G/Box swap - GSA to a GS

[Magwych]

Its that time of year and thoughts turn to new toys....

I have been contemplating changing my 1200GS for a 1200GSA, but really all I want out of the change is the lower first gear, and spoke wheels. So, rather than lose money on depreciation, I started musing as to whether it os possible to fit the gearbox for a GSA into my GS ? Does anyone know?

I have a 2005/6 model ( hooped centre stand) with servo integral ABS brakes. I spoe top one person who suggested it might work but I would have to use a GSA box for a similarly braked model.


At first sight it seems like a much cheaper way of getting theGSA spec I wanted, without the heavy fuel load.

 

[Brian ROSEN]

Winter project?

If you are contemplating doing this just to pass away the long winter evenings and you enjoy dismantling and putting together your bike then why not? But as a practical way of converting your bike it seems a complicated course of action. Before you embark on any heavy expenditure you might find a GSA with the same mileage/age as yours and a part-exchange would be a more economic way of achieving your object; If you don't want 33 litres in your tank - you don't have to fill it. (I don't think that there is that much difference in initial price of a GS and a GSA.)

 

[cookie]

AFAIK all 1200GSs and GSAs have the same gearbox right up to the new 08 model which has a low first as an option.

 

[Brian ROSEN]

Further thoughts!

Here a GSA costs 1150€ more than the GS - about £725. For that you get (in addition to the spoked wheels and lower gear ratio) a much better screen and better protection bars and a bigger tank of course. Surely a part exchange would be cheaper than a new gearbox?

 

[Jon P]

AFAIK all 1200GSs and GSAs have the same gearbox right up to the new 08 model which has a low first as an option.

You are correct...........All gear ratios (in the box and the final drive) are the same on the GS and GSA. Only on the 2008 GSA is there a lower first gear.

 

[Brian ROSEN]

What a huge amount of money and time you have saved!

 

[Magwych]

What a huge amount of money and time you have saved!

Err, yes.

Seeing as I am very happy with my 120GS, apart from first gear being too high. So to get a 120GSA with a lower first gear (standard I have been told by BMUU on GSAs up to '07 - an option on '08 onwards) I have to sell a bike I am otherwise happy with, taking a bit of a hit on depereciation, then buy another bike.

To do this against a new one I am looking at around £6.5k - £7k cost to change. OK, it gives me a brand new bike again and another 2 years warranty.

Thoughts I am having is that for that money I could keep my 1200, and get an 800GS too. Or upgrade my bike to the spec I want, offestting the remainder of the £6.5k against future failures - FD unit, shocks etc.

But, if Cookie is right amd BMUU wrong ( not the first time) then this is all wishful thinking and a complete waste of time.

 

[cookie]

after a bit of a search on the web, i found these ratios given for the standard 1200GS 2.277 / 1.583 / 1.259 / 1.033 / 0.903 / 0.803

i was unable to find any info on ratios for the GSA, but i have got a brochure for the original model that makes no mention of any change of gear ratio in the Adventure variant.

i do distinctly remember comparing the two bike's transmission specs on the bmw website before buying my gsa to make sure i wasn't going to be lumbered with a buzzy bike for touring. i'm pretty sure they were the same ratios.

AAMOI the 12 actually is quite buzzy compared with my old E box 1150. revs are approx 500rpm up at cruising speeds.

i should say, my memory is a particularly fuzzy facculty.

 

[Brian ROSEN]

Surely not?

"....To do this against a new one I am looking at around £6.5k - £7k cost to change....." That seems a very high amount; Looking at the magazine published in France Box'RMag there are 350 S/H BMW's for sale in the latest issue. 10,500€ seems to be the minimum asked with high mileage. Dealer prices are around 12 - 13,000€ A new GSA is around 15,000€ I think - so I would expect to pay 5 - 6,000€ to change (about £4,300) That is of course quite enough!

