800GS shock bolt design flaw?

Aren't we all Rob?

This is a world wide public forum, unless you want spam and such, you might want to edit your post and send your personal info via PM.

FYI Wilbers top mount looks like this.

And this, and seems to be a one piece bush. Not sure what the groove in the inside centre is for.

Same as my the Elka, Hyperpro and Ohlins shocks. Two piece bushing. You may want to get one of Indy's kits depending on your riding style.


Pics of mine.
http://www.advrider.com/forums/showpost.php?p=12393008&postcount=763

Actually the bush seems to be one piece, or if not it must be joined together in the centre somehow. I can't turn the two halves separately, will have to wait until I can remove it to be sure.

Yes indeedy Indy's fix is on it's way, just sorting out sizes, the bush is 22mm OD, 12mm ID and 39.9mm long.

Hey Mike,

Those are 2 piece bushings when you pull them out from both ends you will find a spherical bearing inside that has a 26 mm O.D. You will press that out from one end only. There may be a clip to remove as well.
Then you press in my 26mm O.D. Bearing until it hits the 24mm shoulder and install the shock with the rest of the kit. It will all make sense when you put one of the bushings in a vise and pull the shock away revealing the spherical bearing behind the 2 bushing halves.

Thanks Indy I am sure it will be a no brainer, just got to get my head around it and some shed time.

Hey Mike, I just installed mine, no worries at all. PM me if you want some help.

Is there a trick to getting the retaining clip for the spherical bearing out? I'm looking at my Hyperpro, and it's not the regular circlip style jobbie, there's no holes to pinch it out.

It is a 6 beer pain in the butt to get the Hyperpro clip out to press out the bearing. Try and get a real small drill bit to put a small hole in the clip on one end so you can get something to hook onto. The pick and mini screwdriver method took me an hour to get it out of the shock.

I've got about 800 miles on my upper shock bolt setup (stock BMW/Sachs shock w/Hyperpro spring, Ralle-Moto brace, BMW upper bolt grade 10.9). Today I pulled out the bolt to see how it's holding up. I'm happy to report that my bolt was straight as an arrow. I've ridden hard these last 800 miles, and over many things which put this setup to the test fully. These include:

-The wrecked and potholed streets of Minneapolis which include potholes that are 2-3 feet in diameter and 3-5 or more inches deep.... ridden at speed and slow. (ya can't avoid 'em. It sucks. The city is finally getting around to patching some of them, but there's still a ton)

-lots of gravel roads, some with exceptionally f*#@ed up bumpy sections.

-a few 2-track farm trails. All of which were gnarly, and tested this setup to it's fullest. One trail I'm remembering from a couple weeks back, had these HUGE whoop sections (I'm assuming formed from the farmer driving his tractors to and from the field). I felt the suspension using it's full travel through these sections. I may have even bottomed the rear over one of the whoops, because earlier before the ride I had stupidly forgotten to crank the preload up, making the shock exceptionally soft. (this one in particular is what sprang me to check the bolt today)

The Ralle-Moto brace seems to be working quite well at supporting the upper shock bolt. At least with my stock shock fitted with a Hyperpro spring. Oh and btw, I've always used a torque wrench and properly torqued the bolt to 100Nm, using no thread locker as the service manual states. I do, however, use a greased washer under the head of the bolt.

I'm pleased so far. And Indy, if I buy an aftermarket shock, I'll be getting your kit! Over and out.

I've been running the stock shock while the Ohlins has been getting re-worked.
The frame looks to be straight. Top bolt is pretty straight. The bottom bolt is another story. I'm going to a 12.9 lower bolt.
The Ohlins will be back on the bike this week w/ Indy's kit.
I may bore out the RM brace. I'm not sure there will be enough material left to be effective.

You bent the bottom bolt??:huh

That bolt span is only as wide as the bottom shock eyelet! That had to have been from the Ohlins. Does the Ohlins run the same multi-piece eyelet design on the bottom too or something??

Whatta thread!

I got to thinking about the slightly bent lower bolts that I see on 1150s. Very slight; just enough that I can sense a bit of wobble as it unscrews. It's another one of those systems where the cylindrical bolt head provides some support.

John, I think the 12.9 bolt might help with the bottom due to the shorter span. I don't see it having much effect at the top, though. The higher grade means there's a higher yield strength which means the bolt can flex more before it's plastically deformed, but the 'springiness' is the same which means the amount of deflection is the same. In an application where everything recovers from that deflection, it helps. Typical bottom shock bolt comes to mind. But where something else suffers from that deflection, that something else is still going to get damaged. The frame tabs, the mating surfaces of the Ohlins bushing halves, etc.

In fact it would be illuminating to inspect the Ohlins bushings after a severe bending event. You have two sleeves fitting fairly tightly into the eye. If that system flexes because it's less rigid than the stock shock's single bushing, where is the deflection happening within those three parts? Does one bending event damage those parts so that they offer less support afterward?

Increasing the diameter of the beam (the Indy fix) looks like the way to go as long as there's no need for the angular flex that you're losing by eliminating the original shock eyes. I kind of wonder if there's a piston wrist pin out there that's the right dimension...

Thanks for sticking with this and being civil.

Gadget Boy has asked me to move my "Vendor related" posts and answers to another thread found in the Vendors section:

http://www.advrider.com/forums/showthread.php?t=580250

Future inquires for the kits can be posted in that thread or PM me.

Thanks.

Bottom bolt bent w/ the stock shock and the Ohlins.
I won't waste my time buying from BMW anymore.
I'm also getting tired of replacing the Ohlins spacer bushings every time a bolt bends.

Hopefully this is all behind me now.

well you can add me to the bent bolt club! Finally got a new shock for my bike and took out a wobbly bolt from the old shock. I see tt has a heavy duty bolt has anyone tried that? just read thru more of this thread and was wondering if indy has any parts left for his fix as i think thats a pretty good idea!

You'll be golden if you're running the stock shock w/Hyperpro spring, Ralle-Moto brace, and grade 12.9 bolt.

If you get any bending with that setup, I'd be utterly shocked.

So to speak . . .

Yes, I do.
I am now offering a kit for the lower bolt as well for the guys that really ride hard off road.

Post at http://www.advrider.com/forums/showthread.php?t=580250 or PM me