Saturday, February 26, 2011

Spin cycle: Changing Gears part 2

I have to learn some things the hard way - experientially - by working through problems over and over again until a solution slowly emerges and makes me want to just slap my forehead and wonder why it took me so long to figure it out. 

At the beginning of the month, after 11 months of randonneuring, it finally dawned on me that a different rear cassette might make a better gear combination for my ride.

Having made the change, and done so with a greater appreciation as to how cadence and gears could work together, I've done one 200k and had a couple of training rides. The difference has been significant - gear selection has become more precise while pacing and efficiency have improved. I am much more able to use my gears to maintain cadence and use both to control effort. Seems like customizing gears may be the best upgrade going, especially considering the relatively low cost and immediate benefit.

Surprise surprise - it turns out that I am not the first to figure this out. In fact, Ken Kifer wrote a very informative piece (with links) on this topic over 10 years ago.  As he points out, this topic is for the nerdiest of bike nerds, but just in case there are some of you out there who want to really want to dial in their ride, don't know this already, and don't need to learn things the hard way, the information is out there.

Note: This is a link to the current page for Bicycle Gearing for Wisconsin Hills  which is referenced in Kifer's sidebar. The calculator at the bottom is a nice tool for figuring out gear needs.


  1. I always have to lick the electric fence before I understand too.

    This is really interesting. All I know for sure is my lowest (on my road bike) is somewhere in the mid-20s, and my folder goes down to 21.5". (I put an internal gear hub on it expressly for towing 130 combined pounds of offspring and trailer up a 20% grade.)

    How far down have you taken Esmerelda?

  2. Now the lowest combo is a 26/36 which gives me 19.7 gain inches. But this information in a vacuum does not really say anything. This combo would have a different result for different folks. For it to have meaning, one has to factor in weight, strength (watts being produced) and percent incline. Plugging in my numbers shows me that this combo should allow me to climb a 10% grade at 60rpm by putting out 200 watts - very do-able - and a good mid-point for my bailout mountain gear.

  3. In my initial scenario, hauling kids up the hill by the Little Red Lighthouse, 19.7" would mean I stall out and fall over.

    I guess I should start using the heart rate and wattage components that came with that bike computer. Maybe that'll make this season's (late) training fun again.

  4. Nice work. There's a big difference in gearing needs between a 25 mile club ride and what we can reasonably expect at the end of a long brevet. Between correct gearing and appropriate pacing you'll be tearing up that Big Wild Ride!

  5. Keith - The higher the gear inches # the harder it is to pedal, so my 19.7 is actually EASIER than pushing 20+ gear inches. If you can haul that load with 21, you can go even faster with 19.7. As for the HR and wattage features, they can be fun/helpful if you like that kinda thing. I don't have watts monitored on the bike, but I am using the HR monitor to structure training and, more importantly, track recovery.

    Bill - ssshhhh! The BWR is not public information ;-). (I need to maintain plausible deniability.) Right now I just want to get through an R12 and a SR series.

  6. Yeah, but what's missing from that line of thought is the point at which you just can't spin any faster but the bike is going too slow to stay upright. I was just above that threshold at 21.5 gear inches on the hill I had to tow my boys up. Any lower and I'd have been going slower with the same maxed-out spin. Result: FDGB.

    (Fall Down Go Boom.)

  7. Actually, your cadence just decreases if the gear inches are too big to allow you to spin uphill. That when you go slow and power grind your way up.

  8. When you've got a combined rider/bike/trailer/child/child weight of 380 pounds on a 20% grade, "power grind" is definitely the term.

  9. I tried to read the link I really did but then my eyes glazed over and feel asleep at the keyboarddddddddddddd..... oh sorry! you could solve the problem by simply installing training wheels or do as I do and just avoid hills. :)

    I'm with ya in the "plausible deniability" or actually I won't be with ya when you're spinning up those mountains.