 

[Jon P]

after a bit of a search on the web, i found these ratios given for the standard 1200GS 2.277 / 1.583 / 1.259 / 1.033 / 0.903 / 0.803

i was unable to find any info on ratios for the GSA, but i have got a brochure for the original model that makes no mention of any change of gear ratio in the Adventure variant.

i do distinctly remember comparing the two bike's transmission specs on the bmw website before buying my gsa to make sure i wasn't going to be lumbered with a buzzy bike for touring. i'm pretty sure they were the same ratios.

AAMOI the 12 actually is quite buzzy compared with my old E box 1150. revs are approx 500rpm up at cruising speeds.

i should say, my memory is a particularly fuzzy facculty.

I do very clearly remember seeing that the 1200 GS and GSA have exactly the same gearing and have read it in a couple of places - but of course now I can't find it.............

BUT - Simple to find out - Had a look at the part numbers for the gears on the output shaft.

First gear (and all the others) have the same part number for both the GS and GSA

 

[Brian ROSEN]

The answer to your problem

In the Haynes Manual it states : Final drive ratio R1200GS 2.28 to 1 R1200GS Adventure 2.82 to 1 (Gear ratios and primary drive ratio are the same)

 

[Kenny Rodkiss]

big boxes wee boxes

You could have endles fun mixing and matching boxes and final drives.

....................2006 GSA.............2008GSA

Primary............1.824..................1.737

1st..................2.277..................2.375...option of enduro first = -10%

2nd.................1.583..................1.646

3rd..................1.259..................1.296

4th..................1.033..................1.065

5th..................0.903..................0.939

6th..................0.805..................0.848

final drive..........2.82....................2.91

I was a bit worried that the 2008 bike might be too revvy at cruising speed but if my calculations are correct, and there is every chance they are not, the new gearing only increases the revs by less than 150rpm at 70mph.

I suppose that if you really hated it you could put an earlier 2.82 final drive, which is the same on the GS and GSA, both are 2.82-1 with same part numbers, on to the 2008 bike.

 

[Tim Cullis]

I CAN confirm the ratios are exactly the same. Just a very slightly lower final drive which is why the 1200GSA can't reach the same top speed as the 1200GS.

The lower first gear in the new GSA isn't anywhere low enough for you to even notice any difference, so that would be a total waste of money.

I can just about have the clutch fully home on my GSA at 7mph. What's needed is walking pace (3-4 mph). HPN in Germany do a lower first gear that presumably could be retrofitted and would be a lot cheaper than a gearbox swap, but it was only something like 5% lower, and what's needed is about 40-50% lower.

The 1200RTP police special has a walking speed first gear which is intended for accompanying parades and motorcades. The RT gearbox is the same as the GS other than the black exterior. I tried to find out more but drew a blank at the dealers I tried.

 

[Magwych]

Thanks everyone for your input.

So, it looks like that avenue of thought was going nowhere...

 

[luckylucian]

Thinking laterally, wouldn't it be better to swap out the clutch plate for a ceramic one that would take the abuse of constant slipping in 1st gear?

 

[Jon P]

I CAN confirm the ratios are exactly the same. Just a very slightly lower final drive which is why the 1200GSA can't reach the same top speed as the 1200GS.

Not sure about that Colin - what Haynes are quoting was a miss-print that was 'doing the rounds' about 6 months ago. The 2:28 is wrong, should be 2:82 on both bikes.

Again the best source for this is the part numbers - you will find that they both have the same gears in the box and the same final drive.

Slightly lower top speed is simply that the GSA is a bigger bike.

 

[Brian ROSEN]

".....Not sure about that Colin - what Haynes are quoting was a miss-print that was 'doing the rounds' about 6 months ago. The 2:28 is wrong, should be 2:82 on both bikes...." Which is why Haynes write.'....no liability can be accepted by the author or publishers for loss, damage or injury caused by any errors.....in the information given.' Just as well you didn't change the final drive.

 

[cookie]

Which is why Haynes is known as the "book of lies" by regular readers

fixed