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r1100rt engine speed @ 60mph vs 1150rt


armand5000

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Hi all,

 

Currently a rider of a 2000 1150gs. Great bike, etc, etc, really wanting more wind protection so I'm adding an RT to the stable - either an 1100rt, 1150rt, or 100rt. (choices, choices)

 

Currently the r1100rt is surprisingly in the lead: no linked brakes, fantastic oilhead power, and a low enough a price to consider my custom, no decal, dark-chocolate paint scheme. (looks great in my head - almost like a strange, chocolate, alien jellybean levitation device) But I digress...

 

Question about gearing. On my 1150gs:

 

6th: 3k @ 60mph, 4k @ 80-ish mph

 

How do those speeds compare on an r1100rt? I'm worried about having a "buzzy" engine as California highways move at about 80mph.

 

BONUS QUESTION: what does a r100rt mono run at those speeds? Could a 1989 keep up with 80 mph traffic?

 

Just for kicks, here's my current r1150: https://drive.google.com/file/d/1eLGTXkQqyEELWkt756MHy8hgdty9bVPo/view?usp=sharing

 

Thanks from (Northern) California!

 

-Armand

6970.jpg.d055b89a1d21a1308859a6a28ba5b465.jpg

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Hi all,

 

Currently a rider of a 2000 1150gs. Great bike, etc, etc, really wanting more wind protection so I'm adding an RT to the stable - either an 1100rt, 1150rt, or 100rt. (choices, choices)

 

Currently the r1100rt is surprisingly in the lead: no linked brakes, fantastic oilhead power, and a low enough a price to consider my custom, no decal, dark-chocolate paint scheme. (looks great in my head - almost like a strange, chocolate, alien jellybean levitation device) But I digress...

 

Question about gearing. On my 1150gs:

 

6th: 3k @ 60mph, 4k @ 80-ish mph

 

How do those speeds compare on an r1100rt? I'm worried about having a "buzzy" engine as California highways move at about 80mph.

 

BONUS QUESTION: what does r100rt mono run at those speeds? Could a 1989 keep up with 80 mph traffic?

 

Just for kicks, here's my current r1150: https://drive.google.com/file/d/1eLGTXkQqyEELWkt756MHy8hgdty9bVPo/view?usp=sharing

 

Thanks from (Northern) California!

 

-Armand

 

Afternoon Armand

 

Hopefully you will get some feedback from current 1100RT/1150RT riders.

 

Just keep a couple of things in mind when you get the feedback--

 

Both the 1100 & 1150 are kind of notorious for having inaccurate (optimistic) speedometers so at an indicated 80 the bike might only be actually traveling at 75 mph. You want accuracy then ask for GPS speed vs RPM's.

 

The 1150RT also had a couple of high gear overdrive ratios available so when comparing MPH vs RPM's be sure that you are both riding on the same top gear ratios.

 

I can't remember what the R100 ran RPM wise at 80 mph but it could sure run along at well over 80 mph for a good long distance if needed.

 

My personal opinion is that I liked the 5 speed 1100RT better around town & at speeds up to about 75 mph (GPS) as the engine had smaller pistons so didn't have as harsh of buzz periods.

 

At anything over 75 mph the 1150 overdrive was really nice but I never really liked the gear spacing on the 1150 for my type of riding.

 

The BMW 1200RT really got the trans gear ratios sorted out & THAT is what the 1150RT should have been fitted with.

 

 

 

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Approximately........

 

5th gear, 4K roughly 70 mph, 3.5K roughly 63 mph. I wouldn't ride my RT for much time at 3K, too slow engine speed.

 

4th gear, 4.5K roughly 65 mph

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Thanks guys,

 

Follow up question. To this:

"My personal opinion is that I liked the 5 speed 1100RT better around town & at speeds up to about 75 mph (GPS) as the engine had smaller pistons so didn't have as harsh of buzz periods.

"

 

Personally, I've experienced less buzz on my fathers r1100r vs my own r1150gs. (both TBs synced correctly) I could never quite figure out why his motor just seems "sweeter" but this sounds like a good explanation.

 

Can anyone else comment further on this, I find it interesting. Did the 1150s get their larger displacements by simply boring out the pistons?

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Thanks guys,

 

Follow up question. To this:

"My personal opinion is that I liked the 5 speed 1100RT better around town & at speeds up to about 75 mph (GPS) as the engine had smaller pistons so didn't have as harsh of buzz periods.

"

 

Personally, I've experienced less buzz on my fathers r1100r vs my own r1150gs. (both TBs synced correctly) I could never quite figure out why his motor just seems "sweeter" but this sounds like a good explanation.

 

Can anyone else comment further on this, I find it interesting. Did the 1150s get their larger displacements by simply boring out the pistons?

 

Morning armand5000

 

Unless WAY out then TB sync has very little effect on higher RPM boxer buzz as the higher RPM buzz is almost all mechanical-- Remember that the BMW boxer engine is solid mounted to the chassis & has 2 fairly large pistons that completely stop then re-start in the opposite direction twice per revolution. Plus the pistons are not directly across from each other due to having separate crankshaft throws so THAT gives the engine a twisting or rocking shake as the pistons stop & start on each firing stroke.

 

Piston size is different between the 1100 & 1150 boxer engines-- 1100= 99mm bore x 70.5mm stroke ____ 1150= 101mm bore x 70.5mm stroke

 

 

 

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  • 2 weeks later...

So I went ahead and bought an RT:

1999 r1100rt, 34k miles.

 

From what I can tell:

 

"Reported speeds":

 

60 mph @ 3100rpm

80 mph @ 4100-4200rpm

 

I know that these might not be ACTUAL speeds, but this is roughly 200-400rpm within the engine speeds of my 2000 r1150gs (6-speed)

 

The gears make much more sense (not all of those meaningless shifts in the middle) and this thing pulls STRONG up to about 110 MPH indicated. (gotta love 4th gear)

 

So far I'm very pleased. All this in a package with fantastic aeros, a big comfy seat, and chrome bits all over for just $2,200 US!!!

 

First plans are:

1. Brake line bleed with new front pads

2. Stainless steel brake lines all around

3. New rear tire

 

I can tell that the old style cam-chain tensioner is present but it really doesn't rattle much. Only a tiny bit at startup, unlike my GS which would rattle away at idle.

6978.jpg.27ec4183ed4151aaac0189a90dd09904.jpg

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So I went ahead and bought an RT:

1999 r1100rt, 34k miles.

 

That's a beauty!

 

Where ya from?

 

&

 

How did you get that file to upload? I had a devil of a time.

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Armand5000- I would guess your speedometer is about 5 - 10 mph overstated, that's pretty normal for a non-authority speedometer.

 

Good looking bike and a very good price.

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