Alwaysalicia

Hi guys,

I am relatively new to the forum and hoping I am posting to the correct thread.

I have recently developed the "Folder Addiction". I love folders, they are cute (Yes I am a girl) and convenient. Currently I have an el cheapo xtremeride citybike 20" and a Dahon Mariner or Classic 16". I find that the 16" is more preferable to my geometry as I am basically a fetus on wheels. On my Dahon I can go pretty fast as it has some pretty high gearing on it. I am not sure of the exact specs and how many teeth it has, but I know it has 3 gears and top gear is pretty hard to pedal if you don't have the leg strength. I have googled high and low for a proper speed comparison of a 16" vs a regular sized bike and have come up with nothing. Many say it is impossible for a smaller wheel to be faster than a bigger one but I find that hard to believe as you can accelerate faster with a smaller wheel (so I have read).

So... I need a favor from you lovely cyclers. If there is someone out there that commutes and happens to have their hands on both a 16" folder and a regular wheeled bike (24" or above)--I would like you to do a speed comparison of the two. It can be side by side or timed. I just cannot find anything on the web that will show this.

A video would be awesome!

Can anyone help?

SN: I highlighted the specifics in red. I would really prefer a comparison between a 16" and a regular sized bike.

fietsbob

same creature power source is atop the saddle , and given a fact that in order to go very fast,

the air resistance is also common factor in all situations.. a smaller wheel will rotate more often to cover a measured distance.

As to how much , that factor is the circumference of the wheels in question, for your Math calculations..


I have a 38:16 drive train in a 26" wheel and a 53:16 in a 20" wheel bike

the distance covered with the 1 complete pedal rotation is very close to the same.

Alwaysalicia

Thank you for your fast response fietsbob .

Your comparative calculations give me hope. Do you have a 16" wheel to compare to?

Wilfred Laurier

THe difference is not as big, but smaller 650c wheels used to be (or still are) popular among competitive triathletes. I think the reason was that they had less aerodynamic resistance (smaller frontal profile) than the larger 700c standard used by most road racers.

My point is that there might be some small trade-offs - on paper smaller wheels have more rolling resistance - but these generally matter less than the way the bike fits the rider, the riding conditions, and the rider's fitness. If you are so fast that you are thinking of turning pro then your sponsors should give you a bike with larger wheels. Otherwise don't sweat it.

prathmann

Agreed. There are some small differences that are related to wheel diameter, but other differences between two particular bikes are likely to have a larger effect. As stated, if everything else is equal, then smaller diameter wheels will have somewhat greater rolling resistance and a bit less air resistance. But even here other things are rarely equal and a good small diameter (16" or 20") tire with smooth tread and supple sidewalls may have less rolling resistance than a larger (700c or 26") tire that is less efficient.

And smaller wheels have a slight edge in air resistance and are also lighter (again, if everything else is equal). But they might lose the air resistance advantage if the tires are wider and the weight advantage due to different materials or design.

Choice of gearing can be used to get the same speed at the same pedaling cadence regardless of wheel diameter. For example, my 700c road bike has its highest gear with a 52t chain ring in front and a 13t cog in back. My 20" folder uses a 60t chain ring and an 11t cog to get almost an identical high gear.

fietsbob

I have a Brompton* and a Bike Friday & 2 26" wheel bikes ans 4 700c wheel bikes ..

but the 67& 11/12ths year old meat-motor pootles along at the same rate of speed on all of them .

*54:15 & a S-A 3 speed + 2 speed Mountain drive crankset ..fwiw

osco53

I found for me that 16" wheels can get swallowed by small holes and big cracks and be stopped dead by miss timed curb hops.

20" wheels for me have none of these problems and sloppy curb hops are less freaky.

But then again I don't live and ride on groomed streets, I ride with the pot holes, sidewalk cracks and worn down curbs.

1nterceptor

I have a Brompton folder(16 in. wheels/349 ETRO) and a BMC Gran Fondo roadie(700 X 23 tires).
I've used both on long rides; 60 to over 100 miles. I finish long rides faster/easier on my roadbike.
I've used both on my 16.5 miles commute. I get to work/home quicker on the roadbike. But I don't
think that it's the 16 inch wheels that's making me slower. The roadbike was designed to put all of
your effort towards forward momentum; aero position, most efficient seat/pedal/crank position
relationship, etc. While folders in general are designed to occupy the least amount of space. So you
see that even though both are bikes with two wheels; their design/purpose varies.

My Brompton passing bikes with all kinds of wheel sizes:
https://www.youtube.com/watch?v=lmFU...6zPoymgKaIoDLA

Alwaysalicia

Thank you 1nterceptor!

Good music on the vid btw.

What you state makes sense, aerodynamics is key to a faster commute as well as geometry.
How much slower is your brompton compared to your road bike? Is it a significant difference? I wish you could ghost race yourself with both bikes (like mariokart) lol.

Alwaysalicia

@osco53

I haven't tried curb hopping on my dahon 3 speed... I'm too chicken. I did try going down stairs on my 24" mountain bike (again, I am the size of a fetus) and that almost didn't end well.. but I did it

jur

A speed comparison would be very hard to do accurately. As you get to say 20km/h, wind resistance becomes dominant, so it would be important to get the same aerodynamic position on both bikes.

Assuming this is accomplished, then it would be fair to compare bikes with the same type of drivetrain, say a derailer system, of equal gearing ratios. And both drivetrains would need to be equally clean and maintained.

Now we get to smaller issues like rolling resistance. The tyres are dominant. Getting tyres of the same construction (sidewall suppleness in particular) would be the important thing, as this factor dominates. They would need to run at the same pressure.

