Low Gear Ratio on a 1200GS?

[ExpatinIstanbul]

I'm intending to get my 1200GS a bit dirty this year and I've been wondering if it's possible to alter the gearbox to match that of the Adv (lower ratio first gear). It doesn't bother me that for road use I'll need to change up earlier, as I tend to click through the box quickly to get to third quickly anyway (3rd is my favourite.....mmmmm 3rd gear, lovely).

Will this just mean adapting the gearbox or something much more complicated and of course, expensive?

 

[Phil Clarke]

Depends on the layout of the box. It might just be a case of getting two pinion from BMW (assuming the new 1200 ones fit your 1200) expensive.....

Sometimes the layshaft has the first gear pinion as part of it which means buying a whole layshaft - very expensive.... Ask the dealer??

 

[ExpatinIstanbul]

I'll have to take it to the dealer at some point, but I thought I'd get clued up by the good chaps on here first.

Can there really be much difference between the boxes on the GS and GSA, other than the lower ratio 1st gear? I realise the other gears also have different ratios but will these need changing too or can they stay as they are?

Please bear in mind that putting petrol in is the most technical thing I'm able to understand, so my questions might be a little dumb.

 

[Shep]

I think on the 2008 models all the ratio's have changed including the final drive, so you may find just chucking a couple of low gears in may not work as well as you thought, unless the lot, including the final drive, is changed. (or indeed it may work better)

Not worth it IMO as a retro fit, but I would order it if a new bike was on the way.

Shep

 

[ExpatinIstanbul]

I should have mentioned, mine's a 2005 model. I was thinking of chopping it in for an adv but the loss I'd make would be too much. I was hoping that I could just change some of the box's internals, BMW must have spares from early 1200adv's which I could order if it's doable.

 

[Shep]

I should have mentioned, mine's a 2005 model. I was thinking of chopping it in for an adv but the loss I'd make would be too much. I was hoping that I could just change some of the box's internals, BMW must have spares from early 1200adv's which I could order if it's doable.

Perhaps TT or Wunderbra do a replacement gearset for a 1200?

 

[Magwych]

I started to go down that path for my 2005 GS...If yo have ABS, or ABS and servos the bill can start to get a bit expensive. You need to make sure that your existing brake circuit components will fit the mounting points on the GSA gearbox. When all is done you will get a first gear ratio about 5% lower than you already have, hardly worth the time and effort.

There have been threads about using the gear pinions from Police model 1200RTs, which have a lower first gear, but information on that is hard to come by, and dealers in the UK seemed unwilling to research it.

I eventually went for a new GSA, with the Enduro 'box option. The later '08 boxes apparently have different design bearings that allow larger pinions to be fitted. It is noticeably lower (10% than my GS) , but I would like it lower still ....

Reading back through that it doesn't really seem much help. Perhaps you could try a 1200RT Police box in there, if you can find one 2nd hand ?

 

[Phil Clarke]

I didn't think there was any difference between the pre 08 adv. gearboxes and the standard 12s. The 1150 adv had lower firsts than the standard 1150 but when they brought out the 12 it had a first gear similar to the 1150 adv.?? My 12 defo has a lower first than a standard 1150.

 

[ExpatinIstanbul]

It looks as though my best bet will be to just give it a go as it is. From what I can gather from the info here http://www.r1200gs.info/misc/specs/#ADV pre '08 GS & GSAs had the same ratios, as Phil has pointed out.