Just got back from the Nindigully trip and noticed the lower shockie mount stud was bent

Any ideas will be given due consideration. I am even thinking a 14 or 15mm stud but that means changing the shockie as well.
My wife's K75 has broken a stud I have broken one that was made from material that was heaps stronger than OEM and now I have bent this one after only 12 months and 8000km.
WTF do I have to do.

Will post a photo shortly of a brace we use.
peter J

Get someone to make one of these, this is a rough one I made years ago.
Sorry about the focus
Bolts onto 2 of the s/arm to f/drive bolts & the outside of shock mount
Never bent a bolt on over 180,000 klm of side car use.

It's a paralever rear drive. I wish it was that simple.

Hi there, I´ve been reading about the stud issue and there is one thing in my mind, the stud is not designed to take the bending/shear stress, it is supposed to be torqued enough that the bending and shear stresses are taken by the shock´s head and nut due to he torque´s axial pre-load, under that condition the stud will be only under axial stress.
So if the stud is not properly torqued it will fail. Under torque will not achieve the required pre-load. Over torque will stretch it plastically loosing the required pre-load.
To guarantee that you can give the correct tension (torque) to the stud, and you dont run out of threatened length, the original design is a full threated one, as there is a friction connection there will be no lateral contact with the shock´s head.
Just my thoughts
Best regards
JAP

RicK G wrote:It's a paralever rear drive. I wish it was that simple.

Sorry for that.

You can still make one for paralever, I have seen them fitted.

make a steel 'C' that fits around the bulge below the stud, (can be lined with rubber)
with a piece that goes up wards to fit on to the end of the stud to support the stud end.

Hope you can follow that, I do not have a photo or drawing.

Peter J

I have been having a search around and came across some ideas that were actually for a sway bar for a K1100 with a chair and had a close fitting section and attached to the end of the shockie bolt and down to the anchor arm bolt as well.  I got an idea from that so I might build a roughie and try it
I might get ROE to do it (Rick's Over Engineering)

I finished up getting some 12mm 8.8 bolts with a non-threaded shoulder. Cut the head off. Cut the threaded section to the required length, so that it is a snug fit in the FD housing, but not bottoming out. I then cut a thread from the head end the required distance, so that the shock mount has a non-threaded smooth surface to pivot on. I made mine long enough to accept Sidecar Paul's brilliant piece of metal bashing outer support. I also drilled a hole through the bolt for a split pin to ensure that the Nyloc nut WILL NOT come off. Screwed the stud in using a couple locked nuts, with some Loctite.

I believe that if the shock eye is allowed to move away from the FD housing, more bending moment is available. This is what caused mine to fail on the Bingara trip...the retaining nut had backed off and allowed the bottom of the shock to move away from the FD housing.

The "down side" I can see SCP's support plate is that is able to "slide" towards the rear of the housing. But, I believe it is better than nothing.

I am making a similar thing but for the paralever drive which has not got a flat area where the support can rest.

Whats that bit of the F/D made of? if it doesn't have delicate internals right there, couldn't you weld a shoulder where you need it to carry a bracket like the 100s do??

I never had this problem, but please bear with me. How can you get a bent bolt if all is tightened good? The bolt should only be under sheer stress, as the swing arm bearings and frame will only allow minimal lateral relative 'disposition' (frame bending a bit) and therefore remain in line. If there was any lateral movement I'd expect the strud to take it up. If the bolt can get bent like that isn't that indicative of having problems elsewhere (loose wingarm bearings/frame cracks/bents)? Just wondering...

The lower bush on the shockie is rubber with a very thin steel bush and there is no way to lock the stud very well.
A shockie with a ball joint would be a much better proposition.
This seems to be very much a problem in Australia most likely because of our crap roads. In the Nindigully thread I said that on the Sunday I travelled on the worst bit of sealed road ever 40km of potholes joined by patches and corrugations. 

Keith it has a needle roller bearing right under it, 5-6mm of alloy.

Been working on a thing to give it some support and will be selling the Koni and getting a RAM with a ball joint.

Been working on the mark 2 version today. The mark 1 version went in the bin.

