Burning Question: Are Mixed-Wheel Bikes Here to Stay?

Is mixing wheel size a golden ticket or mere sticking plaster? It’s now been well over two years since Loic Bruni and Martin Maes announced the potential of the mixed wheeled bike to the world at large at the opening events of 2019. In the subsequent downhill season we also saw Loic Bruni take his maiden overall World Cup win while riding a mulleted Demo. These of course were not overnight successes that were decided upon last minute but, as we’ll find out by talking to Bruni, they were the result of careful planning, foresight and a team willing to leave no stone unturned in their pursuit of speed.

Over 24 months on and more bike companies are rolling out production bikes that have been built around the mullet platform.

There is no reason that bike design should be held back by something so arbitrary as both wheels needing to be the same size and, after a raft of everyone putting smaller wheels, bigger wheels and seemingly just about anything that would fit, on either of their bikes, we take stock of how we got here and wonder whether this was inevitable due to the way we design and sell our bikes? And, is there a divergence between the need of the racer and rider? Might you suit a mullet better than you might have thought?

I spoke to some of the great and the good of mountain biking, each with their own unique insight into their own experiences with the idea - both the earlier adopters as well as the skeptical.


Firstly, I spoke to Mr Geometron himself, Chris Porter. Chris has probably forgotten more about bike design than most ever know so he seemed a very good place to start.

---

Chris, what were your initial thoughts when you heard about people slapping in smaller wheels?

I tested with Jack Reading and his team with 29 front and 27.5 rear at the Fort Bill BDS in 2016. They were all faster with the 29 front wheel, and in fact Jack matched the Danny Hart head-cam winning run time to the deer gate in training with the big front wheel, the lead and the neutral gear! But they didn't race on it because stupidly one of the team asked the UCI whether it was legal or not... No-one would have noticed!

Nicolai and Geometron now offer a mixed wheel bike as well as mutator chips - is this a long term trend? Can you see the flat 27, as we’ll call it, being culled out altogether?

I see this set-up working for more people than the full 27.5 pairing but it will take a long time to filter through to production because production managers will find it difficult ordering two different sized wheel. Oh well… We designed the G1 to be able to run the hybrid (mullet) set up from the off. I have been using it for 5 or so years non-stop and the way the bike steers with this set up just suits me. So we wanted to make sure we could cover full 27.5, hybrid and full 29 in our design…

Do you think it’s possible to make a good job of a mullet without substantial changes to the frame?

Most 29er bikes have too high a bottom bracket and too steep a head angle so hybrid really sorts the handling out. I remember Steve Jones doing this on a Trek years ago and loving the resultant Frankenbike.

The reason it works is the rear wheel tends to steer more when the head tube/front axle is higher than the rear. In my mind it means that the bike is still steering in the middle of the turn and doesn't require too much steering from the front tire to finish the turn. It won't suit everyone and really good riders will just adapt their weight shift and steering to make the bike work with whatever wheels are on there! For an old dog the new tricks come with set up.

---

Is it a man? Is it a plane? Is it a racer with a keen eye for UCI legal sub-clauses and a love for a Patrick Swayze’s luscious 80s hair? No, of course, it’s Super Bruni. Loic Bruni, in fact, if we forego crowd-adorned-titles. He instantly felt that the mullet platform had a lot to give, but he was well aware of the issues around racing legality. I spoke to Loic earlier this year during the off season.

---

So Loic, in regards to refining the wheel size idea, how much difference is there from the first experiment compared to your current bike?

Not much difference, we totally adapted the geometry to this wheel size setup before we even started riding the new Demo. We readjusted a lot the winter previous to 2019 to be ready for World Cup 1 and since then we are fairly close to the first experimentation. I was against full 29er, not so fun and not fitting my style. So it was the perfect choice for me.

What was your initial impression and who's idea was it to change? If racing was off the table what wheel size would you be on?

