Why haven’t small wheels caught on?

There’s three main reasons

There’s three main reasons imo why small wheeled bikes have a bit of a bad/niche reputation.

1. most small wheelers are folding bikes and are either cheap heavy and crap, or expensive like Birdys, Bromptons, Moultons. Most who buy small wheeled folders do so for short hops from the train etc, or from the car boot, so buy cheap uns, then complain how they are rubbish.

2. UCI etc regulations banned small wheel bikes from competition in the 60s, which is why “racers” are basically fixed around the same 27/700c size. Mountain bikes came from cruiser/utility cycles which tended to be 26″ although still derived from the UCI biggish wheels and 3 stick frame basic design. It’s diversified a little but stayed roughly the same. So that’s what is in the shops.

3. Raleigh. Moulton basically invented the small wheeled bike and it was almost perfect. It took all the skills of Raleigh to strip out the suspension (which made the head tubes fail), replace with stupidly fat bouncy draggy tyres. They sorted the frame out by using offcuts from north sea oil rigs.  

I’ve ridden Moultons for over 20 years and love them to bits. The design makes them a bit love hate though. They are the stiffest frame I have ever ridden, but the suspension makes them feel compliant and comfortable. It’s like riding a velvet covered I beam. Besides the ride, I find the actual design appealing, the horizontal cross member is just the right height to carry and is the CoG. the racks are designed to keep the luggage suspended and centred on the CoG again, and unlike most folders the ride is not overlly twitchy or cramped unlike a lot of other small wheeled bikes, although they do handle quicker than a big wheeler.  

They are superb allround bikes, and excellent for all day riding, and mixed surface riding and  commuting. The only thing they don;t like is soft surfaces like, deep mud, sand or gravel. 

I can easily fit the same width tyres to my Moulton as I can my conventional road bikes and be as quick, or wider knobblies for off road riding

Moulton was the first to put a full suspension MTB into production with the Moulton ATB. The design of which evolved into the Moulton APB and then the TSR.  The design may seem dated against todays moulded carbon bikes, but they hail from a time when the only alternative to steel was thin alloy pipes glued into lugs.

Moultons have held many speed records, and are used successfully in Triatlons.

My Moultons weigh pretty much the same as my 531 conventional tourer. 

Twenty.. Twenty five years
Twenty.. Twenty five years ago I was riding a lot. My mate ‘the flying Flea, ‘ was a bright bloke with not much formal language training.
He was going on about fitting drop bars to a mtb and commuting.
His old man was pretty stoked with his hybrid (wide 700c) ride. Being young I declined the challenge because the tracks we rode would destroy 700c rims and the road time I might as well stay on a mtb or bmx and find a thin wheel roadie because his hybrid was just too slow.
Anyway, years later and budget minded, just about to finish my build of a dropbar hybrid (common now aka gravel bike). If my body was smaller mtbs would work well.
From experience, bmx 24 inch would stay true after 10+metre jumps, mtb 26 inch would survive 10 footers and 700s were crap unless wanting fast on a flat track.
They’re all good, thank you much regarding moulton as I never knew these existed. An old friend is looking at bikes and was considering a girl frame to ease entry upon. I’ll be informing him that Moultons exist. Glad to read that they ride nicely.

Griff500.
Griff500.
Look my broken English hard to understand.
Like what you wrote regarding easy long ride stick with 700c.
My thoughts. They track better. Their angular momentum assists their tracking because they resist forces such that their momentum/inertia remains as such. Larger wheels do this better than smaller wheels with identical parameter point masses. This inertia/momentum holds true when cornering when side wards forces tempt the tyre to skid yet the wheels momentum resists such with it’s response such as no thank you because I’m travelling this way.
Although smaller the wider smaller wheels might weigh more thus increasing their momentum yet the translation at the fulcrum is from a narrower radius and being a measurement of square that has a large effect on the wheels inertia; the wheels want to maintain track. The side wards temptation to skid can be reduced by increasing grip which is often found using wider tyres.
I can’t write plain English, been awake 20 hours.
Would you trust 28mm tread on a 20 inch coming down grade through sweepers?
Hence just typing too much, smaller wheel need more grip.
I think the Moulton looks fantastic as a comfortable throw in a car and drive half way and ride any road with because (I’m guessing now) the tyres are wider.
Looks great per that aspect of cycling. Eg. Storage, easy to ride, stronger wheels? Comfortable ride on wider tyres, light weight, transportable, list goes on.
I hope I helped. I had a similar argument with a racing car manufacturer many years ago. 20inch vs 700c. End result. Stiff ship enjoy what you use. Self preservation might be key factor as to where the bikes get ridden.

