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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 03-11-09, 12:30 PM   #1
manuelche3434
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Brakeless gear ratio???

I recently made a bike and I currently have a 46 front and 17 back gear and well I was wondering what your gear ratio is front and back cogs?? any advise
I was think of eithar getting 19 for the back or keeping the 17 and changing the front one to 44 I wanna be able to do sitting skids but not sure if maybe what I have now is to high or do I just need practice I can lock up the back wheel for like a second and If i dont do right I really hurt me knees.
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Old 03-11-09, 12:34 PM   #2
anemptygun
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I am in the same position as you. I don't know the answer, but I would like to hear if someone else knows...
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Old 03-11-09, 12:59 PM   #3
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46/16 on the flip and 46/17 on the flop. I used the 16 as a starting point to kind of build up leg muscle and work on slowing down without skidding. When I finally got skidding down on the 16 tooth cog switching to the 17 was cake.

I live in Austin and there are small rolling hills and only a few minor climbs that I have to mildly attack, so the 17 tooth cog works for me. It also gives me 17 skid patches. When I skid I do very minimal lifting from my saddle, nothing at all close to those nuts to stem guys (which is not all that good for stopping anyway).

I would highly recommend a front brake. I have a front brake and today was the first time I've really used it in something like 3 months of it being on. A driver was paying no attention and drove into my lane. I would have ate some serious **** cause skidding wouldn't have bailed me out of that one.

I say you should keep with 46/17. Develop a little muscle and you should get the hang of skidding with a minimal amount of your ass off of your saddle. Then you could go for the 19 and it is going to be way too easy to skid.
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Old 03-11-09, 01:03 PM   #4
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I ride 46x17 brakeless and I dig it.
I don't go around skidding all over the place to stop.
Skips and back pressure to stop, skids for just screwin around.
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Old 03-11-09, 01:19 PM   #5
anemptygun
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Thank you, that helps a lot.
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Old 03-11-09, 02:20 PM   #6
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48/15 . it doesn't matter what ratio you ride
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Old 03-11-09, 02:28 PM   #7
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I started out 46/16 and it kicked my ass for a while. Once I could manage myself on that ratio, picked up a 17t cog and ride full brakeless. Its perfect.
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Old 03-16-09, 02:28 AM   #8
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Used to ride 48/17, now I ride 46/17 and love it.

Lots of skid patches and not too spinny on the downhills.
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Old 03-16-09, 09:45 AM   #9
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Me:
Langster Comp is 49x16.
Surly Steamroller is 47x16.
This should mean nothing to you.

Technical term for the "front cog" is Chainring.

Brakeless gear ratios are the same as gear ratios with brake(s).

Gear Ratios are seldom used to compare. The common unit of measurement to dictate gearing is your "Gear Inches". Gear inches are the number of inches you move with every 1 full rotation of the crank. You should use THIS calculator and play around with it. A lower GI will be easier to accelerate (and decelerate) with, therefore will be easier to skid with but will require faster pedaling to maintain the same speed of that of a higher GI. A higher GI will be more difficult to skid but will allow you higher speeds at a lower pedaling rpm (aka Cadence) than that of a lower GI.

It's a person preference what ratio (i.e., what combination of chainring/cog) you run. If youre entire criteria is based on seated skids, you either need to go to the gym and beef up those stems and learn them with the ratio you are currently running OR lower your gear inches by going with a larger cog and smaller chainring. This in turn multiplies (or divides depending on how you calculate it) the torque between the crank and the rear wheel allowing you to exert less force to lock up that back wheel.

Review:
Chainring = front
Cog = rear
The closer you get the number of teeth between the Chainring and the Cog = lower gear inches, i.e., 44x19 is lower GI than 49x16.(Technically, the ratio between the cog/chainring dictates GI but nobody runs smaller chainrings than cogs in practical applications).
Higher gear inches = harder to skid.
Lower gear inches = easier to skid.

Now go practice!

