Raxel

Smallwheelers DO have enough potential to be as fast as top road bikes (given the road is smooth enough), but they are SERIOUSLY outdated - Modern road bikes have both featherweight AND aerodynamic carbon fiber frames & wheels.

Nowadays sub-kg frames are common, and you can build a very light roadbike quite easily. I have built a 13.2lbs one for my dad, and most people around myself are now riding ~15lbs machines. Have you seen ANY light and stiff framekit options for smallwheelers? I haven't seen anyone except for Tyrell scandium frame which costs more than most carbon road frames.

And for aerodynamics... nowadays deep section carbon wheels are very common, and developers are throwing a lot of money for windtunnel testing and improving them. Aerodynamic frames with wind-foiled cross section are also popular. How can one claim that smallwheeler are more aerodynamic, even without a single windtunnel test?

SesameCrunch

+1 !!! My sentiments exactly.

jur

I bought a new tyre and tube for my wife's Reach. I think it took me less than 15s to take it off and I wasn't speeding.

makeinu

Do it and keep doing it and you could become the Sheldon Brown of the youtube age.

Downtube 20". Thank god I haven't had to take off my 8" tires yet....the tire levers are almost bigger than the rims!

I also have a 26" walmart bike which I've changed the tubes on, but those tires basically just fall right off once I release the pressure (don't even have to touch them).

Amuro Lee

It seems that everyone here has only discussed about speed issues on small wheeled bikes. However, no one has mentioned about the safety issues.

I think that small wheeled upright bicycles are quite dangerous when you're riding them in a very high speed:

1. Small wheels with high pressure tyres can overcome the rolling resistance made by deformation of tyre surfaces. However, that also reduces the grip between the tyres and the road surface.

2. When the front wheel hits an obstacle and stop the bike immediately, the rider on a small wheeled bike will be easier to go over the handlebars than the rider on a large wheeled bike because a small diameter wheel has a lower pivot point than a large diameter wheel when the riders are on the same riding position and height.

kamtsa

Are there any small wheels on top level competitions? I would think that professional road racer will use any technical advantage they may have, if these claims are correct.

Kam

makeinu

Small wheels are used almost exclusively in all top level technical competitions and win all the top spots.

However, professionals typically don't participate in these competitions because, without rules eliminating all technical advantages in order to guarantee that only the strength of the riders themselves determine the outcomes, these events don't garner enough attention to attract sponsors.

EvilV

This is especially true when the bike is configured like the short wheel base and very upright Strida where the rider is pretty much sitting about two feet behind the centre of the front wheel with a considerable amount of his body mass even further forward than that. The more forward the rider's mass is, the more likely he is, given a small wheel, that he will be pitched over the front if he hits some kind of obstruction on the road like a deep pothole. In the case of a Strida which has a steep part of the frame right in front of the rider, he also risks some kind of castration event when he is stuffed into the frame with his legs either side of the handlebars.


Still, the strida is a VERY neat solution to urban commuting, but you do need to bear its limitations in mind when riding it.

If you don't, you'd better have a good arrangement with your dentist and have saved some sperm in advance so you can still have children after you've pitched into the frame and then somersaulted over the bars.

Of course, if you're an old git like I am these things don't matter and you can ride it as crazily as you like and enjoy your crash.

datako

It's not a small wheel issue, it's a design issue.

On my 1965 Moulton I feel safe on fast downhills even on rough surfaces (apart from the brakes which are original). On my Dahon Hammerhead I also feel safe on fast downhills (apart from the brakes which are ok otherwise). If anything, the Moulton which has the smaller wheels feels better. It has a longer wheelbase. Both bikes have a properly set up front fork trail. On the other hand my old Boardwalk gets very excited at over 25mph on rough surfaces.

As far as speed is concerned I have done a back to back with the Hammerhead and a 700c wheel bike using the same tyre type (Schwalbe Marathon Racer). The bigger wheel did the course 2 minutes faster than the Hammerhead (about the 50 min mark), but it was a small enough difference to be negligible.

makeinu

First of all, the Strida has an extreme rearward weight bias (not forward). It's nearly a semi-recumbent.

