Singlespeed & Fixed Gear - what chainring/cog ratio is everybody running?

i have on a 38/18 which is perfect for flat ground but on long or steep climbs it tends to be difficult. might go with 36/18...

I got all the parts together and Monday I'm going to build RegularBike with a 36/18. I can't tell you how it will work though. In fact, having an appropriate gear ratio is the thing that makes me most nervous about going singlespeed.

I'm running a 36/18. Fortunately it is pretty flat around here so that works out quite well.

I'm running 34/17, or 2 to 1 as it is commonly known.

Right now, I've got knobbies on my ss. When those wear out, I'll probably get semi-slicks. When I do, I'll probably switch to 34/16. I use the bike for mostly around town and I usually won't hit the single track unless its dry.

Currently using 40/20 combo. a 2:1 ratio is a good starting point but what you run really depends on your topography, terrain and fitness level. Singlespeeding is a compromise. If you pick a ratio that can get you up the hill easily then you'll be spinning like a madman just to maintain speed going back down the hill. Experimenting with ratios is fun and relatively inexpensive.

34x17 for my mountain bike
42x17 for my 700c fixed gear
44x17 for my 26" commuter/utility bike

Originally posted by riderx
34x17 for my mountain bike
42x17 for my 700c fixed gear
44x17 for my 26" commuter/utility bike


Whats up riderx? Long time no see!!!

I've got a 39/16 on my commuter SS. I also ride it off road, but the 36/19 is a little tough for that. Even on teh road, I'm not spinning as fast as I'd like to. I may go for a 39/18 and see how that works. Whatever ratio I use, I have to keep it 2:1 plus an odd number. Like right now it's 2:1 plus 7, with 39/18 it would be 2:1 plus 3. Having and odd number seems to keep the chain tension right with out having to go to a tensioner.

Originally posted by fubar5
Whats up riderx? Long time no see!!!

I've got a 39/16 on my commuter SS. I also ride it off road, but the 36/19 is a little tough for that. Even on teh road, I'm not spinning as fast as I'd like to. I may go for a 39/18 and see how that works. Whatever ratio I use, I have to keep it 2:1 plus an odd number. Like right now it's 2:1 plus 7, with 39/18 it would be 2:1 plus 3. Having and odd number seems to keep the chain tension right with out having to go to a tensioner.
Fubar - Glad to see you got bitten by the SS bug. I've been busy lately and just haven't had the time to post like I used to.

A few people have told me the "rule of 4" works good for gearing changes once you find a cog/chainring combo that works. Add the number of Cog and chainring teeth togther - in your case 39+16=55. Add or subtract 4 teeth from this total or multiples of 4 and you should have a usable gear. If you try it, let me know if it works.

Is that rule for vertical dropouts? Or just finding a good gear?

Actually, after thinking about it, it would work for me.. The biggest problem I have run into is chainring sizes, a 35 would be a good one. As long as I maintain the 2:1 plus an odd number gear I'm ok. 16+16=32, 39-32=7, or 18+18=36, 39-36=3. If I was looking for a big gear using the rule of four, I could do a 39/12, which would give me 2:1 plus 11!!! almost 3:1! Or I could go 39/20, which I think would be waaaay to easy. I had a 28/14 while I was doing fixed gear, and spinning that sucker was tough!! I have one hill during my commute though, and it barley makes the cut as a hill.

Originally posted by fubar5
Is that rule for vertical dropouts? Or just finding a good gear? Vert. drop outs. Once you find one that works w/o a tensioner use the rule of 4 to find other combos that will work. Or so I'm told ;)

i know one speed, i ride a 26 cruzer with 700 wheelset, with 50 chainring and 17 cog. with 167.5 crankarms. with the short arms less spin, 50 chainring gets going down hills fast, and on flats should not spin out. beside when riding with roadies they look at you like you are monster. and wonder how you do it.

This is interesting. I thought I was running a pretty low gear on my fixie at 39/17. I'm not familiar with the 2:1 concept. Maybe I should put a 19 on back. It is flat here so I'm not worried about having low enough gear, but my primary objective of riding a fixie is spinning. On my ss freewheel I have 48/18 for more all around use. All of my bikes are commuters. Lately, I have mostly been riding the fg.

Originally posted by RainmanP
I'm not familiar with the 2:1 concept. The 2:1 concept is for off-road riding. On the road it is way too small, especially on a fixed-gear.

I'm running mostly a 42/16 now on my fixed gear (although the flip-flop hub also has an 18 tooth freewheel on it currently), but I usually run a 50/16 combo in the summer.

