UKC

So on mountain bike in the market now we have three main wheel sizes 26 which has been around for years and two others 29 and more recently 27.5/650.can all three survive? Is 29 already on the way out. Are the new sizes just a way for bike manufacturers to sell more bikes

In reply to neil0968:

I think in part that they are a sales pitch.

I got a new mountain bike recently and having not even tried either of the "new" wheel sizes I hired a couple of demo bikes, one 29er and one 650b and rode the same trails on them. TBH I couldn't tell the difference between my existing 26in bike and the 650b (or 27.5in which is actually more like 27in) but the 29er was a whole different ball game. It was (and is) huge fun to ride, completely unquantifiable I know.

As to which will survive, in a way there's room for all three. If you are short then a 29er bike just doesn't look right - you look like a kid on an adult's bike, so the choice would be between the 26 & 27.5. As far as I can tell, the biggest uncertainty about the 29er is how strong the wheels are for hard core riders but this may be an unfounded rumour designed to sell the 650b size.

I think it's more likely to be the frame manufacturers that end up deciding which lines to produce as they'll need say four frame sizes for each wheel size - the geometries are slightly different for each wheel size so it's not a case of simply moving a frame from one series to another. Then add in the multitude of models and you end up having to produce rather a lot of different frames. Given that the modern compact road frame came about as a way for manufacturers to reduce the number of frame jigs, it's a bit odd for them to head down this route.

In reply to Bob: cheers bob fantastic reply.

In reply to neil0968:

As an example of how many frame sizes you can end up with, here's what a small UK manufacturer, Cotic, have to make to cover the wheel sizes. Their classic hardtail is the Soul, they produce a 26in and a 27.5 version as well as a 29er that's called the Solaris but is essentially the same frame. They do Soul, XS, S, M & L; Soul 27.5 - S, M & L; Solaris - S, M & L. So that's ten frame sizes for what is essentially the same frame covering three wheel sizes. (I've got the Solaris BTW)

Note that 29er wheels are basically the same rim diameter as 700c road wheels but obviously end up being a bit bigger because of the larger volume tyres.

Another point to note is that when selecting gearing for a 29er you have to take in to account the fact that the circumference of the tyre is about 13% greater which is about a gear so 42/12 on a 26in wheel is about the same as 42/13 on a 29er.

In reply to neil0968:

Been riding a 650B since Nov last year.

The difference is subtle, but I think 650B is definitely better/improved/faster over 26". Not noticed any downsides.

Newer bikes are also typically longer and lower, with wider bars, which all add to the package (fast & stable).

29er - now they are just silly [only kidding]

26 is going to become a niche product (if not already!).