Second of all, bicycle pitch over is extremely unlikely with proper technique and if it does happen the most likely cause is front wheel lockup due to something getting stuck in the wheels or the rider losing control (for which smaller diameters are obviously less susceptible), not wheeleating potholes:
https://www.sheldonbrown.com/brandt/over-the-bars.html

While I have to admit that theoretically it would take less force for a wheeleating pothole to throw a small wheeled rider over the bars, I'm all but convinced that I'm more likely to find the boogey man in my closet than a wheeleating pothole on the road.

EvilV

I'm afraid what you said there is totally outside of the realm of facts. It is the most upright bicycle I ever rode my friend.

Have you seen the video of the guy going over the Strida handlebars in the shop?

Also, if you aren't likely to take a flight over the top, why is there a sticker on the handlebars of these and the clones warning you not to apply the front brake on its own because you will go over the top?. I've bought a good few bikes in my day and this in the only one I ever took home that has such a sticker.

You are right about the weight on the rear wheel being more than the front, but the weight is still VERY near the front because of the extreme shortness of the Strida. The wheel centres are only 35 inches apart. What I was trying to say was that the weight is so near the front wheel that if the front wheel is arrested suddenly by a pothole, it is much easier for the rider to end up flying over the bars than if he was further to the rear. In order for the rider of a long wheel based bike ( a standard one) to go over the bars,when the front wheel is arrested rapidly, his mass has to be lifted a certain distance as he travels upwards and then forwards in an arc. The shorter the distance between the centre of the front wheel and the riders centre of gravity, the less work needs to be done to make him flip over the bars. In my opinion this makes taking to the air more likely in a small wheeled bike ESPECIALLY A RADICALLY SHAPED ONE LIKE STRIDA. Even riding my knock off down a steep hill that I often negotiate, I purposely slide my backside and move my weight as far to the rear as I can because if I stay in the normal position, it feels like I'll do a header on the slightest bump.

EDIT:

Also, having read the remarks of the most esteemed Sheldon Brown on this matter that you linked to, he points out the importance of the rider bracing himself against rapidly sliding forward. The posture of a rider on a bicycle like Strida hsi essentially sitting way above the bars in an absolutely vertical position and holding bars just below his waist. I don't know about you, but for my physique that doesn't allow a great deal of bracing. On a road bike or an ATB, I am stretched out forward like a bridge and have a very easy time in bracing myself against forward motion. On the Strida, I am certainly not.

Don't get me wrong, I am loving the flying triangle even if it is a copy. I just look at it and it puts a grin on my face because it is so radical in design.

This video shows a kid going over the bars without sliding forward until the event is almost completed.

https://uk.youtube.com/watch?v=t-2yY0-ab3M


This video of a strida rider demonstrating the header potential of the bike is the definitive response to your remarks. All the words in the world are not as convincing as this clip.

https://uk.youtube.com/watch?v=DA3BNAgZS7A

sqynt

What does sitting upright have to do with the price of tea in China? Weight bias have nothing to do with it either. Speaking with no scientific background what-so-ever, take this with a grain of salt.

At the point in which a bike's deceleration generates enough force to pick the back wheel up off the ground, only two things matter, assuming nothing "funny" is going on.

* The center of mass in relation to the front fulcrum point (axle plus tire radius)
* Inertia of the entire moving mass.

You can sit bolt upright on the handlebars of a "normal" bike, and you're still going over when you hit that pothole. Similarily, you can have 70/30 weight bias over the front wheel on a "pedal forward" recumbent and never need to worry about flipping over.


It should be fairly obvious that these "stunts" were deliberately performed, the former from kids screwing around, and the latter to comical effect. The dead giveaway is how each rider was able to avoid jamming his knee or thigh into the handlebar. When's the last time you performed a split when stopping your bike?

Sixty Fiver

I had the opportunity to ride a vintage Moulton Speed this summer... my friend is the owner and a master mechanic of cars and bicycles and he has done a lot of modifications to upgrade the stock wheels, brakes, cranks, etc to make the bike as light as possible.

It runs an SA 4 speed but an ASC is in the works to make it a fixed gear.

Anyways...

The combination of road speed, comfort, and stability on the Moulton has to be experienced to be believed and that Kool Aid is very tasty indeed.

EvilV

I don't know if you have quite got hold of what I'm saying. I must not be explaining properly.

