Schlumpf hubs: general discussion.

Is there a certain point where after you break X amount of spokes you should just completely rebuild the wheel with all new spokes? I hadn’t broken a spoke on my geared 36 for the first 700 miles or so, but now I have broke 4-5 spokes and keep getting it trued. I also just got my first flat tire EVER in my many years of riding a 36er =[. I wonder if it had to do with overtightening one of the spokes or something.

Ken said it is best to always use a new set of spokes when building a wheel. They build internal stresses that can’t be seen when the wheel is built.

Was your wheel built with a tension meter, or just by truing?

FWIW, my wheel that I built with Chuck (without a tension meter) lasted quite a while before I started popping spokes. Eventually the hub failed, and I rebuilt it with a new set of spokes.

But, I don’t really know the answer to your question.


If you broke the 4 -5 spokes all in a short period of time (am I reading this right?) I would consider rebuilding the whole wheel with new spokes.

When I bought my 36’er I had 3 spokes fail not long after I bought it. Shortly after I replaced them another 3 broke so I had the whole wheel rebuilt by someone who knew what they were doing. It was 12 months before the next spoke broke and then 6 months before a second spoke broke.

Good quality spokes help too.

(What am I doing in a Schlumpf thread?)

wheel building

It is possible that with all the messing with your nipples (perv!) the thin rubber band that protects the tube from the inner side of the nipple could have gotten dislodged, twisted, or pinched. You should always take the tire off to do much of anything with the wheels, and if you’re doing more than a truing touch-up let the air out of the tire at a minimum- and be sure to double check the protector whenever you have the tire off.

That said, replacing all the spokes and rebuilding the wheel is really more of a comfort thing- as mentioned, use good quality spokes of a large enough gauge, if you’re breaking too many you may want to bump up the gauge a step to make them stronger (and heavier). Personally, I go for beefy spokes on my unis, because I’m more concerned about what happens when I take my 36" down a flight of stairs than the extra grams of spoke weight. (I also happen to use extra thick thorn resistant tubes and kevlar thorn protectors on all my unis for peace of mind- they work against glass in the urban jungle too, and I’ve pulled glass pieces out of tires without flatting before. It weighs more, but it makes me feel better, and I’ve never gotten a flat while riding that way, not even a snake bite/pinch flat.) If your spokes are too thin gauge, it won’t matter how well built your wheels are.

Good luck!


To respond to the three replies above…

My wheel was originally built by a wheelbuilder back in DC, but I don’t believe he had a tension gauge…he did it by feel. It was great for 700 miles. After I broke a spoke, I brought it back to fix it, a quick fix was done and not much more effort was put into it…I immediately broke another spoke on my next ride. I then brought it to a friend who is a great wheel builder and he used a tension gauge to true up the wheel and replace the spoke…and the wheel seemed really nice. After <150 miles I broke another spoke, and had someone fix it up and then I had a flat. So it is very possible that it was overtightened and I had a pinch flat.

I just ordered a few more replacement spokes from UDC with my last order (gonna try out 165mm cranks and the KH T-bar) - so I am now going to bring it to another bike shop to fix up the wheel. If I get ONE more broken spoke…I guess I should give up hope and order a whole new set of spokes and get someone to completely rebuild it.

I have never had any issues with broken spokes on my ungeared 36er, but I am sure that the extra force from the high gear and the fact that I use a brake with my g36 doesn’t help. It is getting to the point of being very annoying and I hate it when my ride is not reliable.

Would 4 cross help my situation out? I know most people just use 3 cross, but maybe my wheel would be more reliable with 4?

You probably remember this thread about spokes breaking since you were in it. Where are your spokes breaking? Did you try spoke washers? I’ve only had one spoke break on my latest wheelbuild with the M3 stainless steel washers so far. I don’t suppose you get the same problem with the hole being too big on the geared hub.

A 4 cross wouldn’t help.

Why is that? I would trust your judgment more than mine since I have zero wheel building experience, but the Schlumpf has pretty large flanges, and from some brief research online it seems that 4 cross is better suited for large flange hubs.

It is just what I heard from some sources; the extra strength isn’t worth it. If you are breaking spokes, it is probably due to the wheel build.


