Downhill Schlumpf on fast flow trails in Bike Parks

So just built up my Schlumpf in a KH 29 with the Duro Crux 29x3.25 and 137/117mm Spirits. Yesterday and today went for my first off-road rides and liking it a lot: Shifting up and down is working pretty well.

Really only one concern/issue at present:
Even though I’ve been doing lots of DH muni on the normal 29+ as well as lots of XC on my 36 with 125mm cranks and lots of uphill, also on short cranks (125/127), I still feel like the Schlumpf (29+ currently with 137mm cranks) stresses the knees a lot more. Just from the raw math it does a little: 36"/125mm10mm/1cm2.54cm/1"=7.32 gain for 36" vs. 30.5"/137mm10mm/1cm2.54cm/1"*1.55(Schlumpf)= 8.76 gain for 29" Schlumpf, which is 20% more. But it feels like more than that. My guess is that both the play in the Schlumpf that delays the feedback just a touch as well as the relationship between higher gain but smaller wheel means that the angle the rider/unicycle is off balance when the feedback “arrives” is then greater in relation to the wheel size, so the necessary force of correction in even higher than 20% more.
As a result it is much more stressful for my knees (I’m hoping most of it is just because of something new and my knees will strengthen and adapt to it).
Plus it’s just so tiring and taxing. After maybe an hour of schlumpfing on trails I feel like I’m drained like after a massive race or a half marathon run (and I am in pretty decent shape after just having done 3x DH,XC and uphill races the last 6 weeks in Italy).

Although I’m interested in using the Schumpf for longer tours, getting to the trailhead faster and for XC, what I’m really interested in is riding fast flowy trails like in Downhill Bike Parks.

In the past I’ve ridden non-geared unis in quite a few bike parks (Whistler, Crested Butte, parks in the Austrian Alps, etc.). It was a good experience but even on a 29+ with 127mm cranks it’s just not fast enough to really ride the trails like a mountain bike: i.e. it’s just too slow for the banks, berms and up and downs that require lots of momentum.

Last summer I borrowed a 29" Schlumpf from a friend for a few weeks and got to ride once in a bike park: I was there with mtb friends and biked a bit and then took the unicycle for 2 runs. The first run was fun but really hard. Almost every single transition in every “flow” part of slightly uphill threw me off, so that I would ride 10 to a few hundred meters and then dismount. It was of course very tiring. On my second run I greatly improved on the transitions between up and down and was able to ride with flow. It was really really fun but also incredibly tiring. I guess it was basically max power/concentration almost the entire time just to stay balanced over the ups and downs. But it was SO fun.

So my questions:

  1. Anyone else riding flow trails with the Schlumpf? experiecnes, impressions?
  2. Why is it that I’ve heard almost nothing about Schlumpfing on fast flow trails? I was just in South Tirol for all 3 stages of the Italian Muni Race, where about half of the best DH unicyclists in the world live and train (Rabensteiners in Villanders). And while many of them own Schlumpfs, they said they don’t really ride DH on them (they ride DH on non-geared 27.5" with 110-117mm cranks)

Next week I’ll be in Finale Ligure Italy, which is a MTB mecca with lots of flowy DH trails and lots of shuttle companies. I will give the Schlumpf a try, although I’m not sure if I’m yet strong enough to do a full shuttle day with mountain bikers (5-6 downhill runs for the day). I will probably start with a single one-way shuttle and see how fast I am and then go from there.

I think you need to add “beginners’ inefficiency” to the equation. Just as beginners burn out after short distances on un-geared unicycles, you are also burning out on the geared unicycle because you have less experience on a guni.

What you mentioned about larger corrections manifests itself in the use of the fast-twitch muscle fibers as opposed to slow twitch muscle fibers, causing you to burn out faster. Larger corrections = more force. For me, getting-tired vs. not-getting-tired seems to have more to do with thresholds of effort than it does total energy expended. I am pretty much of a novice on my geared unicycle, and when a lot of corrections are a part of the equation, I find the geared unicycle more tiring for the same ride.

I have no idea how people like you are able to ride on such short cranks. I would feel totally out of control on a G29/137 setup.

Let alone down a bike park! :astonished:

I still run 150’s on my G26er and find it best for steep climbing (20+ grades) and in high gear it moves like a bat outta hell! :sunglasses:

Finale Ligure report

Just returned from my trip to Finale Ligure. I did a fair amount of freeride mountain biking (2 days of shuttling plus some pedal tours) as well as muni.

