Rear Shocks for BMW GS Tugs

[Stroker]

My rig is on the heavy side but a Wilbers model 641w/option 625(remote adjustable preload) and a 59/59-245-175 coil spring works for me. I believe that the Paralever geometry is slightly different between the 1100 and 1150 models. If you have a sway-bar the sidecar and rear suspension will affect each other as well. On the front I have a YSS shock with a Hyper-Pro coil spring, 1cm longer than stock with adjustability for another 1cm. This takes care of the smaller front wheel. I'll check the front coil spec ASAP.

[davebig]

Originally Posted by eastbloc

My OEM front shock has given up the ghost after 12 years of duty -- I find myself bottoming out over speed humps and big potholes.

Who has replaced their front, with what, and what parameters? Did you go for a stiffer/longer/shorter spring? I see it as a good opportunity to boost up my ground clearance, which has diminished considerably from the steering mod combined with the Stroker front wheel. I do have a spare Adventure shock laying around somewhere, which might do the trick and last a few more thou, but I'd rather have it sorted for good seeing as how I have proper shocks on the side and the rear now.

A couple of thoughts my fronts got a 12-56 with the shortened A frame the lever compressing the spring is shorter I don't seem to need as much spring. One of Strokers wheels and my install of a 145/65/15 front tire tipped me down, it didn't seem to make much difference in handling but I was down to about 6+." clearance under the sub frame, I had no pre load on front Ohlins cranked in 1/4" pre load and a 3/8" spacer at top of front shock and my subframe sits level. 65 series tires front and rear.
While in garage this morning I checked my other GS it has a shortened torque arm in the rear, that pulls the front end up its got just over 8" under the skid plate, Tug GS has just over 7" I bought another billet torque arm and will be shortening it to see if I can get a little more height.Even for a serial tweaker this sidecar stuff is tedious. DB

[DRONE]

Originally Posted by eastbloc

My OEM front shock has given up the ghost after 12 years of duty -- I find myself bottoming out over speed humps and big potholes.

Who has replaced their front, with what, and what parameters? Did you go for a stiffer/longer/shorter spring? I see it as a good opportunity to boost up my ground clearance, which has diminished considerably from the steering mod combined with the Stroker front wheel. I do have a spare Adventure shock laying around somewhere, which might do the trick and last a few more thou, but I'd rather have it sorted for good seeing as how I have proper shocks on the side and the rear now.

I got my stock wheel with a DMC trail reducer, and I use an Ohlins 216 shock with a Adventure-length shaft. It has a 15/62 spring which is rated at 354 lbs/inch. Last summer was the first season using it, and I was really pleased with it.

[davebig]

http://www.yacugar.com/products/shoc...k-options.html
Mikepa's images of busted Ohlins, gave me pause to wonder, my current shocks have allot of miles but not many with a chair.
I called Ted Porter :http://www.beemershop.com/ in CA about buying a Wilbers for the rear of my CSM GSA rig, I've been one of Teds customers before and like him.I have Ohlins and have no complaints but only about 4k miles with chair. He suggested the Yacugar it's on sale and has a 16mm shaft and steel body, they and Hyperpro are evidently the leftovers from WP that KTM acquired and moved to Austria. Ted had lots of reasons that he felt Ohlins were not sidecar suitable mostly cause they are lightly built as a performance shock.They have 4-5wk lead time so we shall see.DB

[DRONE]

DB--How big a spring you getting?

[eastbloc]

If I recall correctly, I got a 500lb spring on my Ohlins rebuild (or whatever the stiffest possible from the OEM was) and it's perfect for me at 235lbs.

[davebig]

Originally Posted by DRONE

DB--How big a spring you getting?

Good question, they demand that they take your info and select what spring Yacugar thinks is right to start out with or they won't warranty the shock should it be damaged, so I estimated the chair at 350,GSA with Jesse luggage etc remembering that I think you scaled yours and said it weighed 850ish I said it should come in around 900ish.DB

[DRONE]

Interesting approach. Wouldja ask Ted to find out what spring they end up choosing for you so you can post it up here or on your "small Schnauzer" thread, then later you can tell us if they guessed right or not?

FWIW, on my rear Ohlins, I have a very very big spring, I use no preload (for maximum travel and most comfortable on-road ride), and I have the rebound damping turned up pretty high.

