Mullet Bike Conversion – GT Force / Crankbrothers E11 Mixed

YouTube video

We’ve been quite curious about all the hype around Mullet bikes (29″ front wheel / 27.5″ rear wheel), and seen top racers such as Martin Maes piloting those setups to great success on the EWS circuit. The curiosity brought us to try this out, by swapping some bits on our GT Force 29 Pro. Crankbrothers were kind enough to help us with this swap by sending their Synthesis E 11 Carbon “Mixed” Wheelset. As far as we know, they’re the first brand to offer a high end complete wheelset for Mullet bikes. Anyhow, to see the steps we took to make this conversion possible, while keeping proper geometry numbers intact, check out the video below.


The crankbrothers wheelset is tuned differently from front to rear, to meet the demands of Enduro racing and riding. This is done starting with a lower front and higher rear spoke count.

Additionally, the wider inner rim diameter of the front wheel provides a wider, more supportive tire profile in front, increased volume and contact patch.

The stiffer rear wheel supports higher loads, enhances stability and tracking at speed, and the narrower inner rim width provides a better tire profile for the dynamic forces a back wheel deals with.

Using a 160mm air spring ($42) we dropped the Fox Float 36 from 170mm down 10mm to help correct the geometry for the smaller rear wheel.

We used an offset bushing from Burgtec, to help lift the BB height up, bringing the bike’s geometry numbers back to nearly the same as before the wheel swap. We also put the bike in the ‘High’ setting, as it’s got two options.

After taking ‘before’ measurements, we installed the Synthesis E 11 Carbon Wheelset on our Force 29 Pro, and re-measured to see where things settled.

We were quite impressed with how closely we were able to match the stock geometry numbers. The BB height only dropped slightly.

Handlebar height remained in a very similar range, and the wheel swap put us at a desirable height of 41 1/2 inches. If we wanted to adjust this, an easy rearrangement of stem spacers could fine tune the bar height more.

These measurements were taken in the same place, on flat ground, and we were happy to find the same head tube angle after we changed wheels.

The numbers reflected in this project show that mullet bike conversions can be very effective if you take the right steps and have some options at your disposal.


After our first bit of trail riding on the new wheel setup, we’re extremely impressed, and certainly see the appeal. Having the smaller rear wheel allows more fun in the tight corners, yet the large wheel up front provides speed and rolls over trail obstacles with ease. We particularly noticed the compliance the Crankbrothers E11 wheels have, and the distinct difference between front and rear. We’d encourage curious riders to try a conversion of your own, and to keep the E11 “Mixed” wheelset in mind as a good candidate for the Mullet swap.

More at: GT and Crankbrothers

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