SRAM PC48/58 pins - not flared!

[still me]

[sorry 'bout the new thread, but the other one has degraded]

So, I called SRAM. If the tech guy there knows what he's talking
about, the PC48/58 pins are straight thru. I haven't actually pulled
one and examined it under a microscope.

So, I think the initial question remains: Even if the plates are
tighter initially in nester chains, the resulting fit should be at
least as good as we had in the 'ol days after pushing a pin out/in. I
don't recall any chain breaks due to pin fitting unless we messed up
the job.

Maybe these companies push the power link for legal reasons?

Comments?

 

[Ozark Bicycle]

On Jun 28, 11:29 am, still me <[email protected]> wrote:
> [sorry 'bout the new thread, but the other one has degraded]
>
> So, I called SRAM. If the tech guy there knows what he's talking
> about, the PC48/58 pins are straight thru. I haven't actually pulled
> one and examined it under a microscope.
>
> So, I think the initial question remains: Even if the plates are
> tighter initially in nester chains, the resulting fit should be at
> least as good as we had in the 'ol days after pushing a pin out/in. I
> don't recall any chain breaks due to pin fitting unless we messed up
> the job.
>
> Maybe these companies push the power link for legal reasons?
>
> Comments?

Back "in the 'ol days" was prior to the use of Hyperglide-type cogs
(and the notion of shifting under full pedal pressure), which put much
higher side loads on a chain.

 

[still me]

On Thu, 28 Jun 2007 09:40:54 -0700, Ozark Bicycle
<[email protected]> wrote:

>
>Back "in the 'ol days" was prior to the use of Hyperglide-type cogs
>(and the notion of shifting under full pedal pressure), which put much
>higher side loads on a chain.

Good point! (But someone is going to argue the physics now

Would the last generation of SRAM freewheels be considered
"Hyperglide-type cogs" ?

 

[Ozark Bicycle]

On Jun 28, 11:55 am, still me <[email protected]> wrote:
> On Thu, 28 Jun 2007 09:40:54 -0700, Ozark Bicycle
>
> <[email protected]> wrote:
>
> >Back "in the 'ol days" was prior to the use of Hyperglide-type cogs
> >(and the notion of shifting under full pedal pressure), which put much
> >higher side loads on a chain.
>
> Good point! (But someone is going to argue the physics now
>
> Would the last generation of SRAM freewheels be considered
> "Hyperglide-type cogs" ?

Yes, the term applies to any freewheel/cassette with ramped cogs.

 

[Peter Cole]

still me wrote:
> [sorry 'bout the new thread, but the other one has degraded]
>
> So, I called SRAM. If the tech guy there knows what he's talking
> about, the PC48/58 pins are straight thru. I haven't actually pulled
> one and examined it under a microscope.
>
> So, I think the initial question remains: Even if the plates are
> tighter initially in nester chains, the resulting fit should be at
> least as good as we had in the 'ol days after pushing a pin out/in. I
> don't recall any chain breaks due to pin fitting unless we messed up
> the job.
>
> Maybe these companies push the power link for legal reasons?
>
> Comments?

I checked one this morning with a reasonably good caliper. The pin was
definitely larger in diameter at the ends -- about .003". It also seemed
like I could see the bulge with a loupe. The ends of the pin have
distinctive impact marks consistent with use of some impact/compression
tool.

 

[Ozark Bicycle]

On Jun 28, 12:33 pm, Peter Cole <[email protected]> wrote:
> still me wrote:
> > [sorry 'bout the new thread, but the other one has degraded]
>
> > So, I called SRAM. If the tech guy there knows what he's talking
> > about, the PC48/58 pins are straight thru. I haven't actually pulled
> > one and examined it under a microscope.
>
> > So, I think the initial question remains: Even if the plates are
> > tighter initially in nester chains, the resulting fit should be at
> > least as good as we had in the 'ol days after pushing a pin out/in. I
> > don't recall any chain breaks due to pin fitting unless we messed up
> > the job.
>
> > Maybe these companies push the power link for legal reasons?
>
> > Comments?
>
> I checked one this morning with a reasonably good caliper. The pin was
> definitely larger in diameter at the ends -- about .003". It also seemed
> like I could see the bulge with a loupe. The ends of the pin have
> distinctive impact marks consistent with use of some impact/compression
> tool.-


Yep, the so-called 'peened over' pins.

