Front and rear sprocket bolts

[64duc]

 If you do not buy the bolts from Ducati, get either Grade 8 (I forget what the value is in metric) or a stainless steel bolt. If you get the el cheapo bolts, you may get the ones that will shear the heads off when you go to torque them down or when you go to take them back out.




 Metric equivalent to grade 8 is 10.2.  Elcheapo is 8.8.

[duckb0y]

If you do not buy the bolts from Ducati, get either Grade 8 (I forget what the value is in metric) or a stainless steel bolt. If you get the el cheapo bolts, you may get the ones that will shear the heads off when you go to torque them down or when you go to take them back out.

 Metric equivalent to grade 8 is 10.2.  Elcheapo is 8.8.

FYI, stainless bolts are ungraded, and therefore should be treated as weaker than grade 3.  I doubt that the bolts are undergoing any serious shear forces as they are only M5, but still, I would use grade 8 as corrosion should not be an issue in the highly lubricated front sprocket area.

[Ducatl]

FYI, stainless bolts are ungraded, and therefore should be treated as weaker than grade 3.  I doubt that the bolts are undergoing any serious shear forces as they are only M5, but still, I would use grade 8 as corrosion should not be an issue in the highly lubricated front sprocket area.

+1 to that, stainless is probably not the way to go.  Metric bolts are rated by class, class 10.9 is roughly grade 8 equal.  Zinc coated bolts do fairly well against corrosion.

[brimo]

Corrosion isn't really the issue nor is shear force during operation, as it is only holding the plate in position.
The tightening torque required is pretty low, it's only when you have to undo the bolt and as it's loctited in, may require a bit of force to undo and you may end up breaking the bolt. That is why a hightensile bolt is the better option and for only a couple of cents difference, why go the cheapo route?
As for that rear bolt, take a bolt out of the rear carrier, take it to a bolt suppliers and say "I want one of these". The average hardware store will not stock something like this so you need to find a specialist supplier in the phone book.
Read the torque settings thread for reassembling it all.

[Speeddog]

+1 on brimo's post.

[minnesotamonster]

I picked up and installed the stainless bolts already. Is it ok that I went with the stainless?

I'll do that with the rear. I believe there is a place near me that is a specialty store.

Thanks again for all the help   

[Desmo Demon]

FYI, stainless bolts are ungraded, and therefore should be treated as weaker than grade 3.

Come to think of it, I never really looked up the specs for stainless stell fasteners and compared them to carbon steel. I've just gone by the fact that I've never snapped the head off of a stainless bolt and have a difficult time cutting them with a hack saw or drilling a hole through them. I can easily cut and drill factory bolts, so just figured that the stainless ones to be a stronger replacement because of this.....and a whole lot cheaper.

And, yes, there are no real forces being exerted on those bolts. Your main concern will be that it will loosen and back off, as these did. You could "almost" get away with using a paperclip or safety wire in this application. I'm just used to getting grade 8 (10.9) or stainless bolts for a fraction of the cost of OEM and have made it a bit of a habit. I remember buying a set of bolts for front rotors and getting all of them for less than Ducati wanted for ONE bolt.

Some pretty good responses after my post. Made me think a little.


Edit: Interesting page on tensile strengths here - http://www.geocities.com/dtmcbride/home_garden/bolts.html

Looks like this site says 316 stainless is about the same strength as a grade 5 (8.8 ) medium carbon heat-treated steel. A 304 stainless is rated at 104,000 psi compared to 74,000 psi for a grade 2 low-carbon steel rating.

I like this page, too - http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

[duckb0y]

Come to think of it, I never really looked up the specs for stainless stell fasteners and compared them to carbon steel. I've just gone by the fact that I've never snapped the head off of a stainless bolt and have a difficult time cutting them with a hack saw or drilling a hole through them. I can easily cut and drill factory bolts, so just figured that the stainless ones to be a stronger replacement because of this.....and a whole lot cheaper.

Edit: Interesting page on tensile strengths here - http://www.geocities.com/dtmcbride/home_garden/bolts.html

Looks like this site says 316 stainless is about the same strength as a grade 5 (8.8 ) medium carbon heat-treated steel. A 304 stainless is rated at 104,000 psi compared to 74,000 psi for a grade 2 low-carbon steel rating.

I like this page, too - http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx

You probably never broke a SS bolt because it wasn't rusted into whatever you were taking it out of.  SS bolts can still get stuck in threads, as they have a tendency to gall, that is if you do not use anti-seize thread lubricant and the threads are not clean, you can actually weld the SS bolt into the hole.  This is due to the high hardness (which is the reason you have a hard time cutting SS).   Also, SS bolts are more likely to gall going into dissimilar materials, such as your engine case or steel gearbox output shaft, etc.  I work in an industry that uses stainless steel hardware exclusively, and we treat it as an ungraded bolt.

Basically what I am saying is shit yeah, I use SS hardware, but not on things that will cause me to die if the bolt breaks, or things that are highly loaded.  I think if its more than a 10mm bolt, I would leave it the stock material as it is probably load carrying.

Another thing to note, you don't want to use a bolt that is too hard or strong, because you could strip out the threads of the material you screwing into.  i.e. a grade 8 bolt into aluminum is a recipe for disaster.

[Desmo Demon]

You probably never broke a SS bolt because it wasn't rusted into whatever you were taking it out of.  SS bolts can still get stuck in threads, as they have a tendency to gall, that is if you do not use anti-seize thread lubricant and the threads are not clean, you can actually weld the SS bolt into the hole.  This is due to the high hardness (which is the reason you have a hard time cutting SS).   Also, SS bolts are more likely to gall going into dissimilar materials, such as your engine case or steel gearbox output shaft, etc.  I work in an industry that uses stainless steel hardware exclusively, and we treat it as an ungraded bolt.

Unless I use Locktite on the bolt, I use antiseize on everything. I have access to some really good antiseize in huge quantities.

You are also correct about the issues with galling (typically with aluminum or other soft metals) and galvanic corrosion caused by disimilar metals. In many situations, I will consult with a table of ionic charges to reduce the chance of galvanic corrosion. This is one reason why I try not to use high-carbon steels with aluminum and I use antiseize if I cannot get around it.

There is a lot of interesting and complex information that can be researched on galvanic corrosion and strengths of materials.