Welcome to the Dark Side,
I too recently came from Harley's. I just bought a 2009 R1200RT. I use to own a RoadGlide Ultra. This RT is the Bees Knees! It has power, comfort and handles the twisties better than my Harley could ever! And I had JRI Shocks and RaceTech GoldTopEmulators and springs in my forks!
The weight difference is amazing! I lost 300 pounds of unnecessary weight. Storage is great, I love the center stand and it accelerates like a bullet. I have to be careful not to cruise too fast, I don't want a performace award from the local LEO's.
Since you already have the Ohlins, just fiddle with them until you like the ride. The best thing I did was to add ZTecknik Engine Guards and Iliumworks highway pegs along with a Corbin saddle that I bid on EBay for.
Enjoy the ride,
John & OP:
John: Agree with most of your post except for the "just fiddle with them until you like the ride." That's a recipe for a bike that soon gets re-sold because "I could never quite feel comfortable on it."
Ohlins are the best I've tried. I've also had some pretty great Wilbers shocks but my Ohlins were the nicest riding and handling.
I've had 4 RTs. One was an '05...with 3 way adjustable Wilbers in back and one adjustment in front for rebound. That's the bike I put the most miles on of all of them. It went to a good home.
My new bike has BMW electro-shocks. I have to say, they rock and, so long as they continue to work this well, I won't replace them with aftermarket.
If those Ohlins have more than 20K on them, The OP might want wait until the end of his riding season to remove them, put the stock shocks on and send the Ohilns in to Beemerworks for rebuilding and setting up. Those guys really do a nice job of setting shocks up. They'll rebuild them and set them for his bike, weight and normal use. He will love it.
Otherwise, reading ALL of the links above, printing them out and really getting the idea of what a good setup does and how to find it will work OK. It's not difficult, but it's easy to get lost. I can't stress enough that you have to write things down.
Here are basics:
1. Look in the Rider's Manual and find out what the total wheel travel is for the rear. Write that down. I think it's 5.5" but look it up.
2. Get a wooden paint stick from the hardware store. Get a pencil. Get some masking tape. Get a calculator.
3. With bags removed and bike on the center stand, the rear suspension will be fully extended. Set the paint stick on a flat part (or at least a repeatable part) of the final drive casing. Hold the stick vertical and touch one end down to the FD case.
4. Find a spot on the rear bodywork that can serve as a measuring reference. Some part of the upper stick should touch this reference. If there's no edge as a reference, put a piece of tape on the bodywork. Leave it there for like ever. Doesn't hurt anything and it will make your paint stick hold it's value.
4A. Mark the name of your bike, "'05RT" or some such, on the stick. You will save this for later.
5. Mark the point on the stick that touches the reference point.
6. Take the total wheel travel number of the rear (5.5"?) of the rear wheel and divide by 3. Write down the answer. (1.83"?)
7. Put a second mark on the stick exactly the distance from your previous mark as the answer to 6 (1.83"). I happened to have a digital caliper in my tool box and used it to mark my stick. Very handy for this, but it's not really a precision operation. We just need to get within 1/4" or so for this.
8. Get an assistant.
9. Take the bike off the stand. Sit on it with an average load for your average use.
10. Match the second mark on the stick to the reference on the bike. Adjust the rear spring pre-load until the 2nd mark touches the reference. It goes way better with two people or more to hold the bike steady while you balance on it. BTW, I figured out that you can put your thumb nail at the point where the reference touches and pull the stick away to read it. I have rarely been able to find a willing assistant.
11. That 1/3 of wheel travel setting is a nice cruising pre-load. If you want to hit the curves, a 3rd mark about 1/4th (1.375") of the total wheel travel can help the bike turn in a bit better. More than that will probably be too stiff.
I color in my stick between the 1/3 mark (1.83" and the 1/4th mark, 1.375". It's a range that will give you the best of two different priorities...Pick your poison! If I tell you to set it at 1.5", I'm not far wrong, but you miss the value of the extremes that, if exceeded, will not give you joy.
11A. If the spring is too tight for the load, the bike will hit the end of the travel after bumps and lift the rear wheel off the ground. This is obviously not a good situation for cornering or for comfort.
