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  1. #1
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    Changing Gear Ratios

    Although I've only ridden a tandem a few times, I've wanted one for decades. I finally bought one - a ten year old Nashbar (KHS, I'm told) "Sport Tandem". I paid $450. the seller said it was almost never used and it looks brand new. The only thing that strikes me about it is how low the gears are (26-36-46 chainring and 7-speed 13-28 rear). It weighs in at a total of 45.4 pounds.
    I think that selling anyone who isn't a racer wannabe and who lives in a hilly area anything short of a triple with an 11-34 cassette constitutes abuse.) I'm a fairly fit geezer and that's what I use with pleasure and gusto on my regular bike, so the tandem seems absurdly low-geared. What options would be reasonable to consider to get higher gearing on the top end and where can I get them? Can I just replace the chaninrings with ones with more teeth, (Existing is 5 arm Sugino Fiso 62mm bolt center to bolt center), or would I have to get whole new crankset. Would existing front triple derailleur work with most any new triple?
    I wouldn't mind more range on the rear as well. Can I just switch to an 8-speed (I think I saw an 11-30 8-speed)? If so, would I need new levers as well (existing Shimano RSX levers)?
    Initially I'd like to spend as little as possible to try things out although I wouldn't mind spending more once I have more of a grip on things. I have read that reasonably strong tandem riders appreciate higher gears more than lower (within reason) owing to double strength - right?
    Now if only I can get my wife on it with me!
    Thanks!

  2. #2
    Senior Member Retro Grouch's Avatar
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    I'm going to guess that your crankset has a 110 bolt circle diameter. Chainrings up to 54 teeth shouldn't be hard to find. If it was my bike, I'd pay the extra money for rings with the built-in shifting aids. You'll have to install a longer chain. You'll probably also have to get a road triple front derailleur. It should work fine with your present flat bar shifters. Santana, Burley etc. all used mountain shifters with road bike front derailleurs until the relatively new flat bar road shifters came out.

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    Levers, bolt circle

    Thanks for the reply. Handlebars are conventional road bike drops with Shimano RSX shift/brake combo levers. Front already a triple (Suntour), which works fine.
    How do you determine "bolt diameter"? I measure about 110 from bolt center to bolt center for pair most nearly directly across from each other, but with this 5-arm unit not only are none directly across from each other, and their distances from each other varies.

    Quote Originally Posted by Retro Grouch
    I'm going to guess that your crankset has a 110 bolt circle diameter. Chainrings up to 54 teeth shouldn't be hard to find. If it was my bike, I'd pay the extra money for rings with the built-in shifting aids. You'll have to install a longer chain. You'll probably also have to get a road triple front derailleur. It should work fine with your present flat bar shifters. Santana, Burley etc. all used mountain shifters with road bike front derailleurs until the relatively new flat bar road shifters came out.

  4. #4
    Time for a change. stapfam's Avatar
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    Take the crank into the LBS and They will sort out the rings for you. I ride mainly offroad but have the occasional foray onto the black stuff. Believe me when I say that we need our low gears of 48/36/24 and 11/32 9spd rear- Even on the road. I think for our hills- our low end gearing is about right but that 48/11 does not get used much, and not many solos stay with us on the road. 48/11 with 26x1.4 tyres will give us a top speed of 25mph at our comfort cadence of 90. Cadence of 100 will give us 30. and to be honest there are not many occasions when we actually need the 48/11 on a normal ride. That gear is left for showing the solos with their 53 front rings that they don't need it. Mind you- when it comes to a 15% uphill slog- that 24/32 is quite handy at times.
    How long was I in the army? Five foot seven.


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    Maybe my post wasn't clear. I am asking about how to get higher gears without sacrificing too much at the low end and at not too high a cost. I have found that I can get much better advice here or on a newsgroup than from any of my LBSs, who are either not knowledgeable or are not inclined to take time with me.
    I find the 52/11 fine on my single bike and only use the 30/34 as a bailout, usually using my 30/29 for most climbs, including very short ones of 33%. I like to zoom down long easy descents at 40-50 mph and power up rollers so my tandem 46/13 would spin out frequently. 52/42/30 by 11/32 I'm sure would be more than adequate for me.

    Quote Originally Posted by stapfam
    Take the crank into the LBS and They will sort out the rings for you. I ride mainly offroad but have the occasional foray onto the black stuff. Believe me when I say that we need our low gears of 48/36/24 and 11/32 9spd rear- Even on the road. I think for our hills- our low end gearing is about right but that 48/11 does not get used much, and not many solos stay with us on the road. 48/11 with 26x1.4 tyres will give us a top speed of 25mph at our comfort cadence of 90. Cadence of 100 will give us 30. and to be honest there are not many occasions when we actually need the 48/11 on a normal ride. That gear is left for showing the solos with their 53 front rings that they don't need it. Mind you- when it comes to a 15% uphill slog- that 24/32 is quite handy at times.

