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

I was wondering if anyone has an opinion on fitting a r1150r rear shock on a Rockster (ie slightly too short) i.e. opinions for/against and what would be the best way to do this?
change the front shock as well (to what size)?
change the paralever arm (to what size) ?
any other considerations?

I've only had the rear shock loose on my rockster once, so I'm no expert. I think the way it fits etc. and what it fits too is probably the same as ther R1150R - I expect it'd go straight in with no drama.

Trouble is, the front fork rake/trail of the Rockster is different to the R1150R, as it uses the R1100R/.Boxer Cup front and rear suspension. Also the Rockster has a 180 section rear tyre, while the R1150R has a 170, which means it'll take slightly longer to roll over to the side of the tyre tread. My concern would be that dropping the rear will slow the steering down by altering the steering head angle and affect the feel and the handling adversely. I'm not sure, but I think that the R and the Rockster front shock is the same length - it's the fork themselves that are different.

Can you drop the front forks a few millimetres to quicken the steering and (slightly) lower the front? I confess I have no idea, buit you'd need to be careful that you didn't clobber something when the forks were on full depression.

If you issue is a too-tall seat height (and I'm not long in the leg, so do sympathise if that's the reason), then have you considered the low-seat option? BMW do make a lower seat (although I can't vouch for the comfort!)

Goes straight in.

I have one in now.

it doesn't change the handling by any huge degree (you might notice it, but it won't affect much), and if you do, get a GS Paralever arm to lift the back up again.

(GS Paralever arm and R-R shock gives virtually the same ride height as standard Rockster items).

Oh - you may find the rear wheel will be a LONG way up off the ground on the centre-stand, and the bike will be a bit more upright on the side-stand (kick-stand).

Curiosity has got the better of me..... Why fit a shorter rear shock and then a GS paralever strut, to end up back where you started (unless you simply needed another shock and an 'R' and a GS strut happened to be handy)? I'd have thought that otherwise you might as well keep the original set-up? If it's a way to get a lower seat height, that makes sense to me (without the GS strut of course). Am I missing something - is there some other benefit to fitting the R1150R shock instead of the R1100S one the Rockster comes with?

The S model shocks do not fit the Rockster, they are not a shared part. Although I do not know the O.P's intent, I can only guess that the availability of Rockster specific shocks is not that great. When I went to purchase Ohlins, I was prepared to buy 1150R shocks and add the GS torque arm to put me back at a comfortable height, but as luck and money would have it I had a set built to the Rockster specs (I think Sweatmark did something similiar).

As Riceburner pointed out, there are no issues with installing 1150R spec'd shocks on a Rockster, you just lose about 5mm ride height in the back.

grwrockster wrote:Curiosity has got the better of me..... Why fit a shorter rear shock and then a GS paralever strut, to end up back where you started (unless you simply needed another shock and an 'R' and a GS strut happened to be handy)? I'd have thought that otherwise you might as well keep the original set-up? If it's a way to get a lower seat height, that makes sense to me (without the GS strut of course). Am I missing something - is there some other benefit to fitting the R1150R shock instead of the R1100S one the Rockster comes with?

In my case:
I had the GS Paralever arm already fitted (to increase ride height and speed up the steering), and then needed a new shock urgently - an R-R shock was the only one I could afford.


I've not looked into it, but it could well be the case that R-RT or R-RS shocks may fit.

R shocks occasionally pop up on Ebay, but i've never seen Rockster ones. New Rockster shock, if you can find them, are very expensive. Hence my question.
5mm at the shock means a much larger distance down and back at the axle, so i was worried about the geometry as per grwrockster's thoughts.
It looks like changing paralever arm will sort this, and probably best to get a fully adjustable shock so the rest can be tweaked to suit.
Have to make sure that cost of fully adjustable R-shock + paralever arm is less than new Rockster shock though!
Thanks your help y'all

If memory serves me well, if you have problems procuring Rockster shocks, one choice is to swap both front and rear with the "R" shocks, the handling will not be affected, the bike will be ~ .250" to .500" closer to the ground.

by boxermania » Wed Sep 22, 2010 8:17 am If memory serves me well, if you have problems procuring Rockster shocks, one choice is to swap both front and rear with the "R" shocks, the handling will not be affected, the bike will be ~ .250" to .500" closer to the ground.

My go-to mechanic said the exact same thing, that by lowering the front and rear together, handling will not be affected or at least noticed by 99% of the riders on the road.

Ves' topic re: Ohlins install for Rockster... with comparison to Roadster-spec Ohlins:

http://r1150r.org/board/viewtopic.php?f=3&t=14003

See his documentation of install process here:

http://www.vesware.com/OhlinsOnRockster ... ckster.htm

I miss Ves' contribution here.