Posted on the RANSbike owners forum:
 
My name is Mark Pippin. I am the product manager for chains at SRAM Corp. I  
was forward your e-mail a couple of weeks ago. Sorry for not getting back to you  
earlier, I have been on the road. Let's see if we can answer some of your  
questions.  
Re: Riveting Process The goal of a riveting process is to deform the metal  
rivet to prevent the opening of the chains side plates under load. The ways that  
you increase the strength of the chain riveting process is by A) increasing the  
displaced amount of metal of the rivets and B)the thickness of the outer plate.  
Re: Rivet Types: At SRAM we use 5 different levels of riveting. 1)Standard  
Rolled Rivet: The fastest, cheapest, and least strong riveting. What happens  
here is that the chain is pulled thru a set of round dies that deform the  
rivets. This is used on single speed non-derailleur bikes. It also has the  
tallest rivets, and receives the least amount of side loading. So it's weaker,  
but in it's usage pretty darn strong. 2)Step Rolled Rivets: This is also a  
rolled rivet, but much more precision and slightly slower in processing speed.  
This type of rivet is shorter/flatter and is used on our basic derailleur  
chains. It's has about 50% more Push Pin Power than the Standard Rolled Rivet  
process. It's about 1500NM's (sic). The step riveting is moving more material  
than the standard roll riveting. 3)Cross Step Rolled/Stamped Rivets: Is a double  
riveting process that rolls the step rivet, then hits it again to displace more  
material. It's one of our strongest types of riveting at over 2000NM's. With all  
the above methods of riveting, the hole in the side of the plate is straight  
with no draft/radius. So the deformation of the rivet flows over the outside of  
the link itself. 4)Cylindrical Riveting (Hollow Pin type): With this type of  
riveting, the material is displaced into a chamfered/tapered hole and the  
thickness of the plate plays an important roll of the Push Pin Power. For  
example, our PC89R Hollow Pin has a PP Power of 1500NM's, while our PC99 Hollow  
Pin has one of 2000NM's. The difference is that the 89R uses .90mm plates, while  
our 99 uses 1.0mm plates. Cylindrical riveting is much slower since it must  
strike every rivet individually. 5 Round/Orbital Riveting: This is our strongest  
rivet, but is only used for Power Links. It is pretty tall and displaces a lot  
of material, but is not really a good method for the complete chain. Chains must  
be cut a couple times in their lives, once to obtain the correct length and a  
second time to be adjusted to the bike. This rivet is almost un-open able and  
would cause problems for both us on the production side and also for the  
consumer. We use it on our Powerlink since this rivet will never be opened.  
Re: Durability of a rivet. In general, there is no major difference in the  
rivet method vs. longevity. Yes, you could argue that a larger displacement of  
materials would offer more longevity, but only slightly. Durability of a chain  
comes from the hardness of the pins and of the inner links that ride on them. We  
are doing a research project with the University of Coimbra on what causes chain  
stretch. Chains really don't stretch, they are just wearing out. Yes, in extreme  
cases the material of the outer and inner link could deform and stretch, but  
this is rare. What is happening is that the rivet pins and the inner links are  
wearing.  
Re: Differences in Models. In many cases, what is changing is the plating,  
but the underlying materials are the same. So, you are correct. The only caveat  
to that is the all the materials thickness and process (heat treatments) are  
[not] the same. Please note that we do not use the same links and then just  
change the color at will. If we are going to do a nickel outer link, we would  
have to change the hole size for the rivets to compensate for the nickel  
plating. Yes a chain is that precise.  
Re: Replacement. This is a tricky one. You could argue that any change in  
length above 12.7mm pitch, you should change [the chain]. You need to remember  
that there are 114-116 links times x amount of wear. It does not take much to  
cause a chain to get too long and start to effect the rest of your drive train.  
I would say that most of the chain length testers are pretty correct to use for  
a guide. Sorry that I cannot offer a more precise answer on that one.  
Re: Cleaning of chains. The reason why we do not suggest leaving chains in a  
solvent tank is because it takes out all the lube between the pin and the inner  
plates. If we could make sure that people would then use a liquefied grease,  
then let it cool, we might suggest that people clean chains in a solvent tank.  
This is how we do it at our factory. We recommend that the user use cleaners  
that only attack the outer surfaces of the chain to take away the dirt and grime  
then re-lube. I personally have only used a rag to clean my chains for years and  
stay away from solvent tanks and jet washers. It's cheaper to replace a 10-15  
dollar chain than it is to replace a Ti cog set and an XTR chainring set!  
I hope that this helps you better understand chains and SRAM chains in  
particular. If you have any more questions, feel free to ask.  
Best Regards,  
Mark Pippin SRAM Product Management

Quote from bikerteam on Oct 7^th, 2008, 2:45pm:

 
 
http://sports.groups.yahoo.com/group/RANSbike/