core – Member
…I wonder if the bike industry itself will get tired of all the differing standards and having to manufacture all these products in a range of sizes?

This conversation has been going on for over a century. 🙂

I have bikes with the following sizes of 26″ wheels
ERD
559 Usual mtb size
584 26×1½” aka 650b
590 26×1?” the smaller British roadster size.
597 26×1¼” sporty British bikes – especially prewar

Don’t have all the full variations, there’s also 571 or 599* 26″ wheels 🙂

The British bike industry missed an opportunity to pioneer the mtb over 70 years ago. They were selling bikes to the colonies with 2″ tyres (I think 599mm) that looked very similar to the later Raleigh Bomber but with more conservative bars.

I have bikes with the following sizes of 26″ wheels

Arent yours are on different bikes though?

Might we see more of the same bike offered with different rim sizes, but roughly the same overall rim + tyre diameter?

I have bikes with the following sizes of 26″ wheels

Aren’t yours are on different bikes though and different types of bikes too?

Instead, might we see more of the same bike offered with different rim sizes, but roughly the same overall rim + tyre diameter?

epicyclo – Member

I think so. It’s an ideal way to have a general purpose bike.

Assuming that the 29er size was for road and gravel use, you’d be using a tyre slightly bigger than 2″, so let’s pick 2.15″ as a medium choice.

<snip>

Then for trail riding you use the 650b+ size with say a 3″ Nobby Nic

<snip>

So theoretically bugger all difference in diameter and no geometry changes needed.

And all you have to do is give up a load of flexibility and capability, for no reason. No idea why anyone would accept a 29er that can only run skinny tyres in 2017. (OK, you could run bigger tyres, at the cost of a higher BB… but that’s daft)

TBF adjustable geometry isn’t just the right way to do it, it’s the only good way. It’s easy to do, and has no significant downside. The entire point of a transformable bike is choice so why do it in a way that reduces it?

We can have bikes that do both jobs as well as a “29er specific” or “b+ specific”, in fact it’s not even hard. Why settle?

Northwind – Member
And all you have to do is give up a load of flexibility and capability, for no reason…

I don’t follow your reasoning. Why would you need adjustable geometry if it comes out the same with both wheelsets?

I would like adjustable geometry, but I don’t see it as being needed or adding anything in this situation.

Realistically most people would expect to be able to run a 29×2.3 (739mm OD) and plenty would be keen on a 29×2.5 (749mm)

Let’s say you really want to run that on trend “27.5×3″ wide tyre too (736mm), compared with the 29×2.5″ there’s 12.5mm in it diametrically, radially it’s 1/4″, let’s be generous and say you’re going to need to find an extra ~7mm of extra radial clearance to accommodate biggish 29” tyres, it van be done on a 420-430mm chainstay…
And a minimum of say 82mm between the stays, it’s really not that much of a logical leap to make and sell frames that can clear a reasonable sized 29″ tyre and a clownish “27+” and have some broad market appeal from a single set of tooling…

I’d buy that (for the right price), and probably only ever fit 29×2.2-2.5 tyres (who really wants to bother swapping wheels?), but choice is apparently what the people always want, so give it to them…

an you elaborate further on that?

Sure. As mentioned tyre sizing is nominal not fixed, in summary right now:

26 tyre = 26.5″ diameter
27.5 = 27.5″
29 = 29.5″

27+ varies between around 28.25 and 29.

However the sustainable trend seems to be for 27.5 to get bigger, maybe settling in the 2.5/2.6 region in the long term width wise. Wider tyres are taller, a 2.5 Maxxis WT measuring just shy of 28.25 diameter, a 2.6 would definitely get there. So I predict that plus will fade, replaced by 2.5/2.6 tyres on 27.5, and dying off pretty much as a 29+ format.

That would leave us with 27.5 measuring up at an average of about 28.25, and 29 going more towards the XC market again at 29.5.

This trend actually makes the 27.5 tyre the legit tweener size it was always claimed to be, rather than closer to 26.

epicyclo – Member

I don’t follow your reasoning. Why would you need adjustable geometry if it comes out the same with both wheelsets?

It doesn’t come out the same, except with small 29er tyres. So basically you’re making a bike that’s a good plus bike and a compromised 29er. And the important thing is, there absolutely no reason it can’t be equally as good with both.

cookeaa- your logic is sound. My Pact is basically what you’ve described.

A set of 27.5×3 and a set of 29×2.2 are easily interchangeable and I find the difference in geometry (BB height) to have no affect on handling.

The SS giant in a previous post is again the same frameset. It uses a sliding dropout to support both wheel sizes and gears or SS. You can get the geared model in the UK, and SS easily 🙂

esher shore – Member
The SS giant in a previous post is again the same frameset. It uses a sliding dropout to support both wheel sizes and gears or SS. You can get the geared model in the UK, and SS easily

That’s good to know. I wonder how available the requisite dropouts are, or frames for that matter.

That would leave us with 27.5 measuring up at an average of about 28.25, and 29 going more towards the XC market again at 29.5.

benpinnick, I broadly agree although 29″ seems to be gaining traction for “enduro” bikes and shorter travel 29er trail bikes are getting more common.

Orange Bikes launched today, the Stage 5 and Stage 6 are both 29″ trail and enduro bikes respectively. They already have the Segment as a short travel trail bike 29″ option…. no plus bikes though

I’m still really hoping 26+ becomes a thing.

Isn’t that just a fat bike on a diet?

Goldigger – Member
I’m still really hoping 26+ becomes a thing.

Been around since 1998. Buy a Surly 1×1, they fit 3″ tyres.