a KH frame (unless there’s a crack in it). Grab both cranks and see if you can move them back and forth within the hub. If so, that’s a sign of a mechanical problem with the hub which will eventually result in failure.
Mass and diameter are no doubt huge factors. My curiosity stemmed from how similar the 26" wheel spinning in high gear feels to my ungeared 36" wheel, at a similar pedal cadence. Although both mass and diameter are greatly reduced, at a similar cadence the 26" wheel is spinning at a significantly higher angular velocity. Velocity is also a factor in the equation, right? I mean, all wheels have the same angular momentum while sitting still. Unfortunately, while I think I’m conceptualizing this correctly, the particulars of the math elude me (and I’m too lazy to research/learn it in detail :p).
I think the particulars of the math work out to be that angular momentum, in terms of gyroscopic effects, is a negligible factor in terms of the handling of the unicycle. The factors which matter are rotating weight and leverage. Leverage on a geared 26" is similar to (slightly less than) a 36" given the same crank length, which results in somewhat similar feel. Rotating weight is a good bit less on a 26" (unless it’s set up with major DH 3" tire and tube), so it will be somewhat more nimble. Other contributing effects are a smaller roll-over diameter, and drive train slop.
Hi; is it the hub with the small bearing or the large one? That seem to be a problem with the smaller bearing. I am living with it on my KH36; it also rubs if I ride really hard up really steep hills. The updated hub doesn’t seem to have this problem.
the 324 has new bearings.
find the problem:
move the tire sideward while observing the bearing:
is there tolerance between the bearing and the hub?
is there tolerance between the inne and outer ring of bearing?
I have had a corrosion problem in the bearing cause riding to much in winter conditions with a lot of salt on the road…
When I move the tyre from side to side there is a bit of play between the bearing and the hub on the outside of the big ring of bearings.
If I have the brakes right out it’s not too bad but then I can’t brake as effectively. lol
I still would not trade it. It’s the most fantastic feeling to ride.
I’m building up for 2 50km MTB races over the next 2 months so I’m wanting to make sure I don’t have any hub issues before the races. Napalm is doing the 100km option on one of them, but he’s crazy fit.
Out of curiosity, how many km’s a week do you guys ride on average and is it mainly flat or hill riding?
just trying to work out if my training is enough.
I supposed that.
You can send it to Florian and he will insert the bearing with loctide (I hill have a look wich number ), but I guess you wont do this
If you or some friend is experienced in changing bearings at bikes or cycles or so you can do it yourself and safe a lot of time…and cash for shipping.
I just remembered a dream I had last night. I was visiting somewhere out of town with my guni and my Schlumpf started making a bad grinding noise when I rode. I remember how awful I felt in my dream.
I’m glad it wasn’t real.
Perhaps I’ll treat my friend to a few milliliters of grease just to be safe. :o
I love waking up from bad dreams and hate waking up from good dreams. Sometimes I dream that I can jump really high on my uni and then wake up :(. I can’t even hop up a curb.
From another thread, Tholub said, “The geared 26 is designed to ride to the trails in high gear, and ride the trails in low gear. High gear off-road for most riders will be limited to smooth fire roads.”
What tire do you use? I worry about wearing down my off road tires on pavement. Is there a recommended tire that has a good bite on dirt yet won’t wear away on the street? It’s a 26 so there are lots of options. I’m getting sort of itchy to try my Schlumpf on dirt. First gear is easy, but mostly useless on the road.
I actually have a 29er, so the tire I use is the WTB Stout 29x2.3". It’s pretty good on roads and doesn’t wear down too quickly (plus on a geared unicycle your tire wears evenly). There is a 26x2.3" version of the same tire.
[QUOTE=mbalmer;1456750]
From another thread, Tholub said, “The geared 26 is designed to ride to the trails in high gear, and ride the trails in low gear. High gear off-road for most riders will be limited to smooth fire roads.”
QUOTE]
I ride my 24 guni in high-gear on “real” trails all the time. I think I need to make a video soon.
Here is another question, Tom and others. Do you carry a tire pump with you? I would ride to the trail (minimum 6 miles) with high tire pressure, ride the trail with low tire pressure, and then ride home wanting high tire pressure. When I ride short bits of road, I put up with low tire pressure (but it’s annoying). I suppose I could ride there, do the trail, and call for a ride home :D.
Unfortunately, while I think I’m conceptualizing this correctly, the particulars of the math elude me (and I’m too lazy to research/learn it in detail :p).
I remember how awful I felt in my dream.
Your trails look scary for high gear.
