Chain install - FS MTB.

[Jonesy]

A riding pal came up to me and said, "hey, how do you
know how many links to leave when you put a new chain on
your bike?"

I told him, "loop it around the big/big combo, not
threading it through either derailleurs and leave one full
link overlap."

Then, after he took off, I thought about it a little, and
realized he had a FS MTB. Since the distance between the BB
center and hub center might get longer under suspension
compression, that length of chain might not be enough. While
I know that the big/big combo is not going to be used on
purpose under any real MTBing conditions, it is possible to
accidentally get into that combo. On my bikes, the effective
chainstay length is always the same, due to the bikes'
designs (hardtail, softtail,) but his virtual chainstay
might grow, and bust stuff.

What *is* the correct method for determining chain length
on a FS MTB?
--
Jonesy

 

[Michael Dart]

In news:[email protected],
Jonesy <[email protected]> typed:
> A riding pal came up to me and said, "hey, how do you
> know how many links to leave when you put a new chain on
> your bike?"
>
> I told him, "loop it around the big/big combo, not
> threading it through either derailleurs and leave one full
> link overlap."
>
> Then, after he took off, I thought about it a little, and
> realized he had a FS MTB. Since the distance between the
> BB center and hub center might get longer under suspension
> compression, that length of chain might not be enough.
> While I know that the big/big combo is not going to be
> used on purpose under any real MTBing conditions, it is
> possible to accidentally get into that combo. On my bikes,
> the effective chainstay length is always the same, due to
> the bikes' designs (hardtail, softtail,) but his virtual
> chainstay might grow, and bust stuff.
>
> What *is* the correct method for determining chain length
> on a FS MTB?

Take the spring (air or coil) off the shock and compress the
suspension. Find the point where the distance from the BB to
the rear axle is the greatest, then do the big/big
measurement. My four bar Intense M1 grows an inch into it's
compression and takes a full 119 link chain.

Mike

 

[Jonesy]

"Michael Dart" <[email protected]> wrote in message news:<[email protected]>...
> In news:[email protected],
> Jonesy <[email protected]> typed:
> > A riding pal came up to me and said, "hey, how do you
> > know how many links to leave when you put a new chain on
> > your bike?"

[snip]

> > What *is* the correct method for determining chain
> > length on a FS MTB?
>
> Take the spring (air or coil) off the shock and compress
> the suspension. Find the point where the distance from the
> BB to the rear axle is the greatest, then do the big/big
> measurement. My four bar Intense M1 grows an inch into
> it's compression and takes a full 119 link chain.

I called him up, and he had not yet got around to installing
the chain. I told him what you said, and he said, "I'll just
used my old chain as a template."

Uh, duh, yeah, good idea. :bangs forehead with palm,
repeatedly:

Thanks for the answer.
--
Jonesy

 

[Michael Dart]

In news:[email protected],
Jonesy <[email protected]> typed:
> "Michael Dart" <[email protected]> wrote in
> message news:<[email protected]>...
>> In news:[email protected],
>> Jonesy <[email protected]> typed:
>>> A riding pal came up to me and said, "hey, how do you
>>> know how many links to leave when you put a new chain on
>>> your bike?"
>
> [snip]
>
>>> What *is* the correct method for determining chain
>>> length on a FS MTB?
>>
>> Take the spring (air or coil) off the shock and compress
>> the suspension. Find the point where the distance from
>> the BB to the rear axle is the greatest, then do the
>> big/big measurement. My four bar Intense M1 grows an inch
>> into it's compression and takes a full 119 link chain.
>
> I called him up, and he had not yet got around to
> installing the chain. I told him what you said, and he
> said, "I'll just used my old chain as a template."
>
> Uh, duh, yeah, good idea. :bangs forehead with palm,
> repeatedly:
>
> Thanks for the answer.

Hehehe...well there's that. But it's still good to know if
you build up a new frame. It's actually in the Shimano Rear
Drive installation instructions.

Mike

 

[Jonesy]

"Michael Dart" <[email protected]> wrote in message news:<[email protected]>...
> In news:[email protected],
> Jonesy <[email protected]> typed:
> > "Michael Dart" <[email protected]> wrote in
> > message news:<[email protected]>...
> >> In
> >> news:[email protected],
> >> Jonesy <[email protected]> typed:
> >>> A riding pal came up to me and said, "hey, how do you
> >>> know how many links to leave when you put a new chain
> >>> on your bike?"
> >
> > [snip]
> >
> >>> What *is* the correct method for determining chain
> >>> length on a FS MTB?
> >>
> >> Take the spring (air or coil) off the shock and
> >> compress the suspension. Find the point where the
> >> distance from the BB to the rear axle is the greatest,
> >> then do the big/big measurement. My four bar Intense M1
> >> grows an inch into it's compression and takes a full
> >> 119 link chain.
> >
> > I called him up, and he had not yet got around to
> > installing the chain. I told him what you said, and he
> > said, "I'll just used my old chain as a template."
> >
> > Uh, duh, yeah, good idea. :bangs forehead with palm,
> > repeatedly:
> >
> > Thanks for the answer.
>
> Hehehe...well there's that. But it's still good to know if
> you build up a new frame. It's actually in the Shimano
> Rear Drive installation instructions.

Damn - you are right. A little digging, and there it was. I
*knew* I'd read that somewhere.

Keyboard input fix: "I'll just use my old chain as a
template." Grrr, fat-fingered it again!

Thanks again for the info,
--
Jonesy