And Another Bit Breaks....

Tornado

Tornado

VIP MEMBER
Joined
Dec 5, 2017
Messages
4,865
Country flag
And Another Bit Breaks....


At mid point of a 160 mile ride, stopped for fuel up and as i swung KS out, the stand went limp. Short end hanging off stand bracket hole. Long end hanging down from bike frame hole.

I'm pretty sure this was an RGM stainless spring, in use for 3 or 4 yrs. Counting myself lucky it did not let go while riding.
 
Do not condemn stainless hardware out of hand. Just like any steel, there are various grades. There are plenty of 'regular' steel bolts that have the strength of mildly aged cheese. Some are not so marked. You want
steel bolts that are the real deal then buy aircraft and pay the price.
Specify the grade. After all, look at Space X and their big SS ship.
 
Onder said:
Do not condemn stainless hardware out of hand. Just like any steel, there are various grades. There are plenty of 'regular' steel bolts that have the strength of mildly aged cheese. Some are not so marked. You want
steel bolts that are the real deal then buy aircraft and pay the price.
Specify the grade. After all, look at Space X and their big SS ship.
Click to expand...
Was about to say something similar myself - people who condemn all stainless are just demonstrating their ignorance of grades - just like carbon steels.
There's a reason ARP choose stainless for their high tensile, excellent hardware.
 
@Tornado is talking about a spring, not a bolt! Yes, there are various grades and materials used in stainless bolts and some of them fall between the various grades of steel bolts.

Generally, stainless is harder than non-stainless. AFAIK, more hardness is not great for springs. Original, 50-year-old side stand springs don't tend to break in the middle! I have no idea if it broke due to being stainless, or had a bad spot in the metal, or was rubbed by something, but I am sure it has nothing to do with bolts!

I agree with @ashman. Steel formulated for springs (i.e., spring steel) is what you want for springs!
 
I would never use stainless steel on a British bike - it is out of character. Many parts used to be cadmium plated, however cadmium is poisonous, and zinc is less corrosion resistant. Steel which is used for springs is totally different from stainless steel. Stainless steel usually contains less than 80% of iron. Spring steel contains well above 90 % iron, and responds differently to heat treatment. Cadmium or zinc plated parts can suffer from hydrogen embrittlement, if not baked in an oven after the plating process. When they are under tension, they can simply fail and break.
It is really strange how I presume other people know what I know. I would have thought most of you would have known about this stuff. However I worked with plating shops in two factories making bits for aircraft and missiles.
 
Last edited:
When I made the primary chain cover for my Seeley, I simply got a strip of mild steel, and fitted it around the chain, the got a local guy to weld the ends together and add four tabs for Dzus fastener springs. I took it to Albury, and got it zinc plated and chromate passivated. I showed it to the guy who welded it. He had never seen that finish previously. It was used on the parts which were inside the doors of every old car. However I outsmarted myself. I got a speck of battery acid on it, and it fizzed. I need to rub some wax on it. The four Dzus fasteners hold an aluminium cover to the steel strip. You can see it in my avatar.
 
Last edited:
gpzkat said:
Stainless vs carbon steel - reminds me of the Air Moorea flight crash. I rode that Twin Otter 1 year before it went down. It was clapped.

en.wikipedia.org

Air Moorea Flight 1121 - Wikipedia

en.wikipedia.org en.wikipedia.org
Click to expand...
Interesting read!

Redundancy, we don't need that! Change the material of a critical component and not the checking schedule - why bother?

Even though the investigation didn't (it seems) end with a root cause, it did find many causes one of which was using stainless to solve one problem without thinking about the consequences.
 
marshg246 said:
I have no idea if it broke due to being stainless, or had a bad spot in the metal, or was rubbed by something, but I am sure it has nothing to do with bolts!
Click to expand...
The spring DEFINITELY rubs on the stub of the pivot pin. That was the first thing I thought of when I saw your photo.

It was top of mind because I just repaired the one on my monoshock bike.
 
OP is right in their observation of being lucky the spring didn't let go while riding. A kickstand in the down position almost put me into a tree.
 
marshg246 said:
@Tornado is talking about a spring, not a bolt! Yes, there are various grades and materials used in stainless bolts and some of them fall between the various grades of steel bolts.

Generally, stainless is harder than non-stainless. AFAIK, more hardness is not great for springs. Original, 50-year-old side stand springs don't tend to break in the middle! I have no idea if it broke due to being stainless, or had a bad spot in the metal, or was rubbed by something, but I am sure it has nothing to do with bolts!

I agree with @ashman. Steel formulated for springs (i.e., spring steel) is what you want for springs!
Click to expand...
And the best knives are made from carbon steel.
 
Lineslinger said:
OP is right in their observation of being lucky the spring didn't let go while riding. A kickstand in the down position almost put me into a tree.
Click to expand...
Has anyone come up with a failsafe to keep KS or CS up if spring fails? Something like a strong magnet or one of those hardware store clips for holding brooms etc to a wall?
 
Tornado said:
Has anyone come up with a failsafe to keep KS or CS up if spring fails? Something like a strong magnet or one of those hardware store clips for holding brooms etc to a wall?
Click to expand...
I think you’re over thinking it. Just replace it with a none stainless spring and keep your eye on it for any signs of rubbing etc.

If you’re still unsure, just replace it every 5 years or so for peace of mind.
 
Tornado said:
Has anyone come up with a failsafe to keep KS or CS up if spring fails? Something like a strong magnet or one of those hardware store clips for holding brooms etc to a wall?
Click to expand...
When you worry about things or over think things then it will happen.
 

Similar threads

lcrken
  • Locked
And Another One (Sprag) Bites the Dust
Replies
7
Views
1,078
EstuaryBoy
EstuaryBoy
Old Bloke
  • Locked
And another Camshaft identification question.
2
Replies
22
Views
1,937
batrider
batrider
Back
Top