changing the gearing on the 1150gs for sidecar use.

Discussion in 'Hacks' started by extreme11, Feb 26, 2018.

  1. extreme11

    extreme11 Adventurer

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    I am considering purchasing a 2004 R1150 GS for side cars use which would be use for road and trail riding ( spain) Which is the best and easiest way to do this . 1 Change the whole drive with a R850 or change the whole gear cluster. and of course the most economical.
    How difficult is the drive shaft swap as I have read that it is essential to get the shimming right.
    Any info on this would really be appreciated
    #1
  2. Wolfgang55

    Wolfgang55 Long timer

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    Go to smaller wheel & use an auto tubeless tire.
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  3. davebig

    davebig Another Angry Hun !

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    Ok if you have a 1150GS the 37/11 final drive from the r850 works the best but they are usually not available with an abs port in the housing people often remove their abs especially if it's iabs. The 37/11 is necessary because 6th is so damned high.
    If you have a 1150gsa the adv model it has more reasonable gearing a 33/11 or 34/11 works well with them.
    As Wolfie pointed out you could use a 33/11 and a 15" wheel and run a 175/65/15 a shorter tire it will help but its still high when starting on a hill one needs a gas and go clutch user.
    Tire size calculator https://tiresize.com/calcuhttps://tiresize.com/calculator/lator/
    r850 37/11 rare with abs almost impossible BMW gives mechanics 3-5 hrs to correctly shim final drive building one gets costly fast.
    r1100 33/11 easy and plentiful
    r1100rs early model 34/11 hard to find with abs
    RT models 1100/50 both use 32/11 easy to find quite great on a GSA with a short tire.
    r1150 31/11 plentiful no one wants them.

    If you're committed to the 1150's they are the easiest to deal with in the long run and most adjustable easiest to repair (Sod Off you r1200 Lads:jack)
    One can get a transmission built with the low 1st from the r1150gsa and the OD 6th from the 1150gs again not real cheap but not that crazy either.

    I might as well add the r1150gssport from 03 came with no abs and trans with the higher gs low gear and the lower gsa high gear.
    There's a chart someplace Dana knows where it is.
    Experience and a garage shelf full of final drives taught me allot :-)

    GS clutches hate being slipped allot !!!!!!!!!!!!
    #3
  4. mtrdrms

    mtrdrms Been here awhile

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    Davebig is right. I used a final drive from an 850 I got on eBay from Europe I believe. Made a huge difference and 6th gear was usable again.
    #4
  5. Ridn3

    Ridn3 Lopsidd

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    am happy with the 37/11 that I purchased from DaveBig. It is on my RT and makes all the gears more usable, esp 6th gear. It still has the 1000 rpm difference between 5th and 6th but moves the problem speed down to 55 and who rides at 55? :) 1st gear is great for starting on a hill.
    #5
  6. jaydmc

    jaydmc Long timer

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    We usually go with a fully assembled R850 final drive or just live with the stock gearing which works fairly well as long as you are not towing a trailer or doing real slow off road riding.
    For your bike we make sidecars, steering modifications as well as an automotive rear wheel and tire.
    Jay
    DMC sidecars
    www.dmcsidecars.com
    866-638-1793
    #6
  7. DRONE

    DRONE Dog Chauffeur

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    If you can find a complete 850 final drive with the drive shaft attached, the swap is easy because there is no shimming. Shimming needed only if you replace the Final Drive alone. If you need an R1150 Service Manual, PM me with your e-mail address and I can send you one written in Spanish. Here, for example, is the page on shimming --->

    shimming.png
    #7
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  8. davebig

    davebig Another Angry Hun !

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    Just a little confused I think DRONE but you mean well ! :-)

    The drive shaft has nothing to do with shimming final drive, the shimming process is about setting the pinion gear in the center of the ring or acorn gear as they are referred too by BMW. One shims to get the pinion in the middle of the ring and at a proper depth which is why BMW gets up to 5 hrs to do it. Often requires assembling and measuring depth and gear pattern several times. The failed 1150gs FD from several years was BMW cutting corners on assembly.
    Note no 2 gear sets or housings are exactly the same which is why final drives need to be setup and shimmed correctly.

