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Thread: 48t or 46t?

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    48t or 46t?

    Hey guys...I'm not sure if this question has been asked lately or not, but I was unable to find any threads addressing my question within a few pages of results.

    Basically, I'm about to buy my first single speed bicycle...and I was unsure as to which gearing might be more reasonable for me...mostly based upon the terrain where I live. I'm looking at two bikes...one with a 46t chainring...and the other with a 48t chainring, both have a 16t cog. I live in Northern IL...north of Chicago...there aren't many hills...so the roads are generally flat. Does anyone ride a 48/16? or a 46/16? Do you think there would be much of a difference between 48t and 46t? Would the 48t be noticeably more difficult to ride? I'm going to be commuting with the bike...maybe 3-5 miles each way...that's the main reason for my question about how difficult a 48t would be compared to a 46t...and if there is even much of a noticeable difference between the two. Thanks everyone

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    the difference between 48/16 and 46/16 is very minimal . i rode 48/16 in newyork city for abotu a year ad its a good gear for flat surfaces. may not be the best brakeless gear if your just starting. i just moved to boulder co for a little while and im riding 43/16 and theres a pretty decent difference there. its hilly here and the gear is great for most of the terrian. plus its a really good brake lessgear . but i think the biggest diffrence between 48 and 46 would be skid patches and i dont really know to much about that.

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    The 46 would be better for tire wear considerations. This is especially true if you ever lock your leg to skid the rear tire. Since 48/16 is an integer the same part of the tire will always be in contact with the road for a given crank position. Even for normal riding you'll tend to exert more torque at certain crank angles and therefore you'll tend to wear the tire more in the corresponding spots.

    Edit: ignore this if it's really a single-speed freewheel and not a fixed.
    Last edited by prathmann; 07-18-09 at 12:05 AM.

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    Quote Originally Posted by rickrickrick View Post
    but i think the biggest diffrence between 48 and 46 would be skid patches and i dont really know to much about that.
    This is right. 48/16 only gives you two points on the tire to bear the brunt of skids, while 46/16 gives you eight. Of course, if you use brakes, this isn't an issue.

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    Fixed-gear roadie JacoKierkegaard's Avatar
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    Really depends what you're looking for. Some comparisons:

    With most rear cogs, the 46 will give you more skid patches than the 48, which is a factor in tire wear if you plan to do a lot of skidding.

    With any given cog, the 48 will be a (slightly) taller gear. The smaller the cog, the bigger the difference between the 46 and the 48 will feel. This is due to the fact that the difference between 46 and 48 will be larger relative to the size of a small cog than to the size of a large cog. Given a 16t cog, the difference will be minimal, but it should be a lot more noticeable with, say, a 13.

    Conversely, changes in rear cog size will make a greater difference in gearing with the 46 than with the 48, for a similar reason to the above. Any change in cog size (expressed as the number of teeth) will be a larger percentage of 46 than of 48, yielding a greater proportional change in gearing.

    In your case I'd make the decision based on how much skidding you plan on doing. The correct answer is: use a brake and buy whatever you want.
    2008 Masi Speciale Fixed

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    I think the OP has a single speed and not a fixed gear.

    =====

    Convert your bike to a fixed gear and put a 17t cog with a 47t chainring on it just for the prime number coolness.

    This will give you 17 skid patches, but, more importantly, it will give you 72 gear inches, which will enable you to stop with back pedaling instead of skidding.

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    Quote Originally Posted by prathmann View Post
    The 46 would be better for tire wear considerations. This is especially true if you ever lock your leg to skid the rear tire. Since 48/16 is an integer the same part of the tire will always be in contact with the road for a given crank position. Even for normal riding you'll tend to exert more torque at certain crank angles and therefore you'll tend to wear the tire more in the corresponding spots.
    Darn! I never even thought about that! The even integral between the teeth ration puts the same piece of tire rubber on the road when you skid.
    Man, I've got alot to learn about fixies! Maybe I should just stick with S.S.?

