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News & Updates
27.5 inch – the perfect blend?
10.13.2008 - Australian Mountain Bike


The emergence of the 27.5 inch, or 650B, wheel size is meeting a mixed response in the mountain bike industry. To some it is an exciting evolution that will improve and refine the way mountain bikes handle; to others the move is another unnecessary step away from the standardisation, that will further muddy the waters. We caught up with Kirk Pacenti, pioneer of 650B, to find out more.


AMB: Hi Kirk. Can you tell us what inspired you to develop the 650B wheel size?

KP: Lot’s of things, but primary impetus for the 650B wheel design was my increasing frustration in designing frames around 29” wheels. Don’t get me wrong, I like 29ers, and have been a long time advocate of the wheel size. And to be fair, when 29ers were being developed no one envisioned a 5” travel full suspension rig as the “everyday, every man’s mountain bike”. Ten years ago 5” was still the realm of Free Ride and DH bikes.

But as suspension travel increased for XC and Trail use, so did the compromises designers had to make  simply to accommodate the 29” wheel in a frame with 100mm or more of suspension travel. I have come to the conclusion that one can’t design a ‘proper’ 29er full suspension bike with more than 80mm of travel, and I am not alone in that assessment.

From a designer’s point of view, the strength of the [650B] wheel size is that it allows a frame to be designed with 4-6” of travel or more using pretty standard and well proven 26” wheel frame geometries. Basically you’re getting most of the benefits of a 29” wheel in a tighter, lighter and better handling package. It also works well across a much broader range of frame sizes and platforms than 29” wheels do.

AMB: When did you begin developing the size?

KP: I only learned about the 650B wheel size in early 2004. By November of 2004 I had failed to convince any of the big tyre makers to manufacture 650B MTB rubber. This is when I made the decision to go forward with my own tyre designs.  

Interestingly enough, it was only after I had produced my first tyre did I find out that some of the well known pioneers of mountain biking used 650B wheels in their early bike designs. From what I understand it was only the lack of 650B knobbies coupled with the emergence of aluminum 26” rims that meant they settled on 26” wheels for MTB use.

AMB: How do you answer critics who say that mountain biking needs more standardisation, rather than more new standards?

KP: I’d say that 650B wheels are a long established standard and have a lot to offer as an alternative to either 26” or 29” wheels. I also say there is a historical precedent for the wheel size in MTB use as I mentioned above. But there are even earlier examples of 650B wheels being used off road in ‘Moto’ type use as early as the 1950’s in France. What’s more, I think people may have the wrong idea of what “standards” are all about…

AMB: How have the industry responded - particularly tyre/rim/wheel

KP: The response so far has been very positive. I can say there are nearly a dozen mid-sized, well known brands that plan to launch bikes in the coming year. Remember, I only introduced the 650B tyre a year ago… We are much, much further along than I would have ever imagined.  Already Rawland, Haro, Ventana, Vassago, Fuji, SE, Rivendell, Soma, Carver, Lynskey, Seven, Ibex, Independent Fabrication, Kent Eriksen and Australian brands Thylacine and Baum are producing 650B frames.

As for tires, besides my Pacenti Neo-Moto and Quasi-Moto tires, Kenda, Schwalbe, Panaracer and WTB all have said they plan to produce tires for 2009,  and word is that Hutchison and CST may join the fray as well. This is a key point for me as I knew from the very beginning that the bigger tyre makers would have to get on board if 650B MTB tyres were to be successful. I have privately and publicly encouraged every known tyre maker to get on board.

Rims are very easy to make in any size you’d like. Velocity was the first to offer a 650B rim in their Synergy and Blunt models. Sun, Stan’s, WTB Alex and Weinmann quickly followed and I suspect more rims / wheels are just around the corner.

Forks are the next big hurdle, but there is already plenty to work with. White Brothers was the first to offer a 650B specific fork. But X-Fusion, Maverick, the Cannondale Lefty and USE S.U.B. forks should all work with out much trouble or modification. Word is there are one or two big name fork makers working on 650B compatible forks for 2009 as well.

Update: - X-Fusion has given their official OK for 650B wheel use in their Velvet R forks.

AMB: Who will the 650b wheel size appeal to?

KP: Lot’s of people; smaller riders who want bigger wheels but can’t fit on a 29er. Bigger riders who want stronger, lighter wheels than 29ers can offer, but will also want to smooth out the trail better than 26” wheels. The list goes on, and on but endurance racers seem to be the group expressing the most interest at the moment. I am particularly keen to see DH and 4X riders test the wheel size.

Look, I have a lot of money invested in the wheel size, but I refuse to become dogmatic about it. I think 650B wheels will appeal to most anyone who enjoys riding bikes, but people should ride whatever works best for them.

In the end it’s just another option, and a good one to have. I look at 650B wheels as the next step in MTB evolution, further refining and improving the breed. Ultimately it will be the myriad of clear performance benefits 650B equipped bikes can offer that  is going to make them successful in the market place.

AMB: Thanks Kirk, cheers.

KP: No problem!

 Keen to check out 650B?

Definitive Cycles, the Australian distributor for Pacenti Tyres, have competitively priced 650B wheels sets ready to roll. You can pick up a complete set up, consisting of White Industries hubs, Velocity rims, DT spokes and Pacenti Neo Moto rubber, for $895. Or if you only want to try 650B on the front it will set you back just $370.

We’ll be testing the new Carver Bikes Killer B 27.5” inch bike next issue.

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