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Thread: 7 Speed Gearing

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    7 Speed Gearing

    I ride in San Antonio, TX which is a mixture of flat roads and rolling hills. What would be the best gearing for a 7 Speed. I've got a 52/39 up front The back has 7 speeds but I'm not sure of the teeth count or how to recognize the gearing. I want to be able to use my older bike on fast group rides without having to give away too much. I do have a 20 speed "modern" bike I could use but it has been collecting dust ever since I got into steel.

    Thanks

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    Senior Member Grand Bois's Avatar
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    Count the teeth on the biggest and smallest cogs.

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    The small cog, if it's 11, will have a 23T as a large. In which case, going to a 12/25 will make a noticeable difference, a good one for hills. Using a 13/28 or 14/28 will be better for hills, shifting suffers just a little and the rear derailer you have now should work.

    No were to go from 11/23 for speed and if you have 12/25.. STAY WITH IT. you'll regret it on ANY sort of a 'hill' even in your Texas Flatlands.

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    Bianchi Goddess Bianchigirll's Avatar
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    what chainrings are on your 'modern' bike? if you can keep up with that match the chainrings to the steel bike, unless they are compact. then do the same to the rear cluster although you might have trouble finding one. is this a cassette or freewheel?
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    Quote Originally Posted by Bianchigirll View Post
    what chainrings are on your 'modern' bike? if you can keep up with that match the chainrings to the steel bike, unless they are compact. then do the same to the rear cluster although you might have trouble finding one. is this a cassette or freewheel?
    My Cervelo is set up as 39/53 in the front and 11/53 in the rear. My Gios is a freewheel.

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    If you need some extra oomph making it up hills, Shimano has a nice 13-15-17-19-24-32 that has great close high end spacing for cruising, and that special extra low bailout gear for old fat guys like me. My wife has a 34 bailout gear, but the spacing isn't nearly as nice.

    It's hard to find, but it is out there - and cheap, too.

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    Quote Originally Posted by sciencemonster View Post
    If you need some extra oomph making it up hills, Shimano has a nice 13-15-17-19-24-32 that has great close high end spacing for cruising, and that special extra low bailout gear for old fat guys like me. My wife has a 34 bailout gear, but the spacing isn't nearly as nice.

    It's hard to find, but it is out there - and cheap, too.
    Interesting, what derailer ? or is it original... etc. Curious to know how it would work, I mean really fuction with a short cage type. I meen what dr.Train does the bike have ? Biggest I've tried was 28, that 32 (or 34) sounds real nice .

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    My wife has a long cage Veloce. I have a med cage Chorus. Both of us have 34/50 compact cranks.

    We go up some pretty steep hills. I mean, we're old and fat, but dammit, we still go up some really steep hills. And loaded for touring, too.

    Here's mine:



    It's all on a '69 Competition, so it's somewhat CV. Only the crankset and derailleurs are modern. They just work so smooth...it's irresistible.
    Last edited by sciencemonster; 10-14-09 at 08:26 PM.

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    Quote Originally Posted by Tabularosa78 View Post
    My Cervelo is set up as 39/53 in the front and 11/53 in the rear. My Gios is a freewheel.
    Wow, I've never seen a 53t rear cog, I bet you can climb walls with that!

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    THANKS sciencemonster, so advised on the gears. I bookmarked your site. May I ?

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    Quote Originally Posted by Old Fat Guy View Post
    Wow, I've never seen a 53t rear cog, I bet you can climb walls with that!
    Oops! I meant 11/23 lol

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    Quote Originally Posted by old and new View Post
    THANKS sciencemonster, so advised on the gears. I bookmarked your site. May I ?
    Help yourself! It's slow, but there's plenty of stuff there. It started as a small site to list my movies, but then started growing, and then people started sending me stuff...and it got kinda large. It runs on a laptop in my basement, though, so the bandwidth is real limited. What do you want for free!

