I usually take 51 minutes 28 seconds to 52 minutes to commute 20 km using my singlespeed Dahon geared at 62 gear inches from door-to-door with or without the fairing. Pics of the setup here.
To test the theory that I should be faster using gears, I put back gears (SRAM 8 speeds) on the bike, lengthened the chain and tuned it up again. I even have more aerodynamic trekking bars that allow me to crouch into a more streamlined position. The idea behind gears is that I can go spin uphill and go faster downhill and faster on the flats. So I cycled with the same commitment I usually do today.
Today's time? 55 minutes 12 seconds. Longer time by 7%. My average speed went from 23.3 km/h to 21.7 km/h. I don't understand. I really wanted this to work. I was faster without multiple gears and using just a flat bar with bar ends.
If you know Vancouver, my commute is from west Richmond by the dike, to River Rock Casino, across the CanadaLine bicycle bridge, north on Cambie Street from Kent Ave all the way into downtown (huge uphill all the way), right to Waterfront Center or Sinclair Center at Howe and Cordova.
Why was I slower? I rode just as hard as I normally do.
Maybe you just need to get used to gears again and learn the optimal combo for each situation. One ride means nothing, repeat several times and report back. I'm usually faster with gears but there are times where I'll just get lazy and spin easy
Last edited by hairnet; 09-09-10 at 12:43 PM.
Originally Posted by Scrodzilla
I often need to flip my brain to the freewheel side when reading this forum.
No guys. I was using gears correctly by changing gears to keep a constant cadence (80 and above). My comfortable cadence in in the 90s. I'm thinking slight but measurable transmission losses with a derailleur. Hills are definitely easier on the knees with lower gears though!
Banzai, I think you are right. AVS drops due to being in a lower gear for periods of time compared to the SS gear. Was also sitting and spinning on the hills rather than attacking the hills. Will measure a few more commutes to see. Thanks.
I know the hill well. I always get pinched by a bus at the Canada Line station then hammer that hill with 81 gear inches. On my road bike I sit down and try to keep my cadence at 90. I go noticeably slower.
I feel there is no shame in wanting to continue being a fixed roadie. I've spent my life without a derailleur, my road bike is on CL and getting picked up tonight.
Going slower isn't that big of a deal. In this town, a road bike gets you places a fixed bike might not go.
Banzai and vw addict, upon further reflection, I think my avg. cadence also dropped. I believe being in a lower gear for a portion of the time and lowering my avg. cadence contributed to the slower time.
Banzai, 81 inches? Wow. Monster legs brutha! I doubt I could turn the pedals from Kent all the way to 35th Ave on Cambie Street with that gearing. I gotta buy you a milkshake or ice cream for that one. I've tried the bike routes on Ontario and Heather but the grading on those are steeper than Cambie Street. Go figure.
chi-james, I've timed the commute enough times to know that 3min + is outside the normal standard deviation for my times.
Hills are definitely easier on the knees with lower gears though!
Right. By removing the stress on your knees, you're also removing the speed when you climb. That, right there, is the difference.
When I ride single speed I find that I usually climb much faster simply because I need to in order to survive the climb, in a gear that's really too tall for the hill. A lot of standing up, a lot of mashing, a lot of grunting.
Also, when I do group rides on my single speed, I almost always pass people when climbing (most of them are on geared road bikes). Same explanation.
Last edited by Doohickie; 09-09-10 at 02:16 PM.
I stop for people / whose right of way I honor / but not for no one.
Originally Posted by bragi"However, it's never a good idea to overgeneralize."
I don't think I see the point of riding a geared bike if you're just going to mimic your static singlespeed GI. Unless you really want to collect that one empirical data point.
I ride a lot of flat and my engine only does X over distance Y. Matching what my usual sustained cadence and speed is not wrong.
I can keep 35kph up no problem on a non-windy day. Why would I park in a gear with the same cadence but that nets me 29kph? I won't be working as hard.
I'm no roadie (close), but I have two modes of riding. Exercise and "going for a rip". The exercise part of my riding I like to maximise.
So with a geared bike I would like to keep my efficiency as close to what I have on my fixed, but when I hit an incline I just change gears to make it easy. Maybe I just view my road bike as the "easy ride". I'm not really getting my point across I think. :|