My mechanic had the idea to change for a while but this UCI rule was in the way. I could feel that Specialized was pushing the team to hop on 29ers, so I really pushed Laurent to work on the “political” side of it and have the rule removed. This rule was useless for our sport and I saw the opportunity to get a compromise and come up with something new. Even though Specialized did it ages ago with the BigHit, it was new in racing and I wanted to be one of the pioneers. Specialized was seduced with the idea of showing up with a brand new bike made for 29/27.5.

I’m pretty happy the UCI was smart enough to allow the withdrawal of this rule and push the sport a bit further. I think we shook up the industry when I see what most of the brands sell now.

If it wasn’t for racing I would still run a mullet I think. It’s such a good mix of everything. Efficiency and fun. I’d be curious to try a full 27.5" again to see. But the grip and the stability the 29 front wheel brings is insane in the brain.

---

So, if Bruni was so convinced of the benefits of a mullet, I wondered if it was a one-size-fits all solution. Somebody I immediately thought of was Veronika Widmann, who enjoyed multiple podiums as well as third in the overall aboard a 29er, in a year many of her rivals were mixing wheel sizes. It seemed somewhat peculiar that the 29 inch downhill bike, initially talked of as bringing a bazooka to a game of conkers at the start of 2017, now seemed the more conservative platform. So, I wondered what it was about it that made Widmann feel so comfortable? I spoke to Veronika during the off-season as announced her move to Madison Saracen.

---

Veronika, Despite not being in the 180cm plus height bracket, you seem very at home on the full 29. What do you put this down to? And what’s the feeling you achieve that you couldn’t on the smaller wheels?

I am 170 cm tall. Of course first I was a bit skeptical about the full 29 but trying it out I soon felt at home on it. Of course on some tight switchbacks it was different and maybe a bit harder to maneuver around, but on the rough stuff the bike felt smoother and I had the feeling I have to put less physical work into simply holding the bike. The fact that in these days World Cup tracks are getting faster with bigger jumps ect, the full 29 bike also felt in favour for that. I also have to say at that point I never tried a mullet version but the 29 definitely suited me more than 27,5. However, there are more factors to a successful year than just a wheel size. Confidence is a big factor, and the more you spend time on a bike, the better you feel and the faster you get. That year I spent more time on that bike than in previous years, also in the off-season.

You spent a lot of time on a 29er (a YT Tues) - did you suffer from any of the issues associated with tire to backside clearance? And, if so, what did you do to alleviate these?

I guess you get used quite quick to the bigger wheels and adapt your body position on it. I would also say my natural position on the bike is more over the front, so backside clearance has not been a big issue for me.

Over the winter you must have a lot of time to ponder your new setup. Do you have a curiosity about the mixed wheel setup?

I am feeling very good and completely recovered after my injury. I will ride the Saracen Myst with 29" front and 27.5" rear. I am still in the early process of adapting and figuring things out, so I don’t feel I can say too much about it just yet. The first feeling definitely felt really good which I was surprised at given two years on full 29. As I said, I’ve never tried a mullet setup before so 29 felt good to me, but this new setup might even be better. At the moment I feel that the stability of 29 is there, but under turning the bike is more nimble and also feels like it pumps better when getting up to speed. I guess this could also be down to the Saracen though.

---

Will You Be Riding A Mullet in a the Near Future?

Riders like Bruni and Widmann are elite athletes, and maybe their demands differ from ours - but what about us mere mortals? Not everyone goes out to go as fast as possible. Some of us just enjoy the age old pastime of dragging brakes and casing jumps.

The racers will always do what they think is fastest, but it is of course the masses that decide what trends hold sway over the course of time and stick around in a broader sense. I’m curious to know, are we, the great unwashed, actually interested in taking brands up on their offer of mixed-wheeled-nirvana?


There does seem to be a genuine interest from the consumer and that is of course vitally important. Bike brands can often occupy themselves in our minds, as well as our hearts, with both fondness and sentimentality, but whatever it is you feel about a brand ultimately they’re not philanthropic exercises and they do need to clear the books in order to function.

