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Thread: Final drive gear ratios?

  1. #1
    Smoooooth at 430 gch71's Avatar
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    Smile Final drive gear ratios?

    Referring to two airheads, one was bought in Europe new, the other state side.
    First one is the European bike a 1974 r60/6... With a ratio stamped on the final drive of 37/11 or 31/11 kind of hard to read. What does this ratio give me, top end speed or quick low and go acceleration?
    The second bike is a US bought bike a 1975 (sept) R60/6 with a stamp of 32/9.. What does that give me? High speed low rpms or quick acceleration? I am stumped , any advice?
    Thank you.
    Oooops just found this in references, but please I'll take any input on performance and cruise speed.
    Anton Largiader’s page – http://www.largiader.com/
    Last edited by Gch71; 04-20-2012 at 04:25 AM. Reason: Link
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  2. #2
    Unregistered User dduelin's Avatar
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    The first number divided by the second is the final drive ratio so we have a 3.36 vs a 3.55. The 3.36 FD will turn a little less rpms for the same road speed mph and will possibly have more top speed and a little better gas mileage compared to the 3.55. The latter will offer a little better acceleration and slightly higher rpms for a given mph.
    Dave
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  3. #3
    Liaison 20774's Avatar
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    It appears that the 32/9 was an optional final drive offered for the R60/7. Mostly the R60/6 and R60/5 got the 37/11. Note that the speedometers will have different internal ratios depending on which final drive is installed.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #4
    Smoooooth at 430 gch71's Avatar
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    Final drive ratios

    Thank you gentlemen, I had a brain dump last night , for the life of me I couldn't remember how to convert the # or what the ratios meant. To much Jonhy Walker black. My intent is to keep the bikes original but with slight modifications for my personal preference, longgggg cruises.
    I did chech out snowbumbs and a few other sites and got my memory back.
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  5. #5
    Grammarian no, Rider yes ISAMEMON's Avatar
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    Quote Originally Posted by dduelin View Post
    The first number divided by the second is the final drive ratio so we have a 3.36 vs a 3.55. The 3.36 FD will turn a little less rpms for the same road speed mph and will possibly have more top speed and a little better gas mileage compared to the 3.55. The latter will offer a little better acceleration and slightly higher rpms for a given mph.
    this is correct info.

    it is also noted if you switch final drives your speedo may be less accurate then it is now.(are they ever acurate anyway) Speedos and final drives are matched.
    Or you could luck out, when I bought my currrent ride, the speedo had been switched with no regard to ratio, etc., why the po did that , I have no idea.
    In an attempr to lower high speed and get better mpg, I switched final drives from the non stock 37/11 ( for my RT) to a 32/11
    Ended up the speedo was the correct one for that ratio

    also the above referenced site , will give you more info in a graph format http://www.largiader.com/

  6. #6
    Smoooooth at 430 gch71's Avatar
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    Quote Originally Posted by Isamemon View Post
    this is correct info.

    it is also noted if you switch final drives your speedo may be less accurate then it is now.(are they ever acurate anyway) Speedos and final drives are matched.
    Or you could luck out, when I bought my currrent ride, the speedo had been switched with no regard to ratio, etc., why the po did that , I have no idea.
    In an attempr to lower high speed and get better mpg, I switched final drives from the non stock 37/11 ( for my RT) to a 32/11
    Ended up the speedo was the correct one for that ratio

    also the above referenced site , will give you more info in a graph format http://www.largiader.com/
    I checked them both out, still chewing on the info. I will be in between jobs in a couple of months so I have to pinch $$$. I am formulating a plan of attack for when I get another job. The speedometer issue, well I have two laying around for parts so I might get lucky on that. As for the final drive that's gonna be some $$$, I looked at max bmw just for the gears (not shims or bearings or seals) alone are $490, ishhh?
    I'll just keep plugging along an look.
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  7. #7
    Grammarian no, Rider yes ISAMEMON's Avatar
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    Quote Originally Posted by Gch71 View Post
    I checked them both out, still chewing on the info. I will be in between jobs in a couple of months so I have to pinch $$$. I am formulating a plan of attack for when I get another job. The speedometer issue, well I have two laying around for parts so I might get lucky on that. As for the final drive that's gonna be some $$$, I looked at max bmw just for the gears (not shims or bearings or seals) alone are $490, ishhh?
    I'll just keep plugging along an look.
    your not alone on between jobs, tell me about it. Im pushing 60 and nothing , lost it all in the market, and talk about pinching, jeez.
    but these R80's are great bikes, I am dong all I can to keep mine.
    maybe mpg is not great, but a great bike, hold on to it if you can
    just remeber, its not a honda civic a yota prius, or some kind of mpg record setter
    its a great bike and the smiles per gallon are worth it

