BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi. I am familiar with Airhead final swaps and correct ratios, but I'm not sure what to do with my old/new 02 R1150R bike. I am currently running a 31/11 final ratio. I would like a little more low end, so I don't have to slip the clutch. I am also cruising at 70 @ 3500 rpm. Should I go up to a 2.91 from an RT or a 33/11 from an R1000R for a little better all around performance. Any suggestions would be appreciated. Thanks.

Sooner or later I will rebuild (or have rebuilt) my Rockster final drive with taller gearset in order to lower RPMs throughout the operating range. The Rockster does not have the "overdrive"-type 6th gear and thus runs at higher RPM during freeway riding compared to Roadster. Installation of taller gearing will certainly impact my bike's acceleration, but I figure the transmission's 1st-3rd gear ratios are sufficiently low/short to balance a taller final drive, and the bike's never going to be a performance machine anyway.

Since you have the tall transmission 6th gear in Roadster, you might find your best blanace of performance with the 33/11 gearset: better pull at low speed, and not (too) much increase in cruising speed RPM.

My final drive gearset strategy is centered around the unit's bearings, with goal of preemptive surgery and bearing upgrade(s) to prevent possible failure. And since the final drive removal will involve Paralever pivots, it will be good opportunity to replace OE bearings with JL bushing kit:

http://rubberchickenracinggarage.com/bushings.html

f4tweet wrote:Hi. I am familiar with Airhead final swaps and correct ratios, but I'm not sure what to do with my old/new 02 R1150R bike. I am currently running a 31/11 final ratio. I would like a little more low end, so I don't have to slip the clutch. I am also cruising at 70 @ 3500 rpm. Should I go up to a 2.91 from an RT or a 33/11 from an R1000R for a little better all around performance. Any suggestions would be appreciated. Thanks.

Be careful what you wish for, I have the short 6th gear in my Roadster (which is apparently a rarity ) and I'd kill for a taller 6th gear on long highway sections. I'm at 4100RPM at 70, give or take. 80 is close to 5000RPM which wears on you.

Well, well! Finally somebody else who is thinking along the same lines - changing overall gearing
via a final drive ratio change.

To be more specific, I wanted to reduce the spread between 5th and 6th, and to increase road speed
at reasonable / comfortable rpms in 5th on 2 lanes where I do most of my driving, partly to avoid
either lugging the engine in 6th up grades and with a passenger in the 60 mph range - of course without
significantly increasing my rpms in 6th on freeways.

So, after much research into available options and not wanting to invest way too much in the form of
a new gearset (which wouldn't solve my 5th to 6th rpm spread problem) and dealer setup costs, I found
what is probly a unique approach. It ends up providing very close to the same overall ratios from 1st thru
6th as the R1200R which BMW advertises as "a more active 6th gear rather than just an overdrive".

I acquired an RTP trans (same ratios as your Rockster) and then - well, here's my solution to the final
drive situation.

http://www.mediafire.com/?gj1qdmm22tj

If I am in 5th gear and shift into 6th, I drop 1,000 RPM. I don't think I can find a CHP trans with the lower 1st gear, so I many have to settle with the FD change. Thanks for the help.

Actually I found mine on ebay - guy out in CA buys bikes the CHP quits using and
sells or parts them out, I see those trans on ebay every once in awhile.

And as you know they're the exact same trans as the Adventure models, opening up more
possibilities.

And there's always getting on beemerboneyard's list.

I'm getting laid off sometime probly fairly soon or I'd "finish" my project
with a new tire and those pivot bushings. But you never know, if the weather
gets warm enuf, it just might happen anyway!

What about a GS transmission?

I thought it would be easier and less $ to do a Final swap.

It would be easier not having to remove the trans, but I wanted to lube the clutch
splines and check them out, as well as the clutch.

But the main reason for me personally for the trans swap from my perspective was
narrowing the 5th to 6th rpm spread. Doing that plus adding a higher FD gives me
a real nice 5th gear range for 2 lane driving without lugging or over revving. And I
get that while only adding 200 rpm at any given mph in 6th gear compared to the
stock roadster trans & 2.82 FD.