I just got my wheel back from a good wheel builder here in Denver and he also confirmed that 4 cross would not be good for the geared 36er. There was a long explanation. I will be taking a wheel building class sometime soon because I need to learn how to build and true my own wheels.

The wheel feels great now, even tension and true. I can’t wait to get back on my g36 and try out my new saddle and KH T-bar and 165mm cranks.

Just wanted to update this…165mm cranks on the geared 36 feel awesome. It is noticeably slower in low gear but high gear feels great, and shifting is actually very easy (I think I was just having problems with 165s bc Roland’s pedal/shift button set up is different).

Once it gets a little warmer I will tackle some mountains out here and see how the set up works. I think 165s will handle long mountain climbs in colorado better than 150s.

The T-bar is pretty cool as well, it feels nice having the handle in a comfy position a little bit further out than a T7, but I do miss the control and acceleration I got with the shorter handles on my GB4.

I love my kh/schlumpf!

Last week I ordered a KH26x3, 137/165 dual moments and a Schlumpf hub. I can’t wait to ride it but since I often ride on muddy trails I wanted to know if the dirt can be much of an issue. Do you clean the hub and cranks everytime it gets dirty?

And another concern is about shifting by accident. Does this happen often or never? I am thinking of riding technical XC/downhill trails where bumps may cause your foot to move on the pedal and then you shift… and… UPD :roll_eyes:

So far, I never shifted by accident, but: I do not ride on really rough terrain with my KH29. I would say that it can happen if you are really unlucky, but it should not be a big issue. My guess is that it will happen much less frequent than UPDs for other reasons.

I haven’t really ridden in really muddy conditions with the schlumpf but I’m sure it will be just fine.

I have never accidentally shifted and you shouldn’t have any accidental shifts with those long 165s.

yes it happens, at least it did for me, not just once, several times… that’s why on don’t ride a schlumpf at the moment on my 26" (for a time i took the caps out and shifted gear bay hand…) an other reason was the weight, because i do alot of hiking in my muniing… …but it looks like i’m going back to a schlumpf on the 26er…

Am I right if I assume that UPDs because of shifting by accident can be quite nasty? Another reason for wearing my protection gear :sunglasses:

i’m not sure, but mostly when i shifted by accident it was from low to high gear, when it was really technical, with hopping, so it wasn’t that nasty (means not in highspeed, but maybe nasty because of the unfriedly upd-terrain… if you know what i mean :smiley: ), and it kinda shocked me everytime, because i wasn’t ready for that…

Yes, I know what you mean :wink: What I was thinking about was the half rev (or how long does the shifting process last?) you are coasting after shifting. Isn’t that an issue when you have a lot of pressure on the pedals?

I’ve had two unintended shiftings in the two years I’ve had my Schlumpf. Both from low gear to high, and both with 165mm cranks. On the first one I was just riding down the street at a very modest speed and my heel hit the button just right. There was a fair amount of slop in the gears on that shift so I landed flat on my butt. Fortunately, I had my backpack on with my laptop in it. So my computer protected my valuable equipment (my butt) from serious damage.:slight_smile:

On the second event I was riding pretty fast through town when I accidentally shifted into high gear. There was virtually no slop in that shift and I seemlessly shifted into high gear and kept riding. Woo Hoo! What a feeling!


A couple of things I have come across with my Schlumpfs:

  • Serious mud can be problematic because it fills up the little screw in the shifter buttons. The dirt has to be taken out of there before any adjustments are tried on the screws.

  • Accidental shifts haven’t happened often but I think they are more likely to occur in technical terrain, which is where they are the most unpleasant…

  • Sometimes the shifting happens at an unexpected time, quite a bit later than initiated, which can lead to UPDs. This is usually when shifting up.

  • On my now retired 26er hub (waiting forever for the replacement) I noticed that sometimes when I did small drops (in low gear) the cranks would slip one slot further or something like that. I haven’t ever heard of anyone else who experienced that, though.

  • The 150mm cranks are fine for most of my rides but I am thinking about getting some 165s for steeper climbs. Accidental shifts would be pretty much impossible on those too, I guess, especially with not so large feet.