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Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 1:01 am
by Rigby
I recently bought a 2004 R1150R (5800 miles on it) that aparantly has a non-overdrive transmision. My round-trip to work and back is about 50 miles, cruising mostly at 65-70mph. I want to get the most gas mileage, mechanical longevity, and comfort out of this bike that I can. I am a very conservative driver. Can an OD tranny be installed in my bike, and at what cost just for the parts? Would I need to get a hold of a whole transmision or just part of the assembly? My dad is an auto mechanic, so I have access to just about any tools that I could possibly need to undertake such a project myself (Probably with my dad's help). Any advice would be greatly appreciated. Thanks in advance.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 7:22 am
by Green Hornet
Here is a link to a complete transmission
They could tell you all need to know
http://www.beemerboneyard.com/23007677008.html
Micky
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 10:54 am
by sweatmark
Surprised that your transmission is not the tall 6th gear type, if your bike's a Roadster. Was the transmission type an option for 2004 bikes? Somebody here surely knows.
Options to get that loping highway gear:
(1) Swap transmission;
(2) Swap final drive gear set;
(3) Modify transmission to get new ratio for 6, maybe 5 also.
I've been thinking about this myself, since our Rockster (with overall short gearing) is really a touring bike, and we really like our Roadster's "overdrive" transmission.
Option 1 is straighforward.
Option 2 needs some research, as I've yet to find good info about a swap for the R1150R aimed at lower engine RPMs for given vehicle speed... what I'm really considering is a potential rear drive modification to use the crown/bevel gear set from an R1200C if such fits inside the R1150R/GS/RT final drive assembly.
Here's some final drive info I've compiled from a variety of inaccurate Googlesources:
final drives
model R1150R R1150RT R1100GS R1100S R1200C R1100S R850R
ring 31 32 33 33 33 34 37 crown
pinion 11 11 11 12 13 11 11 bevel
ratio 2.81 2.90 3 2.75 2.54 3.09 3.36
change 0.0% -3.2% -6.5% 2.4% 9.9% -9.7% -19.4%
Option 3 is a venture into the great unknown.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 2:27 pm
by Airman
Rigby wrote:I recently bought a 2004 R1150R (5800 miles on it) that aparantly has a non-overdrive transmision. My round-trip to work and back is about 50 miles, cruising mostly at 65-70mph. I want to get the most gas mileage, mechanical longevity, and comfort out of this bike that I can. I am a very conservative driver. Can an OD tranny be installed in my bike, and at what cost just for the parts? Would I need to get a hold of a whole transmision or just part of the assembly? My dad is an auto mechanic, so I have access to just about any tools that I could possibly need to undertake such a project myself (Probably with my dad's help). Any advice would be greatly appreciated. Thanks in advance.
Are you sure that you don't have the overdrive ratio ? What RPM do you have at say, 80 mph in sixth ?
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 5:49 pm
by stilldking
Check the top of your final drive. There should be a set of numbers indicating the ratio.
Bad photo, but you can make-out the numbers 31/11 near the vent. (I think that's what that is.)
John C.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat May 17, 2008 8:36 pm
by Rigby
Are you sure that you don't have the overdrive ratio ? What RPM do you have at say, 80 mph in sixth ?[/quote]
I go about 4000rpm at 80mph.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sun May 18, 2008 12:50 am
by ruddy
You have the "overdrive" transmission.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Thu May 22, 2008 7:55 pm
by Airman
ruddy wrote:You have the "overdrive" transmission.
I checked mine the other night. It runs about 82mph at 4000 rpm. He does have the OD transmisson.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 5:43 am
by towerworker
"I checked mine the other night. It runs about 82mph at 4000 rpm."
You guys are gonna get a ticket.

Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 10:31 am
by gregor
Whew, I only get around 70mph at 4000rpm. That should stop me from getting a ticket.
Never felt the need for a higher gear to be honest -mine is still happy cruising at 80mph. Fuel mileage is around 47mpg (UK gallons). Or are UK miles shorter?
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 10:36 am
by gregor
By the way, a tranny in the UK is a cross-dresser.
Nudge nudge , say no more.....
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 3:00 pm
by Airman
towerworker wrote:"I checked mine the other night. It runs about 82mph at 4000 rpm."
You guys are gonna get a ticket.

