Center Stand bolt sheared...

[azcycle]

Thanks to Altritter, my r65 has been sporting a center stand for the last few months.  At the time, I purchased new mounting hardware including the bolts and one spring (didn't know there were two springs then).

For the past week, I had been noticing the bike leaning more and more to the right when it was on it's center stand.  When I got home yesterday, the right side of the stand was dangling, missing it's pivot bolt. When I got to to work this morning and parked in my normal spot, I found this lying on the ground... sorry for the bad cell phone pic:



The bolt sheared off.  I couldn't find the bushing piece so it must have rattled out of the frame on the ride home.  I'm going to buy some new bolts but before I do... Would you all consider this a "normal" thing or is there something wrong to cause the bolt to shear. Maybe I got a bad bolt... maybe I'm using too much force to get the bike on/off the stand? Just doesn't seem normal to shear off after two months of use.

Thoughts?

[Barry]

I don't think its that common for the bolts to shear.  

Maybe it was loose for a while and the shock loading caused it to shear.

[montmil]

Graeme, Were those the original bolts or do you have a reference? Could have been a stress riser in the bolt for an extended period and the shank finally failed. I've not heard of this happening before. The center stand bold passes through a shouldered bushing that reduces the shear loading on the bolt.

Just glad your scoot didn't fall over. I'd suggest you replace both sides with BMW OEM bushings and bolt hardware. Kinda of a PITA to swap stands. I put an easier to operate '83 stand on my '81 several weeks ago. Now much easier grunting that puppy up on the stand.

Monte

[Bob_Roller]

It's an overly common occurrence as far as I'm concerned .

The problem with the countersunk bolt/screw, is that there are shear forces in the threaded area, the bolt should have an unthreaded area, commonly referred to as the bolt 'shank' .

The bolt shears due to the forces being placed in the threaded area, with the threads in the bolt, it gives a concentrated force in a small area, instead of across a large unthreaded area .

Kind of like a piece of glass, you can bend it when it is free of any scratches without breaking it, but once you run a glass cutter over it, it now has an area where stress is concentrated in a small area, then the glass breaks along the scribed line with little force applied .

I got some bolts from work a few weeks ago, that look pretty close to the correct diameter, with an unthreaded area that should solve this problem .

I've had the bolts shear on my '81 about 6 times in almost 30 years so far .

I have spare bolts nuts and spacers on hand for when it happens again .

[azcycle]

Thanks all. Not the original bolts. Purchased them brand new from BikeBandit's OEM section in early June when I installed the center stand. The stand itself is an original that Altridder sent me.

I'll order some hardware (with extras), and make sure to check them routinely for any looseness.  I should have checked them when I first noticed the bike starting to lean, but I honestly thought the old stand may have been slightly bent so I didn't worry about it.

[Rob Valdez 79 R65]

Check these fasteners along with many others, once a year.

I lost one nut and sleeve (I think), but the bolt didn't break.

I've never lost another one.

It happened to me at a gas stop.  I went to put the bike on the center stand, and it started to fall to the right side!  I had to grab it quick and pull it back toward me.

(and if you saw the nightmare that I am fighting with my '74 Honda center stand pivot, you would have NO complaints!)

[trolle]

Melena had a nice way to deal with the heavy springs: When they are stretched out, place shims between the coils to prevent the springs to contract. This makes it much easier to install or dismantle the centerstand.

I used the trick last week when the nut on the right side had worked loose making the bushing fall out and disappear  

greetings from a cloudy and showery north

[azcycle]

Iron Horse didn't have any in stock but they'll be in tomorrow.  Got to get the stand back in order because I just received the rest of my tire-changing goodies.  Saturday is going to be dedicated to putting some new rubber on the r65.