Last edited by RichPugh; 03-16-09 at 10:19 AM.
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Old 03-16-09, 09:50 AM   #10
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I have yet to see a truly seated skid on dry pavement, so don't feel like you're gearing is preventing it. It's physics that prevents it. I could be wrong, any video of a skid initiated while maintaining contact between seat and ass?
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Old 03-16-09, 12:32 PM   #11
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Originally Posted by jtarver View Post
I have yet to see a truly seated skid on dry pavement, so don't feel like you're gearing is preventing it. It's physics that prevents it. I could be wrong, any video of a skid initiated while maintaining contact between seat and ass?
i used to be able to do it with 48/17 but now i can't with 48/15. It depends on chain stretch, and tire wear. it was cause i had just gotten a new chain and my tire was pretty slick. I also couldn't do it if i had a bag on or anything extra other than my body
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Old 03-16-09, 03:28 PM   #12
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42/18. skidding is siiimple.
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Old 03-16-09, 04:16 PM   #13
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46/17. Works great on the hilly UCSC campus. However, I'm thinking of dropping down to 46/18 for easier climbing. Do whatever works for you.
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Old 03-16-09, 06:25 PM   #14
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I love my 46/17 (this my second post in the thread bahaha)

I'm an ambidextrous skidder on every type of skids (trick/seated/hop/you know what I'm getting at) so I've got a **** ton of skid patches. I live in a windy and hilly area and its perfect. I can still play with traffic without spinning out like hella. Best ratio I've ridden. (although I've ridden only 4ish others)
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Old 03-16-09, 08:41 PM   #15
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Quote:
Originally Posted by RichPugh View Post
. Gear inches are the number of inches you move with every 1 full rotation of the crank.
I thought gear inches were a measure of how big a wheel you would have on a penny farthing bike with the same gear ratio
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Old 03-16-09, 09:46 PM   #16
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Originally Posted by RichPugh View Post
The common unit of measurement to dictate gearing is your "Gear Inches". Gear inches are the number of inches you move with every 1 full rotation of the crank.
wow, i surely hope not!
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Old 03-16-09, 10:57 PM   #17
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It was originally the diameter of the penny farthing's wheel--which goes around once with each crank rotation. So the distance traveled in one rotation is actually the circumference of the wheel. The use of two gears makes a bike with smaller wheels go the same distance. But the distance is not the gear inches. My bike is the equivalent of a 73 inch wheel on a penny farthing, which travels 19ft in one rotation.

Correct me if this is wrong. I got confused writing that because I just figured it out in my head.
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Old 03-17-09, 12:25 AM   #18
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Gear inches is actually the distance you would travel with one crank rotation divided by pi.

ie: for a 27" diameter wheel, a 45 tooth chain ring, and a 15 tooth cog . . .

Circumfrence = 27" x pi
Ratio = 3:1
Distance traveled in one rotation = 27" x pi x 3 = 81" x pi
Gear inches = 81"

It is intended to equate the diameter of the old penny farthing to modern bikes.
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Old 03-17-09, 10:11 AM   #19
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I ride 48/16 and have no problem skidding if I need to stop quickly. It really depends on how strong your muscles get. When I first started I could barely do it with 46/16, had to really put my crotch to the bars to be able to skid, but after riding a year or so, I can skid seated with my current ratio.
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Old 03-17-09, 10:33 AM   #20
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i ride 46/17. i can skid sitting down, and ride up the big hills to get to my apartment. there are like 34 skid patches if you can "go both ways."
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Old 03-17-09, 10:36 AM   #21
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skidding in a 46x17 is easy (that's my gearing). To do seated skids "better" you just need to practice your technique.
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Old 03-17-09, 11:13 AM   #22
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Sorry, thanks for clearing up the gear inches stuff. I left quite a bit out. My mistake. I didnt mean to say if you had a gear inch of 80, you would only travel 80" with one rotation of the crank LOL... I meant to convey the higher GI, the further you would move with one rotation of the cranks, and lower GI, the less... I simplified it a bit too far for the OP.

Gear inches = drive wheel diameter x chainring teeth / rear cog teeth.

i.e., If your bike has a Gear Inch measurement of 80, one turn of the pedals moves the bicycle the distance equal to the circumference of an 80" wheel.

Last edited by RichPugh; 03-17-09 at 11:30 AM.
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