I hope not. And it's research anyhow, eh? But as you know the bikes with the higher ratio would not be happy at the speed limit (60) in 6th. The paths I take to and from work contain large numbers of speeders, scofflaws and traffic violaters of every sort, cover for researchers such as myself in other words. I like to travel a little faster then the flow because I don't like stuff creeping up on me, but the flow is about 75 mph at night. At 80 I sometimes still get passed. I-405 is dangerous in the daytime because the differential speeds are so high. The car pool lane runs 25 mph higher then the other lanes. Or more. I saw the results of a bike/car crash there one day. The guy got pushed into the jersey barrier. Makes me
very careful through there.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 5:46 pm
by dnat928
My '02 also runs at about 80-mph @ 4k-rpm. Not that I would go that fast.
And it's not likely I would get a speeding ticket either. Actually, I just keep it at the flow rate +1. In SoCal, on the slab, there's ALWAYS someone going quite a bit faster than 80-mph. Easy pickings for the CHP.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 6:21 pm
by Biff's R
My 03 was at 80 mph at 4000 rpm in 6th.
My 04 is at 72 mph at 4000 rpm in 6th.
The milage difference is in the 0-2 mpg range, and that has been on about 50,000 combined miles.
gregor,
I try to avoid trannys, too.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Fri May 23, 2008 9:35 pm
by touchton
My bike goes the posted speed limit no matter what gear or RPM it's running. That's my story and I'm sticking to it.
.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Wed May 28, 2008 3:29 pm
by MattPie
sweatmark wrote:Surprised that your transmission is not the tall 6th gear type, if your bike's a Roadster. Was the transmission type an option for 2004 bikes? Somebody here surely knows.
I was an option, as have the 'low' 6th gear. 70mph@4000RPM (80@4500, give or take) US 2004 R1150R ABS. Kinda of annoyed I missed that on the sheet, I'd rather have the higher ratio, since 6th is pretty much for highway use anyways.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Wed May 28, 2008 3:49 pm
by cworley5150
I have heard some owners complain about the overdrive 6th gear being too high to use unless you were going 65mph+. I have the low 6th in my Rockster and wish I had the overdrive. There is very little difference between 5th and 6th gears. Only about 500 rpm difference at 70mph. I would like to have the overdrive so the bike doesn't feel so "strained" when cruising at around 80 or so. It's not that big of a deal though. Sometimes I find myself searching for 7th gear.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Wed May 28, 2008 4:26 pm
by Biff's R
cworley5150 wrote:I have heard some owners complain about the overdrive 6th gear being too high to use unless you were going 65mph+. I have the low 6th in my Rockster and wish I had the overdrive. There is very little difference between 5th and 6th gears. Only about 500 rpm difference at 70mph. I would like to have the overdrive so the bike doesn't feel so "strained" when cruising at around 80 or so. It's not that big of a deal though. Sometimes I find myself searching for 7th gear.
I too, find myself shifting to 7h on occasion, but I blame my old R with the higher 6th. The higher 6th was/is useless anywhere besides the interstate.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Sat Jun 15, 2013 11:36 am
by hesallwet
I'm new here. And, very interested in finding an answer to this question. Can anyone tell me the best way to go about getting a taller 6th gear?
Background.......I live in New England, where the riding is just so, so. Due to frost heaves, or cultural bias, most of the roads seem to have been built to run alongside rivers and in valleys. I do enjoy leaving New England to ride the two lane roads along mountain tops, in other parts of the continent (NC, especially). Which means 4-lane slab to get there. So, I'd like to have the taller 6th gear. (My son has the taller gear in his R1150RS, so I know what it can do.) But, other than 6th gear on the 4-lane, I much prefer my R1150R to his RS.
If it is a simple enough procedure to swap out a gear within my existing transmission, then I'd also like a shorter 1st gear. As, I find myself having to ride the clutch, to get off from a hillside start, or when traveling up steep mountain switchbacks (5 mph hairpins) two up.
These are not NEEDS, just wants.
Re: Can a non-overdrive tranny be upgraded to overdrive?
Posted: Wed Jun 19, 2013 1:13 am
by f4tweet
I have been told you should not be cruising under 4000 RPM . If I fall under 4K, I downshift to 5th gear so the engine isn't lugging or loading the driveline. I went from a 31/11 (2.81) to a 32/11 (2.91) and would never go back. I am reading 4200RPM @ 78MPH. My sixth gear is now a part overdrive, part 6th gear.