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Offline netaron

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Need more low-end torque
« on: July 16, 2020, 04:41:43 PM »
Has anyone played around with gearing to address the lack of low RPM torque with the 850, especially when fighting mud or the like? I've played with engine settings, but that seems to mainly affect total power output at the higher RPM range.

Offline Sooty01

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Re: Need more low-end torque
« Reply #1 on: August 02, 2020, 05:19:31 PM »
I have taken the sprocket cover off and found the front sprocket is only just above the swing arm top. Any smaller and the chain will probably rub on the buffers. It's also too snug to fit a larger sprocket.
Any changes will probably have to be made at the rear sprocket.

Offline netaron

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Re: Need more low-end torque
« Reply #2 on: August 02, 2020, 05:32:18 PM »
Good to know; usually the rear change requires a chain length adjustment, but it's still a bit easier to work with compared to the front sprocket. I have not seen any data, but from memory, the 800gs seemed beefier in the lower rpm range, but that could just be the additional 50lbs of chub the 850 is sporting.

Offline Sooty01

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Re: Need more low-end torque
« Reply #3 on: August 13, 2020, 06:01:42 PM »
I was wrong in my assumption a smaller sprocket will not fit. I have just fitted a 16 tooth sprocket with no problems.
It's the best £17.00 I have ever spent on a bike and has transformed the riding experience. It's more responsive and cruises easily in 5th now.
I think I could get to like this bike now.

Offline netaron

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Re: Need more low-end torque
« Reply #4 on: August 13, 2020, 06:39:14 PM »
So that would make the lower RPM torque delivery worse??  :034:

Offline Sooty01

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Re: Need more low-end torque
« Reply #5 on: August 13, 2020, 08:44:30 PM »
No, by needing slightly more revs in each gear it is much more tractable and so much easier to set off up hill or drive in traffic. On twisty roads I used to ride in 4th to reduce the number of gear changes, now it's quite happy in 5th unless you really need to press on.
Don't forget my bike is the 750, identical engines but BMW have cheated us out of quite a bit of power and torque by re programming the electronics for some reason. They never changed the gearing to suit.
For £17.00 it's not an expensive or difficult experiment. It took 30 mins to swap and the only unusual  tool is the large torques socket on the swing arm bolt. No mods to the chain are required so it can swap back if you don't like it.
For me I'm now grinning while riding, it's made a just average bike into a fun ride.

Offline WHS

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Re: Need more low-end torque
« Reply #6 on: August 13, 2020, 10:17:01 PM »
Hmm, I wonder if this simple sprocket change would work for the 850 GSA ?   I wish it had just a slightly lower 1st gear.   And I know the Adventure model is already supposed to be lower geared as compared the GS models.   

Offline netaron

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Re: Need more low-end torque
« Reply #7 on: August 14, 2020, 01:08:40 AM »
I hear ya! I have been thinking about +2 in the rear and call it a day, I can always swap back to stock for longer trips. The centerstand should help make this a quick deal, granted the chain adjuster can accommodate it.
« Last Edit: August 14, 2020, 01:11:24 AM by netaron »

Offline Sooty01

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Re: Need more low-end torque
« Reply #8 on: August 14, 2020, 05:16:21 PM »
   I think stock it's 17/44 giving 2.58:1 reduction.
   My new sprocket  16/44            2.75:1
   46 tooth rear       17/46            2.7:1
 It will cost a bit more for the rear sprocket, please keep us informed how it works for you. Yours may be the way to go as the increased sprocket diameter may reduce the chain slap on the buffers.
« Last Edit: August 14, 2020, 05:18:32 PM by Sooty01 »

Online Matty589

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Re: Need more low-end torque
« Reply #9 on: August 14, 2020, 05:48:07 PM »
Iíve had all 3 bikes and the power difference is negligible. The 850 GS a bit more go (not much) but itís all over 6,000rpm. With the F650/800 the torque profile for the ďcheaperĒ bike was better for the road, and although the gearing might be the same I find the 750 more responsive up to illegal speeds. But then maybe I ride like an old fart!