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Long or Short 6th Gear Revisited
Posted: Wed Dec 07, 2005 9:43 am
by Boxer
Does anyone have an idea when the shorter 6th gear came standard on the Roadster with the longer 6th as an option?
I'm talking manufacture dates here...Not model year?
Biff, I believe you said your '04 has the shorter 6th, right? What is the manufacture date on yours? Do you know when BMW started doing that? Was it with the beginning of the twin-spark engine or sometime later?
Posted: Wed Dec 07, 2005 1:04 pm
by machew01
Phil, mine was built 0204 and came with the smaller-ratio 6th gear. I don't remember it being an option.
mac
Posted: Wed Dec 07, 2005 2:13 pm
by Boxer
So Michael, what are your approximate RPMs at 80mph?
I'm compiling some info for another board I use.
Posted: Wed Dec 07, 2005 6:30 pm
by boxermania
Boxer
All of the R's that I have seen here in the US have the .80 ratio for 6th gear and the 31/11 = 2.82 final ratio.
This combo gives an
approximate indicated speed to rpm's in six gear of:
60 mph = ~ 3,000 rpm
70 mph = ~ 3,500 rpm
80 mph = ~ 4,000 rpm
A lot has been written about a .70 ratio 6th gear, primarily on the European bikes, I have never seen one, but if someone had one it should reflect the following rpm's in 6th gear
60 mph = ~ 2,600 rpm
70 mph = ~ 3,050rpm
80 mph = ~ 3,500rpm
Based pn the above the best way to tell if you have the "long" (smaller numerically) or the "short" (larger numerically) is to cruise at 80 mph indicated and see what the R's are:
If 4,000 rpm you have the .80 ratio
If 3,500 rpm you have the .70 ratio
Hope this helps...................

Posted: Wed Dec 07, 2005 7:46 pm
by Boxer
Al, I know you're the engineer, so I won't question your figures. I just need an explanation. My manual says my 6th gear ratio is 1.511. How does that equate to .80 that you gave above?
And I may be nuts but I DO remember some folks here discussing thier different 6th gear ratios. BiffsR for one said he had a different 6th gear on his new bike than the old one he had before.
Okay, everyone, alltogether now. Open your manuals and read the 6th gear ratio figure out loud. It should be in that smallish manual which is titled "Service and Technical Booklet" near the back with all the other spec numbers.
Posted: Wed Dec 07, 2005 8:01 pm
by Biff's R
Boxer, you are correct.
My 2003 R had the "overdrive" 6th gear, which was about 4000 RPM at 82 mph(indicated). (I don't know the manufacture date, but I have it somewhere.)
My current 2004 R has the "standard" 6th gear, which is about 4500 RPM at 80 mph(indicated). The manufacture date on the '04 is 11/03. Which is after the euro/dollar exchange rate took a major change.
I think that BMW tried to use the "overdrive" tranny as an add on the try to adjust for the currency change. This was about the same time that they made the heated grips a $225 extra.
FWIW, I would bet that I am the only person on the board who has had both an ABS, and a non ABS R1150R.
Posted: Thu Dec 08, 2005 10:20 am
by tor1150r
boxermania wrote:Boxer
All of the R's that I have seen here in the US have the .80 ratio for 6th gear and the 31/11 = 2.82 final ratio.
This combo gives an
approximate indicated speed to rpm's in six gear of:
60 mph = ~ 3,000 rpm
70 mph = ~ 3,500 rpm
80 mph = ~ 4,000 rpm
A lot has been written about a .70 ratio 6th gear, primarily on the European bikes, I have never seen one, but if someone had one it should reflect the following rpm's in 6th gear
60 mph = ~ 2,600 rpm
70 mph = ~ 3,050rpm
80 mph = ~ 3,500rpm
Based pn the above the best way to tell if you have the "long" (smaller numerically) or the "short" (larger numerically) is to cruise at 80 mph indicated and see what the R's are:
If 4,000 rpm you have the .80 ratio
If 3,500 rpm you have the .70 ratio
Hope this helps...................

