ok, just thinking this over.

based on a typical 32/16 gear and typical cycling cadence of 90rpm.

circumference of mtb wheel being about 2.05m.
wheel will be spinning twice as fast as pedals, so 180rpm.
180 x 2.05 = 369m/minute.
369 x 60 = 22140m/hour = 22.14km/hour (13.78mph).

unless you spin faster than 90rpm, as a max speed that seems pretty slow, have i gone wrong somewhere?

Nope, seems about right.

Teaches (forces) you to spin as well as grind.

I would not put 90 rpm as “spinning” IMO a nice comfy cadence but not spinning, if you’re spinning out at 90 rpm (as suggested if it is your max speed) something is wrong.

13.78 mph is still faster than most people travel on the flat off road, and if your going downhill not pedalling is usually ok.

Wouldn’t have a clue on my cadence, but 14-15mph is fine on my 29er running a 32:18 over a few hours riding. Anything faster starts to get uncomfortable over a distance.

Check this out.
[video]http://www.youtube.com/watch?v=NsjR8ZHsAQ0[/video]

You can spin a lot faster than 90

spinning might have been the wrong word, and the only time i’ve ever known my cadence is on an exercise bike! having said that, it didn’t feel like i could comfortably turn the pedals much faster, hence the conclusion. what would people say is a likely max cadence, then?

unless you spin faster than 90rpm, as a max speed that seems pretty slow, have i gone wrong somewhere?

Your figures seem right, but 90rpm != max speed.

/edit don’t know what my max cadence is, but I run out of rpm ~20-23 mph.
Can’t sustain that though.
But I couldn’t sustain that speed on any mtb for long 🙂

Personally I would expect most people to be able to maintain 90 rpm and if the terrain is conducive to pedalling spin out at 110 – 120+ min. On a rollers (so perfectly smooth) more still.

I can sustain 22 to 24km/h with a 4.1m gear.
I can sprint briefly to about 30km/h, which is about 120rpm.

That’s with clipless pedals. I wouldn’t like to try 120rpm on flats.

Sheldon Brown reckons 14.1 mph, assuming a 2.35″ tyre.
Check out his gear calculator

I can spin like a spinny thing and comfortably stay at a high cadence. so for me, personally your numbers are way off. 😀

My commuter has a 36/11 top gear equivalent and I can hit 30 mph or a bit more – anyone know what that cadence is? spinning like a loon thats for sure

Edit 120 or a bit more according to sheldon brown

so the cadence was the weak link in my calculations. what are other people’s top pedalling speeds, then? and with what gearing?

there’s a longish gentle downhill bit of road on one of my regular rides; on my old 26er ss running 32:17 = 3.86 gear metres I’d spin out* at about 19mph on my speedo = 30.4km/h.

Back calculating, that’s 30400 m/60 mins = 507m/ min / 3.86 = 131rpm

* i could pedal at this speed but not for long, feeling like my legs were not really applying any real force but just about keeping pressure on.

I would not put 90 rpm as “spinning”

120 rpm is sustainable for reasonable periods. imo.

tbh the only time that gears have SS is top speed & it’s generally in situations that aren’t ideal mtb anyway; tarmac or very smooth trails.

My max cadence at ssec was about 210rpm….

On the rollapuluza 😉

Seriously though max out at 45kph on 42:19 average alot lower ! Thats on sscx bike. Dont worry about that stuff then on mtb just roll with it and go where my nose takes me !

My max cadence at ssec was about 210rpm….

Sub 23 second 500m is fast, but the National Championship winning time is sub 20 😯 .
My best is 198 rpm, but on the road it’s about 160 downhill. Off-road, I don’t count or care.

Right that is it the P7 is getting converted, too long have I thought about it. You have inspired me, what gear ratio would be good for round Pitmedden, Lomonds, Dunkeld?
I am fit and do ride a Genesis Day 1 to work so have ss experience just not on MTB.
Sorry for the thread hijak 😯

start at 32:16 and work from there.

aye djaustin 22:21 – it hurt … and they made us do it 4 more times!

im blaming that for a lackluster performance at the actual SSEC race……

Fixed gear.
42:17
36mph down hill…

I’m sure Sheldon can figure that one out….

DrP

I’ve managed 25mph (34:18 29er) in a road sprint to the pub, and once kept 20mph for a mile or so on a disused railway line when the rest of the gang on geared bikes thought they’d try to leave me behind after a beer stop. They failed.

32/14 on 26er.
Absolute max speed 25.7mph – about 130rpm.
A nice pace for a couple of hours is 90 rpm – so 15/16mph.