Ulrich_Grabau wrote:I finished up getting some 12mm 8.8 bolts with a non-threaded shoulder. Cut the head off. Cut the threaded section to the required length, so that it is a snug fit in the FD housing, but not bottoming out. I then cut a thread from the head end the required distance, so that the shock mount has a non-threaded smooth surface to pivot on. I made mine long enough to accept Sidecar Paul's brilliant piece of metal bashing outer support. I also drilled a hole through the bolt for a split pin to ensure that the Nyloc nut WILL NOT come off. Screwed the stud in using a couple locked nuts, with some Loctite.

I believe that if the shock eye is allowed to move away from the FD housing, more bending moment is available. This is what caused mine to fail on the Bingara trip...the retaining nut had backed off and allowed the bottom of the shock to move away from the FD housing.

The "down side" I can see SCP's support plate is that is able to "slide" towards the rear of the housing. But, I believe it is better than nothing.

Having the non threaded section is not as important as you may think because the sleeve inside the rubber is clamped tight and any movement is taken up by the rubber so the shock doesn't actually move on the bolt.

Would the sheer value on the caliper mounts be to high to carry a bracket to the shockie mount even if it had a foot to rest on the F/D below the shockie mount??

I did think of picking up a bolted point there but they are a long way of so would require a fairly solid bracket.
The one I have been working on today has 2 feet that mount onto the flat area back and front of the stud and comes down to the angled section below the nut and that prevents it wanting to fold under when the weight comes down onto it and just fits on the extended stud.  I did think of making a taper seat like a wheel nut and it may still get that.
I reckon it will work ok well at least be good enough to be worth a try.

Probably not inexpensive but why not look at getting a shock stud made out of better metal with better shear strength and less plasticity, like titanium.

Yes that would be lighter as well, um just a U shape with the bottom conforming to the F/D and held by the shockie mounting bolt, making it lock in.

K75cster wrote:Yes that would be lighter as well, um just a U shape with the bottom conforming to the F/D and held by the shockie mounting bolt, making it lock in.

Yes that works quite well on a few side cars & solos that I know of that have done quite a few Klm.

Peter J

I have just finished the prototype which will be the finished article soon. It fits very well after some grinding and work on the linishing belt. Don't think I will need a tapered seat on the nut but time will tell, It pulls in really tight and lifts the stud about 5-6 thou as it comes in.

Man that was quick all done in half a day.

It took half a day to stuff up the mark1 version 

I was wondering, in the initial pic I see a bent full thread, It occurred to me that a shoulder on the thread that ensured the bolt didn't actually bottom and being of similar thickness at to imitate a washer of 5mm thickness would allow the shockie stub to be firmly set in place and the shock to be mounted with a solid unthreaded post that could be threaded only to ensure the shock was locked in place, would in principal give greater resistance to bending. Would such a pin create greater chance of it sheering like Rickmiesters, without notice or just bend like RickG's the shoulder being 5mm thick shouldn't offset the shockie by too much maybe a turned down 18 to 20mm bolt would do it.

You are describing the one that broke 12 months ago. How did you know what it looked like?  

The rolled thread on the stud that is going in is quite a bit stronger than the lathe cut thread that was on the previous bolt.  I would prefer to have the rolled thread there, they are far less likely to break but bend as the current stud did.  If it had been lathe cut it probably would have fractured at the bottom of a thread.

I actually sheered off my lower shock mounting stud. I was doing about 55MPH on a steep downhill that suddenly changed to a steep uphill. The sudden compression of the shock must have snapped it, and next thing I knew, I had a low rider. Had to travel the rest of the way home standing on the pegs to keep the fender off the tire. Not fun and silly looking, too.

There has been a few go just among the guys on this forum. I don't think there are many in Australia that have not had the experience.
What are the roads like where you ride. Once we get away from the coastal strip where the vast majority of the population is the roads are appalling and the one I was on last weekend was the worst of all
When mine broke I had just come out of some twisties and bang down it went, quite a surprise fortunately I was on the road verge when I stopped and to make things good a mate was following in his work truck with all the gear to fix it and I had a spare stud. My luck didn't hold as that afternoon I broke a valve then I was waiting for number three but it didn't happen.

Rickg I must of read about it here 

The finished article just in case someone needs to copy it

Does it come in other colours?

ainsjac wrote:Does it come in other colours?

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