A couple of years ago, I purchased on eBay two Öhlins shock absorbers with springs for my BMW R 1100 RS. As you know, the late R-series twins have a Telelever swingarm front suspension with a spring/shock absorber, and a single-sided swingarm also with a spring/shock unit.
Purportedly, the front unit I purchased was used but the rear was not. Then recently, the front suspension blew out in that its damping went away completely, and its damping adjuster “clicker” no longer clicked. The rear suspension was working fine, but I decided that since I had put more than 15,000 miles on the set and the bike would be out of service anyway, I may as well send both in to Öhlins USA to have them rebuilt and/or inspected.
In the course of the shock service, I had several conversations and exchanged e-mails with Marty Lange, an Öhlins USA technician. Here is some of what Lange told me. “The front shock did in fact blow out, which generally means the seals had failed. It lost the majority of the nitrogen and oil, and the main reason the seal failed was probably because the recommended service interval had not been followed. Most people think that shocks do not need to be serviced and should never leak, especially when you pay a decent price for them. These same people, however, follow the recommended service intervals on their engines and generally do not question it needing parts. Our product needs to be serviced so that leaks/blowouts do not occur. The recommended service interval quoted from the shock’s owner’s manual is 30,000 kilometers, which is around 18-19,000 miles. Generally, we recommend 15-18,000 miles or once a year, and we recommend that both the front and rear be serviced together.”
Lange told me that my BMW’s front shock is considered an emulsion shock, which means there is no separating piston between the nitrogen and oil. “Generally, when one of our shocks develops a leak it’s in the seal head, which seals where the shaft enters the body. We also replaced the piston band on the main piston. The shock was re-valved back to its original specification. The oil we use in our BMW shocks is 105-01, which is heavier than our R&T oil so it does not break down (lose its viscosity) as quickly. We also use nitrogen in our shocks, which minimizes pressure changes brought about by differences in temperature.”
The rear shock was serviced as well. “It’s a dividing piston shock; this means there is a solid piston separating the gas from the oil. We replaced the seal head and the piston band on the main and dividing pistons. The shock was not leaking, but I could see scarring on the sealing surfaces which tells me it was more than likely also past its recommended service interval. As above, we always recommended having your shocks serviced together. Just as with the front shock, fresh oil and nitrogen were added and all internals cleaned and inspected.”
The stock springs were left intact as the spring rates were in the correct range for my weight. Öhlins adjusted preload for my weight, which they do for every customer. They also reset the adjusters to factory specs, and recommended riding the shocks with the clicks at factory settings, then making my own adjustments as I felt appropriate.
With the rebuilt shocks installed the ride was primo again. They were plush without being loose, yet firm and well controlled without being harsh. As for price, the front shock service labor is $75 and the rear shock $130, which does not include hard parts such as O-rings, seal heads, piston bands, etc., or shipping. A general BMW front and rear shock service is in the $350 range total, including labor and parts. For a bike with conventional twin rear shocks the price would be similar. These shocks may require a few more parts, but Lange tells me they are generally cheaper and smaller.
For more information: Öhlins USA, 703-C Old Spartanburg Road, Hendersonville, North Carolina 28792; (828) 692-4525; www.ohlinsusa.com