Back Issue | Bike Test: Zumbi F-11 Custom

The Number of the Beast

Sometimes it’s cool to do things differently, to be unique and to find your own style. When it comes to buying a new bike, we devour the magazines, digesting all the latest tech and innovation. Manufacturers dominate our biking culture, telling us what we need, what is cool and what will work for us. New models scream for our attention in a market saturated with amazing technology and positive reviews, and no matter what bike we chose, in a year we will be lusting after something else. But there is another choice: we could rebel against mass-market conformity, take a risk, and build something really unique, a real one-off.

We all love customising our rides, selecting each component to make it perfect for the trails that we love. But what if this creative customisation could be taken further, right to the very heart of the bike, the metal itself? What would you do if you could choose not only the colour and the specification, but also the geometry, angles, and the fit of your frame, free from the confines of pre-determined sizes! How would you build your own shred machine?

Now, everyone loves a hand-built bike, the plucky underdog. There is nothing cooler than welds that have been meticulously laid by hand, the ribbons of alloy portraying an art developed through years of practice. However, most bespoke bikes tend to be hardtails, and although they are things of beauty, they lack the capability to handle the riding that we enjoy the most! So, when a chance email from Pawel Matuszynski, owner of Zumbi Cycles, hit my inbox, showcasing his totally custom 150mm full-Suspension frame, the 650B F-11, I immediately picked up the phone!

Zumbi Cycles is a rider-owned company based in Poland, and they have been hand-manufacturing gravity and enduro bikes for nearly ten years. Prototype frames are thoroughly tested by a team of world-class riders, and as all the manufacturing is done in-house, Zumbi is able to rapidly turn feedback into production design. The welders and craftsmen at the Zumbi factory used to work on MIG fighter jets, so they are easily able to make a rocket of a bike. Now here is where it gets interesting, as each frame is built to order: for those looking for something unique, the F-11 is available with custom geometry. This allows you to choose the seat tube length, top tube, head angle, and many other options — so you can have a bike as unique as the trails that you ride! After many hours looking at geometry figures from bikes that I had enjoyed, I was able to select the characteristics that I liked and discard those that had not work for me!

Like Frankenstein’s monster, my custom bike evolved from a collective pool of awesome features. The bike was going to be used on some of Europe’s toughest trails, and be raced in the EWS, so it would need a high-performance and aggressive geometry! Thus it seemed right to start at the front with the head angle. I was hoping for a brute of a bike, a nimble but aggressive thoroughbred that could take on the toughest stages in Europe and laugh it off, a bike that would take me out of my comfort zone and scare the pants off me, so it was going to be very slack: 65 degrees, in fact!

Now that I had turned the geometry up to 11, the rest of the bike had to follow. For me, reach is everything; a bike that is too short feels nervous and unstable at speed, while a bike that is too long feels dead and unwieldy. I wanted to run a 35mm stem and 780 bars, and at 180cm tall, 605mm seemed the perfect length. Combined with the slack front end it should be stable at speed, and not so long as to understeer through tight turns. It needed to be long and low, so it was time to factor in huge standover, keeping the weight low and giving the bike a chuckable feel. We agreed on 430mm, giving the bike a really long and low front centre.

As I sent off the geometry to Pawel, I knew that it was going to be some machine! The rest of the options were more conventional options such as internal cable routing (not used as I swap test gear a lot) and 142x12mm rear axle spacing. I did not want any provision for a front mech, as this bike would be 1×11 all the way! We even designed the rear triangle to perfectly fit my favourite 2.35 Hans Dampf tyres, and with super short chainstays this was going to be a very special bike!

The F-11 frameset is Zumbi’s enduro/all mountain offering, with 150mm of travel in 650B, handmade in the factory from 7020 aluminium tubing with 7075 CNC linkages. Weighing in at 3.18kg with shock it’s a respectable weight. The 26” F-11 has been tested and refined over the last 1.5 years and this would be one of the first 650B bikes built.

The F-11 uses Zumbi’s floating pivot suspension (FPS) system, using four pivots to determine the start and end leverage ratios, wheel travel, and the influence of the suspension on pedalling and braking forces. The FPS suspension remains fully active during hard braking and with 6Al4V titanium for all the pivots and 150mm of travel, this is a bike you can really throw around. The shock drops right into the down tube, keeping the centre of gravity super low and helping keep the bike planted in hard corners.

The next month was an agonising but very exciting time as Pawel sent over photo after photo of the bike in production. My final difficult decision was what colour I would like, but in the end it had to be ENDURO magazine blue! Just a few days later a well-packaged frame arrived at the UK ENDURO Magazine office.

Unboxing the frame I was stoked, as even un-built the bike screamed speed and stability — it looked long, low, and slack and had an air of purpose, and it was certainly going to be a handful! But the best thing was that it was unique to me, built to my specification: I felt like putting this work of art on the wall! I now owned a hand-built bike that was truly individual. There are many bikes like it, but this one is mine!
I wanted an uncompromisingly aggressive bike, a bike that would reward speed and sometimes frighten me, a missile of a bike, and that is exactly what Pawel delivered.

It simply rockets down the trail, making me want to make jet fighter noises as I throw it though the corners. The FPS suspension system is highly effective, remaining sensitive under hard braking, and has quite a distinctive feel. I would not describe it as a super plush machine, as it does not have that bottomless feel of some other bikes on the market, and it’s more suited to a firm, fast and aggressive setup. I found that with 30% sag, the bike felt too sluggish and it seems to hang up a little on big hits; however, running 25% it flies. The bike skips down the trail, the low and wide front end urging you to go full-gas, dispatching the trail rapidly. The low BB works well with the long and low front triangle, and the huge standover and short rear end makes the bike feel like a mini downhill machine. It’s a proper ‘Rock And Roll’ bike which loves to be thrown into corners and encourages you to late-brake everything.

It was always going to be a risk creating such a unique bike; we did not know how it would ride until it was finally built up, but I could not have been happier. I wanted a bike for smashing runs in the woods, STRAVA battles, for local races and the odd big event, but more than anything, I wanted a bike that would make me smile, and that is exactly what I got. Every ride on this bike is rebellious fun! I am not sure if it’s the fastest bike, but hell, it feels like a missile at my limit, and that’s all that matters.

Price: € 1830

Travel: 150mm

Weight: 3.18 kg (with shock)

Geometry

Size: S / M (tested) / L / XL | Top Tube Horizontal:600mm | Seat Tube Angle: 73°| Chainstay Length:430mm | Head Tube Angle: 65°| Wheelbase: 1195mm | Seat tube:430mm | Wheelsize: 27.5″

Words: Trev Worsey Photos: Catherine Smith