I think that we’ve gone through the early teething stages of, as Chris Porter alluded to, “‘kin hell, let’s get that head angle back in line! Somebody, pass me a small wheel!” and then saying that the bike that was perfection a couple of years ago is now magnificent and cutting edge again if only reincarnated.

I like the idea of modular design within brands, and if done correctly it could make bikes cheaper and increase their versatility. I also like what some brands are doing by making separate, mixed-wheel specific rear ends, although combining multiple travel platforms as well as mixed wheel sizes might get a little complicated. Changing the bike with aftermarket kits might not always be cheap as you would hope, but I’d like to think that the cost saved by the brand would filter down the consumer in terms of initial retail pricing.


But, what about those mainstream brands? What do they think and what have they got in the pipeline? I got in touch with Lars Sternberg at Transition, a brand that is known for progressive bikes and often being on the right side of development history, about where they see the mixed wheeled platform going in the long term as well as what it means to their customers today.

---

As a company that supports a variety of riders, you certainly have different demands to satisfy. Do you think that we’re going to see a divergence between the bike of the racer, these big brutish 29ers, and the bike of the customer, who may well not desire the same characteristics?

Not only do we have a wide variety of riders we support, we also have a diverse mix of riders within the walls of Transition. We have employees out racing regularly, in fact, one of our employee's John Richardson is over in Val Di Fassa racing the EWS this weekend. We have other employees that just like to get out and enjoy riding without any racing. The same could be said for the variety in our customer base as well. As to whether a certain type of bike is better for the racer, weekend warrior, etc.. is for them to decide. So for sure, we will continue to make bikes that we want to ride and we will continue to have a variety of options for our customers.

If we look back on the past decade, Transition has been relatively quick to cater to the demand for each wheel size. It wasn't so long ago the industry was awash with plus tire compatibility. With mixed wheel bikes, do you feel this is initial curiosity or something longer-lasting?

Our recently launched Patrol is our second foray into mixed wheel territory, and time will tell if the mixed wheel options will expand within our model line. Thankfully we haven't had to eliminate any plus size models because we felt all along it wasn't for us. That said, we certainly aren't expecting to have to get rid of any bikes with the mixed wheels. We live in a great time as mountain bikers; there are so many great bikes to choose from, and all sorts of different configurations to serve all kinds of riders.

In your 2021 range you have included mixed wheeled bikes, are you seeing much interest from the consumer?

Absolutely. There are definitely some folks who feel like it's not for them, which is fine. To each their own. In those cases we have dual 29 and 27.5 bikes to choose from, the more options the better in our eyes. We have had great response to the Patrol updates, as well as the Spire which has the ability to be ridden as a dual 29 or mixed wheel bike.

It could be argued that the coming of 29 inch wheels was largely customer-led, as opposed to 27.5 which perhaps got a leg up from an industry push - where do you see this change coming from? And do you ever see the full 27.5" bike going the same way as 26"?

That's a great point. I will also add that the customer's interest in 29 wheeled bikes was aided by a major industry-wide revisit to the 29 chassis and geometry. A lot of bike brand's current 29 bikes were revamped around a similar time period with big improvements in handling. There are most definitely customers who still prefer a dual 27.5 bike, there might not be as many as say 3 years ago, but they're still out there. We're seeing a trend for less sales in larger size 27.5 bikes, but increased sales in smaller size 27.5 bikes. To the question, I'd say we don't see 27.5 bikes going the same way as 26.

---

There you have it - four different perspectives on mixed-wheel setups. Pinkbike tech editor Seb Stott recently did a round of testing with a 29" vs. a mixed wheel setup - if you haven't seen it, be sure to check that out here.

Posted In:
Reviews and Tech World Cup DH Burning Question Chris Porter Lars Sternberg Loic Bruni Veronika Widmann