  6. #6
    hors category TandemGeek's Avatar
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    Make sure you ride the thing and learn to hate it before dumping more money into your new tandem. You might find the gearing is OK for the types of riding you do, and or you may find the thing collecting dust in the garage...

    If you feel compelled to press ahead with the gear changes check out www.harriscyclery.com

    Harris Cyclery offers 7 speed freewheels in 11x28 as well as 11x34t "mega" range for about $24. However, you may find that your stock rear derailleur doesn't have enough capacity for the 34t cassette so if you opt for the "mega range" make sure that the idler wheel doesn't "roll" against the 34t sprocket... a sure indication that you'll need a rear derailleur with a longer rear cage.

    As for the chain rings, Harris also has a wide assortment of 110/74mm BDC 5-arm chain rings and inner rings.
    Your stock FD will probably handle a few more teeth than the 20 it is supporting now (46-26=20) so you could conceivably go up to a 53/42/30. If the current one doesn't seem to do the job, look for a mid-90's model Shimano XTR front derailleur, e.g., FD M737. These things were the OEM front derailleurs on a lot of road tandem sporting 53/42/28t chainrings. The cage isn't a perfect fit with the contour of the larger chain rings, but it's close enough. As others have noted, some of the newer road triples would also work. If you Also, as someone else noted, be sure to get a new chain that will be long enough to wrap your big chain ring and largest rear sprocket.
    Last edited by TandemGeek; 08-22-06 at 02:08 PM.

  7. #7
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    Half Step Gearing

    Just another idea to consider in your quest for adequate tandem gearing. I run my Santana with 54/49/32 chain rings and a 12-32 cassette. This gives me closely spaced ratios on level and rolling terrian with good low range when we have to climb.
    The only concession that needs to be made is the double shifting of the chainrings and cassette to maximze the available ratios. The double shifting is only needed on the nonclimbing terrian and has became completely second nature and is never an issue.
    This bicycle is ridden from a city whos' monicker is " City of the Hills". Situated between the Catskill and Adirondack Mountains the bike climbs alot and is suffciently geared to make the tops and still spin efficently through the valleys.
    Hope this info is helpful.

  8. #8
    hors category TandemGeek's Avatar
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    Quote Originally Posted by MGOBEL
    I run my Santana with 54/49/32 chain rings and a 12-32 cassette.
    Please tell me this is an early Santana with a six speed freewheel....

    IMHO, half-step gearing made a lot of sense in the days of 3-5 speed rear gearing, but has become increasingly unnecessary as triple chain rings and the 6th through 10th sprockets found their way onto the rear hub.

    Normal disclosure applies: Go with whatever works well for you...
    Last edited by TandemGeek; 08-22-06 at 12:40 PM.

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    Just following along to see if I might learn something, but am confused. For the sake of this thread, has the meaning of the terms "low gears" and "high gears" been reversed??
    Last edited by Ben There; 08-22-06 at 12:59 PM. Reason: correction

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    To me "low gear" is what you use going up steep hills, whether smaller chainring in front or larger cassette cog in the rear or both - higher rpm at a given speed.

    Quote Originally Posted by Ben There
    Just following along to see if I might learn something, but am confused. For the sake of this thread, has the meaning of the terms "low gears" and "high gears" been reversed??

  11. #11
    hors category TandemGeek's Avatar
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    Quote Originally Posted by Ben There
    Just following along to see if I might learn something, but am confused. For the sake of this thread, has the meaning of the terms "low gears" and "high gears" been reversed??
    Bicycle gearing follows the same rationale as motorcycles, cars, and anything else with a variable ratio transmission. Rather than re-inventing the wheel, here's what Sheldon Brown provides in his glossary of bicycle terminology:

    Low Gear
    - A low gear is one in which the pedals move rapidly compared to the speed of the wheels.
    - Low gears are achieved by using small chainwheels (aka. chain rings) and large rear sprockets (aka, cogs).
    - Low gears are used for climbing hills, or for starting up from a stop.

    High Gear
    - A high gear is one in which the pedals move slowly compared to the speed of the wheels.
    - High gears are achieved by using large chainwheels (aka. chain rings) and small rear sprockets (aka cogs).
    - High gears are for going fast, when the terrain permits. The rider must push much harder on the pedals in a high gear, so high gears are not suitable for lower-speed riding, due to the great strain that hard, slow pedaling puts on the joints.

