There’s some pretty inspiring bikes coming out of the Czech Republic custom scene these days, especially the off-road sector. One workshop that’s spearheading that movement is Tomas Kutin’s SingleBe. This is his latest weapon: the emphatically-named Rock’n’Rolla.
Tomas breaks down the story of the Rock’n’Rolla for us, in his own words: “It’s a fully rigid single speed 29er mountain bike with our tapered steel fork.
“The top and down tube is from Reynolds 725 heat-treated series, the rest of the tubing is no butted 25CrMo4, where the frame weight is about 2.15 kg and the complete bike weight is 10.5 kg.”
“Last year when Autumn time was coming, I started to think about constructing this bike. But due to a lot of work with regular orders this ‘toy’ had been postponed for several months. First intention was to have a reliable simple bike for winter rides, where I could apply some new concepts because ‘prototyping’ is what I really love.
“The target was to have a playful bike with fast wheels and responsive cornering characteristics. Such a bike which gives you a wide smile and calm mind after each ride!”
“Trail oriented geometry with short chainstays, which is between 420 and 432mm. Rigid taper fork simulates suspension fork with 120mm travel, head angle is 68 degrees and could be increased with 100 mm suspension fork. Also geometry could be slightly modified with rear asymmetric dropouts tensioning direction.”
“Our prototype fork has an oversized tapered steerer which ends with bottom oversize tube where the fork legs are welded on.
“This top part has the same diameter as bottom Nukeproof headset bearing and it creates clean and robust look.”
“My friend Richard from Dutch eRveha Bikes — the singlespeed genius — gave me advice about SS gear ratio. It is actually 32×16 so you can go quite fast on a flat course and you can also train your speeding/spinning skills. On the other hand you can overcome quite steep hill and let gears featured riders to look at your back!
“Due to some trial roots I installed bash guard just in case there are some ‘needs’ to ride over stones and obstacles… Also for the future SS drive can be switched to 1×10 or 1×11 drive, and you can install chain guide on the top arm.
“Internal cable routing for rear brake and also for possible adjustable seat post remote control. There are new eccentric dropouts. That was the choice because they are very easy to set, and you don’t have to re-tension chain every time when you remove rear wheel.
“The only keys that you need are hex keys 4 and 5, which are part of all the bike tools. You release the bottom security screw, and put the 5 key to the dropout which acts as an arm, tension the chain and fix the dropout with the screw again.
“Standard 135×10 goes through a DT Swiss axle, with quick release is a part of the system. Dropout travel is 12mm, so you should be able to tension one whole chain pair. Easy and light. After the first testing in hilly terrain and among big roots and stones, it seems that it is working perfectly—and the wheel is seriously fixed.
“Asymmetric BB area allows having big tire clearance (2.4″ in mud conditions) together with good chainring / chainstay clearance for all the chainring sizes and chain lines. Adjustable seat post control or possible rear derailleur hanger cables could be installed within top tube as well.”
“I had a chance to have a couple of rides with Rock’n’Rolla and that was enough to fall in love with. The bike accelerates like a rocket and it is very easy to do wheelie and it corners very easily. Unfortunately at the end of the photo shoot I had a small stupid crash on a local pump track and I have broken a couple of small bones in my both arms…
Another brilliant builder / rider that’s come a cropper over the last couple of weeks! Here’s hoping Tomas heals up fast so he can get out and enjoy riding Rock’n’Rolla some more. Head to the SingleBe website for more builds from the Czech workshop.