That will be from just under 55 at 3000 rpm to 68 at about 3800 rpm, all without any
up or down shifting - perfect for those hilly & twisty 2 lanes.. You could do that without
changing the trans by just putting in a higher FD ratio, but first gear in the roadster trans
even with the stock 2.82 FD ratio is already too high. Even going to a used 2.75 FD which
bolt right in you'd have an even taller 1st gear and still not get that nice range in 5th.

With the trans swap to the CHP/Adv trans and the higher 2.62 FD I'll still have
about a 7% lower 1st gear than the stock roadster trans and 2.82 FD - admittedly
not much but a whole lot better than making it taller by 3% - making it easier -
and less clutch abuse - for starting out up hill i.e. from a stopsign and /or with
a passenger.

So the net effect is that I'm moving that wide spread between gears from 5-6 to
1-2 and, being a street & road bike and not a drag bike, I'd rather have the better
narrower 5-6 spread. What would be ideal would be if the trans ratios were all
just about 100 rpm farther apart, then they would be pretty much the same spread
between all gears, but that just ain't gonna happen - no trans available like that
unless the r1200r trans would swap in, I think that's more evenly spaced between
all gears if I recall. But I've done enuf research - I'll leave that to somebody else.

As far as cost, I shopped over a period of time and hit some good deals, so at the
worst spent the same as just buying new gears and having the dealer install and
set them up. If I choose to sell my 25k mile takeoff trans and FD and rear wheel
and brakes, it'll end up being quite a bit less overall. I should be able to sell my
roadster trans, FD, brakes, and smaller parts for roughly the same as I paid for the
CHP trans and higher FD/brakes/wheel, so really not much net cost - way less than
having a dealer install new gears in the FD. And I can do all the work myself so
no dealer labor cost at all, and then have the chance to check out & lube the trans and
driveshaft splines.

A GS trans (a non-Adventure GS) I believe is the same as our roadster trans.
It's the GS Adventure trans that's the same as the CHP. So that opens up the
availability for used.

I finally was able to ride just at freeway speeds for a couples of hours yesterday to check gas mileage. With the 33/11 FD I got 42.2 MPG, combined street and Freeway I get 32-33 MPG. I figure that gives me a MAX range of 220 miles, and I will probably be looking for gas at 175. My cruising speed was 4000-4200 at 75-80 indicated. With the original 31/11 Final, I got 49.5 MPG at highway speeds, and the tach was indicating 3500-3700. Around town and some Freeway I would get 36-38. I like the 33/11 around town and with my Granddaughter on the back, but for a long road trip I might switch the 31/11 back since the 1150 only has a 5.2 gallon tank. I would guess the 32/11 (2.91) would allow me to get 45 MPG. Thanks for your patience with my slow project.

Your change in fuel consumption 49>>42MPG is surprising.

Thanks for posting your results... good reminder about the final drive gear ratio change I was considering last year. Given my Rockster's short 6th gear, I'm really curious about potential changes in cruising performance if taller final drive is installed:

http://largiader.com/articles/gearing/

Either the R1200C or CL ratio would be a significant change from 31/11.

With $4/gallon gas, I'll trade some extra MPG for lower RPMs + weaker acceleration.

I was surprised about the drastic mileage drop to. It is nice to have the roll-on acceleration in 6th gear, but my biggest concern is the frequency of gas stops due to reduced range. At 42 MPG I would only use an extra gallon of gas from LA to Phoenix. (360 miles). As an example, I would have to gas at Palm Springs, 125 miles, Blythe, another 100 or so miles, and maybe make it to Phoenix.

I guess maybe I'm not alone in my quest for better gearing after all!

I have an 04 roadster and nearly all my driving has been on 2 lane 55 mph (60 mph) roads.
That either put me close to the bottom of the buzz range in 5th, or lugged it in 6th,.
and 1st always seemed like I was starting out in 2nd.

