650B or not 650B, that is the Question

When we as a bicycle storeĀ heard about another wheel size in the form of 650B, we swore, shook our heads and banged our fists. Please, we don’t want to stock more tyres, tubes, rims, rim tape, spokes, wheels and bikes… please no more bicycle options! We have been through this before with 29ers, and now the 650B wheel standard (aka 27.5ers) threatens to confuse things a little more.

But when Nino Schurter won the opening round of the 2012 XC MTB world cup on a prototype Scott 650B mountain bike, the success of the 650B standard was kick started. And now that he has won a silver at the London Olympics and overall 1st in the 2012 World Cup XC Series, the 650B standard has begun. So as the consumer, what do you need to know? What is the situation NOW? Where are 650B, 29ers and 26ers going to be in 5 years?

Let’s get the simple stuff out the way, what do you need to know?
– the 650B wheel is commonly called a 27.5er but this is misleading because the rim size is not equally in between a 26″ rim and a 29″ rim. In fact it is more like a 27er, or about 1/3 the total difference between a 26″ and 29″ larger than a 26er and 2/3 smaller than a 29er.
– the implications of the wheel being closer in size to a 26er means that some 26″ specific frames will fit 650B wheels and tyres!
– this is a cheaper way of keeping up with your mates on their 29ers.
– a little bit of good news… all 26er tubes WILL WORK on 650B!
– 26 and 29 refers to the imperial measurement standard called inches, so a 26×2.125 tyre is 26″ in diameter and 2.125 wide. Like road bike tyres and wheels standards, the 650B is measured using metric units so a 650x57c tyre is 650mm in diameter and is 57mm wide.
– 26″, 29″, and 650mm aren’t always the actual wheel or tyre diameters. Why? Google it. The measurement actually falls somewhere between the rim outer diameter and tyre outer diameter. For example, a 650B rim has an outer diameter of 584mm, and a 650x57c Schwalbe tyre has an outer diameter of about 698mm.

You want to convert your 26er to 650B?
– first, you will need to test a 650B back wheel and tyre (we have one) in your 26er frame to check clearance (including when your rear shock is fully compressed)
– you will need a Fox fork (note that the other brands don’t have a high enough bracing arch, and that Fox does not endorse this conversion), or buy a 650B specific fork
– and then if all goes well, you will need to purchase a new set of rims, new spokes, new tyres and a new tubeless conversion
– this will cost you between R3000-R4000 if you buy the good stuff.
– rather buy a whole new set of wheels with extra rotors, tyres and cassette for R6000-R8000
– handy tip: stockpile some tyres, they are not widely available yet.
– finally, when converting your 26er to 650B wheels and tyres, the angles in the bikes geometry won’t be affected (you must convert both wheels), BUT the Bottom Bracket (BB) height will increase by approximately 16mm. The impact of this upgrade is better clearance over obstacles, but a higher centre of gravity. The improved rolling momentum of 650B tyres and improved approach angle over 26″ tyres should outweigh the negative impact of a higher centre of gravity.

What is the situation NOW?
Niche (small) brands are experimenting with 650B designs but few of the mainstream brands (Scott and Rocky Mountain are examples) have jumped at the opportunity with many of the belief that the overall size is too similar to a 26er to make a worthwhile difference. Tyres are difficult to find with limited widths, brands and tubeless options and generally inflated prices. Getting yourself a 650B bicycle is currently best achieved by converting an appropriate 26er bicycle as described in the steps before.

Where are 650B, 29ers and 26ers going to be in 5 years?
Tough question. Specialized have flat out refused to even consider the 650B standard. Maybe, as an American brand, they just can’t get their head around the metric measurements šŸ˜‰ But they are not the only ones. The serious reason behind their refusal is the claim that 29ers are better than both 26ers and 650B, so why go backwards.

Here are our predictions. For XC bikes and Trail bikes (ie travel up to 130/140mm}, we agree that 29ers are the best, but for Freeride and DH bikes (travel over 140mm), the 650B standard might be the ultimate choice. Rocky Mountain and Pyga are releasing 150mm travel 650b All-Mountain bikes that look amazing. The 650b wheel allows better rear end travel designs for longer travel bikes where the large 29er wheel would just get in the way. The alternative approach is basing the tyre size choice on the riders height, or in other words, treating adult riders like children, and we say “why not?”. Kids have been sized according to tyre size and not frame size for decades… 12″, 16″, 20″, 24″ and then onto 26ers when they hit puberty. So why not build Xtra-small adult bikes as 26ers, Small and Medium bikes as 650B, and Large and Xtra-large bikes as 29ers. It probably won’t happen that way, but it does make sense and few brands have even considered it.

So we end how we began, will we as a bike store need to stock more tyres, tubes, rims, rim tape, spokes, wheels and bikes? We don’t expect 650B to be “the next big thing” because we genuinely believe that 29ers are best for the majority of riders in RSA, but for riders who don’t want to change the bikes they love, want more than 5″ of travel, or don’t like the feeling from the larger 29er wheel, 650B could offer the best of both worlds… improved approach angles, grip and rolling momentum when compared to 26ers, and better handling, weight and longer travel when compared to 29ers.

We have multiple tyre choices, rims, and the correct (difficult to find) spoke lengths for 650B’s, making us the leaders of 650B conversions in Cape Town. We have a 650B back wheel for you to test your current 26″ frame so see you at the shop.

Stirling Jnr

PS: 26er frames that work with 650B wheels… check out the list on 650B palace