***At last: Stainless Fastener Kit for 1200GS***
- Thread starter davedyer
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seems a bit expensive for 5 bolts
Sorry if this sounds like I'm a party pooper, but . . . .
What specification is the steel?
Beautiful shiny bolts, but if they're made of 'cheese' they may not so what you think they're supposed to do w.r.t. securely holding critical parts of your bike together when the going gets tough.
What specification is the steel?
Beautiful shiny bolts, but if they're made of 'cheese' they may not so what you think they're supposed to do w.r.t. securely holding critical parts of your bike together when the going gets tough.
davedyer
Registered user
I've emailed him to find out.
Surely the steel fasteners, stainless or otherwise, be stronger than the alloy they're screwed into and are therefore unlikely to fail before the alloy lets go?
Dahoum
Registered user
Sent a question on ebay as well. Most items are not too critical but I would be wary of replacing caliper or disc bolts without some detailed information.
davedyer
Registered user
Just got this reply from Chris Shaw:
"Hi Dave,a mixture of A2 & A4 grade stainless is used in these kits. As a family we have been supplying these to Motorworks and Moto-Binns for the last 20 years and have not received any negative feedback.
If you require anything further please visit my website: www.shawstainless.co.uk.
Many thanks for your interest Chris"
On doing some digging I also found this off the Aprillia forum from someone who queried a fastener supplier:
"Dear Sir,
Thank you for your enquiry. Most nuts and bolts are standard High Tensile
Carbon Steel. In general, High Tensile Carbon Steel Bolts have a term such
as '8.8' stamped on the head (other examples are 12.9 or 6.8). A2 stainless
steel, such as the bolts that we stock, are not as strong as 8.8 high
tensile carbon bolts, and are thus not recommended in strength critical
applications as a replacement for the stronger carbon steel fasteners.
You may also have heard of A4 stainless steel. There is a common
misconception that A4 stainless fasteners are stronger than their A2
equivalent and have a similar strength to 8.8 carbon fasteners.
The difference between A2 and A4 stainless is not its mechanical properties
but its chemical composition. A4 is generally for marine applications where
its extra corrosion resistance is required for the constant splashing of
corrosive salt water. A2 provides sufficient corrosion resistance for most
applications.
Our fasteners are A2-70 grade. The 70 signifies that the Ultimate Tensile
Strength is at least 700 N/mm^2. More importantly: the stress at which A2-70
begins to yield is at least 450N/mm^2. A4-70 has exactly the same ultimate
tensile strength and yield stress.
Standard carbon steel fasteners are generally 8.8 grade. The first figure
signifies that the Ultimate Tensile Strength is at least 800N/mm^2. The
second figure signifies that the fastener will begin to yield at 80% of the
Ultimate Tensile Strength, ie at least 640N/mm^2.
To get similar strength stainless fasteners you would require A2-80 or
A4-80 where the yield stress is 600N/mm^2. There are significantly fewer of
these on the market as A2-70 are sufficient for the majority of
applications. In practice fasteners generally fail due to the excess load
applied to them when they are assembled not when used in operation. It is
these A2-80 or A4-80 bolts that are supplied in stainless brake kits.
If you are replacing 8.8 carbon steel fasteners I would recommend that you
purchase A2-80 or A4-80 (or even A4-100 if you can find them) for your brake
discs/forks/callipers which, unfortunately, we do not stock.
I too have replaced the original fasteners on my motorcycle with A2-70
stainless items even in strength critical areas though I would not recommend
that you do the same.
I hope that this makes the situation clear. Please email me if you have any
further questions.
Many thanks,
I've emailed Chris Shaw asking if his SS is A2/A4-80 grade.
"Hi Dave,a mixture of A2 & A4 grade stainless is used in these kits. As a family we have been supplying these to Motorworks and Moto-Binns for the last 20 years and have not received any negative feedback.
If you require anything further please visit my website: www.shawstainless.co.uk.
