BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi guys,

I am finally putting my Rockster back on the road after 2 1/2 years. Prior to parking the bike, the rear shock gave up the ghost after 67k kms, approx 38k miles. As you all know Ohlins stopped making kit for our bikes a while ago, so I had a local suspension shop tweak a pair of Roadster shocks for me. I am still 6-8 weeks away from being back on the road, so in the mean time behold my new gold - http://www.flickr.com/photos/kromedome/ ... 411781809/

What exact customisations did they make? I assume they did something about the different overall lengths??

riceburner wrote:What exact customisations did they make? I assume they did something about the different overall lengths??

I provided them with the specs for the Rockster shocks, from an old Ohlins catalogue, they confirmed with Ohlins USA and set them up to ensure that the bike maintained stock geometry while adjusting for my weight and intended riding style, which is what I requested.

Length changes were accounted for, and the rear shock's cylinder tube was changed.

I provided them with the specs for the Rockster shocks, from an old Ohlins catalogue, they confirmed with Ohlins USA and set them up to ensure that the bike maintained stock geometry while adjusting for my weight and intended riding style, which is what I requested.
Length changes were accounted for, and the rear shock's cylinder tube was changed.

This sounds similar to my Ohlins rebuild. I purchased a used rear Ohlins spec'd for R1150R Roadster, and subsequent rebuild to fit Rockster required exchange of the shock body. Local suspension specialist pulled up his microfiche Ohlins specs for front/rear Roadster versus Rockster, and confirmed the differences between the shocks in terms of installed (free) length, stroke, spring length & stiffness. In order to modify the Roadster rear shock, new shock body was ordered from Sweden, but IIRC that was the only major part aside from maybe an internal bushing, spacer or something.

For now, I'm running the Roadster-spec Ohlins rear spring, which is a touch soft compared to the Rockster-spec equivalent, and I might bump up spring stiffness when the rear shock gets refreshed down the road.

As for the front shock, I decided to use the Roadster-spec Ohlins unit as is; the difference in length between Roadster and Rockster spec was not sufficient to warrant the expense of rebuild. The slightly longer Roadster shock increases trail, but is balanced to some degree by use of the short GS Paralever strut which reduces trail by steepening the Telelever's steering axis angle.

sweatmark wrote:

I provided them with the specs for the Rockster shocks, from an old Ohlins catalogue, they confirmed with Ohlins USA and set them up to ensure that the bike maintained stock geometry while adjusting for my weight and intended riding style, which is what I requested.
Length changes were accounted for, and the rear shock's cylinder tube was changed.

This sounds similar to my Ohlins rebuild. I purchased a used rear Ohlins spec'd for R1150R Roadster, and subsequent rebuild to fit Rockster required exchange of the shock body. Local suspension specialist pulled up his microfiche Ohlins specs for front/rear Roadster versus Rockster, and confirmed the differences between the shocks in terms of installed (free) length, stroke, spring length & stiffness. In order to modify the Roadster rear shock, new shock body was ordered from Sweden, but IIRC that was the only major part aside from maybe an internal bushing, spacer or something.

For now, I'm running the Roadster-spec Ohlins rear spring, which is a touch soft compared to the Rockster-spec equivalent, and I might bump up spring stiffness when the rear shock gets refreshed down the road.

As for the front shock, I decided to use the Roadster-spec Ohlins unit as is; the difference in length between Roadster and Rockster spec was not sufficient to warrant the expense of rebuild. The slightly longer Roadster shock increases trail, but is balanced to some degree by use of the short GS Paralever strut which reduces trail by steepening the Telelever's steering axis angle.

Mark - can you tell me (us) what the differences are between the Roadster, Rockster and GS shocks? I'm going to need a new rear shock soon and can't afford a new one, so was going to look 2nd hand from breakers yards. If a GS shock will fit a Rockster I'd FAR prefer it, the bike drags it's ass something chronic with a Roadster shock (even when fitted with a GS Paralever arm).

...differences are between the Roadster, Rockster and GS shocks?

riceburner, don't trust my accuracy, but here's what I found in an old data file:

Öhlins shock absorber - Ohlins web site 2006

BMW R 1150 R Rockster 2003
Part No. BM 349 Type 46DRS Length 372 mm Stroke 50 mm
Part No. BM 350 Type 36DRL Position front Length 324 +10/-0 mm Stroke 75 mm

BMW R 1150 R 2002
Part No. BM 049 Type 46DRS Length 366 mm Stroke 56 mm
Part No. BM 050 Type 36DRL Position front Length 334 +6/-4 mm Stroke 73 mm

R1150GS Adventure (02-05)
46DRS Rear, Length: 390mm, Stroke: 70, Shock PN BM215
46ER Front, Length: 344.5mm, Stroke: 101.5, Shock PN BM216

Actually - a few Google clicks led me to better data:
http://www.ohlinsusa.com/us/catalog/Rec ... 6-10_1.pdf
There's your answer regarding both R1150GS and GS Adventure, though no confirmation of what I grabbed previously for Rockster.

More Googling: here's spring rate information
http://www.advrider.com/forums/showthread.php?t=111505

sweatmark wrote:

...differences are between the Roadster, Rockster and GS shocks?

riceburner, don't trust my accuracy, but here's what I found in an old data file:

Öhlins shock absorber - Ohlins web site 2006

BMW R 1150 R Rockster 2003
Part No. BM 349 Type 46DRS Length 372 mm Stroke 50 mm
Part No. BM 350 Type 36DRL Position front Length 324 +10/-0 mm Stroke 75 mm

BMW R 1150 R 2002
Part No. BM 049 Type 46DRS Length 366 mm Stroke 56 mm
Part No. BM 050 Type 36DRL Position front Length 334 +6/-4 mm Stroke 73 mm

R1150GS Adventure (02-05)
46DRS Rear, Length: 390mm, Stroke: 70, Shock PN BM215
46ER Front, Length: 344.5mm, Stroke: 101.5, Shock PN BM216

Actually - a few Google clicks led me to better data:
http://www.ohlinsusa.com/us/catalog/Rec ... 6-10_1.pdf
There's your answer regarding both R1150GS and GS Adventure, though no confirmation of what I grabbed previously for Rockster.

More Googling: here's spring rate information
http://www.advrider.com/forums/showthread.php?t=111505

hmmm - so at first glance the GS shock is significantly longer.... hum... (don't want a wallowy GS shock thinking about it... oh well.).

According to that Ohlins tech manual, regular R1150GS rear shock length is 383mm versus Rockster's 372mm = 11mm of potential excitement.

And similar to "Spinal Tap's" Nigel Tufnel amplifier, turning things up to eleven might just be best.

sweatmark wrote:According to that Ohlins tech manual, regular R1150GS rear shock length is 383mm versus Rockster's 372mm = 11mm of potential excitement.

And similar to "Spinal Tap's" Nigel Tufnel amplifier, turning things up to eleven might just be best.

it's a thought..... will end up with front forks that are absolutely vertical!