    I'm working on a page for the Competition, but as you can see, I take crappy pictures.

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    I would also recommend the 13/32 also but you will need a long cage rd to use the 32 cog. I have this freewheel on one of my bikes and the Deore LT will make the jump from the 24 to the 32 OK but it is not a happy shift. It does a 28 to 32 shift very easy. I do like the 13 to 24 cogs. They are close enough to allow me to keep my cadence in most conditions.

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    You can go 13-26 and still use old Campagnolo SR with no problems, and climb most hills with it.

    At least I can, and I'm old and fat.

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    Quote Originally Posted by Old Fat Guy View Post
    You can go 13-26 and still use old Campagnolo SR with no problems, and climb most hills with it.
    That would be my vote. I changed the Bianchi from a 42/23 low to a 42/26, which I rarely use, but it is very nice to know it's there for a 16% grade or for any climb after I "bonk." The change from 23 to 26T is definitely noticeable.

    With a 7-speed, you may want to pay attention to how the gear ratios on the two rings interleave with each other. Ideally, you want the 53-39 percentage change in front (52-39 would be exactly 4:3, i.e., 33%) to be 1.5 times the percentage change in back, so you should be looking at an average progression of about 22% between rear cogs. I run a somewhat tighter 12-speed on my Bianchi (plug this into an Excel spreadsheet): 50-42/14-16-18-20-23-26. I have also happily used a 13-15-17-19-21-23-26 freewheel with the same ringset. Stock gearing was 52-42/13-15-17-19-21-23, which gave me a higher-than needed 108 gear-inch top, a Tour de France 49 gear-inch bottom, and several redundancies.

    For my wife, I once built a 52-42/16-18-21-24-32 setup, which has a nice tight 1.5-step progression in the middle and top ranges, coupled with a true hill-eating granny. The 88-inch top is a bit low even for my tastes, and I am definitely not into high gears. Newer 6- and 7-speed freewheels solve the problem nicely -- 10 gears were never enough to give me both the ratiometric density and the range I needed.
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    Quote Originally Posted by Old Fat Guy View Post
    You can go 13-26 and still use old Campagnolo SR with no problems, and climb most hills with it.

    At least I can, and I'm old and fat.
    Ha! I got you beat! I'm old, fat, AND out of shape!

    Seriously, my knees can't take the hills. I could man it out, but if I'm doing 50 miles today, 40 miles tomorrow, and again the day after, I can't be putting my knees through that. It's brutal.

    I pedal easy and the medium cage Campy (10 speed) makes it up to the 32T ok. The wife's 34T only has to make the jump from 28T. Not so bad.

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    Quote Originally Posted by John E View Post
    That would be my vote. I changed the Bianchi from a 42/23 low to a 42/26, which I rarely use, but it is very nice to know it's there for a 16% grade or for any climb after I "bonk." The change from 23 to 26T is definitely noticeable.

    With a 7-speed, you may want to pay attention to how the gear ratios on the two rings interleave with each other. Ideally, you want the 53-39 percentage change in front (52-39 would be exactly 4:3, i.e., 33%) to be 1.5 times the percentage change in back, so you should be looking at an average progression of about 22% between rear cogs. I run a somewhat tighter 12-speed on my Bianchi (plug this into an Excel spreadsheet): 50-42/14-16-18-20-23-26. I have also happily used a 13-15-17-19-21-23-26 freewheel with the same ringset. Stock gearing was 52-42/13-15-17-19-21-23, which gave me a higher-than needed 108 gear-inch top, a Tour de France 49 gear-inch bottom, and several redundancies.

    For my wife, I once built a 52-42/16-18-21-24-32 setup, which has a nice tight 1.5-step progression in the middle and top ranges, coupled with a true hill-eating granny. The 88-inch top is a bit low even for my tastes, and I am definitely not into high gears. Newer 6- and 7-speed freewheels solve the problem nicely -- 10 gears were never enough to give me both the ratiometric density and the range I needed.
    Ok this post kind of made my head spin. Does anyone have a good reference site for understanding gear ratios?

