Chainring rivets. Why?

[Cyprus]

A rather trivial question I must admit, but I am curious about it. On my outer chainring there are four flat headed rivets, which seem to have no purpose whatsoever, and I cannot figure out a reason as to why they are there. They do not actually 'do' anything.

The rivets are flat headed on the inner face of the chainring aswell as the outer face, they do not fix or hold anything in place. Just seems pointless why a manufacturer would install them if they do nothing.

In the whole scheme of things it is trivial and unimportant, just curious about them! See pic ......

 

[ColinJ]

To help pick the chain up from the little ring when changing up to the big ring. I assume that there is a small bit of the rivet head sticking out on the inside?

 

[cyberknight]

To help pick the chain up from the little ring when changing up to the big ring. I assume that there is a small bit of the rivet head sticking out on the inside?

What he said

 

[KneesUp]

To help pick the chain up from the little ring when changing up to the big ring. I assume that there is a small bit of the rivet head sticking out on the inside?

If it caught the chain it would cause problems going down though, surely?

 

[ColinJ]

If it caught the chain it would cause problems going down though, surely?

The chain gets chucked straight down past them. Without the rivets to shift up, the chain could be scraping against the inside of the big ring for a while before a tooth snagged it and pulled it up.

See Sheldon Brown's article.

 

[DaveReading]

Interesting comment by Sheldon:

"These features help improve shifting, and make rider skill less important in shifting"

How does a skilful rider shift differently ?

 

[ColinJ]

Interesting comment by Sheldon:

"These features help improve shifting, and make rider skill less important in shifting"

How does a skilful rider shift differently ?

Be more gentle with the shift lever? Back off the pedalling a bit so the chain is not under such great tension when shifting?

 

[Cyprus]

To help pick the chain up from the little ring when changing up to the big ring. I assume that there is a small bit of the rivet head sticking out on the inside?

Never would of thought it. The rivet head on the inner face barely protrudes above the surface of the chainring. Neat idea.

Learn something every day!!

 

[Smurfy]

Never would of thought it. The rivet head on the inner face barely protrudes above the surface of the chainring. Neat idea.

Learn something every day!!

Look carefully, and you'll probably spot some profiled teeth. That is, teeth that are slightly shorter than the rest, to help the chain hop on and off the chainring.

 

[wisdom]

Nice chain suits the rings well

 

[winjim]

Interesting comment by Sheldon:

"These features help improve shifting, and make rider skill less important in shifting"

How does a skilful rider shift differently ?

With old-fashioned non index shifters and without the pins there's a definite technique to shoving the lever in just the right way to get a good shift. I haven't ridden such a bike in years, but I do remember it, it kind of involves throwing the lever just a little too far and then backing it off a touch.

 

[KneesUp]

The chain gets chucked straight down past them. Without the rivets to shift up, the chain could be scraping against the inside of the big ring for a while before a tooth snagged it and pulled it up.

See Sheldon Brown's article.

Thanks - that's my thing learned for the day

Might go back to bed now

 

[Dogtrousers]

I didn't know about these things.

I ride 50/34 chainset with a friction-shift and it changes so sweetly. Much nicer than the previous one, where an up-shift had to be done cautiously to avoid throwing the chain off the outside, and that didn't have such a big gap (40T little ring).

Until now I prided myself that this was because I'd set it up so well, and maybe I have mystical gear changing fingers, but the real reason is probably that my modern chainset has all these secret little magic gubbins.

You live and learn

 

[fossyant]

They work.... Really....