11B. If the spring is too loose, the bike will bottom on some bumps. Very uncomfortable and not particularly good for the bike either.
So...That's the right way to set spring pre-load. Once you know where the sweet spot is, you can count turns to all the way stiff and write that down. Then you don't need to carry the stick around with you. I write it ON THE BIKE somewhere so I know where "home" is. This is very important when you're experimenting. Easy to get quite confused.
So, you want the static loaded bike, with rider(s) and luggage, to be sitting somewhere between 1/3 and 1/4 of wheel travel below full extension. That is a mouthful and hard to follow! All the steps above get you there.
12. Obviously, pre-load should be adjusted when you significantly change the weight. You can use the stick to set up a loaded bike before you go on a trip, for instance. I bungie my side case onto the seat so I have all the weight and can still use the stick. If you have a pillion, he/she can hold the side case while sitting on the bike.
After a while, you figure out how much extra pre-load works with how much extra stuff. Keep the stick around the garage in case things get out of whack.
I don't know which Ohlins he has, lets assume he can only adjust the rebound setting.
After one has the spring preload right...
1. Take the bike off the stand again. Jump or push on the bike hard enough to compress the suspension a good bit, then let go. It should take 1 second to fully recover back to normal ride height.
2. The bike should not rise above the static position. It should go down from the push and rise up. If it goes above static and comes back (bounces), it needs more damping. If you put full damping (slowest setting possible) and it still bounces, your shock is gone.
3. Make sure you understand the rebound adjuster and how it activates on the shock. BMW stock shocks are notorious. They have little metal button on the side of the shocks under the mud-guard (dust cover?). A long adjustment screw is attached to the mud-guard (of the shock). It hangs in the air on the inside for 10 turns or more before the screw even contacts the actual adjuster button on the side of the shock.
Most riders with stock shocks leave them fully fast (almost no rebound, not realizing that the adjustment they just made didn't change or even touch any part of the shock adjustment button thing. These are the people riding "scared" through corners. You have to get down there and look. Adjustment doesn't start until that screw touches the metal button under there. The Rider's Manual wisely advises to adjust the screw all the way in to start, then back off a set amount. I like this way for these type shocks.
If the adjustment is on a separate block on a hydraulic line away from the shock, it's a little more straightforward.
4. Rebound adjustment isn't
a comfort adjustment. It's not "stiffness". Rebound adjusts the speed that the suspension RECOVERS from a bump.
If this recovery is set too fast, the bike will "baby-buggy"...wallow up and down over bumps and feel unstable in turns. Feels like the front wheel has no grip...scary. Strange that a loosely damped rear wheel can affect the feeling of the front so much...but it really does.
If it's too slow (too much rebound damping), the bike will not recover well from a series of bumps and will get harder and hard riding as you continue over the bumps. If it starts out feeling OK, then you ride on a washboard type road and it gets extremely uncomfortable, it's too slow on recovery...too much rebound damping. The bike actually rides lower and lower with every bump because it's not recovering enough. Evenutally it gets near bottom and that's very uncomfortable and feel wrong. When I adjust new shocks, I find a road like that for tests.
Compression adjusment(s): After rebound is right, time for compression...
Ride Stiffness is adjusted by the Compression adjustment. Most touring shocks don't have this adjustment. Mine had low and high speed compression adjustments. Usually, you use the specified setting and don't vary much. I found that I could get some joy out of increasing, a little, the low-speed compression setting. It would allow a slower rebound setting because my shock wouldn't move quite so much on the washboard road. If it moves less, the time for rebound is less.
This can be set in a way that keeps the bike very tidy without discomfort...Magical and quick!...but, for sure, more is not better. A stiff riding bike isn't fast on back roads and it isn't nice to ride a long distance either.
Finally, if you tighten the spring, adjusting for more weight, you're increasing the force against the shock's damping. If you adjust the spring a lot, you should also adjust the damping a little bit. You can go through the whole procedure or go a little by feel. Point is, you need to know where "home" is or things eventually get confusing. If you make adjustments, write them down. Then change back to the original when the added weight is gone again.