Griff500 wrote:

Griff500 wrote:

Boatsie wrote:

From earlier…  Why do we need less grip to corner with larger wheels? Moment of inertia.  Formula on internet.  Force is proportionate to square of radius. Hence if we use same tyre width/compound on a larger wheel and a smaller wheel then the larger wheel will not only have a larger tendency to remain at velocity from each point of tangent but also more tangents to accumulate sum of forces with. Hence because the wheel is lawful to that of common physics,  a greater force will be required to move such sidewards. 

I take it you didn’t study science at school?  Apart from what you say above being absolute nonsense, your generalisations “same tyre width/compound” are laughable, and ignore the very important contribution of tyre pressure and contact patch size and shape.

Your internet formula describing rotational intertia of the wheel has nothing to do with changing the direction of linear momentum of the bike. Any gyroscopic effect in the wheels is negligible compared to your momentum (mass x velocity) in a given direction, which you want to change to a different direction.

Incidentally, Schwalbe, who I assume know a thing or two about tyres, have some interesting stuff on rolling resistance on their website. A few of the highlights: Larger diameter reduces rolling resistance, but so does a wider tyre up to a point, which might explain the recent trend from 23mm tyres to 25mm and 28mm.  Smaller diameter tyres inflated to the same pressure have a higher rolling resistance than a large one because a small tyre when deformed by load,  is “less round” at the contact point. And you can’t solve this by inflating a small tyre more, because then your contact patch becomes smaller. So if you want an easy ride long distance on road, stick with your 700c tyres.

I’m very well regarding physics thank you.
While at university I drank 1.5 litres of zambuca an hour before our 3hr physics exam. Half hour into the exam I had to walk out due to loss of eyesight amongst other coordination issues.
I achieved a distinction.
I had topped my class the year before in both mathematics and physics.
It is basic law. If you want to know why learn such with your own mind. We are all bright. I don’t teach.
Angular momentum is key. Not gyroscopic force.
Just storming because someone bright can sort out bs and see clear point.
I’m bored but there is no way to tell you how to brake besides hit the accerator and aim at the brick wall. Rotational inertia is key.. Total inertia isn’t as relevant regarding debate of whether small wheels are comfortable. Tyres yes. You ain’t an idiot neither and neither of us are pedantic to language all that read.
Makes sense to me and that most of my care…
Safe riding.

Boatsie wrote:

Boatsie wrote:

From earlier…  Why do we need less grip to corner with larger wheels? Moment of inertia.  Formula on internet.  Force is proportionate to square of radius. Hence if we use same tyre width/compound on a larger wheel and a smaller wheel then the larger wheel will not only have a larger tendency to remain at velocity from each point of tangent but also more tangents to accumulate sum of forces with. Hence because the wheel is lawful to that of common physics,  a greater force will be required to move such sidewards. 

I take it you didn’t study science at school?  Apart from what you say above being absolute nonsense, your generalisations “same tyre width/compound” are laughable, and ignore the very important contribution of tyre pressure and contact patch size and shape.

Your internet formula describing rotational intertia of the wheel has nothing to do with changing the direction of linear momentum of the bike. Any gyroscopic effect in the wheels is negligible compared to your momentum (mass x velocity) in a given direction, which you want to change to a different direction.

Incidentally, Schwalbe, who I assume know a thing or two about tyres, have some interesting stuff on rolling resistance on their website. A few of the highlights: Larger diameter reduces rolling resistance, but so does a wider tyre up to a point, which might explain the recent trend from 23mm tyres to 25mm and 28mm.  Smaller diameter tyres inflated to the same pressure have a higher rolling resistance than a large one because a small tyre when deformed by load,  is “less round” at the contact point. And you can’t solve this by inflating a small tyre more, because then your contact patch becomes smaller. So if you want an easy ride long distance on road, stick with your 700c tyres.

iandusud wrote:

Putting fat tyres on small wheels ruins (suined them). It’s what gave small wheelers a bad reputation as rotating weight and rolling resistance increases. It’s what killed off the original 1960s Moultons and what made Alex Moulton a very bitter man, as he sold a licence to Raleigh to make them only for Raleigh to ditch the suspension for fat tyres to make them cheaper.

There are so many misconceptions about small wheeled bikes. I used to sell the AM Moultons (1983 on) and they sold themselves – the simple secret was giving people a test ride. People couldn’t believe how fast and comfortable they were, and also how well they handle. 

Please stop spreading pseudo-science .

As it’s been discussed many times before, rotating mass is bordeline irrelevant when you take into account the weight of the entire system  (including the rider).

Fatter tyres have LOWER not higher rolling resistance particularily on bad roads when used at proportionally lower pressure.