What is a Frankenstein bike you ask? Well, it is a combination of wheel sizes, most commonly with the bigger wheel at the front and the smaller wheel at the back just like motocross bikes. It isn’t exactly a new thing and has been done by many riders over the history of cycling, but right now it is on the world stage with the UCI lifting the ban and allowing riders at World Cup events to do it.We just had the first World Cup at Maribor and the winner, Loic Bruni was on a Frankenstein Specialized Demo 8 running a 29er front wheel and 27.5 rear wheel. Now Bruni always stood by the fact he would never ride a 29er downhill bike but said that his testing showed the 29er front was great at not falling into holes, had a bigger contact point and more grip, and didn’t get slowed down by rocks and roots. He also added that the 27.5 rear wheel still allowed him to get back over the bike without getting his bum buzzed by the tire and allowed him to still accelerate on the pedals. A win win situation he said.
This has been the same thing said by most of the riders who were interviewed about their decision to go this way. Also, Martin Maes who has won the first two EWS Enduro rounds for 2019 is also running a Frankenstein bike for GT. It is a case of selecting the right bike to do it with, and most people convert their 27.5 to the 29er front, as putting a 27.5 on the rear of a 29er usually lowers the bottom bracket too much and the dreaded pedal strike happens.
I had my first ride back in 6 months after my broken leg, and my Dad’s bike is a Frankenstein bike, so I gave it a try. Even though it was my first ride back, I still know how a bike feels and what I like. Unfortunately, I didn’t like the feel at all. To me, it just felt unbalanced and I didn’t like the way the front and rear wheels felt different across the rocks and roots, and especially how I felt the bike slow down when the back wheel was hitting pot holes or rolling between rooty sections that the front wheel had just skipped over. I probably will try it some more and see how it goes once I get more fitness back, but I am a 29er rider, and just like how the bike rides with the same size wheels.
From what I have been reading and watching about people’s thoughts on the different wheel sizes, it seems that people think that a combination of both will be a great compromise and give the best of both worlds. I think we will see a lot more people riding these bikes, with manufacturers now bringing them out as standard eg. YT and Intense’s new e-bikes. It really is only a front wheel change if you already have a bike running the 29/27.5+ forks which a lot now do, so it isn’t really that expensive to try it out. Some will say it is a fad that won’t catch on, but then they said that about 29er’s and Ebikes and they are going gangbusters, so I think that only time will tell.
By Sam Luff - Pushys sponsored athlete