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Shock bolts.

12K views 51 replies 28 participants last post by  FABSTER 
#1 ·
Anyone know what quality "hardness" the shock bolts need to be?
 
#2 ·
I believe they should be at least be grade 8. My stock bolts are "somewhere" in the garage and my chrome ones do not have any indication on them.
 
#9 ·
i broken enough shit to know what i can use as a fastener. the ONLY reason manufacturers use GRADE 8 or what ever they choose is because of liabilities. so they don't git there ass sued if some dumb ass can't ride/drive operate what ever the fastener is on......
 
#10 ·
i broken enough shit to know what i can use as a fastener. ....
Let's see how this line of logic holds up:

Doctor: "I've killed enough patients to ..."

Airline pilot: "I've crashed enough planes to..."

Chef: "I've poisoned enough people to..."

The OP asked a very simple question: What grade of fasteners are the shock bolts?

To answer this, you really have two options: If you know the (correct) answer. Or just spit out whatever nonsense pops into your head.

Please - just shut up on this subject. You posted bullshit. Quit trying to rationalize it.
 
#14 ·
drew wasn't the one i was trolling for but it worked just the same. :rofl::rofl:
 
#16 ·
I just replaced mine with 304 stainless socket heads. Polished up like chrome and never rusts. As for hardness and grade, they should be pretty close to the zinc plated junk. An M12 bolt torqued to 60-NM is well under its tensile strength, so softness is probably better.
 
#17 ·
Where did you buy them?
 
#18 ·
the stock shock bolts are high tensile bolts(cad plated), harley USED to make a chrome shock bolt kit, ( chroming high tensile steel will weaken it), they stopped this in 04. any grade of stainless steel bolt will not have the same properties as a high tensile bolt (they are too brittle). be careful what you choose! polishing the heads on the stock bolts every so often will keep them looking shiny without diminishing their properties.
 
#19 ·
the stock shock bolts are high tensile bolts(cad plated), harley USED to make a chrome shock bolt kit, ( chroming high tensile steel will weaken it), they stopped this in 04. any grade of stainless steel bolt will not have the same properties as a high tensile bolt (they are too brittle). be careful what you choose! polishing the heads on the stock bolts every so often will keep them looking shiny without diminishing their properties.
There is a baking process that will reverse the effects of hydrogen embrittlement of which you speak. Hydrogen embrittlement even happens during a hard chroming process which is commonly used in the aerospace industry. Just purchase chrome hardware from a quality manufacturer and ask if they peform a hydrogen embrittlement releif process.
 
#21 ·
I've had my shock bolts on and off prob 6-7 times without getting new ones..., changing swingarms. shocks, tires , belt guards etc.... Damn hope I dont have catastrophic failure....
 
#25 ·
when it comes to spension bolts, if you buy that chrome stuff,if there are no markings on the head, the are 0.0 grade. You can not go wrong with 8.8 hardware unless a certan
grade is speced.. There are a lot of times when you need to safety wire them, and you can get a jig (can i say that ) at an aircraft tool supply store. Do not go 130 and and fall down and then say "whoops", i know. spell check is not work'in
 
#28 ·
I have found that there is a lot more involved in selecting the proper hardware for a given application than one might think, especially for automotive or aviation applications. The good thing is that there is a wealth of easily obtained information on the web. I have attached a couple of pdf's of the 30 some that I have collected over the past couple of years for anyone who might be interested. I have also found the "Mechanics Toolbox" software a very useful source of information.
 

Attachments

#32 ·
shock bolt length

Does anyone knows if longer bolts (top ones) are needed with the progressive shocks due to the included spacers?
I had to change mine out. top and bottom. 80mm top & I think 70mm bottom? may have had to trim one on the bottom.

HD Pt.#
4603M 60mm
3074M 70mm
3713M 80mm
3379M 100mm
 
#35 ·
There is no way you would need better than 10.9 quality. The 6 bolts that hold the trailer hitch on my truck are 10.9 and the hitch is rated for 14k lbs. They are I think 12mm bolts. Your talking 500 lbs max on them static and maybe double that shock load. Shear strength on a 10.9 bolt the size of the shock bolts is easily over 10k lbs I have the chart somewhere around here if you want exact numbers. I would use even a lower grade such as 8.8 without thinking twice.
 
#38 ·
Chrome bolts for suspension componentry worry me due to hydrogen embrittlement (mentioned previously)
Many a hot-rodder has been killed using shiny chrome fasteners for the brakes and steering components. Use the correct grading bolt and paint them...it's about your life or someone elses if something goes wrong.

As for bolt stretch this is normally used by professional engine builders on conrod bolts as it's a good method for checking torque yeild (there are spec tables for this from the manufacturer of the bolt)

Over torque a bolt on a critical engine component (once) (conrod) and it's cactus. Bolts for the rear shocks are in shear whereas bolts for conrods are under tension.
This is a good reason to have a quality torque wrench and not something with a needle pointing at a number. Just take into account that the next time you buy a bolt for a specific function (brakes/steering) that 'shiny' is not always safe!
 
#39 ·
Chrome bolts for suspension componentry worry me due to hydrogen embrittlement (mentioned previously)
Many a hot-rodder has been killed using shiny chrome fasteners for the brakes and steering components. Use the correct grading bolt and paint them...it's about your life or someone elses if something goes wrong.
I hope you do not fly on modern airplanes, hard chrome is used in many components in the aerospace industry, including landing gear struts. If you are uncomfortable about the situation, please stay away from modern aircraft. There is a process to reverse hydrogen embrittlement, its performed after the plating process has been completed.
 
#40 ·
Tread lightly Sammy, there's little room here for 21st century technology and know how. sure you'll be getting a couple "You're a fokken idiot" post here shortly from the baby boomer crowd that's been wrenching since before you were a itch in your daddy's crawl.
 
#41 ·
Point taken, but I am a baby boomer myself! Although I still like to learn, just my memory is not what it used to be. At least from what I remember. Now what did I have for breakfast? :D
 
#42 ·
the forum seems to filled with a bunch of "my way is not only the best way, but it is the only way" folks lately. I think certain folks actually believe that everyone that uses SS bolts are getting them from Ace Hardware!
 
#45 ·
In my opinion, the design of the upper shock mounts is really Mickey Mouse, and the bolts are crappy. I weigh like only 190 pounds, never take a passenger, and everytime I have ever removed the upper bolts, they are bent. They go too far into and thru the frame and it allows slack where they bend. They should thread right into the frame, not go thru the frame then into a threaded mount. Also I put chrome shock bolts on with my chrome shocks, and they are soft, I have stripped four now upon installing and removing the back wheel due to those rear axle covers having to come on and off. The allen heads seem real soft. The original non chrome bolts seemed harder at the head, but still bent at the upper mount. Its still a great bike, but some of the chrome fasteners I feel are too soft.
 
#49 ·
Damn, my project is long done but the thread refuses to die!!! 12mm bolts are not easily available in chrome, seems most online shops stop at 10mm. I bought proper strength bolts new and had them chromed.

I ride 2-up quite a bit and have never bent a shock bolt.
 
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