    Thanks for all the replies.

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    I'm running a 53-39 with a 12-28 7 spd Sachs Aris freewheel in the back with a Suntour 3000 derailleur.. I feel like I can climb just about anything - but rarely get into the 39-28 combo. 39-24 works for most of what I ride around here.
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    here you go:

    http://sheldonbrown.com/gearing/index.html

    Or go straight to the calculator:

    http://sheldonbrown.com/gears/

    the stock cassette pulldown has a list of "stock" cassette and freewheel options which is nice to see in one place when trying to pick a new setup to try out.

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    If you change the calculator to 'gear inches' - I don't get ratios at all - then 100 gear inches is like 1st gear- you go real fast. 40 gear inches is like 10th gear. Mountain bikes go down to like 20 gear inches, and the gearing we are talking about like a small 34 in front and a big 32 in back, gets you down to around 30 gear inches.

    John E and Old Fat Guy are macho and are talking about 40 inches or so and they can climb walls. I'm crying and squealing for 30 inches just to make it up the driveway.

    Remember - smaller in front is easier. Bigger in back is easier. Bigger in front is harder and faster. So is small in back.

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    The OP finally counted the cogs.. 11/23 as fast a gear as you can have on a 7 or any speed. Complex gear calc. charts are irrelevant. we've all given more than enough.
    Fast being the operative word defines the 11/23. He's apperently not interested in kind gearing, it's not mountainous anyway.

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    Bicycle Repair Man !!! Sixty Fiver's Avatar
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    Just installed a new 13-34 Shimano 7 speed megarange on my friends winter bike... it's a big jump to that 34 but this means the top 6 gears are a little tighter and with a 42/52 up front it provides a really great bailout for steep climbs or plowing through snowdrifts. The medium cage light action rear d handles the jump to the 34 rather well.

    I just installed the same type of cassette on my commutourer (8 speed cassette) as it tightens up the 7 higher gears but leaves that extra low bailout gear. A more evenly spaced 8 speed with the same range had bigger jumps between gears. This bike has an XT long cage which handles the jump to the 34 very smoothly.

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    Quote Originally Posted by old and new View Post
    The OP finally counted the cogs.. 11/23 as fast a gear as you can have on a 7 or any speed. Complex gear calc. charts are irrelevant. we've all given more than enough.
    Fast being the operative word defines the 11/23. He's apperently not interested in kind gearing, it's not mountainous anyway.
    Bianchigirl asked what I had on my "modern" bike (Cervelo S1) which is where the 11/23 came from. I'm a new biker so if that gearing is hard or easy is hard to answer. I can hold my own and not get dropped on "Texas hills".

    Finally home and able to count my cogs on the bike I would like to modify. So, for the record in the front I have a Campy Athena 52/39 with a C Record derailleur. In the rear I'm running 12-13-14-15-16-17-18 on a Sachs freewheel. I have a C Chorus derailleur in the back.

    Treebound, thanks for the Sheldonbrown links they really helped.

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    Quote Originally Posted by sciencemonster View Post
    If you need some extra oomph making it up hills, Shimano has a nice 13-15-17-19-24-32 that has great close high end spacing for cruising, and that special extra low bailout gear for old fat guys like me. My wife has a 34 bailout gear, but the spacing isn't nearly as nice.

    It's hard to find, but it is out there - and cheap, too.

    Will the rear DR handle the big gear(32T)?
    I have a Suntour Sprint 9000 rear DR and have been wondering about just that?
    bill

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    Quote Originally Posted by bmwstbill View Post
    Will the rear DR handle the big gear(32T)?
    I have a Suntour Sprint 9000 rear DR and have been wondering about just that?
    bill
    Yep. The medium cage does.

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