Once you have all these sorted, the only thing remaining is the difference in frontal wind resistance between the 2 cases, and the rolling resistance difference due to wheel size. It is generally agreed that smaller wheels, due to slightly more deformation of the rubber at the contact patch, have more rolling resistance. The wheels also rotate faster so any speed-dependent drag would be worse.

You can see that for a fair comparison, too many factors are involved, and you would not easily find someone with such a compare-worthy setup.

If you want to compare every-day bikes, then I would say a road-bike would be likely be the fastest followed by 20" wheelers with narrow rubber fitted, followed by 16" wheelers with narrow rubber.

If you throw different drivetrains into the mix, then a clean derailer would be faster than a hub gear setup.

If you add weight to the equation, the the lighter setup would be faster.

But by far, the dominant factor is the engine. I, on a super-duper roadbike, can't hope to beat a pro on a Brompton.

Of all my bikes, my Ti Swift is the swiftest, and the Brompton is the slowest, by 10-15% approximately. I ascribe the difference to all above-described factors.

energyandair

It's worth noting that most speed records over the years have been set using small wheels.

Based on this you may wonder why none of the pro racers use them. I understand that the reason is that the rules prevent it. I believe that they are this way to help make winning more of a test between riders than one between bikes and the nature of road racing may be such that it is safer if the bikes have similar characteristics. It would be very interesting to see what would happen to the technology if there were races without such limitations.

As a practical matter it is easier to find a large wheel bike that is optimized for speed but that does not mean that it can't be done with a small wheel bike.

Bottom line is, so long as your wheels are 16" or larger, don't worry about wheel size, factors other than wheel size are more important.

tdong

We dont' live in a perfect world. The two bikes are not the same. With my road bike i can go faster than the smaller wheels a bit. Due to many thing like position. Drag in internal hub etc. At the end of the day, the engine rules

CliffordK

I agree, there are lots of variables.

I have a 20" Bike Friday Pocket Rocket. I haven't monitored speed on it, but it seems to do reasonably well. No speedo on it though. I'll try to look it over in the next couple of days, then try some speed comparisons.

According the BF, they are essentially as good as a road bike.

If speed is the issue, choose a bike that is well made with a good aero position.

Oh... perhaps one should add a 16" racing recumbent to the mix.

Sangetsu

"It's worth noting that most speed records over the years have been set using small wheels."

Only because these bicycles need small wheels to reduce their aerodynamic profiles, they are only knee high. Pro racers use larger wheels because they are faster. Ride a full-size roadbike over the same course you ride your folder, the road bike will be faster, and probably dramatically so. I have used three folders, a Brompton with 17" wheels, and two Birdies, one with 18" wheels, and one with 20" wheels, the 20" bike is the fastest. The 20" Birdy is 19 pounds, the 18" Birdy is 18 pounds, both run Kojaks at 100 PSI, both have 10 speed drivelines. But neither is nearly as fast as my 22 pound Gios road bike. I usually commute on my Birdy, and the normal commute averages 8 minutes. The average commute on my road bike is 6 minutes, 20 seconds.

Alwaysalicia

Here is a pic of my lil' folder. The Dahon 3 speed. It's covered in washi-tape bc I girl lol.



I happened one day upon a Brompton during a downtown ride and the gentleman was kind enough to let me test ride it and demonstrate the world renowned fold. The Geometry of the Brompton bike was a bit uncomfortable for me, but that was probably that one bike as I guess you can be fitted to one. The guy had some long arms and legs!

dezzie

Many 50 year old Moultons still hold records and have 16" wheels, i have a 50 year old Moulton speed, with 4 gears on marathon tyres and its faster than my 20 inch wheeld 8 speed xootr on slicks and considerably more comfortable. I have the red speed the young kid rides later in the video with the drop bars. https://www.youtube.com/watch?v=Pb5e46nDg5Y

rhm

Assuming all that's true (which I'm perfectly willing to believe), I'm sure the differences in speed are due to factors other than wheel diameter. Folding bikes are inevitably a compromise between a bike and something that folds up; the compromises may be very minor, but they will take a toll. Aside from that, the industry just doesn't make top quality tires in folding bike sizes; and this, too, inevitably takes a toll.

Alwaysalicia

Do you have any pictures of it? That looks like a neat bike.

dezzie

This is how i bought it, currently stripped and being tidied up a bit now and finished in the next few months when i get time! Albeit it does not fold, the modern versions can seperate into two halves but its the point being made about small wheels not going fast.

Ozonation

Welcome to the world of folding bikes! And for the record, you do not have to be a girl to think folders are cute. I think mine is cute.

As for speed, others have commented on the matter already, and frankly, some of the forum members know a lot. All I can offer is a subjective comparison because there are so many factors involved, including the basic issue that the situations in which I ride a folder (16" Brompton) are quite different than when I ride my full size bike (700 wheels). In other words, I'm not likely riding my Brompton for speed or distance, but just to get around.

That being said, under most circumstances, I would estimate that I can reach about 85% of a "nominal fast speed" that I would reach on my full size bike.

Not sure if that helps, but good luck!

dezzie

How it looks now, just adding new bits of alloy etc, tidying up the paintwork, adding new brakes, saddle etc soon.

Alwaysalicia

Very nice. Looks to be single speed too?

I am in love with vintage as well. Another reason when I hit the trail I always opt for my dahon . What size are those wheels?

fietsbob

Ah, that is a Model H handlebar mast , one of the 4 choices Offered by Brompton ... for taller people..

I have a Green M3L (mudguards but no rear rack).

energyandair

Are the gearing and riding positions on all 3 bikes the same?

What are the tires on the Gios?

Are the components of the same quality?