Lassy

This is an interesting tread .. probably more civil than you'd find over on the road bike sections !

I must admit that I am not such a fan of small wheels, the (moulton) argument that the small wheels plus suspension are the same or faster than large wheels all else being equal is slightly biased. Isn't Moulton himself a suspension designer ?, from a rubber making dynasty ? .... methinks there may be a tad of built in bias to some of the claims and tests ie not 100% neutral.

I dont have a copy at hand but the more 'peer-reviewed' bicycling science book, has a rather different conclusion.

I know I am trying to 'walk against the flow' by saying such comments here on this small wheel section - but bob-free suspension is still a holy grail, and without suspension small wheels with high pressures just do not roll as well over anything other than a glass smooth surface. I guess you guys have all sold off your 120psi 700c bikes but next time you get the chance, be objective and do a familiar ride on one.

Flame suit locked on and prepared for the jet blast

SesameCrunch

Nope. I still have my 17lb, carbon fiber, 700C bike that I use when I want to keep up with the boys half my age on the weekend rides. Despite having owned over 10 small-wheeled bikes, I haven't found one yet that can go faster than my road bike.

There are so many factors that come together to make a bike fast. Wheel size is only one of them. These discussions can be pedantic but they're fun, and when the discussion is conducted in a civil manner, it's a wonderful thing.

msincredible

SC and kb, you guys need to ride the course twice, trading bikes the second time. Then take the average.

kb5ql

Let's do this. SC, you around on Turkey Day? I may just have to do a Half Moon Bay loop with you. Provided it can be done really early.

SesameCrunch

Wow... You got a pass to ride on Thanksgiving morning??!!!

Sheesh...You must have paid for the upgraded marriage license.

Let me see what I can work out...

caotropheus

Agree with you on the first and second paragraphs, and no I did not sell my road bike and I still use it regularly for long road journeys.

makeinu

C'est la vie. Why would a 100% neutral party ever bother testing anything?

"Peer review" is just another way of saying "popularity contest" (I should know, my livelihood depends on it). The proof is in the pudding, the Moulton has the world speed record for an upright bicycle, so the fact of the matter is that smaller wheels are faster. Period. However, that's not what we're talking about. What we're talking about is the specific factor known as rolling resistance and distinguishing that from the overall speed is entirely academic (read pedantic).

EvilV

Ah, but then they'll be tired on the second ride and will be slower, or if it's on a different day, the wind might be different, or one of the guys may feel a bit 'off colour', or any number of things. Methinks we will not easily get to the bottom of this problem, unless we can control all of the variables precisely in a lab, and then have another team carry out the same research and see if they find the same results. Then there will be the statistical analysis to arrange, to see that any differences are not so small as could have happened by chance..... Na - let's just ride the damned bikes and brag about how good our particular one is, and then spend days on end *****ing on about how the other guy is biased....

EvilV

I don't know how that test was done. If it was on a velodrome type surface, you'd probably expect that because the surface is perfect and the small wheels would have less wind resistance. On an ordinary less than perfect road surface you might get a different result.

One thing is for sure, small wheels are neat and make the bike a lot more portable, easy to store and very convenient as well as providing excitingly manoeuvrable riding. Personally, I think the motor and racing industries would have large diameter wheels if they provided any real advantage, although, I suppose they are less worried about the last tenth of a horsepower than we are. Come to think of it, most of my riding involves me putting out about a tenth of a horsepower because I'm a lazy wretch.

timo888 

Totally eliminating bob is a 'holy grail' only for those for whom riding a bike is a kind of mythical quest for perfection. I wish those romantics would all move to Camelot, so the manufacturers' ears wouldn't be so full of their palaver and they could be free to concentrate on introducing more short-travel suspension options, front and rear, for road and touring bikes.

I'm sure your suit of armor protected you from that rather gentle dragon-flame

Regards
T

makeinu

What is an ordinary surface? A city street? A dirt road? A runway? A mountain trail? A swamp? Stairs? You can find surfaces on which walking is faster than a road bike.

Like I said earlier, the entire concept of one bike being inherently faster than another is nonsense and the only such concept that makes any sense at all are speed records, regardless of the conditions under which they are conducted.

Of course they would. As Moulton noted, every other prominent land based vehicle except the bicycle has evolved from larger wheels to smaller wheels with suspension. Why would they do so if it weren't advantageous? Unlike bicycles, cars and motorcycles with small wheels don't fold up.

Road bikes have large wheels because they are toys which are ignored by serious racers and designers.

msincredible

Ssshhhh, don't let reality intrude. I was trying to give them each a chance to try out a different folder.

BruceMetras

Here's a little something on the record breaking Moulton based bike..




51.29mph (82.53kph),
unpaced cycling record over 200m

'Liner I broke the unpaced cycling record over 200m (conventional riding position), reaching 50.21mph (80.79kph) at 11th International Human Powered Speed Championships held in Indianapolis in late September 1985. The rider was Jim Glover.

'Liner II (illustrated), built from 'Liner I, was slightly lighter at 45lbs (20.75kg). At the 12th HPV Speed Championship in Vancouver in August 1986, Jim Glover rode the bicycle to set a new record at 51.29mph (82.53kph), which has yet to be beaten. Nearly 100 HPVs took part, but only a dozen or so were able to exceed 50 mph (80.45 kph).

'Liner III, built from 'Liner II, is potentially faster than either of its predecessors. However, it never fully achieved its potential - circumstances always seemed to conspire against it. In testing though, it has exceeded 55mph (88kph). It was, however, the overall winner at the International Festival of the Bicycle HPV event at Hull, Quebec in 1989.

