PDA

View Full Version : Ohlins Question


BruceHarrisJr
Oct 13th, 2005, 7:53 pm
Forgive me for I am ignorant. Why is it that Ohlins shock absorbers raise the height of an LT? I recently purchased an '05 LT that had Ohlins installed new at time of delivery. I am told that the stock shocks and Ohlins springs are the same length-true/correct? If so, why do the Ohlins raise the height of the LT? I really do appreciate the ride quality improvement and handling characteristics of the Ohlins but do not like the extra height by making the bike lean over so much when having the side stand deployed. Other than that I'm mucho happy with my '05. Thoughts and comments are welcomed and appreciated!

HarvRead
Oct 13th, 2005, 8:01 pm
The Ohlins are adjustable, could have the preload cranked up a bit. Also the spring could be a bit stiffer.

bob_menton
Oct 13th, 2005, 8:59 pm
Bruce, at the BMWRA rally in Shelbyville, TN last weekend, Fred Rau (writer for M'cycle Consumer News) was looking in all the vendor displays for a "side stand extender". Seems he had loan of an '05 LT with Ohlins shocks, and it "leaned over too far on the sidestand". Guess you're not the only one with that complaint. Don't know if Fred found anything.


- Bob

nearmisses
Oct 13th, 2005, 11:44 pm
I have an 05 also and if you go an find a oiece of "Starboard" in 1/2 or if needed 3/4" and cut it to fit the shape if your kickstand plate. Then screw it in place. If you need more detaiks PM me and with your email address and I'll send photos. Easy fix.

mneblett
Oct 14th, 2005, 12:39 am
Why is it that Ohlins shock absorbers raise the height of an LT? I recently purchased an '05 LT that had Ohlins installed new at time of delivery. I am told that the stock shocks and Ohlins springs are the same length-true/correct? If so, why do the Ohlins raise the height of the LT?

The stock shock and the Ohlins are the same length, but they have different spring rates and pre-loads.

Over-simplified:

When the bike is taken off the stand (i.e., all the weight is carried by the wheel), X pounds is carried by the front suspension, regardless of which shock is there. Assuming no spring preload, if the stock shock has a spring rate of X lbs./inch, the suspension will "sag" 1 inch. If the Ohlins has a spring rate of 2X lbs./in., the suspension will sag 0.5 inch -- i.e., make the bike stand "taller" since it doesn't drop as much as the stock shock.

Spring rate also interacts with pre-load. If you have the stock shock pre-loaded ("pre-squeezed") by 100 lbs., it's pushing back against the ends of the shock wih 100 lbs of force, so you have to pull 100 lbs of motorcyle onto the shock before the suspension starts to move.

Example:

For the stock shock, assume the bike applies 300 lb. to the shock when it is taken off the stand, and it has a 100 lbs of preload and a 100 lbs./inch spring rate. The bike will sag 2 inches (300-100preload =200 lbs to be absorbed by the spring after the pre-load is overcome, 200 lbs./100 lbs.per inch=2 in).

For the Ohlins, assume 150 lbs. of preload (higher preload), and a 150 lls./in spring rate (stiffer spring). The bike will sag only 1 inch (300-150=150 lbs to be absorbed after pre-load, 150/150 lbs. per in=1 inch sag).


So, that's why you are being advised to dial out some of the Ohlins pre-load to lower the bike -- if the pre-load is reduced to 100 lbs, the bike will sag 300-100=200, 200/150= 1.33 inches, or 1/3 inch lower than before. Of course, trading off preload for height also increases the likelihood of bottoming out -- like all things, pluses and minuses to every choice!

Spike
Oct 14th, 2005, 2:43 am
Mark

Did you just make that up?

Just kidding.

Nick

LeRoi
Oct 14th, 2005, 7:37 am
What is "starboard"? Is it legal to put it on the port side?

mneblett
Oct 14th, 2005, 8:46 am
Mark

Did you just make that up?

Just kidding.

Nick

Dang -- busted!! :)

nearmisses
Oct 14th, 2005, 12:46 pm
Port, starboard, fore and aft too! Marine supply stores handle this material, also plastics places. Remarkable material, cuts and shapes like wood. Dremel tool or small grinder will do.

taylorjn
Oct 15th, 2005, 7:53 pm
Hey, Bruce -
Ohlins did the same thing to my 02. Not a huge issue, tho, as they increased the cornering clearance. Also by that time I was so used to the bike that I no longer needed to flat-foot it to be comfortable. My preload is seeping, and there is a guy local (Minneapolis) who is an authorized Ohlins tech. The shock will be rebuilt after the season ends here. I'll let you know results.