I used the Schlumpf muni 4 days (2 freeride runs of about 500 meters vertical each and 2 XC days) and here are my impressions:

  • my knees seem to be getting used to the extra stress, so I think that is mostly a training/accommodation thing (yeah!)
  • I was able to ride the S3 freeride/DH trails well on the Schumpf: the easier sections as hoped in high gear, and the very rocky technical sections in low gear (and then much slower)
  • However I think it is nearly impossible to use Schlumpf on a full day shuttle tour with experienced freeride mountain bikers (I was *really* fast on the mtb and sadly I just don't think it's possible on the uni even with the Schlumpf). In order to shuttle with a group, it would have to be a beginner/intermediate group where the speed is not so fast and with frequent breaks, otherwise the muni just can't go fast enough.
  • XC tours with mountain bikers is generally feasible if the bikers aren't racers (I was often much faster on the uphills), although on longer flat or slight downhill sections on fire roads the Schlumpf is still slower (I presently max out around 24km/h with the 137m cranks although faster should be possible with more training)
  • likewise on flat road sections: I was with a group of 3 relatively fit mountain bikers for around 10-15km on the road, and they had to purposely relax and ride slowly to wait for me, as I was only averaging about 22km/h whereas if drafting in a group of three they would have ridden 30-32km/h (thus, they had to wait about 12 minutes total over the 15km). However, with the Schlumpf it was still feasible to ride with them, as without I would have been more like 16km/h, which would have been even 15 minutes slower over the 15km (so they would have had to wait 27 minutes for the 31km/h pace of 29 minutes instead of 12 minutes, which I think it a big difference). With "leisure" bikers averaging more like 25-28km/h it should be totally feasible, even for longer distances.

My shifting is improving although in high-stress situations I still need more practice (e.g. going fast downhill in high gear and then a really technical section approaching where I need to downshift, or when in car traffic)

A good friend of mine from Vienna did a mountain bike race last Saturday with his Schlumpf 29 with almost the same setup as mine (117/137mm dual cranks) and did very well. The course was 42km with 900m vertical and he finished with a time of 2:40h (average speed of 15.8 km/h is pretty good).

We’re hoping to ride together in bike parks soon, but sadly Vienna is about 4 hours from Munich, so not so easy to make it happen.

short cranks

I think this is spot on and I can already tell I’m improving, although I think I can improve a lot more :slight_smile:

Since first riding with the Villanders DH muni riders (a uni club in South Tirol with many of the top muni DH riders) about 2 years ago, I was introduced to the short cranks for DH. At first I also thought it was crazy/impossible, but now I am quite comfortable with 127s on my 29+ for DH.

Florian Rabensteiner and the other top DH riders (at the last Unicon they took places 1, 2, 3, 5 and 14 in the men’s elite DH and places 1, 2, 3 and 4 in the women’s DH) presently ride 27.5" with 110-117mm cranks for DH and are insanely fast!

However, with the Schlumpf in high, it is the slight uphill/transition sections of the DH trails that really get me: i.e. where the trail briefly changes from steep downhill to a short uphill over a small bump of ridge. With a bike you just open the brakes and use momentum to the top and the keep going. But with the Schlumpf it changes from controlled braking at speed to quickly reduced speed and then uphill incline where the force required to push the pedals is very high. For me, this seems to be the key to riding a Schlumpf in a bike park: if you can’t master the uphill transition then you will be constantly dismounting, but if you can, then you can keep the momentum and ride and ride…

I ride a lot of flow style XC trails with mixed DH/Tech sections locally. I had my Schlumpf hub in a G26 for a year, then a G36 for a year, now a G29 (only a few weeks). I ride 150mm cranks, but have tried 137mm on the G26 and it was ok.

My Experience is as follows:

  1. The leg stress and fatigue decreases with practice but “nothings free” on a muni. You use more energy to accelerate and maintain the extra speed of the Schlumpf.

  2. The Schlumpf really is best when you know the trail well and you already know where the best sections for high gear are. That way you minimize un-needed shifting. The best sections for me usually involve few/no steep dips, rock gardens or sudden tight curves. Personally I get the most gain from high gear in flat or gentle sloping sections. On steep slopes I often find the lack of control at speed (and the cost of falling) too high. I have improved significantly in conserving momentum over short uphill bumps and staying in high gear, so I expect you will too. Riding steep slopes in high gear is probably a similar skill to riding them with short cranks.

  3. The main drawback of the Schlumpf is the coordination and energy it takes to shift while riding. These skills improve much with practice of course, but still take effort and the schlumpf will always have a bit of uncertainty in the timing of shifting. I often have UPDs while missing a shift down before a technical section.

  4. G29 has been an excellent wheel size for flow trails. I have enough control and power for technical sections and climbing, and the speeds in low and high gear are a good match. G26 was a bit unstable and low gear was a little slow, so I pushed myself to be in high gear too much. G36 was great on flatter XC trails - smooth, stable and fast, but a little bulky on technical stuff and steep climbing was too difficult. Also I never got to a fast cadence in high gear offroad.

  5. I can keep up well with casual/slower bike riders on the G29 (or G36), but it is very difficult to match serious bike riders except sometimes on steeper climbs.

You might also consider trying 150mm cranks for geared DH. I have found a big increase in control between 150 and 137mm cranks in high gear. This would allow you to stay in high gear (and on your uni) for more of the course.