  8. #8
    Supporting our Vets jers99lt's Avatar
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    Quote Originally Posted by Isamemon View Post
    this is correct info.

    it is also noted if you switch final drives your speedo may be less accurate then it is now.(are they ever acurate anyway) Speedos and final drives are matched.
    My 1985 R80RT speedo is FAR from accurate. I have both stock FD (37/11 teeth; 3.36:1 ratio) and a speedo that's labeled w=1.244. At almost any speed (haven't really checked it under 40mph with GPS), I'm between 14 and 18 mph under indicated the faster I go. I just add 15mph and hope for the best past the LEO.

    I've calibrated my LT speedo, but this one is much different. I understand there's a way to do a speedo reset. Any suggestions?

    Thanks,
    Jer
    Jerry Palma
    99 K1200LTI Champagne 'Oh, Kay' (dropped: 6); 97 K1100LT Aspen Silver Night 'The Silver Knight'; 85 R80RT 'Lady in Red';
    I love these bikes regardless of what I've needed to fix on them. I'll: Just Ride 'em!

  9. #9
    Registered User lmo1131's Avatar
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    To much Jonhy Walker black
    Is that ... possible?
    "It is what you discover, after you know it all, that counts." _ John Wooden
    Lew Morris
    1973 R75/5 - original owner
    1963 Dnepr

  10. #10
    Supporting our Vets jers99lt's Avatar
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    Quote Originally Posted by Lmo1131 View Post
    Is that ... possible?
    Yeah, too much Knob Creek.

    Hic,
    Jer
    Jerry Palma
    99 K1200LTI Champagne 'Oh, Kay' (dropped: 6); 97 K1100LT Aspen Silver Night 'The Silver Knight'; 85 R80RT 'Lady in Red';
    I love these bikes regardless of what I've needed to fix on them. I'll: Just Ride 'em!

  11. #11
    Smoooooth at 430 gch71's Avatar
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    Ratios

    My bike still has kPH I'm always multiplying by six then removing the last digit... Works fine haven't been pulled over in twenty-five years yettttt.
    Well Let me rephrase the "to much Jonhy Walker Black"..part.
    Let's just say that it went down O sooo sweet.

    Just came back from an interview , will find out in about two weeks, the only catch...it's in Vegas...Hey, I see a road trip in the near future, Houston to Vegas.
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  12. #12
    Smoooooth at 430 gch71's Avatar
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    Quote Originally Posted by Gch71 View Post
    My bike still has kPH I'm always multiplying by six then removing the last digit... Works fine haven't been pulled over in twenty-five years yettttt.
    Well Let me rephrase the "to much Jonhy Walker Black"..part.
    Let's just say that it went down O sooo sweet.

    Just came back from an interview , will find out in about two weeks, the only catch...it's in Vegas...Hey, I see a road trip in the near future, Houston to Vegas.
    Ok I'm such a dork...yea like I'm gonna get pulled over on a 60/6 for speeding.
    I don't know, yet, if there is a way to change the ratios on the speedos, any one out there with ideas?
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

  13. #13
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    There are numerous places to get a speedometer repaired and/or recalibrated - Palo Alto Speedometer, Overseas Speedometer, etc. Plan on it costing a couple hundred or so to recalibrate, etc - many people just cruise the internet and wait for a working, used speedometer of the proper ratio to show up - often can be had for less $$. On the other hand, a refurbished speedo will have some sort of warranty and should work nicely, and can be set to preserve your mileage/odo reading, if you desire.
    BMWs in my garage: 1982 R65LS, 1978 R100/7

  14. #14
    Smoooooth at 430 gch71's Avatar
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    Quote Originally Posted by boxermaf View Post
    There are numerous places to get a speedometer repaired and/or recalibrated - Palo Alto Speedometer, Overseas Speedometer, etc. Plan on it costing a couple hundred or so to recalibrate, etc - many people just cruise the internet and wait for a working, used speedometer of the proper ratio to show up - often can be had for less $$. On the other hand, a refurbished speedo will have some sort of warranty and should work nicely, and can be set to preserve your mileage/odo reading, if you desire.
    Actually, you just jogged my memory, there is a speedo shop in Austin, Tx I believe called overseas speedometer. I'll call them see what they say, thanks fellow airheads,
    Glenn
    ...driving to work on my airhead
    '73 R75/5, '74 R60/6, '75 R60/6, '80R65

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