My friend Florian wants to prove himself once again! In his spare time, the man in his mid-forties rides in every enduro race he can find. Recently, his bike was stolen: a Radon Jab with a large front wheel and small rear wheel (Mullet). He asked me if I would lend him mine (Radon Jab Full 29) for the Chilli Enduro race on the Geisskopf. Of course, Flori!
How much faster are 29 inch wheels?
After the race, he was unhappy with his position and said he wanted to upgrade to a full 29; he would certainly be faster on that. When I told him that he had just ridden a 29-inch bike, he couldn't believe it. "Excuse me?" Flori had unknowingly carried out a blind comparison par excellence and felt nothing.
The question is on many people's minds: Which is better - mullet or full 29? Many manufacturers now offer bikes in both versions, such as the mail-order company Radon with its Enduro Jab. This made the bike perfect for our test. Would we be the same as Flori?
From a scientific perspective
The better rollover behaviour of larger wheels is not a matter of feeling, but of physics. Larger wheels hit the obstacle at a shallower angle than smaller ones, so they require less force to overcome them. They also have a larger lever arm, which means less energy is required. This results in more efficient manoeuvring on uneven terrain. And: Larger wheels absorb shocks. That's why there are already rumours that the next trend is just around the corner: 32-inch wheels.
A minimal difference
"For me, full 29 in an enduro bike is more of a fashion than a technical necessity," says bike designer Bodo Probst. "Hardly anyone notices the difference!" That's exactly how my brother Laurin and I felt when we tried it out for ourselves. We roared over the trails in Bikepark Leogang, swapped back and forth, rumbled over root carpets, sometimes up, sometimes down, jumped, turned, leaned to the right and leaned to the left - and felt almost nothing! Only when we pulled the bike into the manual was it a little easier in the mullet set-up. The large rear wheel also gave us the occasional "arse kick" on the high steps ("Ah - 29!") - it practically reminded us to position ourselves more centrally on the bike. The 29-inch wheel as a riding technique coach. David Trummer, runner-up downhill world champion, agrees: "I probably wouldn't feel the difference either. I don't need a small rear wheel on an enduro bike or any other bike with less suspension travel. That's because of my height. At 1.84 metres, I have enough legroom". Bike designer Peter Denk summarises the statement: "The smaller, the steeper, the less experienced, the better the 27.5"! However, he adds: "With e-bikes, the poorer rollover behaviour is almost compensated for by the motor. For me, the advantages of the 27.5 rear wheel outweigh the disadvantages: more stability, more braking power, less weight with the same puncture protection."
What now, Team Mullet or Full 29?
A 29er front wheel is set. We both clearly feel the advantages. In reality and in our heads. Perhaps a little more in our heads - the big front wheel generates a lot of mental power on steep sections and root rodeos. But the rear wheel? Laurin is certain after the test rides: for him, the choice clearly falls on 27.5 inches, because he likes steep, winding alpine trails and pulls manuals at every opportunity. Laurin is Team Mullet. I, on the other hand, like Full 29, and since I was told that Full 29 is faster, I feel faster on it. The fact that the tyre rattles my backside from time to time is a good signal for me: "Damn it, don't hang so far back!"
Expert opinions
29ers roll better over obstacles. Limiting factors: Leg length and the steepness of the trail. If you want to ride the steepest trails at 1.70 metres, you won't be happy with a 29er. In short: the smaller, the steeper, the less experienced - the better the 27.5. - Peter Denk, bike designer
I did a lot of comparison rides on my enduro test track. Although I often felt faster with Mullet, the watch said otherwise. I was always faster with Full 29. The better rollover behaviour is a fact, not a feeling!
- Christian Textor, Enduro Worldcupper
For me, Full 29 is more of a fashion for enduro bikes. There is hardly any difference in rollover behaviour. There may be people who feel it. But that's in the per mille range. However, you shouldn't underestimate what goes on in your head. - Bodo Probst, designer of the Radon Jab
Full 29 makes sense for me on all-mountain and trail bikes, and I'm "Team Mullet" for anything with more suspension travel. Especially in alpine terrain, the smaller rear wheel gives you more freedom of movement - especially when things get steep. And: the bike becomes more agile and playful. - Thomas Öhler, extreme biker
In downhill races, I always ride a mullet set-up on my Frameworks big bike. I have tested this extensively. With the small rear wheel at the rear, I'm simply faster in corners. - Asa Vermette, Red Bull Hardline winner
Interview with the 15-time German downhill champion, Marcus Klausmann
BIKE: Does the hobby biker feel the difference between a large and small wheel at the rear, i.e. Full 29 or Mullet?
MARKUS KLAUSMANN: If so, then only in direct comparison. I tried the "back-to-back" and decided in favour of Full 29 because it rolls a bit better. But of course I knew what was what. In a blind comparison, I can even imagine that a lot of it is a matter of the mind. That you can't feel the difference if you don't know which wheel is in the rear.
A placebo effect?
Yes, it's definitely there. You ride a Full 29 and inevitably think: "This rolls better!" Many things play a role in determining whether you get over a root carpet faster.
What do you recommend? Mullet or Full 29?
Counter question: What do you want to do with your bike? If you want to race Enduro, then Full 29. The big rear wheel rolls better, so it's faster. But if you're riding for fun and time doesn't matter, then I recommend the Mullet, because the smaller wheel makes the bike more lively and easier to corner.
And downhill?
I would never ride a full 29 in the downhill, but always a mullet. I've tried that out. But height also plays a role. It may be that I'm simply not tall enough for Full 29 (1.78 metres).
Does the steepness of the terrain play a role?
The difference is most noticeable on steep terrain. That's also the reason why Full 29 is hardly ever used in the World Cup. I estimate that a maximum of five athletes ride Full 29.
What do you think about the criteria of sustainability and robustness?
A good wheel is just as robust, regardless of whether it's 27.5" or 29". If you end up with a dent, it will happen with both sizes. However, sustainability speaks in favour of a full 29, as you can simply swap the worn front tyre to the rear.
Dimitri Lehner
Editor
