not doable with the 44mph on a coker…not even with a geared hub.

Uni Speeds

The following formulas give the speed of a uni of wheel diameter D pedaled at a cadence C (that is rpm = rev/min)

Imperial system (mph): Speed = D*P/336.1

SI: (km/h): Speed = D*P/208.9

So the speed of a Coker pedaled at 150 rpm would be 16 mph = 26 km/h.

It is hard to imagine much higher speeds, but I don’t know what a expert rider can achieve.

The fastest I’ve ever done on a coker sized wheel was 21.5MPH slightly downhill with 110mm cranks and it was very very unstable just from the cadence wobble. Don’t see how much faster you could really go without falling

There are reliable accounts of people hitting almost 30mph on a coker, downhill with short cranks, and not for long.

The RPM on a coker happens to work out pretty close to 10rpm per mph, so that would be something approaching 300rpm cadence, which is way more than I can do but not absolutely ridiculous (unlike Hazmat’s 44mph claim!).

Plenty of good coker riders can do 20mph or so stably.

Personally I don’t feel safe riding faster than 15mph (on 150s), and usually stay around 12 or 13.

Just remembered this is a 29er thread… getting a bit off-topic.

Rob

Wrong Formulas

I should have typed C for cadence instead of P, thus

Imperial system (mph): Speed = D*C/336.1

SI: (km/h): Speed = D*C/208.9

(sorry!)

I have both the 29er and the coker, but I haven’t been on my 29 in a long time. Go with the coker, it is much more fun and I have no problem on light trails.

There are a few videos posted of 29er rides that I saved on my computer when I was deciding to get one. I do not know if any of the links are still active since it was over 3 years ago:

I might be able to repost the few videos that I saved (Joe Marshall’s commute and the urban 29 riding) if those do not work anymore.

29 speed

These links don`t load anymore, i`

m afraid.

I will not go for Coker because 29 Qu-ax cross is much cheaper and smaller.

I will do a lot of bumpy forest trails.

If you’r going to do trails get the 29er, Cokers are mad for commuting

29er

Exactly, 29 seems to be a good choice for my purposes.

Still, i`m curious how fast can one ride on 29er?

I can cruise at about 20km/hr on a 29’er/150mm cranks.

I know of lot’s of Japanese riders that can cruise at 25km/hr on short cranks (eg 65mm or 89mm).

speed

I thought about getting 29er with 125mm cranks - wonder how fast could i ride with this combination?

Depends how fast you pedal.

Only way to find out is to get one.

I’m having the same debate between a 29" and a 36" myself. I plan on Riding The Lobster next year in Nova Scotia, so the 36" obviously makes sense for a 5 day 800km ride like that, but I’d like to ride trails and such aftterwards as well. The 29 seems like a good balance of speed and control to me. Which 29" uni would you recommend?

If you’re going to ride a 29" at RTL, you might want to get one without splined cranks/hub. That will allow you a bigger range of cranks, including down to 89mm for road riding.

Ryan Atkins is the one to talk to about 29ers, that man is a beast.

Here’s the math…

Average speed, I’m assuming that you will pedal two complete rotations per second on a unicycle with a 20 inch wheel. The Circumference of the wheel is 62.83 inches, in two rotations you travel 125.66 inches in one second.

Divide that by 12 to find out how many feet per second… 10.47

Multiply by 60 to get the feet per minute… 628.30

again by 60 to get feet per hour… 37698.00

Now divide by 5,280 to convert feet per hour into miles per hour… 7.14

That’s 7.14 MPH on a 20 inch wheel. That’s only getting two complete rotations per second. If you pedal faster you can significantly increase your speed. Do that same math assuming you pedal three complete rotations per second on your 20 inch uni and you will wind up with 10.70 MPH. Those numbers aren’t really bad on wiki.

Here’s the math…

Average speed, I’m assuming that you will pedal two complete rotations per second on a unicycle with a 20 inch wheel. The Circumference of the wheel is 62.83 inches, in two rotations you travel 125.66 inches in one second.

Divide that by 12 to find out how many feet per second… 10.47

Multiply by 60 to get the feet per minute… 628.30

again by 60 to get feet per hour… 37698.00

Now divide by 5,280 to convert feet per hour into miles per hour… 7.14

That’s 7.14 MPH on a 20 inch wheel. That’s only getting two complete rotations per second. If you pedal faster you can significantly increase your speed. Do that same math assuming you pedal three complete rotations per second on your 20 inch uni and you will wind up with 10.70 MPH. Those numbers aren’t really bad on wiki.

I did the math and it comes out that when i pedal 2 rotations per second i can go 33 km/h on 29"er…

Uni Speeds and Cadence

Some of the claimed speeds in this thread seemed unreasonable to me. The main issue is the cadence (pedal rpm) achievable on a unicycle of a particular wheel diameter. I took the fastest 100m and 1500 m times at NAUCC 2007 for 24 inch wheels and calculated average cadences of the winners as 184 and 166 rpm respectively. This is a surprise because I thought that since racer-level bicyclists peak at about 120 rpm, a speed such as 180 would be impossible on something as unstable as a unicycle. Obviously I was wrong.

At world record level such as for the fastest mile set by Zach Warren (14 Sep 06) on a 42 inch uni, his time was 3:26.22 for an average speed of 17.46 mph (28.09 km/h) at an average cadence of 139.7 rpm.

Repeating my formulae from a previous post: for cadence “C” rpm, wheel diameter “D” inches, the relationships are

Speed [mph] = D * C/336.14 and

Speed [km/h] = D * C/208.86

Thus Zach’s average cadence = 17.46 * 336.14 / 42 = 139.7 rpm.

Assuming no mistakes in math, I think this all means that long rides claimed at high speeds should be checked for cadence to see if the value is reasonable in comparison to what the champs are doing. It would be nice to have more data and make a plots of cadence versus distance for different wheel diameters. Obviously cadence goes down with distance and increased wheel diameter. I can make the plots, if someone has the data.

I think this is wrong by a factor of two. Two revs/sec = 120 rpm so for a 29 inch unicycle wheel the corresponding speed is 29*120/208.86 = 16.66 km/h, not 33.32 km/h.