 

[[email protected]]

Peter Cole writes:

>> So, I called SRAM. If the tech guy there knows what he's talking
>> about, the PC48/58 pins are straight thru. I haven't actually
>> pulled one and examined it under a microscope.

>> So, I think the initial question remains: Even if the plates are
>> tighter initially in nester chains, the resulting fit should be at
>> least as good as we had in the 'ol days after pushing a pin out/in.
>> I don't recall any chain breaks due to pin fitting unless we messed
>> up the job.

>> Maybe these companies push the power link for legal reasons?

>> Comments?

> I checked one this morning with a reasonably good caliper. The pin
> was definitely larger in diameter at the ends -- about .003". It
> also seemed like I could see the bulge with a loupe. The ends of
> the pin have distinctive impact marks consistent with use of some
> impact/compression tool.

I see a difference of 0.01mm on the sample I have and assume that,
like the Shimano chain, the crossed recess at the ends of these pins
is part of a peening process. However, the difference is small enough
and rounded enough to make reinsertion easy. Rather than a retention
mechanism, this might be an assembly feature that allows pins to be
mechanically inserted with minimum press fit that is augmented by post
peening.

Jobst Brandt

 

[Peter Cole]

[email protected] wrote:
> Peter Cole writes:
>
>>> So, I called SRAM. If the tech guy there knows what he's talking
>>> about, the PC48/58 pins are straight thru. I haven't actually
>>> pulled one and examined it under a microscope.
>
>>> So, I think the initial question remains: Even if the plates are
>>> tighter initially in nester chains, the resulting fit should be at
>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>> I don't recall any chain breaks due to pin fitting unless we messed
>>> up the job.
>
>>> Maybe these companies push the power link for legal reasons?
>
>>> Comments?
>
>> I checked one this morning with a reasonably good caliper. The pin
>> was definitely larger in diameter at the ends -- about .003". It
>> also seemed like I could see the bulge with a loupe. The ends of
>> the pin have distinctive impact marks consistent with use of some
>> impact/compression tool.
>
> I see a difference of 0.01mm on the sample I have and assume that,
> like the Shimano chain, the crossed recess at the ends of these pins
> is part of a peening process. However, the difference is small enough
> and rounded enough to make reinsertion easy. Rather than a retention
> mechanism, this might be an assembly feature that allows pins to be
> mechanically inserted with minimum press fit that is augmented by post
> peening.
>
> Jobst Brandt

Did you really get 0.01mm? That's a lot less than I got.

 

[Tom Nakashima]

"Peter Cole" <[email protected]> wrote in message
news:[email protected]...
> [email protected] wrote:
>> Peter Cole writes:
>>
>>>> So, I called SRAM. If the tech guy there knows what he's talking
>>>> about, the PC48/58 pins are straight thru. I haven't actually
>>>> pulled one and examined it under a microscope.
>>
>>>> So, I think the initial question remains: Even if the plates are
>>>> tighter initially in nester chains, the resulting fit should be at
>>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>>> I don't recall any chain breaks due to pin fitting unless we messed
>>>> up the job.
>>
>>>> Maybe these companies push the power link for legal reasons?
>>
>>>> Comments?
>>
>>> I checked one this morning with a reasonably good caliper. The pin
>>> was definitely larger in diameter at the ends -- about .003". It
>>> also seemed like I could see the bulge with a loupe. The ends of
>>> the pin have distinctive impact marks consistent with use of some
>>> impact/compression tool.
>>
>> I see a difference of 0.01mm on the sample I have and assume that,
>> like the Shimano chain, the crossed recess at the ends of these pins
>> is part of a peening process. However, the difference is small enough
>> and rounded enough to make reinsertion easy. Rather than a retention
>> mechanism, this might be an assembly feature that allows pins to be
>> mechanically inserted with minimum press fit that is augmented by post
>> peening.
>>
>> Jobst Brandt
>
> Did you really get 0.01mm? That's a lot less than I got.

That would be .0003937"
How the heck did you guys measure it?
It would have to be with a .0001" indicator.
-tom

 

[[email protected]]

Peter Cole writes:

>>>> So, I called SRAM. If the tech guy there knows what he's talking
>>>> about, the PC48/58 pins are straight thru. I haven't actually
>>>> pulled one and examined it under a microscope.