So, to the drawing board (and the calculator).

First, I discovered the "short" 1st / 6th gear trans which of course would give me a much
better low gear. But as folks have found out, it "wears" on you at freeway speeds with
too high of an rpm - not to mention it just wears the engine out faster.

One option I discovered was that the "short" 1st gear could be installed in the regular
trans, leaving the OD as is. That wouldn't solve my 55/60 mph problem, though.

Another option would be the short 1st with a higher FD ratio to get the 5th gear rpm
down a couple hundred rpm on 2 lane roads.

But the available FD's that bolt right on to a roadster are rather limited in selection for
higher ratios - a 2.75 isn't much different than a 2.82 regarding rpm in 5th.

So, being the "it ain't right till it's right" type, I researched FD's off other BMW models
that might be adaptable to the roadster altho not a straight bolt in.

Found a 2.62 out of an K1200 bike has the same basic FD housing, gearset, swingarm, etc,
but the rear brake setup is different. Different caliper, rotor, etc. HOWEVER - the ABS
plugs into the R1150 ABS wiring and I believe will work as the ABS wheel is the same diameter
and is very nearly exactly the same number of "teeth" per revolution. The brake piping/hoses
bolt up too.

Found and bought a lo miles 2.62, a 4 piston caliper, etc, for fairly reasonable. Also had to get
a rear wheel off of a K1200 as the ABS ring is mounted on the hub instead of on the wheel,
and the ABS ring mounting lugs on the R1150 wheel would interfere. HowEVER - the wheels are
identical in size and appearance! Happy coincidence. So also have one of those to make the setup
complete.

Also found a "short" R1150 trans with a bad front seal and wear on the input splines, and
swapped the intermediate and output shaft assemblies into my roadster trans, giving me
a "short" trans. Even did it myself! http://s719.photobucket.com/albums/ww20 ... ar%20Swap/
Altho, I had found a guy on ADVRider.com that does that at a reasonable cost, and can even provide aftermarket 1st gear parts at about 1/2 of BMW prices, even has 1st gear ratios other than the stock "short" Enduro ratios. But I was laid off so tackled it myself. Came out good, trans shifts fine.
http://largiader.com/ is the guy to contact (Anton). Also LOTS of good tech info on his website.

OK, so where do I end up with all this swapping?

http://www.mediafire.com/?vb149e3b3548b8v

In spite of the higher FD, I still get a 7% reduction in overall 1st gear with the "short" 1st gear.

Stock trans and FD puts 6th at 59mph +, from ~2900 at 59.
My "short" 6th and the 2.62 puts 6th at 60 mph to 75 mph without going over 3750 rpm,
just a couple hundred more rpm at any given road speed in 6th. And being considerably
less "adventuresome" than I used to be - now 64 :-( - 75 is plenty fast enuf for me.

Stock trans and FD puts 5th at 50 mph to not more than 60 mph which is at 3625 rpm,
starting to get into the buzzy handlebar range (even with padded gloves and foam sleeves
and a real sharp tune job).
My 2.62 FD puts my 5th at 52 mph at 2970 rpm to 65 mph at 3635 rpm, so no up or downshifting
or buzzing handlebars or lugging in 5th on 2 lane 55/60 mph roads - exACTly where I wanted it to
be. Just stick it in 5th and drive.

So - 7% lower 1st gear overall, only a 200 rpm increase in 6th so is still fine on the freeway,
and now a beautiful 5th gear covering 52 to 65 mph for 2 lanes without shifting or buzzing or lugging.

Yeah, lots of work, but "it's either right or it isn't"

Could have come close with a short 1st only and 2.75 FD which is a straight bolt in, but 5th still wouldn't have been quite right for me. My old frayed nerves just don't like vibration.

For you with the "short" 1st and 6th, you could put a regular 6th into your trans and leave the 1st
alone which would solve your freeway rpm problem. Only if you want the same benefit for 5th on
2 lane roads would you need to mess with trans gearing.