    One more time so we are all on the same page your not changing just bearings which is easy and may not require removing the pinion but nes putting the 37/11 into an abs usable housing and that needs a complete shim job.:-)

    I've not read this but the process is the same https://www.racingjunk.com/news/2015/03/24/how-to-set-up-your-rear-gear-correctly/
    #8
  9. DRONE

    DRONE Dog Chauffeur

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    Dave, I'm aware of the shimming process if swapping out just the crown and pinion gears. I paid about $600 to get that done on WUMPA. :becca

    But, are you saying that if he buys a complete Final Drive from a 850 (with no drive shaft) he can just bolt it on his 1150 swingarm and no shimming is needed? Or did I just post the wrong page from the manual?
    #9
  10. davebig

    davebig Another Angry Hun !

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    Ok DRONE you didn't need to post the diagram at all.
    The housings are all similar right thru the k11-12's they just arrange the bits a little different. basically all the paralever stuff is very similar on the K's they used old time housings without the abs port but it's all sort of move able.
    I'd delete the abs before I paid to rebuild a final drive again changing gears or cases the one I sold Ridn3 cost him twice what a used r850 would have, it's brand new gears in a abs housing I had and cost me almost twice what I charged him. :fpalm There's no money in them unless you reshim them at home.
    I guess one could use the r850 final drive an abs wheel and brake disk from a K but one would have to see if the K bike abs pickup would work with the GS abs I'd bet that is possible.
    Take the abs off !!!!!
    #10
  11. extreme11

    extreme11 Adventurer

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    Hi Drones.
    What you say about changing the WHOLE drive assembly is what I was considering as I'm not conversant with BMWs at all and thought that doing a complete change would perhaps be the simplest. Having read , here on this forum, about the problems of shimming the drive it's something I would try to avoid. I also don't need ABS as I would separate the chairs brake form the bike. I rode Hacks when I was first married ( 1954) . BMW R69 with stieb and BSA'a with Monza. Rod them for years whilst the family grow up ( couldn't afford a car at the time but wouldn't have bought one anyway). I was considering using my Yamaha XJR 1300 simply because I could simply change the sprockets but it only has five gears and to change that lower would make it terrible in fifth.. I also would need the height and suspension of the BMW. ( my wife complains about the seat and suspension already of the Yam! Mind you we are both in our eighties so I have to be careful with her (lol). This outfit I am researching is for a trip across Morocco so the getting good ground clearance is a priority, it will also be useful for use here in Spain , No need to send anything in Spanish as we are originally from the UK. info@compasswest.co.uk www.compasswest.co.uk.
    [​IMG] [​IMG]

    Can I thank all those that have replied to my question. I spend many hours reading this forum . If anyone is ever is Spain just give me a call we have some great roads to tour. . We also have a trike which we crossed the USA East to west and back and California to Alaska and Back
    #11
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  12. davebig

    davebig Another Angry Hun !

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    :fpalm:fpalm:fpalm:fpalm:fpalm
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  13. Melrone

    Melrone Long timer

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    I have an 03 GSA/Ural and use the stock gearing with no issues. Honestly found no reason to change my gearing. I admit I do more road than dirt. But those times I jump on a service road I have no problems. I’ve ridden Dave Bigs Old GSA rig and it was very fast and had grunt. So it’s my opinion good luck
    #13
  14. claude

    claude Sidecar Jockey

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    There are a ton of similar rigs out there with the stock rear that have happily been putting the miles on for years with no issues. Is lowering the final drive gearing a plus? Yes it is . Is it necessary in most cases? No. You could begin with the stock rear and at anytime switch over if/when desired.
    #14
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  15. cycleman2

    cycleman2 Long timer

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    Gearing boils down to how you are going to use your rig. If slow speed work is something you are going to do a lot, then go for the lower gearing otherwise stay with the stock rear gearing. After you ride/drive it for awhile you'll figure out what will work the best for you.

    Those of us in 60 hp land definitely benefit from the 37/11 gears. They make a world of difference. You have twice the hp, so it is an option for sure.
    #15
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  16. claude

    claude Sidecar Jockey

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    Stock gearing all over the country and still smiling..... outback harold zeller magazine.jpg
    #16
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