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    Quote Originally Posted by bikemeister View Post
    Darn! I never even thought about that! The even integral between the teeth ration puts the same piece of tire rubber on the road when you skid.
    Man, I've got alot to learn about fixies! Maybe I should just stick with S.S.?
    It's really not that big of a deal. Everyone likes to talk about skid patches, but unless you are the guys from the MASH videos fishtail-skidding down 40% grades in SF, you probably don't need to worry about it.

    Summary: if you don't know what a skid patch is, you probably don't ride hard enough to worry about it. I know I don't (I use a brake).


    Edit: As for the OP-
    Go for the 48T chainring. You'll be faster.

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    Quote Originally Posted by Invisibl View Post
    Hey guys...I'm not sure if this question has been asked lately or not, but I was unable to find any threads addressing my question within a few pages of results.

    Basically, I'm about to buy my first single speed bicycle...and I was unsure as to which gearing might be more reasonable for me...mostly based upon the terrain where I live. I'm looking at two bikes...one with a 46t chainring...and the other with a 48t chainring, both have a 16t cog. I live in Northern IL...north of Chicago...there aren't many hills...so the roads are generally flat. Does anyone ride a 48/16? or a 46/16? Do you think there would be much of a difference between 48t and 46t? Would the 48t be noticeably more difficult to ride? I'm going to be commuting with the bike...maybe 3-5 miles each way...that's the main reason for my question about how difficult a 48t would be compared to a 46t...and if there is even much of a noticeable difference between the two. Thanks everyone
    I find it a bit puzzling that you would ask us to suggest a gear ratio for you, when we know exactly 0 about your physical capabilities. Even more puzzling is the fact that people are actually answering with a straight face, as if it was logically possible to give a correct answer. It's hilarious. Well, I guess the prevailing common wisdom is that we are all exactly identical. All hail sameness!

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    golden ratios

    this link can tell you everything you need to know about ratio and skidding, but of course if youre riding singlespeed, ignore the skidding.
    Keep in mind too that a chainring isnt a permanent fixture on the bike. If one doesnt feel right, you can always trade out. I ride a 44/16 right now and i want something a little bigger i think.
    hope the link helps! The second comment has the spreadsheet for ratios and stuff.

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    Quote Originally Posted by wroomwroomoops View Post
    I find it a bit puzzling that you would ask us to suggest a gear ratio for you, when we know exactly 0 about your physical capabilities. Even more puzzling is the fact that people are actually answering with a straight face, as if it was logically possible to give a correct answer. It's hilarious. Well, I guess the prevailing common wisdom is that we are all exactly identical. All hail sameness!
    He's asking for the difference between 46x16 and 48x16. Nobody here is recommending 52x13 or anything.

    Facts:
    He's riding less than 5 miles at a time.
    He's not going up any hills.
    He's not going down any hills.

    It does not take a special athlete to run 48x16. Anyone who considers themselves even moderately healthy can do it. Given the two gear ratios, and the fact that neither is high enough to tax a moderately healthy rider on level ground, 48x16 will be faster.

    If he wants to give us more info about his fitness, he can. In the absence of that information, though, and given the fact he asked us for recommendations based on the terrain, the higher (of the two) gear ratios is the obvious choice.

    Note also that he said single-speed, which generally implies freewheel. Another strike against the lower of the two gear ratios.

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    Do the 48x16. No doubt about it.

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    We are going to let you make that tool, but I would like to help you by giving you the tools to do it.

    You said you are riding a single speed. Try this.
    http://software.bareknucklebrigade.c...it.applet.html

    This is still going to help.
    On the bottom. Gives you gain. How your crank rotation relates to your wheel spin.
    And your gear inches. Some people work with more than others when trying to go up hills.

    I truthfully don't remember where they recommend most people starting at.
    but i think it is around 70inches
    the 46t puts you there
    with 77 gear inches.

    Also certain gear ratios will actually work against you. Either check here first, or check them on paper the Sheldon Brown method.

