Much like the controversial ‘party in the back, business in the front’ hairdo, the mullet MTB can seem odd, but it has several practical benefits. Dedicated cyclists have been experimenting with mixed-wheel setups for several decades, trying to squeeze as much speed and performance out of their mountain bikes by bringing together the benefits of smaller and larger wheels. However, it took the bike market long to catch up with the trend. The vast majority of mountain bikes were manufactured with a single size for both wheels, and installing different wheels on one of these models was always likely to cause problems, particularly in terms of balance.
The first commercially-available mullet mountain bike, Specialized’s Big Hit, was released in 2004 with a 26-inch front wheel and a 24-inch rear wheel. It sold poorly and was eventually discontinued, as its conventional frame showed many of the same issues that you’d experience if you’d just customised a symmetrical-wheel bike.
Fast forward a decade, and manufacturers were finally starting to figure out the mullet MTB, with models specifically adapted to the mixed-wheel setup. And in 2019, the UCI (Union Cycliste Internationale) changed its rules so that bikes with different wheel sizes were now allowed to participate in official competitions. The success of mullet riders created a buzz in the cycling world, and the mixed-wheel design skyrocketed in popularity.
The most popular versions of the mullet bike tend to feature 29-inch front wheels and 27.5-inch rear wheels. These sizes are both relatively new to mountain biking, and they’re the key to the design’s performance on roads and trails, with just the right amount of diameter variation between them. They’re not the only options available, though. Depending on the manufacturer, you might also find 24-inch and 26-inch mullet wheels. If you want to brush up on your knowledge about mountain bike wheel sizes, take a look at this useful Canyon wheel size guide.