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Need Help Sourcing Grade 8.8 Bolts

88bmwjeff

88bmwjeff

SF Bay Area
I need some help sourcing some bolts. I got some bar backs given to me, but a good portion of the hardware is missing. The hardware is M8, grade 8.8 bolts. Both 25mm and 30mm in length. These bolts would have the round, "socket" style heads. While I have found similar size bolts at the local hardware store and online, I cannot find them in grade 8.8. These bolts are visible, so bolts with anti-corrosion coatings is preferred. FYI, I've contacted the manufacturer (SW-Motech), and they do not sell replacement hardware. Does anybody have some suggestions on where to purchase them?
 
I will also suggest McMaster-Carr as a good source for small special (e.g. metric, stainless) fasteners. This won't be as cheap as perhaps the local hardware store, but you should be able to find the length, thread pitch, fastener diameter, head type, and rating desired. The turn around time has been pretty rapid in my experience.

Some other sources, particularly for larger batch purchases that I have used have links below -

https://www.albanycountyfasteners.c...By=bestsellers&f_system_of_measurement=Metric

https://www.metricmcc.com/

https://belmetric.com/
 
Thanks everyone. I looked at the McMaster Carr site prior to posting. The other sites are good to take note of. However, this is where my limited knowledge comes into play. While I am familiar that bolts have grades, I'm not familiar enough to know which grade would be inferior to or superior to an 8.8 grade bolt. That being said, none of the 8.8 grade bolts at McMaster Carr site are sufficient (That doesn't mean they do not have a bolt that would work--It just means that I don't know which bolt that would be.). This also applies to the other sites. So, if anyone has suggestions, I'm hear listening.

FYI, the bolts should be torqued to 23 nm or ±17 ft lbs.
 
FYI, I looked into stainless bolts and 316 Stainless has tinsel strength of 70,000 PSI, while 8.8 bolts have tinsel strength of 120,000 PSI. Both BMW and the manufacturer of the bar backs (SW-Motech) use grade 8.8 bolts for that location/use. As such, I'm sticking with what the manufacturers have provided, which is 8.8 bolts. I'm assuming that both BMW and SW-Motech did the appropriate analysis and concluded 8.8 bolts were required. While it may be a long shot that a bolt would break, I'd rather spend a little more on the bolts than to risk the possibility of a broken bolt that needs to be extracted.
 
FWIW, I just bought 8.8, 1.50 pitch bolts and a few grade 10 nuts at the local hardware store- in the Midwest pull-out draw section.
I have to take a known fitting bolt/nut with me to ID the threads and match from there.
OM
 
88bmwjeff said:
FYI, I looked into stainless bolts and 316 Stainless has tinsel strength of 70,000 PSI, while 8.8 bolts have tinsel strength of 120,000 PSI. Both BMW and the manufacturer of the bar backs (SW-Motech) use grade 8.8 bolts for that location/use. As such, I'm sticking with what the manufacturers have provided, which is 8.8 bolts. I'm assuming that both BMW and SW-Motech did the appropriate analysis and concluded 8.8 bolts were required. While it may be a long shot that a bolt would break, I'd rather spend a little more on the bolts than to risk the possibility of a broken bolt that needs to be extracted.
Click to expand...

8mm 1.25 x 25mm Allen heads, 170000 psi tensile, your choice of anti corrosion coatings

The same in 30mm

These are stronger than 8.8 bolts. You will probably never find an 8.8 Allen head at any hardware or home improvement stores /sites. Belmetric may have them—I haven’t checked their site—and their advantage is that on many items they will pick and ship smaller quantities.

Best,
DeVern
 
Jeff,

Just to keep things realistic here, you need to think of the application. What are these bolts screwing into. If it is your GS, that would be ALUMINUM. In almost any conceivable situation, it’s going to be the aluminum that fails first no matter what grade bolt you use. The bolts are stressed in a clamping direction only so the aluminum threads are the limiting factor. The threads will pull out before the bolt breaks.

Your RT uses steel nuts and the bolts are stressed in a more bending situation. A stiffer bolt MAY be of some advantage.




:dance:dance:dance
 
Last edited:
98lee said:
Jeff,

Just to keep things realistic here, you need to think of the application. What are these bolts screwing into. If it is your GS, that would be ALUMINUM. In almost any conceivable situation, it’s going to be the aluminum that fails first no matter what grade bolt you use. The bolts are stressed in a clamping direction only so the aluminum threads are the limiting factor. The threads will pull out before the bolt breaks.

Your RT uses steel nuts and the bolts are stressed in a more bending situation. A stiffer bolt MAY be of some advantage.




:dance:dance:dance
Click to expand...

FYI, This is for the 2018 R1200 GS.
 
GTRider said:
8mm 1.25 x 25mm Allen heads, 170000 psi tensile, your choice of anti corrosion coatings

The same in 30mm

These are stronger than 8.8 bolts. You will probably never find an 8.8 Allen head at any hardware or home improvement stores /sites. Belmetric may have them—I haven’t checked their site—and their advantage is that on many items they will pick and ship smaller quantities.

Best,
DeVern
Click to expand...

Yep, these are the bolts I will probably get. Of course, now I need to figure out Zinc-Plated, Zinc-Flake Coated, Zine-Aluminum Coated. I have no idea between them. :banghead I feel like I'm making a mountain out of a mole hill, but I'm not that knowledgeable about the differences in bolts.
 
McMaster Car shows a complete line of metric 8.8 bolts in socket head. Just get a finish not prone to rusting, so don't get black oxide bolts.
 
88bmwjeff said:
I need some help sourcing some bolts. I got some bar backs given to me, but a good portion of the hardware is missing. The hardware is M8, grade 8.8 bolts. Both 25mm and 30mm in length. These bolts would have the round, "socket" style heads. While I have found similar size bolts at the local hardware store and online, I cannot find them in grade 8.8. These bolts are visible, so bolts with anti-corrosion coatings is preferred. FYI, I've contacted the manufacturer (SW-Motech), and they do not sell replacement hardware. Does anybody have some suggestions on where to purchase them?
Click to expand...

i would also look to see if you have a fastenall or HTF or some other local hardware supplier ( usually you can go in and pick your own, just make sure they don't go looking for Grade 8 hardware for you cause you will end up with completely too much bolt. Last time I called one up for some missing hardware on my bike they were kind enough to give me a "sample" for free instead of going through the hassle of setting up an account. That probably only works if you work for some industrial style company but never hurts to get free parts.
 
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