89s - road test

Today was my first chance to try out my new 89mm cut-down Dotek aluminium alloy cranks properly. I’ve had 89mm steel cranks on the 24 for a while, but haven’t ridden it that much.

The uni is a Nimbus (US = Yuni) I with the standard Nimbus alloy wheel, a cheap 24 x 1.95 knobbly tyre, standard ‘round’ plastic unicycle pedals, Viscount seat and no handle.

And 89mm cranks. :0)

In 59:54 riding time (let’s call it an hour!) my computer recorded 7.18 miles, and a top speed of 12 mph. These figures are broadly what I was achieving on 102mm cranks. In fact, there seems to be a slight loss of top speed. Is that recording error? Or is it that the control is reduced (cranks are 12% shorter, so 12% less torque) and I’m unconsciously leaving a safety margin when riding fast?

The average speed is difficult to compare because no two rides are the same. Either the weather or the track surface or just my level of enthusiasm could make a difference. Today, I did quite a lot of fairly level ‘cross country’ to see what I could achieve with the short cranks. Conclusions:

  1. Mounting is a knack, but I’ve got it to 100% in normal circumstances.
  2. Idling is more like riding forwards and backwards then the traditional ‘pendulum swing’ style on a standard set up.
  3. The 24/89 combination has the hill climbing ability of a flatfish.
  4. But with care, it will go down quite steep hills - but you have to decide:do I keep it on a tight rein, or do I let it run away? Once it’s gathered speed, there’s no stopping it.
  5. Falling off the BACK is more likely than with longer cranks. It spits you off suddenly and unpredictably if you make the slightest error, especially when slowing down.
  6. It will wade through muddy puddles and slimy mud with the best of 'em. In fact, you’ve got more ‘ride height’ before your feet get wet.
  7. It’s not too good on complex sections of the ride with several turns, bumps and stops close together.

So, good idea or bad idea? Who can say? Compared to 102mm cranks, or even 110s, there is little obvious gain in speed, and it is at the expense of acceleration, control, and versatility. There is no logical reason to use 89 mm cranks. But then again, there is no logical reason to unicycle. :0)

What is good is that a ride which would offer no challenges at all on a standard MUni set up (e.g. 26 inch wheel, 150mm cranks) becomes a technical challenge on a 24 inch with 89s.

AND compared to a standard MUni set up, the speed between ‘interesting sections’ is increased. So if you have a place where you can ride regularly, but it’s not challenging enough for your current level of ability, ultra short cranks are a good way of putting the challenge back in.

Today, I was easily riding sections on the 24/89 which a year ago were difficult on the 26/150… but I was still UPDing on sections which I would now breeze on any of my other unicycles.

And the quality of the Dotek cranks? Can’t fault 'em, although it’s not clear that they perform noticeably differently from the cheaper 89s. They look better, though. :sunglasses:

Once again, thanks to Roger for all his help over these cranks.

I absconded with Lewis’s 29’er and slapped some 175’s on it (it had 125’s)- I’m currious to see if there is still a speed improvement over the 24" Gazz set up with cranks that long for moderate trail racing. The Nano Raptor tread patern isn’t very aggressive, so i worry that it may perform very poor if the race is wet/muddy.

Off-road on short cranks and a 20" wheel can make a boring trail a technical chalange- and fun… if you aren’t inclined to explain defensively the issues involoved to every passer-by (‘If I was on my OTHER cycle-’, ‘Ya, sure kid.’). :slight_smile:

-Christopher

When i did work experience with roger we set up a 28" with a carbon fibre frame and 89 cranks. That got a bit hairy at times…

Re: 89s - road test

On Thu, 6 Mar 2003 11:31:23 -0600, Mikefule
<Mikefule.jvr4y@timelimit.unicyclist.com> wrote:

>89mm cranks. :0)

Thanks for the road test.

Are you planning on trying even lower crank/wheel radius ratios, i.e.
use the 89 mm cranks on a 28" wheel or even shorter cranks on the 24"?
I could understand if you wouldn’t. Are shorter cranks than 89 mm
available from Roger (or elsewhere) in the first place?

Klaas Bil - Newsgroup Addict

“Roses are red, violets are blue, I am schizophrenic, and so am I.”

Re: 89s - road test

89mm on the 28" is like a baby Coker. I would guess for me it would be
similar top speed to Coker +110s as I am not that fast at the top end on the
Coker, but took more concentration and for me more scary (Sam seams to like
it more though I think), less good for long distance. It is nice to ride
generally though, also on mine it did make a very very light unicycle.

Roger

----- Original Message -----
From: “Klaas Bil” <klaasbil_remove_the_spamkiller_@xs4all.nl>
Newsgroups: rec.sport.unicycling
To: <rsu@unicycling.org>
Sent: Thursday, March 06, 2003 10:35 PM
Subject: Re: 89s - road test

> On Thu, 6 Mar 2003 11:31:23 -0600, Mikefule
> <Mikefule.jvr4y@timelimit.unicyclist.com> wrote:
>
> >89mm cranks. :0)
>
> Thanks for the road test.
>
> Are you planning on trying even lower crank/wheel radius ratios, i.e.
> use the 89 mm cranks on a 28" wheel or even shorter cranks on the 24"?
> I could understand if you wouldn’t. Are shorter cranks than 89 mm
> available from Roger (or elsewhere) in the first place?
>
> Klaas Bil - Newsgroup Addict
> –
> “Roses are red, violets are blue, I am schizophrenic, and so am I.”
>
>


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