When a rider is thrown over the bars, his body describes an arc around the centre of the front wheel assuming he doesn't actually jump off himself in an attempt to make his landing easier. Just picture the dynamics of a rider whose bike strikes an unsurvivable pothole at speed and assume that he braces as far as he can against the bars. What I see happening is this:

*wheel comes to a sudden stop

*the mass of his body attempts to continue on its original course, but is prevented by his bracing

*The rear of the bike rises up as the rider's mass attempts to rotate around the front axle and continues on its way

Now, the shorter the distance between the rider's centre of mass and the front axle the less effort is required to lift the rider up and over the bars. On the Strida, the riders mass is very near the front axle and it is far easier for the rider to do that somersault even under heavy front braking.

THAT IS WHY THERE IS A NOTICE STUCK ON THE HANDLEBARS WARNING RIDERS TO APPLY THE REAR BRAKE BEFORE THE FRONT ONE. WHY WOULD THEY BOTHER IF THIS WAS NOT AN ISSUE. Have you ever seen this kind of notice on another bike? I haven't.

Simple Simon

I think that sticker is more to do with the power of disc brakes, when previous versions had drums. With discs, even on my mountain bikes, If i were stupid enough to lock the front I can also go over the bars.

I like the Strida upright riding position - ideal for its intended use, and very comfy. I dont like a laid down sporty position for in-town riding. Its not a particularly short wheel base, but If anything I'd say there is more rear bias.

datako

It's good even on my unrestored one which weighs a ton. Not bad for a bike that was designed in the '60s.

Essentially the Moulton is proof that you do not need to have a poor ride or instability with small wheels.

If you get a poor ride or instability with small wheels you have a design problem.

EvilV

Hey - don't get me wrong, I love it (even though it's a fake).

The idea is brilliant and I just love riding it, even though I don't like the way everybody looks at me when I am.

And you are completely right, it is GREAT for its intended purpose and a bit more actually, now that I've changed the seat to a much more plushy one. I can easily ride this bike ten miles without the slightest quibble now, albeit a bit more stately a journey than say the Merc which is faster having a higher gear available. The position is ideal for looking about in traffic.

Mostly though, I just love riding such a short and compact machine. Thirty-five inches, wheel centre to centre is minute. Even the Merc which is short is seven inches longer centre to centre and with slightly bigger wheels.

I still know I will go over the bars if I am not careful.

datako

Probably says more about about what the company thinks of its target marlet

EvilV

My TSR 30 Moulton which Sesamicrunch now owns was a fabulous ride on the rough pavements. You could fly over them without a twitch. Moulton knows how to make small wheels smooth, fast and predictable.

SesameCrunch

EvilV

I spelled your nic wrongly there Sesamecrunch.

How goes it in SF?

Here it is -3c and snow flurries. I went out before and got my face stung by blasting tiny flecks of snow, and I could hardly open my eyes. Since it was already well dark, I thought better of it and went home after a mile and a half.

I bet you are basking in sunshine....

Sixty Fiver

I ride a modded out Twenty (fixed gear commuter / light tourer) and because it lacks any suspension I run 20 by 1.95 tyres which still roll out very fast and provide a very stable and very comfortable ride... I spent today riding it on roads that are a mix of snow, slush, and ice and as always was very impressed with how well the bike handles and rides.

I would equate this bike's performance with it's larger sisters that were built for commuting / touring and not full on racing... it does not give up a thing.

SesameCrunch

Heh, heh. You would be correct.

I'm going for a ride tomorrow and will have to suffer through sunshine and 56F...

Thinking of taking the Moulton and taking some pictures to share with y'all.

EvilV

Awe - go on. I like to see the old gal now and again, even though I am now cavorting with a younger strida wannabe.

badmother

I`we been toying around with two similar (1970`s detatchables) during the holydays. One I am playing with a new stem setup, the other one I made a fast uppgrade to be able to try out tyres. More to be done later.

I finished last night putting chains on the rear wheel and a homemade studded in the front. Wanted to try it for a short ride today. A lot of -15 to -20C in the last few weeks, so long rides is not interesting, but with these bikes I kept my focus on the months to come. Hoping to do a "no car" holyday trip on them.