The Cadence Conversations

[benphyr]

All
Just read this entire thread with my insomnia and want to THANK YOU for all of your wisdom.

I've been a serious cyclist for years, researching and experimenting. This thread is one of the most informative reads EVER. Makes me wish I were 20 instead of 80.

Indiana Dave
2 months in on my first Bent ... V20
Photo is with 305s. Have 406 and 700 wheelsets for both Fun and FastView attachment 12198

If you go much smaller wheels you will have a MBB skate board. !

 

[bladderhead]

Photo is with 305s. Have 406 and 700 wheelsets for both Fun and Fast

How different does the steering feel? Are the small wheels noticeably more bumpy? Do they have noticeably more rollin resistance? Is it weird being low one day and high the next? I assume that you have to swap the chainring. How do you cope with the change in chain length?

 

[IndianaDave]

BH
Stay tuned ...
When my insomnia kicks in, I'll post
ID

 

[CoolBreeze]

BH,
I’m curious to hear InduanaDave’s reply to your query, but I bet he swaps the same cassette among the different size wheels, so no changes in chain wheels or chain length. Of course using such small wheels must lower the gearing dramatically. Spinning out on the highest gear was common on my Bike E with its 20” rear wheel and 16” front.

 

[bladderhead]

When you install a smaller drive wheel you install a bigger chainwheel to compensate. My Grasshopper has 52t. How big was your Bike E chainwheel?

 

[CoolBreeze]

BH,
I have the Bike E model RX, came with a 3 x 9 drivetrain which uses two short chains instead of one long chain, and rear suspension. The triple chain wheel is mounted near the rear suspension pivot, and the cranks are fixed just behind the headset; the cranks’ chain wheel had 30 teeth, and connects to the triple chain wheel (actually a quadruple) with a 24 tooth cog; this difference makes the 44/32/24 chain wheel effectively act as a 55/40/30.
What I did was replace the 30 tooth crank chain wheel with a 44 tooth, which then makes the 44/32/24 act as a 80/58/44.
The lowest gear then results in a ratio of 1:1.37, which is fine for climbing if using a 20” wheel.
On flat terrain it’s fast, but uphill it’s a ponderous beast.

 

[Rod Butler]

All
Just read this entire thread with my insomnia and want to THANK YOU for all of your wisdom.

I've never for a moment thought about changing out wheels,
not my thing really with a IGH, but very out of the box thinking....luv it!

 

[Bent not broken!]

I had some trigger finger as well. That was mostly fixed by changing the angle of the handlebars (bullhorns correlated with getting trigger finger).

As for cadence-- a higher cadence implies lower knee torque for any particular energy output.
I've found that the thing that mattered more to me was being sure to pull up on the backstroke. This seems easier to do with a higher cadence.

I have no means to verify, but I wonder if a higher cadence doesn't change the blood-flow. There is some evidence that relaxed muscles mean better blood-flow (https://www.ncbi.nlm.nih.gov/pubmed/1642721). The doctors amongst us would know more, probably.

Anyway, if that is true, then a higher cadence might mean less variance in blood flow to the muscle. If the cells exchange oxygen in a manner that is non-linear with the amount of bloodflow, this doesn't matter. If the bloodflow is more linearly coupled with oxygen exchange (and other chemical exchanges which keep the muscles exciting efficiently), then this matters.

I just discovered using my hamstrings to pull. I instantly jump a full mph and my knees feel MUCH better!

 

[Bent not broken!]

I haven't gotten enough seat time on my Vendetta to be sure, but it does seem that what feels like the most comfortable cadence on it is a good deal less than it is on my other bents (CA2 & M5 CHR). There's a one mile stretch of flat road that I use to gauge my level of fitness, and judging by my Strava uploads, my average cadence on that stretch is right around 80 rpm. That's about 10 rpm below what feels best on my other two bents. I'm not sure why that is. I did swap out the stock 11-28T cassette for an 11-32T cassette, but I don't think that has affected my cadence; the primary benefit of the 32T gear is that it makes it much easier to get the bike going on a hill.

Now as a general question, I've always wondered why some bent riders (not on this forum) champion high cadence pedaling. I'm talking about 100+ rpm. I have tried it, but it always tires me out much sooner while producing no noticeable benefit. It seems counter-intuitive to me to pedal that fast, because the very act of spinning your legs burns energy, even when the resistance is zero. For example, there have been times where I just pedaled as fast as I could on my trainer to see how fast I could rotate the pedals. This was done without the tire touching the trainer's roller, so the resistance was as close to zero as it could possibly be. At a normal cadence of say 80-90 rpm, I could of course keep pedaling all day against zero resistance. But at a very high cadence of 140+ rpm, I couldn't keep it going for even one minute. The very act of pumping my legs that fast left me gasping for breath and exhausted my leg muscles in no time at all. Clearly the effect will lessen as you slow your cadence, but it seems to me that at 100 rpm, you're burning energy at a much higher rate just moving your legs than you would be by pedaling at say, 80 rpm, so why do it?

The high cadence is too lower stress on the knee joints. I have bad knees and feel a major difference. My climbing cadence is about 108-114 rpm. My fast cruising cadence is about the same. I trained for a higher cadence for two main reasons:
1. My commuter only has 5 very widely spaced gears. I can ride a few mph faster on my commuter if I spin in 2nd, than if I shift up to 3rd.
2. To protect my knees. A lot of long-time recumbent riders need knee surgery, or replacement, much sooner than is typical. Some are only middle-aged!

 

[Bent not broken!]

The pain in your hamstrings might be because you use the "scraping" pedaling technique on a bent, but not on a road bike. Scraping strongly engages the hamstrings, which I can feel every time I ride my bent. On the DF however, I seem to employ the quadriceps to a much greater degree, so my hamstrings never feel tired after a long ride on a DF. I need to try the scraping technique the next time I ride a DF and see if it works as well as it does on my bents.

I just discovered that technique and it works great for me on both.

 

[DavidCH]

I decided to go 12 speed with a 1x48t up front and a sram force 10/33 cassette. It gets me up the 5% and is ideal to flat and downhills without knee ache at the end of the day. I lose 2kilos as I don't use brifters or di2 or a front derailleur however the engine needs a work over before I can print some fancy numbers. I spin 90 plus however when I am going 60 ... I chicken out.