Chainring modification

Mark Janeba said:

Hi all.

I have an 80's triple crankset I'm running with half-step gearing
(26-44-50 at the moment). I'd like to try adding home-brew pick-up

pins

Quoted message said:

to the old rings.

Granted, I could shell out the $$ for TA pinned rings or the like,

(it's

Quoted message said:

a common BCD), but I'm cheap and like to tinker.

QUESTION: How can I attach pick-up pins to the rings? Drilling and
press-fit is the first idea I had, but that doesn't seem sturdy

enough -

Quoted message said:

maybe supplement that with superglue/locktite? I'm thinking of

modeling

Quoted message said:

after Campy pick-up pins that have simple shapes; don't want to

destroy

Quoted message said:

a Campy ring to see how the pins are attached.

Any advice or anecdotes appreciated.

I've done this, using stainless M4x0.7mm hex socket flat head screw for
pickup pins. I drilled the chainring on its webbing where it had the
most material, tapped the hole, countersunk it slightly, then inserted
the screw. This left the head of the screw slightly proud of the
chainring's surface.

I then Dremeled off most of the excess screw and peened the end so
there was no chance of it backing out.

I have pictures of the process. One of these days I'll get around to
putting them on my webpage.

It seems to work fine- but I tend not to use the granny all that much.
If I were going back and forth a lot it would wear something out or
break off a screw. So far, so good, though.

Jeff

Mark Janeba said:

Hi all.

I have an 80's triple crankset I'm running with half-step gearing
(26-44-50 at the moment). I'd like to try adding home-brew pick-up pins
to the old rings.

Granted, I could shell out the $$ for TA pinned rings or the like, (it's
a common BCD), but I'm cheap and like to tinker.

QUESTION: How can I attach pick-up pins to the rings? Drilling and
press-fit is the first idea I had, but that doesn't seem sturdy enough -
maybe supplement that with superglue/locktite? I'm thinking of modeling
after Campy pick-up pins that have simple shapes; don't want to destroy
a Campy ring to see how the pins are attached.

Drill and tap? I've seen anti-jamming pins behind the crank attached
this way. It probably won't work on modern tinfoil Shimano rings, but
an old chunky ring should take a fine thread. You can then use a die on
a bit of alu rod to make the pins.

Mark Janeba said:

I have an 80's triple crankset I'm running with half-step gearing
(26-44-50 at the moment). I'd like to try adding home-brew pick-up pins
to the old rings.

Granted, I could shell out the $$ for TA pinned rings or the like, (it's
a common BCD), but I'm cheap and like to tinker.

QUESTION: How can I attach pick-up pins to the rings? Drilling and
press-fit is the first idea I had, but that doesn't seem sturdy enough -
maybe supplement that with superglue/locktite? I'm thinking of modeling
after Campy pick-up pins that have simple shapes; don't want to destroy
a Campy ring to see how the pins are attached.

Any advice or anecdotes appreciated.

I've done that:
http://www.yellowjersey.org/photosfromthepast/5049PTXT.JPG
just rivet the stainless pins from a scrap ring.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

I've done that:
http://www.yellowjersey.org/photosfromthepast/5049PTXT.JPG
just rivet the stainless pins from a scrap ring.

Andy, I hope that photo isn't current. FSA offers that ring as a stock
item:
http://www.biketoolsetc.com/index.cgi?&d=single&item_id=FS-RR39M

(And I would use that one if I hadn't screwed up my order. Instead, I
had to create my own pins!)

Jeff

Quoted message said:

A Muzi said:

I've done that:
http://www.yellowjersey.org/photosfromthepast/5049PTXT.JPG
just rivet the stainless pins from a scrap ring.

JeffWills said:

Andy, I hope that photo isn't current. FSA offers that ring as a stock
item:
http://www.biketoolsetc.com/index.cgi?&d=single&item_id=FS-RR39M
(And I would use that one if I hadn't screwed up my order. Instead, I
had to create my own pins!)

FSA 'offers', huh? Funny thing, that.

After being told "sure, no problem" by several vendors over
a 2 week period I needed to finish the damned bike and get
paid for it. I made the ring rather than wait any longer.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971