Revelation of disapointment! No 2:62 but 2:75 as others suggested

[Dr. Curve]

Doing top speed runs today.............I realized something was wrong. Even though I had been assured, and it was written on the sales ticket for the bike when I bought it.............my R12S does NOT have a 2:62 rear end as I have stated many times............but upon closer checking today after checking top speed..............I confirmed that I have a 2:75 in the rear of my bike just like many of our Pelican brothers had suggested I did. Perhaps I can get one in time........but after today I realize that 160 mph plus will be problematic............no matter how long the straight is.

[ckcarr]

Hmmm... Sounds like the fabled 2:62 is non existant in these bikes.

[Steve Carlton]

I thought you said you read the numbers off the rear drive unit?

[wswartzwel]

Watch Him guys... Sounds like he is trying to lure someone into a top end run.. and then take their money... Never believe a racer when he is complaining about his machine not being up to par... Especially a old Veteran racer like Curve!!!

[pdonnell]

but after today I realize that 160 mph plus will be problematic............no matter how long the straight is.
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That took some guts Curve. I'm proud of you to acknowledge some irrational exhuberance over the latest boxer twin.

[Bob Hancock]

I just think it's kinda weird that the standard ratio listed in the owners manual is 2.62, but seemingly all the bikes have the Alternative Ratio of 2.75. Now with 375 miles on my bike I don't think I'd want the taller gearing for what I will do with it. I suspect that they had the 2.62 as engineering standard sent to the printing presses and then started riding them more and realized....a bit too tall.....need to change this just a tad.
Jim...does yours have the 33/12 stamping on the bottom of the rear drive like mine?

[dee jones]

DR. What was the top speed achieved ? Were you just a tad shey or was the S just out of the ball park?

[Dr. Curve]

Dee, indicated 158-160 on speedometer. The stampings I thought I had should have read more like 34/13 rather than the 33/12 as Bob mentioned. Oh well...........if one can be ordered........it will soon be on the way. For now..........more zip........less speed.

[Deans BMW]

Hopefully we can get a radar reading on the San Jose R1200S at Daytona March 3&4. If so, I will post.

If the schedule permits, we will take the bike to Bonneville for the Bub speed trials Sept 2-6.

[Bob Hancock]

Originally posted by Deans BMW
Hopefully we can get a radar reading on the San Jose R1200S at Daytona March 3&4. If so, I will post.

If the schedule permits, we will take the bike to Bonneville for the Bub speed trials Sept 2-6.

Dean....what ratio are you guys running for Daytona?

[Deans BMW]

Last October at the 8 hour, we ran the R1200RT final drive ratio.

Anything beyond that is unknown until race day.

[Bob Hancock]

I guess that would be a 2.62.

[Seventies Man]

So thats good news, just mount up an RT final drive and you got an overdrive. Get a Gps mounted and try for 165mph.

What about the prevailing wind? Shouldn't there be a "feels like" speed similar to the chill factor on weather reports?
A mere 150 into a headwind could feel like 170.

I'm tempted to change the subject but sapeed is relative was my thought. -Martin

[GotRoad?]

Originally posted by Seventies Man
Shouldn't there be a "feels like" speed similar to the (wind) sic chill factor on weather reports? A mere 150 into a headwind could feel like 170.

HAHAHA....you're killing me!!!

[Dr. Curve]

Not to worry. I will have one on order by Tuesday afternoon. Both the RT and ST have just what we need. Expensive.......but worth it. Then, perhaps, things (true stock parts top end) will clear up some. Like 70sMan said........the wind was so gusty and cold today here in south georgia that 110 felt like 160........so I was very relative in my thought.

[GotRoad?]

I don't know why you would want the 2:62 over the 2:75, I would prefer the acceleration advantage of the 2:75 over the final windout top speed of the lower ratio gearing; but then that's just me.

[RoundelRider]

Originally posted by GotRoad?
I don't know why you would want the 2:62 over the 2:75, I would prefer the acceleration advantage of the 2:75 over the final windout top speed of the lower ratio gearing; but then that's just me.

Your out of your mind!

I go 160 everywhere..........thats how I get to your place in 10 minutes!

So............does BMW honor the "Gentlemans Agreement" set by UJM manufacturers to limit top speeds to 186mph?
Just courious.

[Dr. Curve]

I agree with you GR............I just want the option of either one and also when running for top end the 2:62 will allow a stock R12S to run 160 plus.......or so I hope. The 2:75 is better in the everyday world, more practical, zippy-like out of the corners........while the 2:62 is for crossing Texas.

[MoDog]

I've thought for a long time that the 2:62 in the R1200S was an urban legend. After CKCarr posted a picture of how to tell, every R1200S (in five states) I've crawled under has been 2:75

[BMW Atlanta]

Originally posted by Dr. Curve
Not to worry. I will have one on order by Tuesday afternoon. Both the RT and ST have just what we need. Expensive.......but worth it. Then, perhaps, things (true stock parts top end) will clear up some. Like 70sMan said........the wind was so gusty and cold today here in south georgia that 110 felt like 160........so I was very relative in my thought.

DONT order a final drive from an RT or ST,........it is not a direct fit as the speed sensors are different because of the different ABS. There is a part# specific to the 2.62 final drive for the R12S, we have ordered them. The RT/ST FD will bolt up and work just fine, but you will have no ABS and no odometer, but you will have speed from the front wheel if ABS equipped. Also rumor is we have a 2.54 final drive on the way from some secret dungeon in da fatherland