1x11 gearing on a bent

DIscuss anything relating to non-standard cycles and their equipment.
User avatar
Tigerbiten
Posts: 2503
Joined: 29 Jun 2009, 6:49am

Re: 1x11 gearing on a bent

Post by Tigerbiten »

What's your riding style ??
Are you happy to just tick along in the most efficient gear possible or are you after a higher average mph ??

I like the look of the double setup, even spaced gears across the whole range.

The triple is a bit more iffy.
The 12t sprocket looks like a filler simply because you didn't have anything better to fit there.
How usefully is a single close spaced gear ??
If the +90" gear is a downhill only gear then I'd probably accept the inefficiency and use the 11t sprocket for a higher spinout speed.
If you can use a +90" gear then maybe I'd be more inclined to push the limits of the front derailleur and bias the top end of the cassette with close spaced gears.
Something like a 48-36-24 triple and start the cassette 12-13-14-15- to -32 gives you the same range but with a bias towards the top.
Again I'd accept the slightly lower efficiency of the smaller chainring to get the close spaced gears at the top end.

Luck ............ :D
UpWrong
Posts: 2401
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

Re: 1x11 gearing on a bent

Post by UpWrong »

I need a slight downill to use a 90" gear. Generally quite happy ticking along although I prefer 13-15 smallest cogs to 11-13 because of the smaller incremental change.

So I did a 35 mile ride yesterday and made some use of my new 42T bottom cog, and everything worked impeccably. Changing from a 42mm rear tyre to a 32mm one has also lowered the gearing a bit. I'm unsure about switching from the 33/48 crankset to 32/48 because of further exceeding the RD capacity and running the risk of chain-wrap. At the moment all gear combinations are usable and I did use the 33/13 combo quite a bit. I ran on the small ring near junctions and on shared paths, switching to the bigger ring when I had clear space ahead of me. The image below shows my current gearing with the smaller tyre. Bear in mind I'm using 150mm cranks so it's harder to push these gears than with standard 170mm cranks, maybe 10% harder:
gears_2021_04_05.jpg
User avatar
Tigerbiten
Posts: 2503
Joined: 29 Jun 2009, 6:49am

Re: 1x11 gearing on a bent

Post by Tigerbiten »

UpWrong wrote: 5 Apr 2021, 10:30amBear in mind I'm using 150mm cranks so it's harder to push these gears than with standard 170mm cranks, maybe 10% harder:
But your feet don't move so fast per rotation with shorter cranks.
So keeping your natural foot speed, your cadence will be around 10% faster with 150mm cranks vs 170mm cranks.
This faster cadence lowers the pressure needed to push the pedals around with 150mm cranks back down to what you're used to with 170mm cranks.
So as long as you don't run out of gears down on a hill, crank length doesn't make much difference in energy used in any gear, there's just a slight cadence difference with different crank lengths.
It's only when you run out of gears down on a hill and your cadence drops does shorter cranks becomes more inefficient vs longer cranks.

Luck ............ :D
UpWrong
Posts: 2401
Joined: 31 May 2009, 12:16pm
Location: Portsmouth, Hampshire

Re: 1x11 gearing on a bent

Post by UpWrong »

This is what I've settled for in terms of 2x10 gearing. This is provided by a Spa super compact double, which is actually a 74/110 BCD triple with a chainguard as the outer ring, and a custom cassette:
paseo_gearing.jpg
I've used this quite a bit and it is pretty slick and user friendly. It's using 43T of RD capacity, so a triple altrenative would be:
paseo_gearing2.jpg.png
This gives one higher ratio and slightly closer spacing, apart from the 11T overdrive sprocket with an 18.2% shift.

So, at the end of the day I'm not sure I achieved anything apart from appreciatiing 10-speed XT kit. The chianguard is nice to have though.

EDIT: I seem to be noticing gaps more these days. So maybe an 11-32 cassette would be an improvement:
paseo_gearing3.jpg
User avatar
[XAP]Bob
Posts: 19793
Joined: 26 Sep 2008, 4:12pm

Re: 1x11 gearing on a bent

Post by [XAP]Bob »

Tigerbiten wrote: 5 Apr 2021, 5:06pm
UpWrong wrote: 5 Apr 2021, 10:30amBear in mind I'm using 150mm cranks so it's harder to push these gears than with standard 170mm cranks, maybe 10% harder:
But your feet don't move so fast per rotation with shorter cranks.
So keeping your natural foot speed, your cadence will be around 10% faster with 150mm cranks vs 170mm cranks.
This faster cadence lowers the pressure needed to push the pedals around with 150mm cranks back down to what you're used to with 170mm cranks.
So as long as you don't run out of gears down on a hill, crank length doesn't make much difference in energy used in any gear, there's just a slight cadence difference with different crank lengths.
It's only when you run out of gears down on a hill and your cadence drops does shorter cranks becomes more inefficient vs longer cranks.

Luck ............ :D
I wonder if natural cadence is foot speed or leg speed?
Given that on long cranks I am ticking over at an average cadence in the 100-110 range nowadays, dropping to 150 would mean I might take off.

I was looking again at gearing the other day - an 11-36 on a CS-RK3 with an HSD up front really does give insane gearing (with a nominal 26" wheel that gets 16" to 236") at 100rpm that's pedalling from 4mph to 70mph :lol:
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
User avatar
Tigerbiten
Posts: 2503
Joined: 29 Jun 2009, 6:49am

Re: 1x11 gearing on a bent

Post by Tigerbiten »

I'd put your natural cadence down to your fast/slow muscle fibre ratio.
The more fast you have, the higher your cadence will be.
I have a natural slowish cadence, my ideal cadence is in the 70-80 rpm range.
With training, end of a long tour when I'm very cycling fit, I can get it up around 85 rpm but not much higher.
My first trike had a top gear of only 100" and I could just hit 30 mph downhill on a certain run with a 100 rpm cadence.
Every time I did that I got to the bottom of that hill with an elevated heart/breathing rate.
I now come down the same hill at the same speed but in a 135" gear and at a 75 rpm cadence and my heart/breathing rate doesn't alter doing it.

My bent trike is biased low, 9.4"-179.4"
I change up into overdrive on my HSD at ~20 mph and I've only once spun it out at just over 50 mph.
But I do tend to stop pedalling at speeds over 45 mph as my eyes start to water at around that speed which makes spotting potholes interesting .... :lol:

Luck ........... :D
Post Reply