Uncle Sixty's Gearing Primer for Newbs
#76
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These are excellent descriptions! I went with 46/17 (73.5 GI) with a bailout of 46/19 (65.8 GI) on 700x35c tires.
46/19... I've only ridden this a few miles just to test it out. Not too bad on flats but excellent on hills. My ride home always includes a one block long, fairly steep hill and this was perfect. Still challenging but way more fun being able to keep up some type of cadence. And the mile of slight incline before the hill was great.
Not enough GIs to be my all around gearing though. A little too much spin on flats. I'll see if I'm up to switching gears for the commute home everyday.
46/17... pefect all around gearing for me. I've commuted 2 1/2 times with this gearing. I immediately noticed the difference from 46/16. Much better acceleration. More spin at top speed. I don't have a speedometer, but I felt I was as fast as I was with 46/16. Fun on slight upgrades and not that bad on that one block long hill to get home.
I can't wait to try both gearings this weekend in the park. I'm guessing 46/17 will be near perfect; great on flats and quite challenging, hopefully still fun on the inclines. While 46/19 will be great for the inclines and not so great on the flats and declines. I'm sure it will be fun trying both.
Not enough GIs to be my all around gearing though. A little too much spin on flats. I'll see if I'm up to switching gears for the commute home everyday.
70-73 gear inches = superb range. At 100 rpm, it produces 21.4 mph (34.5 km/h). At 100 rpm, the force required to turn the pedals is still relatively light. Anything is this gear range produces an excellent balance between acceleration, hill climbing, combating winds and flat road speed. Note that at 20 mph (32.2 km/h), approximately 80% of the power being produced by the human body is being used to overcome air resistance. This is why it is so hard to sustain any speed above 20 mph (32.2 km/h) during a daily commute. If you know how to spin, this gear range will not be slowing you down.
I can't wait to try both gearings this weekend in the park. I'm guessing 46/17 will be near perfect; great on flats and quite challenging, hopefully still fun on the inclines. While 46/19 will be great for the inclines and not so great on the flats and declines. I'm sure it will be fun trying both.
#78
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I started on 46/18 with single and dropped to 46/17 on my first fixed setup. its good so far.
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When I first starting riding fixed (around town not on the track) it was a 47/16 which is a 77.5, and I found it too low. Maybe I wasn't used to spinning so much, I felt like I was topping out and I couldn't go faster.
After awhile I upped it to a 47/15 (82.7) and I kept it at that. I ussualy ride about 20 miles a week commuting back and forth from my girl friends, my ride home has a pretty steep hill, but not that bad (~500ft climb total distance), and though I had to really push up the hill, I was OK with it.
When I built my new all city bike the chain ring I got was a 46, and I ordered a 15t and 14t for each side of the rear cog. When I first put it together I ran a 46/15 (80.9) which was actually pretty nice around town.
A couple weeks ago I flipped my rear tire to the 14t and have been riding the 46/14 (86.7) around town since then, and I honestly feel a bit slower on it than any of my other ratios. I just can't keep up my spin at that ratio, not in the city anyways.
So now with all this knowledge of what its like -for me- to ride a 77.5,80.9,82.7, and 86.7 I feel like for me something in the high 70s low 80s is ideal for me. I'll probably switch my hub around and ride the 80.9 for around the city.
My whole point in all of this is that its important for YOU to try a bunch of different ratios. I personally feel like @Sixty Fiver and @puppypilgrim recommendations are a little too low for me. But most of my friends actually ride between a 70-75 tops and most other forms I read people talk about 75 being too high for them. Is it just me or does anyone else get frustrated at low to mid 70s? Seems like I might be an outlier, or maybe I haven't figured out/don't want to spin that fast to go fast.
After awhile I upped it to a 47/15 (82.7) and I kept it at that. I ussualy ride about 20 miles a week commuting back and forth from my girl friends, my ride home has a pretty steep hill, but not that bad (~500ft climb total distance), and though I had to really push up the hill, I was OK with it.
When I built my new all city bike the chain ring I got was a 46, and I ordered a 15t and 14t for each side of the rear cog. When I first put it together I ran a 46/15 (80.9) which was actually pretty nice around town.
A couple weeks ago I flipped my rear tire to the 14t and have been riding the 46/14 (86.7) around town since then, and I honestly feel a bit slower on it than any of my other ratios. I just can't keep up my spin at that ratio, not in the city anyways.