Many thanks for your interest Chris"
On doing some digging I also found this off the Aprillia forum from someone who queried a fastener supplier:
"Dear Sir,
Thank you for your enquiry. Most nuts and bolts are standard High Tensile
Carbon Steel. In general, High Tensile Carbon Steel Bolts have a term such
as '8.8' stamped on the head (other examples are 12.9 or 6.8). A2 stainless
steel, such as the bolts that we stock, are not as strong as 8.8 high
tensile carbon bolts, and are thus not recommended in strength critical
applications as a replacement for the stronger carbon steel fasteners.
You may also have heard of A4 stainless steel. There is a common
misconception that A4 stainless fasteners are stronger than their A2
equivalent and have a similar strength to 8.8 carbon fasteners.
The difference between A2 and A4 stainless is not its mechanical properties
but its chemical composition. A4 is generally for marine applications where
its extra corrosion resistance is required for the constant splashing of
corrosive salt water. A2 provides sufficient corrosion resistance for most
applications.
Our fasteners are A2-70 grade. The 70 signifies that the Ultimate Tensile
Strength is at least 700 N/mm^2. More importantly: the stress at which A2-70
begins to yield is at least 450N/mm^2. A4-70 has exactly the same ultimate
tensile strength and yield stress.
Standard carbon steel fasteners are generally 8.8 grade. The first figure
signifies that the Ultimate Tensile Strength is at least 800N/mm^2. The
second figure signifies that the fastener will begin to yield at 80% of the
Ultimate Tensile Strength, ie at least 640N/mm^2.
To get similar strength stainless fasteners you would require A2-80 or
A4-80 where the yield stress is 600N/mm^2. There are significantly fewer of
these on the market as A2-70 are sufficient for the majority of
applications. In practice fasteners generally fail due to the excess load
applied to them when they are assembled not when used in operation. It is
these A2-80 or A4-80 bolts that are supplied in stainless brake kits.
If you are replacing 8.8 carbon steel fasteners I would recommend that you
purchase A2-80 or A4-80 (or even A4-100 if you can find them) for your brake
discs/forks/callipers which, unfortunately, we do not stock.
I too have replaced the original fasteners on my motorcycle with A2-70
stainless items even in strength critical areas though I would not recommend
that you do the same.
I hope that this makes the situation clear. Please email me if you have any
further questions.
Many thanks,
I've emailed Chris Shaw asking if his SS is A2/A4-80 grade.
I got the same answer as davedyer, interesting to see the response to the second question.
Stop worrying, i sell a kit for the 1150GS [URL="http://www.ukgser.com/forums/showthread.php?t=87583"]HERE[/URL] never been any problems, plus i've had A2 stainless fitted to all my bikes for the last 25 years , including calipers and discs.
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DavidHale
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I've got one of those kits and, hand on heart, theres no corrosion on any of the bolts. Not that I can see through the packet in the garage, anyway.
Why bother 
davedyer
Registered user
I think Steptoe probably has the right idea.
Here's the latest reply I've got from Chris when I pressed him about the tensile strength of the SS he uses:
Hi Dave, I believe the stainless being used is A2/A4-70, however a lot of time and research has been crried out to ensure that the strength of these are sufficient for the applications they are used for as an earlier comment on the forum says "the most stress these bolts are under is when they are tightened". Once again I would like to say that this family business has been supplying kits for other BMW bikes for over 25 years and we have never had any negative feedback about any bolts supplied and we are 100% confident about the products that we supply.
As you can see from the website we also supply wheel spindle's and these are not just manufactured from any stainless bar that is available, they have been vigorously tested by a university to ensure that the correct grade is used.
Once again many thanks for your interest.
Chris
Here's the latest reply I've got from Chris when I pressed him about the tensile strength of the SS he uses:
Hi Dave, I believe the stainless being used is A2/A4-70, however a lot of time and research has been crried out to ensure that the strength of these are sufficient for the applications they are used for as an earlier comment on the forum says "the most stress these bolts are under is when they are tightened". Once again I would like to say that this family business has been supplying kits for other BMW bikes for over 25 years and we have never had any negative feedback about any bolts supplied and we are 100% confident about the products that we supply.
As you can see from the website we also supply wheel spindle's and these are not just manufactured from any stainless bar that is available, they have been vigorously tested by a university to ensure that the correct grade is used.
Once again many thanks for your interest.
Chris
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