    Before you ask, i run 46/11. happily.
    how to tape your bars http://www.flickr.com/photos/89572419@N00/sets/72157629279270681/

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    Senior Member amor fati's Avatar
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    First of all, your choice of bike should not be dependent on what its present gear ratio is. You should base your decision on more important factors, like what sort of frame and wheelset the bike is comprised of. Changing the cog and/or chainring is a relatively cheap and easy process. Secondly, even though you will be riding around on mostly flat terrain, isn't Chicago known as the "windy city". I think I read in a physics book a while back that pedaling into a 20 mph headwind is 4x harder than riding when the winds are calm. It is generally windy where I live too and I ride a somewhat easier ratio because of it. I would recommend that you get the bike with the better frame, i.e. better material, construction and fit for your body, and then throw a 17 tooth (or maybe even 18) cog/freewheel on the back wheel. It will be difficult to notice the difference of two teeth on the chainring.

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    The gearing change between a 48 and 46 is negligible but I always lean toward running the largest chain ring and cogs possible for a given gearing as it smooths out the drive and extends component life.

    I use a 52:18 on my road bike (75 gear inches) and use brakes I ride too hard and too fast to not have them.

    For most, something close to 70 gear inches is a good all around gearing.

    The other fg bikes have a wide range of gearings to suit their specific purposes... my touring bike just got a half step 48/52 up front and I am waiting to get a 17/21 Surly dingle cog for the rear to give me a fairly wide three gear range.

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    Quote Originally Posted by wroomwroomoops View Post
    I find it a bit puzzling that you would ask us to suggest a gear ratio for you, when we know exactly 0 about your physical capabilities. Even more puzzling is the fact that people are actually answering with a straight face, as if it was logically possible to give a correct answer. It's hilarious. Well, I guess the prevailing common wisdom is that we are all exactly identical. All hail sameness!
    True. If you don't know what your ration preference is, then we certainly can't tell you what it should be. We can give advice based on our experience, but things like gear preference vary so widely that it's nearly useless.

    In my experience it is better to have a slightly lower gear for flat riding than for rolling hills. In Atlanta, where nothing is flat, I preferred a 50x17 (right between 48x16 and 46x16, but closer to 48). I could hammer up the short hills and easily spin down while maintaining speed. I then moved to Thailand where it was pancake flat and I found 50x18 to be much more comfortable and, over longer distances, faster due to the a more comfortable cadence.

    Comments as to which is faster or easier are pointless since we know nothing about you and how you ride. Similarly useless are comments on which gears are the best for skidding or backpedaling. We can offer some comparison between two given gears, the smaller generally being easier to stop, but nothing more accurate than that.

    My recommendation is to get whichever bike fits you best. The difference between 46 and 48 is noticeable to anyone that has a good amount of experience riding. But it may make no difference for you. You, like nearly everyone else that rides SS or fixed, will eventually develop a collection of cogs and rings and you'll probably find the gear you really prefer after a year or so if riding.
    Quote Originally Posted by Josh Frank
    I will derive power from their cries of despair. My crank a speedy dervish, spinning and spinning through the darkest night that anyone with the audacity to try and suck my wheel will ever see...

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    53x17

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    Senior Member TimArchy's Avatar
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    53x11 all the way
    Quote Originally Posted by Josh Frank
    I will derive power from their cries of despair. My crank a speedy dervish, spinning and spinning through the darkest night that anyone with the audacity to try and suck my wheel will ever see...

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    Quote Originally Posted by TimArchy View Post
    True. If you don't know what your ration preference is, then we certainly can't tell you what it should be. We can give advice based on our experience, but things like gear preference vary so widely that it's nearly useless.

    In my experience it is better to have a slightly lower gear for flat riding than for rolling hills. In Atlanta, where nothing is flat, I preferred a 50x17 (right between 48x16 and 46x16, but closer to 48). I could hammer up the short hills and easily spin down while maintaining speed. I then moved to Thailand where it was pancake flat and I found 50x18 to be much more comfortable and, over longer distances, faster due to the a more comfortable cadence.

    Comments as to which is faster or easier are pointless since we know nothing about you and how you ride. Similarly useless are comments on which gears are the best for skidding or backpedaling. We can offer some comparison between two given gears, the smaller generally being easier to stop, but nothing more accurate than that.