[davebig]

Originally Posted by DRONE

Interesting approach. Wouldja ask Ted to find out what spring they end up choosing for you so you can post it up here or on your "small Schnauzer" thread, then later you can tell us if they guessed right or not?

FWIW, on my rear Ohlins, I have a very very big spring, I use no preload (for maximum travel and most comfortable on-road ride), and I have the rebound damping turned up pretty high.

I had planned to post, I'm up two numbers over what Ohlins like for 1150gsa's spring rate per Stieg Pettersens recommendation for loaded GS's and it felt too stiff but it could be the spring roads etc, I've wanted a spare shock as I have a spare front Ohlins so as not to be caught with a broken rig for too long, but the swaybar adds spring rate also and I'm cranking in a little swaybar today.DB

[brstar]

Bought this fournales shock (unused but cheap) second hand a few years back. It was to fit a GS 1150 I think but may be an 1100. Next to it is the stock shock from my Vstrom that was not up to sidecar duties so I adapted the Fournale to fit and it works a treat so far. Ride height? Just add more pressure. gives a very smooth ride and is next to impossible to bottom out. Bonus for me was a bit more ground clearance over the Suzuki shock.
Down side?
A bit tedious to adjust pressures.
Pricey new and it would be better if I had a sway bar fitted as it leans a bit in corners.
For some they may be nervous about sudden pressure loss making the hack all but unridable but it is not my experience so far.
Oh and I had to get a special hand pump rated to 600psi as I run between 300 to 400 psi. The shock is rated to 4000psi fail I believe.
I know this is about Beemers but the shock is applicable.
Cheers Bruce

[davebig]

I thought about it some more and remembered "half measures availed us nothing" called Ted Porter and fount the Yacougar fronts also have a 16mm shaft and steel body and ordered one of them also.DB

[claude]

I know there are many knowledgeble people involved in thsi discussion but for the newbies It is important for them to realize that there will never be a perfect shock under all conditions. What works will work but it can always be improved upon when conditions change. Establishing a decent baseline is a big plus and from there fine tuning can take place for conditions at hand and of course riding styles. If we all ran on the same surfaces all the time and with the same outfits and driving styles we could compare apples to apples a little easier. Good shocks are a good thing...personally my own outfit lacks good shocks in a huge way but it still gets around pretty well. Of course 'rebuildable' is aplus as well as options to change spring rates. The discussion of spring rates can also be apples to oranges of course. This is especially true on the sidecar itself as there are too many variables on how they are mounted as far as angle goes and where they are mounted on the actual swingarm in relation to the axle and also the length of the swingarm would come into play. A while back there were negative reports of progressive shocks failing on some sidecars. Much has to do with how the whock is mounted and so forth. To help alleviate the problem Some went to twin shocks. Was this th eanswewr? Who knows. We have yet to have a shock failure over there using asingle shocks even though we have had rigs in south america and south africa as well as one heading across russia and siberia soon. Will there be shock failures? Probably at some point as they are a mechanical device. Carry a spare? Not abad idea if one is in the true outback . Thanks Davebig...will be putting on your shocks soon.

[davebig]

There he goes again with his rational thought program !! Claude we're in a world of non mechanics who name their rigs and think problems stem from bad karma !
Your kinder than I am, they make me shake my head and wonder.
I wonder what a BMW engineer would think if you told him you where going to overload his tires, brakes and suspension by about 40-50% and you expected everything to work just dandy !!!!!!! LOLOLOLOLOLOL

[Bobmws]

Originally Posted by davebig

I wonder what a BMW engineer would think if you told him you where going to overload his tires, brakes and suspension by about 40-50% and you expected everything to work just dandy !!!!!!! LOLOLOLOLOLOL

He would say "Das ist sehr gut!", but deny it when the warranty people ask about it.........
apologies for incorrect grammer, way too many years since high school German.

[claude]

Boys and Girls we are sidecarists..and we are outside the box. Actually ( seriously whatever) we are looking more and more into other shock options moreso related to dual track vehicles. The cornering forces and handling characteristics we contend with in the sidecar world are different than in the solo bike arena. Also the ones who manufactiure shocks for solo bikes have their market and are good with that...and...rightfully so. Sidecars are NOT motorcycles and never will be. So...no slams here to the shock manufacturers at all but there may be better solutions to meet our known compromises than many of us are really aware of as of yet. How about that for a bunch of words that really said nothing? lol.