>>>> So, I think the initial question remains: Even if the plates are
>>>> tighter initially in nester chains, the resulting fit should be at
>>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>>> I don't recall any chain breaks due to pin fitting unless we messed
>>>> up the job.

>>>> Maybe these companies push the power link for legal reasons?

>>>> Comments?

>>> I checked one this morning with a reasonably good caliper. The pin
>>> was definitely larger in diameter at the ends -- about .003". It
>>> also seemed like I could see the bulge with a loupe. The ends of
>>> the pin have distinctive impact marks consistent with use of some
>>> impact/compression tool.

>> I see a difference of 0.01mm on the sample I have and assume that,
>> like the Shimano chain, the crossed recess at the ends of these pins
>> is part of a peening process. However, the difference is small enough
>> and rounded enough to make reinsertion easy. Rather than a retention
>> mechanism, this might be an assembly feature that allows pins to be
>> mechanically inserted with minimum press fit that is augmented by post
>> peening.

> Did you really get 0.01mm? That's a lot less than I got.

I got 3.64mm in the middle and 3.65mm at the widest part of the end,
crosswise to the slotted feature on the ends of the pin.

Jobst Brandt

 

[[email protected]]

Tom Nakashima writes:

>>>>> So, I called SRAM. If the tech guy there knows what he's talking
>>>>> about, the PC48/58 pins are straight thru. I haven't actually
>>>>> pulled one and examined it under a microscope.

>>>>> So, I think the initial question remains: Even if the plates are
>>>>> tighter initially in nester chains, the resulting fit should be at
>>>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>>>> I don't recall any chain breaks due to pin fitting unless we messed
>>>>> up the job.

>>>>> Maybe these companies push the power link for legal reasons?

>>>>> Comments?

>>>> I checked one this morning with a reasonably good caliper. The pin
>>>> was definitely larger in diameter at the ends -- about .003". It
>>>> also seemed like I could see the bulge with a loupe. The ends of
>>>> the pin have distinctive impact marks consistent with use of some
>>>> impact/compression tool.

>>> I see a difference of 0.01mm on the sample I have and assume that,
>>> like the Shimano chain, the crossed recess at the ends of these pins
>>> is part of a peening process. However, the difference is small enough
>>> and rounded enough to make reinsertion easy. Rather than a retention
>>> mechanism, this might be an assembly feature that allows pins to be
>>> mechanically inserted with minimum press fit that is augmented by post
>>> peening.

>> Did you really get 0.01mm? That's a lot less than I got.

> That would be .0003937" How the heck did you guys measure it? It
> would have to be with a .0001" indicator.

Repeatably with a Mitutoyo digital caliper with 0.00mm resolution.
This is a new unused chain pin.

Jobst Brandt

 

[Peter Cole]

[email protected] wrote:
> Peter Cole writes:
>
>>>>> So, I called SRAM. If the tech guy there knows what he's talking
>>>>> about, the PC48/58 pins are straight thru. I haven't actually
>>>>> pulled one and examined it under a microscope.
>
>>>>> So, I think the initial question remains: Even if the plates are
>>>>> tighter initially in nester chains, the resulting fit should be at
>>>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>>>> I don't recall any chain breaks due to pin fitting unless we messed
>>>>> up the job.
>
>>>>> Maybe these companies push the power link for legal reasons?
>
>>>>> Comments?
>
>>>> I checked one this morning with a reasonably good caliper. The pin
>>>> was definitely larger in diameter at the ends -- about .003". It
>>>> also seemed like I could see the bulge with a loupe. The ends of
>>>> the pin have distinctive impact marks consistent with use of some
>>>> impact/compression tool.
>
>>> I see a difference of 0.01mm on the sample I have and assume that,
>>> like the Shimano chain, the crossed recess at the ends of these pins
>>> is part of a peening process. However, the difference is small enough
>>> and rounded enough to make reinsertion easy. Rather than a retention
>>> mechanism, this might be an assembly feature that allows pins to be
>>> mechanically inserted with minimum press fit that is augmented by post
>>> peening.
>
>> Did you really get 0.01mm? That's a lot less than I got.
>
> I got 3.64mm in the middle and 3.65mm at the widest part of the end,
> crosswise to the slotted feature on the ends of the pin.
>
> Jobst Brandt

Odd, I got 3.61 and 3.68, repeatable, unused PC-48.