  12. #12
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    This is exactly what I am looking for. What brand and model do you have and with how many cassette cogs? Ideally I would like to just change out my chainrings and keep the crank assembly.

    Quote Originally Posted by MGOBEL
    Just another idea to consider in your quest for adequate tandem gearing. I run my Santana with 54/49/32 chain rings and a 12-32 cassette. This gives me closely spaced ratios on level and rolling terrian with good low range when we have to climb.
    The only concession that needs to be made is the double shifting of the chainrings and cassette to maximze the available ratios. The double shifting is only needed on the nonclimbing terrian and has became completely second nature and is never an issue.
    This bicycle is ridden from a city whos' monicker is " City of the Hills". Situated between the Catskill and Adirondack Mountains the bike climbs alot and is suffciently geared to make the tops and still spin efficently through the valleys.
    Hope this info is helpful.

  13. #13
    Banned. galen_52657's Avatar
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    Quote Originally Posted by smitty8
    This is exactly what I am looking for. What brand and model do you have and with how many cassette cogs? Ideally I would like to just change out my chainrings and keep the crank assembly.
    you need to find out the bolt circle for the crank-set you have. Most likely from what you have described it is 110 mm - standard (old school) mountain bike triple crank, with the granny ring being 74 mm. You can get chain rings to fit it from Nashbar or just about any place else.

    Also from the description of your bike it is a flat-bar style bike with 26" wheels. If so, you are not going to need the top end gear of a racing tandem, and you might need the low gear you have already. With a 7-speed cassette, you options are limited unless you want large jumps between gears.

    My KHS is the road model and I am running a 53/40/28 chain ring set with a 12-28 8 speed cassette. My theory on gearing is if you can't spin it on flat ground riding hard, you don't really need it. Some folks like a gear they can pedal down hill, but I don't think it's necessary. Not too many wide-open descents around my way and my stoker takes issue with me going full-tilt down winding country lanes with the occasional driveway.....

  14. #14
    Senior Member Retro Grouch's Avatar
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    Quote Originally Posted by smitty8
    How do you determine "bolt diameter"?
    Measure from the center of one chainring bolt to the center of an adjacent one. If it's 64.7mm, you have a 110 bolt-circle-diameter. The nearest common ones are 94 (55.4mm between chainring bolts) and 130 (76.4mm between chainring bolts).

    By the way, are you sure that you need faster gears? Does Mrs.smitty8 ride now? Is she a hammerfest type or more smell the roses?

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    I would second the statement above. Try it out with the captain and stoker a few times before putting any money into your new tandem. You know you are looking at the gearing so if that is the only thing you find wanting, you are good to go for riding. Then you can actually take care of the gearing with the hints from this thread, otherwise, you might find tandeming is not for you, then you will kick yourself for taking the time to change the gearing.

  16. #16
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    ...I thank everyone for the kind assistance. I feel that I am slowly coming up to speed on how to determine what I have and what options are possible.
    ...I appreciate the suggestions that I not make any changes until riding for a while with the existing. Although I have not planned on prematurely changing gear ratios I suspect that I will want higher gears. If riding the tandem by myself I find the gearing too low, I suspect that it should be even more noticeable with someone pushing from behind!
    ...I suppose that there has been endless discussion about tires. It has 700/28 on now but I suspect that if I ride much with anyone my own weight as stoker (180#) I should probably switch to 32s. On my single I use Gatorskin 23s, which seem to come frequently recommended for tandems, if in larger sizes.
    ...It looks like higher than sidewall recommendation for air pressure is often suggested so I plan on 10% higher. On my single I use 10% less in front but on tandem suppose that adjusting pressure according to total weight and weight distribution not a bad idea.

  17. #17
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    Quote Originally Posted by smitty8
    . Although I have not planned on prematurely changing gear ratios I suspect that I will want higher gears. If riding the tandem by myself I find the gearing too low, I suspect that it should be even more noticeable with someone pushing from behind!
    Ah, but what if s/he is not pushing? You may at times be called upon to put in more than your fair share and that is when the lower gears will come into their own. The guys here speak from experience, give them the benefit of your doubts. Our rig runs 28's front and rear because that is how it came equipped and we have no plans to change it when they wear out. You could also run a 32R/28F. Front at rated pressure rear 10% over. Sizes and pressures for 90% of teams is, I think, a comfort issue rather than a performance issue. Is the rear seatpost a shock absorbing type? This is almost de rigeur (sp) on newer bikes but yours might have missed it by a season. If so, upgrade it. Your stoker will love you and as I have read here many, many times the captains main responsibility is to see to it that his (her?) stoker is comfortable and happy.

    H

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