    My recommendation is to get whichever bike fits you best. The difference between 46 and 48 is noticeable to anyone that has a good amount of experience riding. But it may make no difference for you. You, like nearly everyone else that rides SS or fixed, will eventually develop a collection of cogs and rings and you'll probably find the gear you really prefer after a year or so if riding.
    wtf.... common sense? How did that make it to BFSSFG?

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    Senior Member TimArchy's Avatar
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    my bad. I've been posting on other forums for a while. I'll try to clean up my language.
    Quote Originally Posted by Josh Frank
    I will derive power from their cries of despair. My crank a speedy dervish, spinning and spinning through the darkest night that anyone with the audacity to try and suck my wheel will ever see...

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    Quote Originally Posted by TimArchy View Post
    53x11 all the way
    this. spinning 150rpms all day

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    chicago, while known as the "windy city", is not that windy at all, relative to other cities. chicago is nearly a 100% flat, though.

    70 GI is about perfect for flat terrain riding. sure, one's ability or preference may create a desire for a higher or lower amount of gear inches, but 70 GI is still an excellent starting point at the very least.

    I would go with 48:18 (assuming 165s & 23s).

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    Quote Originally Posted by amor fati View Post
    First of all, your choice of bike should not be dependent on what its present gear ratio is. You should base your decision on more important factors, like what sort of frame and wheelset the bike is comprised of. Changing the cog and/or chainring is a relatively cheap and easy process. Secondly, even though you will be riding around on mostly flat terrain, isn't Chicago known as the "windy city". I think I read in a physics book a while back that pedaling into a 20 mph headwind is 4x harder than riding when the winds are calm. It is generally windy where I live too and I ride a somewhat easier ratio because of it. I would recommend that you get the bike with the better frame, i.e. better material, construction and fit for your body, and then throw a 17 tooth (or maybe even 18) cog/freewheel on the back wheel. It will be difficult to notice the difference of two teeth on the chainring.
    It took 14 posts to get that info?

    Gears will be changed as you see fit... don't even consider them as the purchase of the bike. You may like something totally different than others.... (cruising speed, effort, etc), and will likely be changing and trying different gears anyways.

    Wind is just as likely as hills... you just can't plan on it day after day.

    I ride a 44x17... I can cruise at a lowly 10-11mph with a friend, I can paceline around 20-22mph, and I and I can sprint to lower 30s. Essentially, it's low enough that even in the worst wind or at the end of a hard 70miles, I can still ride. BUT, I'm not limited in top speed when I want to get the fock out of the way, or play around and race friends.
    Last edited by chevy42083; 07-21-09 at 12:55 PM.
    No lugs, no care.

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    Senior Member TimArchy's Avatar
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    Quote Originally Posted by chevy42083 View Post
    It took 14 posts to get that info?

    Gears will be changed as you see fit... don't even consider them as the purchase of the bike. You may like something totally different than others.... (cruising speed, effort, etc), and will likely be changing and trying different gears anyways.

    Wind is just as likely as hills... you just can't plan on it day after day.

    I ride a 44x17... I can cruise at a lowly 10-11mph with a friend, I can paceline around 20-22mph, and I and I can sprint to lower 30s. Essentially, it's low enough that even in the worst wind or at the end of a hard 70miles, I can still ride. BUT, I'm not limited in top speed when I want to get the fock out of the way, or play around and race friends.
    Do you race? You should. With the ability to paceline (I'm assuming that this implies extended periods) at 120rpm+ and sprint at over 170rpm, you are in the upper echelons of cycling.
    Quote Originally Posted by Josh Frank
    I will derive power from their cries of despair. My crank a speedy dervish, spinning and spinning through the darkest night that anyone with the audacity to try and suck my wheel will ever see...

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    Fixed-gear roadie JacoKierkegaard's Avatar
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    Quote Originally Posted by TimArchy View Post
    Do you race? You should. With the ability to paceline (I'm assuming that this implies extended periods) at 120rpm+ and sprint at over 170rpm, you are in the upper echelons of cycling.
    If the numbers work out like that, I'll just read his post as "I can keep the speedo at 21 for a few minutes, and in a frantic burst of exertion I once hit 30."
    2008 Masi Speciale Fixed

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