Reader’s Ride(s) ~ Jeroen’s Custom FatTi BR

Jeroen’s Custom FatTi BR – by Jeroen Oomkens

A short introduction of the builder of this bike, he’s a guy from the Netherlands, and yes, that’s the country which is really flat. So why go fat? He got a fancy for engineering and he likes his bikes. It started two years ago with his very first 26” custom titanium build hardtail, but he found the ride was to bumpy,(he called this a ‘duhhh’ moment)  because the geometry was partly copied from a Mountaincycle San Andreas which is a full suspension bike he rode for over 10 years. So a change was ‘needed’.  And one thing was for sure, no concessions were made with regard to the material for the frame, it had to be titanium, it’s just too d*mn sexy. After a lot of experimenting with different parts, such as the Gates belt drive, a Rohloff hub and fat tires, the conclusion was simple… Less is more, so after 4 months of designing an almost maintenance free (all-mountain) bike was born.

3D frame design

Most of the parts speak for themselves, the geometry is somewhat different in comparison to regular fatbikes. It is more all-mountain oriented and the frame has no offset. This limits the use of some tires, but that’s worth the compromise. The dropper post has proven to be a valuable piece of kit on the bike, especially with the fairly bulky Brooks B17 saddle.

Rohlof hub + Gates Centertrack belt drive + Hope M4 discbrake

The first reaction from onlookers is known to a lot of fatbikers… WOW, fat tires! But for those who are familiar to fat bikes, they are not so often equipped with a Rohloff hub, and let alone combined with a belt drive. This draws a lot of attention were ever you go.

The bike completed

In order to test the bike properly, some nice rides were scheduled.  The kick-off was a Marathon in the Belgium Ardennes, 65Km with 1700 vertical meters. It succeeded with flying colors.

Participating in Raid des Hautes Fagnes (4 hours of rain!!)

However the real deal began in Britisch Colombia were the bike came across some of the most difficult trails you can imagine for  2 whole weeks.  Here the climbs are steep, rooty, rocky and slippery and for the downhills just add some more gradient. Nevertheless, unbelievable fun!! After a few days of acclimatization to the beautiful surroundings, it looked like the bike was made for these kind of trails. In wet conditions a Surly Nate tire would have destroyed the trails, his Larry tire in the rear would occasionally slip and skid.

The very first ride in Canada – The epic trail “Comfortably Numb” in Whistler,BC or as locals call it Uncomfortable bum. So true…

After a fantastic flowy downhill on the Upper and lower Oasis trail in Rossland, BC the belt got hit by a sharp rock, that resulted in a deep cut on the belt itself. The next day it was time for the epic trail “Seven Summits”, after the first summit, the inevitable happened, the belt snapped in a small climb towards the second climb. You guys would think, that’s bad luck, indeed it was, because there was no spare belt. Why? Long story short, the postal service messed up with its delivery, and so it happened to be that the belt was travelling one day behind everywhere the bike went. – Dies diem docet- (We never stop learning)

Unfortunately/Fortunately, a rental was need for a few days, a regular 26” Giant Trance… short description, a chain driven derailleur bike, XC setup, boring! The bike climbed well, but s*cked downhill. This short experience on a regular bike taught a valuable lesson, once you have driven a belt driven bike or fatbike or Rohloff, you either love it or hate it. In this case it was all love at first sight. Of course all the parts on this bike has their own disadvantages, And the most critical one is probably its weight with a total of 31 pounds.

A beltless bike on top of Mount 7 Psychosis, stunning views!

The day was all about downhill, and said to be possible to descend chainless (read beltless). Bring it on was the thought! After watching some footage on youtube about this downhill called Mount Seven Psychosis, in Golden, BC, little spirit was left. This double black diamond downhill is insane!  But once up, you have to come down as well. Here some of the little geometry flaws showed up (maybe a bit less headangle and somewhat lower BB) . But mostly it was about the riders guts, you need serious balls the descend here. One of the co-riders managed the whole downhill on its 29r XC bike, also within a half hour, respect!!

Down on Mount 7 Psychosis, this was an easy part.

The last day of the BC trip the new belt (in courtesy of HC Gates Cooperation) was fetched from a Greyhound express depot in Banff. It was truly a happy moment when the new belt was assembled. And on the Jumpingpound trails the bike proved itself again worthy. The very steep rocky climbs and awesome downhills  were a total bliss! However you never know what the future holds, some bikes can be ridden for decades, let’s hope this one can last for a while 😉

On top of Cox Hill of the Jumpingpound trails in Kananaskis,AL

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8 Responses to Reader’s Ride(s) ~ Jeroen’s Custom FatTi BR

  1. Elvis August 23, 2012 at 5:39 pm #

    ok. Fatbike + Rohloff. I like.

    Is the rear end offset to allow the drivetrain the clear the tyre? Can’t really tell from the pics.

  2. Sean August 24, 2012 at 1:44 pm #

    This story highlights the downside of using belt drives on real mountain bikes. There is no trailside repair possible – you need to carry spare belts. At least you could always convert to chain drive by swapping out the cog and chainwheel, again if you carried spares..

    Sweet bike though

  3. plumberso August 24, 2012 at 9:03 pm #

    My simple Moonlander loves the Seven Summit Trail. Glad to hear of another fat bike in the Kootnays.

  4. Jeroen August 27, 2012 at 4:55 am #

    @ Elvis – This frame has no rear end offset. The configuration is such that the combination between the rim and tire leaves just enough (5mm) of clearance between the belt and the tire. It is possible to cheat with the Rolhloff and gain another 10mm extra clearance, but that’s still in process.

    @ Sean – You are so right. But carrying a spare belt isn’t that heavy 😉 …not the same as a repair chain linkage though 😉

    @ Plumberso – Sorry, it will take a long time for me to be able to come back some time 😉 But the Kootenays trails are definitively one of my all time favorites!!

  5. Sean August 27, 2012 at 1:58 pm #

    Jeroen: – no criticism as to your bike was intended – it’s a beauty (eh!). I just tend to prefer to stick to parts that are more readily available and reliable, and if they aren’t always reliable perhaps more common. 😉

    • Jeroen August 28, 2012 at 1:31 am #

      @Sean – None taken 😉 – And thanks! Honestly it was a gamble, I knew this could happen, and also anticipated it by having a spare send to me way early before I began this trip, however that one arrived home when the trip was already over. But nonetheless.. I would still recommend a belt drive (that is if this one will at least last two years) The belt is always performing well in all conditions, but having a spare is a necessity. If you ever got the chance to drive a belt one day… give it go 😉

  6. plumberso August 27, 2012 at 6:29 pm #

    Could we see or read more about your fork?

    • Jeroen August 28, 2012 at 1:46 am #

      @ Plumberso – The Flame fork is from German-A and is a standard upside down fork in their catalog and it comes in various versions. Sandman bikes and German-A developed a special version of the Flame that’s wider than their regular Flame. This version is able to carry a fat tire and can be ordered on request. The width in between the legs is 105mm, travel 90mm or 130mm (travel adjustment / climbing mode is optional), 20mm axle, no springs or oil baths, completely air adjusted, weight 1900 gram.
      Link to their website –

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