What are mullet bikes? Bikes that have a 29in front wheel and a 27.5in rear wheel. There are hopes/fears that they're The Next Big Thing.

Are mismatched wheel size mullet bikes the next big thing? We’ve recently seen mismatched wheels on e-bikes. The Canyon Spectral:ON was the first big splash. Then only this week we’ve had the launch of the Intense Tazer.

It’s worth pointing out that these aforementioned ebikes have had 27.5+ rear wheels with tyre sizes of 2.8in. We’ve also had cult bikes – like Trek 69ers – from the 26in wheel size days.

Read more: 10 mountain bike products that refuse to die

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Intense Tazer with mismatched wheels

What about a modern era mountain bike with a regular 27.5in rear wheel paired with a 29in front though?

Bikes like this do already exist but they’re cult bikes from more obscure brands (Google for Foes Mixer or certain large sized frame options from Liteville) but are we about to see a whole lot more of them?

One thing that has caused the mountain bike chatterati to start gossiping about mismatched wheel bikes is the new rules from the UCI. Cycling’s governing body have released their new rule book and within is a relaxing of previous rules that bikes must have wheels of equal size front and rear. This is no longer the case. Well, for Downhill and Enduro racing anyway. The same-size rule still applies for all other types of cycling. Yep, including cross-country.

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Who wants mismatched wheels?

Currently, almost nobody in the general MTBing public. But in gravity racing circles – and in some dark corners of the trails populated by pioneering MTB gurus – there is a definite desire there for the ‘legalising’ of running mismatched wheels.

Why do they want them?

To get the both of both wheel size worlds.

Grip and rollover with the 29in front wheel.

With the 27.5in rear wheel delivering lower unsprung mass (lighter than 29in wheel and tyre) for better suspension performance, easier acceleration, claims of increased drive/pump-a-bility from trail features (ie getting ‘free’ speed from the backside of slopes/humps), shorter chainstays, increased tyre clearance, reduced occurrence of rear tyre buzzing your bum on steep sections.

Will mullet bikes ever reach the bike shop floors?

Hard to say. We doubt it’ll be a big thing. We doubt that many bikes will come supplied as 29/27.5.

But we wouldn’t be overly surprised to see downhill race bikes coming with such a setup. Especially in smaller sizes.

We also wouldn’t be surprised to see mismatched wheel sizes being designed into bike frames as an option for the owner to try out in the future. After all, we’re all fairly used to seeing new bikes coming with flip chips to swap between 29in and 27.5+ wheels.

No one bike brand is going to be bold enough to enforce a compulsory mismatched wheel size from the get-go on a new bike model but we reckon plenty of brands are going to start designing mismatch adjustment into their trail and enduro bikes.

It’s certainly one to keep an eye out for when it comes to next year’s bike trade shows and 2019 model years…