Gear Ratios

[martin]

Phillip posted these questions to the list and I figured it deserved being here as well - I know we have some very accomplished one gear guys in here somewhere... (i edited it a bit for forum purposes...)

Anyone care to address gear ratio's? What would someone use for Schaeffer Farms, the watershed? I have heard as a starting point 2:1, as in 32 front and 16 rear, or 36 front, 18 rear. Would these two be the same? What
should we shoot for for versatility? Both front and rear?

[Snot-Rocket]

I'm a huge advocate of 32-front and 20-rear- not cause I have sally legs, but I find I don't ruin my spin SS and this gear ratio allows for more control and less mometum dependency...oh, you still have to muscle through steep technical climbs- just allows more control.

It takes getting used to a bit, but I find this to be a very fun gear- yeah, you spin out fast on flats, but on SS, you can roll fast and not run out...

Joy,

[mscard]

I've been running a 32T chainring and a flip-flop hub with a 16T and 17T Cog for sum time and found that only the steepest or longest hills to be too much with the 32x17. This is also what I ran at Douthat (I believe I road with you and your son on Saturday - I was on the blue Haro).

That said, I'm switching to a 33T up front and a 17T and 19T on the hub. It'll be a little bit lighter than my current options but I've discovered recently that I also like the slightly lighter combo for a quicker spin (although personally I think 32X20 would be too light around here).

Also I recommend 175mm cranks, not 180's. I've been running 180 for the last 2 years and just switched to 175s and find I can ride my SS better in pretty much all conditions with the shorter cranks.

[cloughja]

I ride Schaeffer semi-regularly and find 34x20 to be a comfortable gear. It can be a little low of a gear at times, so I don't think I'd want to try anything easier than that, but I have been thinking about trying an 18t or 19t freewheel.

That said, gear choice is a personal thing, and you should just figure out what works for you and go with it.

Regarding crank arm length, I have ridden both 175's and 180's and also prefer my 175's. I'm 6'1" with relatively long legs, so I loved the longer crank arms for climbing out of the saddle, because they really allowed me to get more of my legs into it. However, I could never get used to them while seated and spinning. Also, I found that the extra 5mm makes a big difference on hitting logs and rocks with my pedals.

[Dirt]

I ride 32x18 with 180mm cranks. My legs are pretty long, so I ride 180s on everything but my road bikes.

I tried 32x16 a few weeks ago and I just couldn't spin it up the big climbs. I was off the bike and running too much.

It might also help to specify if you're running 26" or a 29er. I'm on 26" wheels. I imagine the gear ratios would be a little different with the bigger wheels.

Peter

[drevil]

I run 32x17 year round, unless I go somewhere big like Douthat where I run 32x18. I also use 175 mm cranks. I ride with guys that run 2:1, but they're either stronger than me or walk more :p

About running the same ratios with higher tooth count, there are a couple of pros and cons. With the higher count, the load is spread over more teeth so the rings last longer. Also, the chain links have to pivot around the pins less, so some say that there is less friction, but I don't know if that's perceptible by us mortals. The flip side is that smaller rings give you more obstacle clearance, and less banging into hard objects gives longer life, right? I prefer smaller rings for because I like to try hopping over things.

On my fixie I run 32:16, but you need to run slightly higher so that you don't completely spin out on the flats.

[jed]

I like 2:1 (34x17, 26" wheels) and 180mm cranks. I'm 5'10" with an average inseam, but I like the extra leverage for climbing. Anyplace I am spinning fast enough to want smaller cranks I should probably be coasting or slowing down because it is more efficient. I don't notice any problems with clearance in technical terrain; in really rocky stuff my cadence is slow enough on the flats to allow me to anticipate any potential clearance problems, and once again, the extra leverage is helpful. If it is rocky and tilted downhill, I'm standing and coasting; I'm rarely spinning my brains out in rocky terrain. I figure climbing is the biggest problem when singlespeeding off-road. Last winter I ran 34x16 and it was fine for the most part, but hard in rolling terrain where there are few opportunities to rest. Respect for the blow-up factor caused me to drop it back down to 2:1 for the racing season. I think 2:1 is a good starting point, maybe a bit hard for Gambrill, but about right for Avalon and maybe a bit small for Schaeffers. It really depends on your personal strengths and weaknesses. I started out with 2:1 a few years ago and figured I'd stick with it, but hey, I'm not a compulsive gear changer. Isn't that why we ride singles to begin with?

[skillet999]

33 x 17 w/ 180mm cranks. I just put on the 180's. Prior to that, I was running a 32x16 with 175s. I think the move to 180s has helped my climbing but quite honestly, it all hurts anyway so I'm not really sure. the extra 5mm in crank length didn't seem to adversly hurt my spin as it has others but again, it all hurts anyway so I'm not really sure. Schaeffer has been fine with the 33x17. According to my SSing mechanical engineer bro, the move from 175s to 180s should increase your torque by 2.8571428571428571428571428571429%

Have fun!

[TrailVictim]

If you haven't figured it out by now, Skillet has way to much time on his hands and he's obsessive compulsive.

[Dirt]

If you haven't figured it out by now, Skillet has way to much time on his hands and he's obsessive compulsive.

When I switched to 180s, it only increased my torque by 2.8571428571428571428571428571428%.

;)

Peter