I most often run 42x16 on my fixed gear. However, I change up quite a bit depending upon what I'm going to be riding. I just did a hilly 200k brevet with a 45x17 and I was a bit over geared. For general road riding, I think a 70 inch main gear with a 60-65 inch bailout hill gear on the flip side is a pretty good setup for me.

Dave

40 x 15 on my 700c fixed commuter. The hills are predictable but the wind isn't...

2:1 on my ATB. I leave my commuter in about a 3:1 ratio even though I have a shifter that hardly gets used.

This time of the year I run a 42 x 16 with 172.5 crank arms (I am 6' 5"). It is fairly flat where I am and this allows me to spin around 90-100 rpm most of the time. I live in Michigan and there is still snow on the ground and salt on the roads. For training and lack of cleaning, my fixed gear gets all the miles this time of the year.


After I get in shape, like around June-July I put on 48 x 16 or 15 with 175 arms. This gets me going a little better.

I run a 42-16 on my commuter. It is a little tall for some of the steep hills around here, but Overall it's a good ratio. On my mtb I run a 32-18, 32-16 depending on where i'm going to ride. I look at it this way, if it's to steep I can always walk.

49/17 with 165 arms on my pursuit bike, 44/16 with 170 arms on my 700c track, and 44/16 with 180s on my BMX.

I feel really odd here. I'm running big guns. 52 engagement rings with a 20 all the way down to 15 on three different bikes. I use Surly flip/flop hubs so one will be like the 16 and the other will be an 18 or a 20. I'm riding the 18 more right now to get my spin back, then in a couple weeks I'll be riding the hell out of those 16 and 15. I like to draft the posers, it irritates the hell out of them, specially when it's my turn to pull, and they see I'm grinding on one gear with no brake. I eat hills on these bikes, course the one hill that makes me wanna puke on a geared bike, I haven't even attempted on my fixies.

Y'all have some odd ratios. I'll stick with my 48/16 3:1. Nice and even math. :)

-Andy

I run a 48/16 on my fixed commuter. Houston's pretty flat, but I want to go with a 18t cog so I can spin a little more. My SS mtb is 32/16, but I want to change that because I spinn a little too fast when I use it on the street. I'm using a vertical dropout on the mtb, so I'll experiment a little.

A 2 1/2 year bump. Way to dig that one up!

Track:
49x15
48x16

Road:
42x16
49x18

45x16
52x18

I run 48x15 and 17 on my flip flop fixie.

I run 46:17 on my fixie, soon to be 46:19 (moving somewhere hilly). 2:1 is rarely an appropriate ratio, on or off road. If you swing over to the MTBR SS board, you'll see most of them running 32:18/19/22 or something along those lines. They think 2:1 is steep. And most fixed gear road rides think it's way too small, which I agree with.

53x11.

All the way.

48x14

50 x 16 and 49 x 16

46 Chainring, I have 13 thru 20 tooth cogs depending on my mood & training intentions that week. I've been running an 18 & 20 lately to work on spinning & that's been a lot of fun. I haven't changed the speed of my training, just increased the spinning, up to 165 to 170 cadence on the flats.

42x16 on my fixie
32x18 on my mountain bike. Though I have never taken it on the trails since I have converted it. May drop down to a 16.

SS 52x20
Chicago is quite flat.

Presently 52X17 (81") in a rolling urban/suburban setting with a 800-1000' dynamic range.

I took a long time getting to 52X17, playing with 47t and 48t chainrings and 16t, 17t and 18t cogs on the way.

This winter I might go back down to 47X17 (72") for the control it offers.

40x13
Chicago may be flat, but I've forsaken my masher ways. Plus it is my first fixed so I kind of just took a shot in the dark on the gears.
Can we just make this thread sticky? seems like a common question

48x16 on 700c

42x14 right now. 700c. 175mm cranks. i only ever rode in one gear on my geared bike so i just picked whatever that ratio was when i built my fix.
but i'm thinking of making it 43x14 so i have more than 1 skid patch.

48x17.

42x16 on the 700c SS cyclocross commuter. (170mm cranks)
36x16 on the 24" wheel SS urban rig. (175mm cranks)
34x16 on the 26" wheel SS mountain bike. (175mm cranks)

48x15 for the track... but I want higher still
48x17 IMHO the perfect city gear.

48x16 on my urbanite now with a freewheel so SS, need a back brake still. not need really but the front is getting raggedy, may as well replace with a matched set since it's SS from now on

53 x 14 SS

48x18. 165mm, 700cc.

Old thread!

50 x 17 on my nice bike
42 x 15 on my "beater"

both are used on the street, without hand brakes.

46x17, 700 x 25 tires, 170 mm cranks

52 x 18, eats hills.

49x18, switching to 17. 165 cranks

46x18 down from 48x18. and lovin' it. 9 skid patches!

44x16 170 cranks