While Liner's I and II were based on a modified production AM7, the Liner III, is based on a white prototype AM-SPEED and therefore weighed a little less than the 'Liner II. A unicrown front fork was used, similar to that on the AM-ATB, now APB, and the bottom bracket height was increased by jacking-up the rear suspension. This feature had been used in 'Liners I and II, and allowed the chainwheel to be incorporated within the fairing.

The transmission consists of 86 and 82 tooth chainwheels, driving a close-ratio 9, 10, 11, 12 tooth block, thus giving a gear range of 116 - 162".

The fairing, designed and built by Doug Milliken of New York, attaches to the AM's frame via the standard front and rear carrier mounting points. The main body of the fairing is cut from 6mm thick plastic foam-cored artist's board, with the clear panel formed from Lexan. The top and bottom vacuum-formed sections are high impact polystyrene for the opaque sections, and PETG for the clear panel. Aerodynamic wheel disks were added to the accurately balanced wheels, which would spin at about 1,000rpm. 'Liners I and II used standard AM-Wolber tyres inflated to 120psi. The 'Liner III uses Moulton-Wolber slicks run at 140psi.

EvilV

Dear Sir,

This is interesting, but -

The 'moulton bike' sounds nothing at all like the bike I had that was developed out of the AM type and the test has little or nothing to recommend to the average cyclist, unless he intends to swap his Brompton, Downtub, Dahon Curve, Strida, etc for a fully faired HPV with a bottom gear of 116" and a top one of 164, and a few other esoteric changes from normal cycling practice.

Don't get me wrong - it's great that somebody did this with a Moulton, but it doesn't tell me much about which bike to get for a five mile commute with a train ride at one end and it won't help me ride my bike faster into a blustery headwind like I met today. I suppose I can grit my teeth as I pedal uphill, into the wind and keep chanting, 'Small wheels good, big wheels bad.' in a similarly manic way to that of the animals in Orwell's Animal Farm, who had their own mantra of, 'Four legs good, two legs bad,' to help them get by.

Yours faithfully

Grumbling Old Git

pm124

EvilV, that's probably more or less correct. Unfaired, the Moulton has a lot of little pylons that catch the wind.

Moreover, riders are faster, bikes are a lot lighter, tires are a lot better, and fairings more advanced than they were in 1985. There are not many 17lb road bikes that can be safely ridden at 50+ MPH, which may partly explain the endurance of the record.

SC, a few questions. Given that you don't have a power meter (come on get one) any difference is going to be highly subjective and unscientific. But what *is* the difference in rough average MPH between your TSR and your road bike? Also, what is the difference qualitatively in terms of handling and comfort?

kb5ql

Another problem. My FAR SUPERIOR Bike Friday uses the FAR SUPERIOR 451 wheelsize (w/ Schwalbe Stelvios) pumped to 120psi. The lowly Moulton uses 406s pumped to 50psi.

SesameCrunch

There is a regular ride that I do - 40.5 miles, 3,000 ft of climbing. On the full-size Fuji, I average 17.7mph. On the Moulton TSR, I average 16.0 mph. I generally do these training routes pretty hard, and the level of exertion is pretty consistent (according to my heartrate). So, roughly 10% less efficiency with the Moulton compared to a 17lb roadie.

The Moulton is obviously more comfortable with the suspension. I love it on downhills. It's also very stiff frame, likely stiffer than the all-carbon Fuji. But, at 24 or 25 lbs, I do feel the weight difference, especially on climbs. I must say, I do feel that I accelerate faster with the small wheels of the Moulton, but sustaining speed is marginally more work. The gearing on the Moulton is not as robust on the high end, but low end is better. I regard the Moulton as a great touring bike. And as I have said before, no folder or small wheeled bike (as a package) has been able to challenge the Fuji for speed.

Without power meters, this is all subjective, but I think I've done this route enough to be pretty comfortable about making these assertions.

SesameCrunch

I don't know why you state this. I've had my carbon Fuji over 50 mph on downhills. I haven't felt any structural instability with the bike. Do you know something I don't ??

SesameCrunch

Surely you mean my size 406 quads pumped up to 50psi?!

pm124

Thanks much for your input. The calculator is offline to ascertain whether that 7 pound difference could explain the speed difference on the climb, but seems reasonable.

I'm NO engineer. No more than the obligatory year of college physics. But there are two factors to consider when taking a bike up to 50MPH on a flat. One is frame strength and the other is speed wobble. If you have the strength to push huge gears up to 50MPH, you put a lot of stress on the frame. If the frame holds up, this can cause a well built bike to develop a form of uncontrollable shimmy called death wobble. Ouch.

The fact that the Moulton is both suspended and can handle such speeds is a testimony to its rigidity and build quality.

EvilV

I have to say, when I had that Moulton, it was a revelation at speed on badly surfaced roads. I could shoot along them on downhill stretches at speed and confidently bank over to take a rutted curve. I could hear the suspension taking the punishment that on my other small wheeled bike, would have seen me rattled half to death, losing concentration, and off the road in a heap of pain and tangled metal.

Seeing that photo of my old bike outside Sesamicrunch's grand front door, I can see that the bike has gone up in the world now, and it will probably enjoy the climate better too.

pm124

OH--One critical question for SC. Which tires are you running on it?

SesameCrunch

1 1/8" Stelvios at 120 psi.

pm124

Thanks SC!

pm124

Of course, if someone really prioritized going fast, they would simply ride a recumbent all of the time. Upright folders and 700cc bikes crawl relative to a low racer with small wheels.