Fiddling with me sprockets

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FatFreddy
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Fiddling with me sprockets

Post by FatFreddy »

Am still getting used to the change of pace from my old VFR to my recently acquired f650gs.

Don't particularly want to make it any slower but from my limited forays up a couple of green lanes, can't help feeling first gear is a little tall for tootling along slowly, picking my way around the rocks and ruts.

Haven't really played with gearing since a disastrous experiment circa 1985.

So, would you.......
Leave well alone?
Drop a tooth at the front?
Add a tooth (teeth?) at the back?

And....
How much difference will it actually make?
Will it adversely affect road use?

Any other technical issues I'm likely to encounter?

Any advice or comments welcome.
Tramp
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Re: Fiddling with me sprockets

Post by Tramp »

Lower first gear is approx 4mph on 1 tooth... I only use first for stopping lol... Normally 3rd gear and 2nd for tricky bits.... Look up gearcommander and punch in your bike....

If its 15 front go up 3 rear... And practise more will reap benefits...
Oop North John
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Re: Fiddling with me sprockets

Post by Oop North John »

Have a play on here to find your perfect result:

https://www.gearingcommander.com/
Apophis
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Re: Fiddling with me sprockets

Post by Apophis »

It’s a different animal but the old MT500e I had I used to run a 14 tooth and the 350 a 13 tooth front the standard was a 15 but that was pap on the road going down 1 on the front is the same as going up 2 on the rear
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bowber
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Re: Fiddling with me sprockets

Post by bowber »

For a small change go up a few teeth on the rear.
Usually if you go smaller on the front you can run into trouble with the chain wearing the swinging arm slider more, plus the sprocket will wear faster, I work on 3 rear teeth to 1 front tooth, very rough but close.
My wifes old single F650GS used to run higher gearing than standard and I didn't find 1st very high but we have quite open lanes and I didn't take my wife down any of the tight rough ones.

Steve
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AlanHolt
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Re: Fiddling with me sprockets

Post by AlanHolt »

Changing sprockets doesn't just change the gearing, it also affects the distance between the wheels. Drop a tooth on the front and this pushes the rear wheel back slightly. Put a bigger sprocket on the rear, and it moves the rear wheel forward. Only small amounts, but enough to make a difference. On my zx10r, an extra link in the chain was enough to stop it bucking and made it far more stable at speed.
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steve the grease
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Re: Fiddling with me sprockets

Post by steve the grease »

When I got my bike it was on Heidenau K60's and had a 16 tooth sprocket on the front. A brief foray off road made me think it was geared a bit tall, for greenlaning , at least, so I dropped the gearbox sprocket to 15 teeth. Now it is much happer off road, and as a bonus in top gear the rev and speedo needles now line up! Of course it has lost some of its top speed , but as I'm now running an Army special on the front and a C02 on the rear it all gets a bit lively on the road anyway over 60, so I'm a happy bunny. On the K60's it was happy at any speed the bike would do. 16 to 15 teeth is 100-15/16, so about 7%.
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Steve T
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Re: Fiddling with me sprockets

Post by Steve T »

I've run a F650GS twin at the same time as I had a F800GS.

I found the F650 to have too high a ratio for easy slow speed control off road, but it was OK for normal road riding (only to be expected really ;) )

The F800 is geared really well for off road riding, but only a little frantic on extended road riding . . . . .

Soooo . . . . . . . .

I dropped a tooth on the front on the F650 - the same size that is standard fit on the F800, and it increased the revs per set road speed a little bit. But it was enough to make the bike easier off road.

I did the Paddy Dakar rally on the F650GS with that gearing, after touring down through Scotland, England, Wales and round the Northern Ireland coast to get down to Doune near Limerick for the rally and the gearing was perfect for both jobs.

Thats my experience from owning and running a F650GS twin.

PS - I've also changed the F800 front sprocket for a one tooth bigger cog to get the same ratio as the F650, and it too is a brilliant balance of on & off road riding.

Just my mutterings.

Steve T

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