 

[[email protected]]

Peter Cole writes:

>>>>>> So, I called SRAM. If the tech guy there knows what he's
>>>>>> talking about, the PC48/58 pins are straight thru. I haven't
>>>>>> actually pulled one and examined it under a microscope.

>>>>>> So, I think the initial question remains: Even if the plates
>>>>>> are tighter initially in nester chains, the resulting fit
>>>>>> should be at least as good as we had in the 'ol days after
>>>>>> pushing a pin out/in. I don't recall any chain breaks due to
>>>>>> pin fitting unless we messed up the job.

>>>>>> Maybe these companies push the power link for legal reasons?

>>>>>> Comments?

>>>>> I checked one this morning with a reasonably good caliper. The
>>>>> pin was definitely larger in diameter at the ends -- about
>>>>> .003". It also seemed like I could see the bulge with a loupe.
>>>>> The ends of the pin have distinctive impact marks consistent
>>>>> with use of some impact/compression tool.

>>>> I see a difference of 0.01mm on the sample I have and assume
>>>> that, like the Shimano chain, the crossed recess at the ends of
>>>> these pins is part of a peening process. However, the difference
>>>> is small enough and rounded enough to make reinsertion easy.
>>>> Rather than a retention mechanism, this might be an assembly
>>>> feature that allows pins to be mechanically inserted with minimum
>>>> press fit that is augmented by post peening.

>>> Did you really get 0.01mm? That's a lot less than I got.

>> I got 3.64mm in the middle and 3.65mm at the widest part of the
>> end, crosswise to the slotted feature on the ends of the pin.

> Odd, I got 3.61 and 3.68, repeatable, unused PC-48.

My chain supply is much older than yours. These are Sachs PC-48's
from before SRAM and before people began complaining of separated
chains that they had improperly installed. I bought a large box of
these because I have several bicycles in my family that need chains
occasionally. I'm getting near the bottom of the box and will get
some more before this chain type becomes extinct.

Jobst Brandt

 

[Tom Nakashima]

<[email protected]> wrote in message
news:[email protected]...
> Tom Nakashima writes:
>
>>>>>> So, I called SRAM. If the tech guy there knows what he's talking
>>>>>> about, the PC48/58 pins are straight thru. I haven't actually
>>>>>> pulled one and examined it under a microscope.
>
>>>>>> So, I think the initial question remains: Even if the plates are
>>>>>> tighter initially in nester chains, the resulting fit should be at
>>>>>> least as good as we had in the 'ol days after pushing a pin out/in.
>>>>>> I don't recall any chain breaks due to pin fitting unless we messed
>>>>>> up the job.
>
>>>>>> Maybe these companies push the power link for legal reasons?
>
>>>>>> Comments?
>
>>>>> I checked one this morning with a reasonably good caliper. The pin
>>>>> was definitely larger in diameter at the ends -- about .003". It
>>>>> also seemed like I could see the bulge with a loupe. The ends of
>>>>> the pin have distinctive impact marks consistent with use of some
>>>>> impact/compression tool.
>
>>>> I see a difference of 0.01mm on the sample I have and assume that,
>>>> like the Shimano chain, the crossed recess at the ends of these pins
>>>> is part of a peening process. However, the difference is small enough
>>>> and rounded enough to make reinsertion easy. Rather than a retention
>>>> mechanism, this might be an assembly feature that allows pins to be
>>>> mechanically inserted with minimum press fit that is augmented by post
>>>> peening.
>
>>> Did you really get 0.01mm? That's a lot less than I got.
>
>> That would be .0003937" How the heck did you guys measure it? It
>> would have to be with a .0001" indicator.
>
> Repeatably with a Mitutoyo digital caliper with 0.00mm resolution.
> This is a new unused chain pin.
>
> Jobst Brandt

That's pretty darn good on a new chain pin. I wouldn't expect the form
(runout) of the diameter cylinder to be < .0001" but perhaps they can hold
that tolerance. I was guessing the form to be at least > .00025"
-tom