So now with all this knowledge of what its like -for me- to ride a 77.5,80.9,82.7, and 86.7 I feel like for me something in the high 70s low 80s is ideal for me. I'll probably switch my hub around and ride the 80.9 for around the city.
My whole point in all of this is that its important for YOU to try a bunch of different ratios. I personally feel like @Sixty Fiver and @puppypilgrim recommendations are a little too low for me. But most of my friends actually ride between a 70-75 tops and most other forms I read people talk about 75 being too high for them. Is it just me or does anyone else get frustrated at low to mid 70s? Seems like I might be an outlier, or maybe I haven't figured out/don't want to spin that fast to go fast.
Last edited by blissofbeing; 03-05-12 at 08:08 PM.
#81
Bicycle Repair Man !!!
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My whole point in all of this is that its important for YOU to try a bunch of different ratios. I personally feel like @Sixty Fiver and @puppypilgrim recommendations are a little too low for me. But most of my friends actually ride between a 70-75 tops and most other forms I read people talk about 75 being too high for them. Is it just me or does anyone else get frustrated at low to mid 70s? Seems like I might be an outlier, or maybe I haven't figured out/don't want to spin that fast to go fast.
I also use to ride at 80 gear inches and laid down the same mileage... dropping 4 gear inches just let me spin up a little faster and did not affect my top speed save for the fact I could hold it longer and keep things steadier over varied terrain.
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#85
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so right now I run a 17/46 and I may be picking up omniums on the super cheap but it has a 52 chainring. what size cog would I have to drop to, to keep the same setup?
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46/17 = 71.4GI
52/18 = 76.2GI
52/19 = 72.2GI
52/20 = 68.6GI
Take your pick.
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#90
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turns out the crankset i bought had a 49, not a 52. so ill be running 17/49 for now, see how i like it and maybe ill jump up to a 18 later i dunno..
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Hello! I'm gathering information for my MTB to fixed commuter conversion.
Sorry if this question has been asked already, but is there any difference between 38/15 gearing and 42/17 or 45/18 gearing? All give 2.5 gain ratio and 65 gear inches for my 26 wheel.
Logically the 38/15 will weight less, but will it ride the same as 45/18?
Sorry if this question has been asked already, but is there any difference between 38/15 gearing and 42/17 or 45/18 gearing? All give 2.5 gain ratio and 65 gear inches for my 26 wheel.
Logically the 38/15 will weight less, but will it ride the same as 45/18?
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It's generally accepted that larger chain-rings and cogs wear slower than smaller combos so you'd probably want to use the 45/18 gearing. Weight difference should be negligible and all should ride the same if they have the same gain/gear inches.
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Hello! I'm gathering information for my MTB to fixed commuter conversion.
Sorry if this question has been asked already, but is there any difference between 38/15 gearing and 42/17 or 45/18 gearing? All give 2.5 gain ratio and 65 gear inches for my 26 wheel.
Logically the 38/15 will weight less, but will it ride the same as 45/18?
Sorry if this question has been asked already, but is there any difference between 38/15 gearing and 42/17 or 45/18 gearing? All give 2.5 gain ratio and 65 gear inches for my 26 wheel.
Logically the 38/15 will weight less, but will it ride the same as 45/18?
#94
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Who has the best selection of chainrings/gears? I did a search in google but got tired of wading through hundreds of BMX parts...
What brands are the best?
What brands are the best?
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I like Retro-gression for cogs and Bens Cycle for chainrings.
Locally, Loose Nuts in Grant Park has (or had, it's been a while since I've been there) a good selection of fixed gear stuff since they got a bunch of stock when No Brakes closed.
If you're not picky about running 3/32 stuff you can usually find some good used cogs/rings at So-Po.
Locally, Loose Nuts in Grant Park has (or had, it's been a while since I've been there) a good selection of fixed gear stuff since they got a bunch of stock when No Brakes closed.
If you're not picky about running 3/32 stuff you can usually find some good used cogs/rings at So-Po.
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Thanks!
I'll check them out. I want to get a bigger chainring for riding on the flats. I think the 46 is fine for the commute, but I need a little more if I ride flat terrain.
I'll check them out. I want to get a bigger chainring for riding on the flats. I think the 46 is fine for the commute, but I need a little more if I ride flat terrain.
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Is this a bad thing? If it is, then I guess you got me.
Sorry I asked.