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Interesting analysis of similar rides: one geared, one on a fixie.

Friday, August 22, 2014 by  
Filed under Daily Blog

August
22
2014

As you may have read in Tuesday’s blog, this past Sunday I did a 167 kilometer (104 mile) ride, part of which was done stuck in a single gear (see “Forced single speed on Sunday’s century ride“). In that blog I said that I actually enjoyed the single speed part of that ride, as it added a cool new spin to things.

On Monday afternoon I received an email from my friend Roger Sutton, who is a formidable racer (pick your poison: XC MTB, road cycling, running) who hails from Ocala (near Santos). In his email, Roger contrasted a couple of nearly identical rides: one of the rides was done on his Specialized S-works Venge (fully geared, Dura-Ace Di2), and the other ride was on his fixed gear Jamis Xenith Team (44/15 gearing). The timing of Roger’s email was an interesting coincidence, as I had conceptualized Tuesday’s blog, but obviously not yet published it.

I found Roger’s data and analysis so interesting that I’d thought I’d share it here (I asked for Roger’s permission to do so, of course). I’m sure some of you will find this as interesting as I did.

Before I hand things over to Roger, I need to throw a couple quick definitions out there for those who don’t know the difference between a single-speed bike and a fixie bike.

Single-speed: A single speed bike has a fixed gear ratio. There are no derailleurs, and no shifters. You can freewheel (coast/backpedal) on a single speed.

Fixed gear (aka a “fixie”): Like a single speed bike, fixies have a fixed gear ratio. There are no derailleurs, and no shifters. Unlike a single-speed, however, you can not freewheel (coast) on a fixie. If you’re moving, so are the pedals.

Okay, take it away, Roger! 🙂

John,

I thought you might find this Strava data interesting.

John [Murray] and I did our 20 lap ride at the greenway in Ocala the past 2 Sunday mornings.

We started at the same start time both days and rode to and from the trailhead from his house at a steady pace.

The Avg Speed for the actual 20 laps happened to be identical both weeks.

The only real difference for me was that the first Sunday I was riding a fully geared SWorks Venge with DuraAce Di2. The second Sunday, I was riding my Fixed gear Jamis with a 44/15 gearing.

I thought you would be interested in seeing the differences in the Strava 25W Power Distribution charts.

GEARED RIDE

Even though this is a closed loop with shallow hills (only 1000 ft of climbing over 60 miles) you can see that I coasted for 11 minutes and was under 100W for 32 minutes (18.5% of the ride time). I have seen routes with more hills and with a group push this as high as 30-35%.

[Click image to enlarge]

sutton image001

 

FIXED GEAR RIDE

Essentially there is ZERO time at 0 watts because you cant coast but I did get 30 seconds under 25 w. Also, there are still 26 min under 100W. So, although always pedaling you do get some recovery time. There is a noticeable shift of time accumulation though from 0-50w (geared) into the 50-100w range (fixed).

[Click image to enlarge]

sutton image002

 

The AVG Power for the ride (remember it’s the same speed) shows an increase of about 13w. So, it costs you some additional energy over the course of the ride, as you would expect.

That’s not the total story though. One of the big benefits of riding miles on a fixie is the variance in cadence. On a road bike, we all have a tendency to fall into a cadence that feels natural (comfortable). We shift the gears to stay in that comfort zone. I like riding the fixie so that I force myself (on the same ride) to do both high speed pedaling at learn how to pedal smoothly and not bounce, and also low cadence high torque seated pedaling.

On this particular closed loop its not that dramatic but I will throw a couple charts up anyway.

GEARED RIDE

Its easy to see all the times I stopped pedaling, even if it was brief. Cadence never got much over 100.

[Click image to enlarge]

sutton image004

sutton image003

 

FIXED GEAR RIDE (cadence and speed are obviously coupled)

Same course and similar cadence numbers due to the lack of hills and our steady pace (very little variation in speed).

[Click image to enlarge]

sutton image005

sutton image006

 

Look at the day before though (Saturday) on a 3 hour road ride with some nice rolling hills along the way…

sutton image007

 

I was going down a hill at a cadence of 162 and a top speed of 37.5 mph in that gear. There were other hills that I climbed at a cadence of less than 50. I’ve done some group rides where I have had to hold a cadence of 120+ for an hour…

WHY am I showing you all of this???

Because you are a data guy and I thought you might find it interesting. I’m a huge believer in the training effect of riding a fixed gear bike and obviously John Murray is as well. Someday you might want to consider adding one into you winter base training. I think that it would be something beneficial and also bring a bit of variety into you training. Both of which you would enjoy.

In any case, I hope this is a little bit interesting and I’ll talk with you on a ride soon.

Roger

Thanks, Roger–great stuff!

Roger has been trying to pull me into the “fixie world” for a while now, and at this point I’m pretty much on board. The training benefits, the simplicity, the challenge and the pure fun of fixie riding appeals to me a great deal. I’ll certainly be adding one to my stable at some point.

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