This is bang-on.
Goes for Canadian models as well.....70 mph = ~ 3,500 rpm, using the 31/11 ratio
6th Gear
Posted: Sat Dec 10, 2005 7:00 pm
by hyperion
Mine is 4500 rpm at 80 indicated. Production date is spring 2004.
Overdrive
Posted: Sat Dec 10, 2005 9:09 pm
by zooomart
My 04 was built 07/03 and has Overdrive. Seems to drop the RPM around 1000. Haven't used it unless going at least 70 mph.
Posted: Sat Dec 10, 2005 11:33 pm
by QSIMDO
This was discussed before
My '04 (don't have production date right now) is only at 70 mph for 4k rpm in 6th.
There was another like that in the thread as well.
Even at that I'd like the RT lower final drive.
2.91 I think.
Posted: Sun Dec 11, 2005 8:52 am
by ProductUser
My '04 (MFD of 03/03) R runs an indicated 80 MPH ~3800 RPM. I don't know if the overdrive 6th was an option or std.
ProductUser.
Posted: Sun Dec 11, 2005 12:25 pm
by Deans BMW
zoomart says,
My 04 was built 07/03 and has Overdrive. Seems to drop the RPM around 1000. Haven't used it unless going at least 70 mph.
Why?
Posted: Sun Dec 11, 2005 4:53 pm
by jm1515
I'm pretty sure I have the .7 6th gear. Built June 04.
3k gives me ~60mph
3.5k = ~70mph
4k = ~80mph
Why not use 6th gear below 70 mph
Posted: Mon Dec 12, 2005 12:58 am
by zooomart
The main reason is my bike has about 4 k miles on it. Seems to still use some oil. I've ridden 300 miles or so as the new owner and have used a 1/2 a sight glass worth of oil.
Not sure how the original owner rode the bike but the rings seem to have a ways to go before they are seated. So I keep the rpm 3500 to 4,000 if I notice. I don't like to lug it and we have just enough hills around here to make staying in 6th a short term event... unless I'm on the Interstate
Am I off thinking that if I keep the rpm up alittle this will shorten the break in time? The bike just seems to be happier 3500 to 4000. I'm happier cranking through gears at 6 to 7K

of course
Re: Why not use 6th gear below 70 mph
Posted: Mon Dec 12, 2005 7:06 pm
by jm1515
zooomart wrote:The main reason is my bike has about 4 k miles on it. Seems to still use some oil. I've ridden 300 miles or so as the new owner and have used a 1/2 a sight glass worth of oil.
Not sure how the original owner rode the bike but the rings seem to have a ways to go before they are seated. So I keep the rpm 3500 to 4,000 if I notice. I don't like to lug it and we have just enough hills around here to make staying in 6th a short term event... unless I'm on the Interstate
Am I off thinking that if I keep the rpm up alittle this will shorten the break in time? The bike just seems to be happier 3500 to 4000. I'm happier cranking through gears at 6 to 7K

of course
I've only had a BMW for 8700mi...the total for my 04 Roadster since May of this year.
I basically agree on the 'sweet spot'...somewhere between 3300 and 4500 rpms for me.
I just can't fathom how some play in the 6000+ range...for any length of time anyways. What gear are you guys in???

I shift at ~4500 and motor around in the 3500~5000 range.
My temp gauge says that 60-70mph in 6th is 20~30deg cooler on the engine than in 5th. I can only imagine how much more heat is there for you all who venture near red-line......
Re: Why not use 6th gear below 70 mph
Posted: Mon Dec 12, 2005 7:20 pm
by JCsman
jm1515 wrote:I just can't fathom how some play in the 6000+ range...for any length of time anyways. What gear are you guys in???

For some of the hooligans/hoons on this board I think the correct question is not what gear, but what
speed are you guys at?
