Dropout width

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear dropout
width measures 126mm. How much damage will I do to the
frame if it is spread out to about 137mm?

Sheldon doesn't recommend it for al. From sheldonbrown.comgloss spOpen ↗
ss.html#spacing:

"Re-spacing is not generally feasible with aluminum, carbon
fiber or titanium frames."

see also: sheldonbrown.comframe spacing.htmlOpen ↗ and
sheldonbrown.comgloss cn z.htmlOpen ↗

Jay Hill said:

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear
dropout width measures 126mm. How much damage will I do
to the frame if it is spread out to about 137mm?

Sheldon doesn't recommend it for al. From sheldonbrown.comgloss spOpen ↗
ss.html#spacing:

"Re-spacing is not generally feasible with aluminum,
carbon fiber or titanium frames."

So he says, but I am not aware of respacing Al frames
causing many problems in practice. Of course his experience
is rather greater than mine...but is this actual experience
of problems, or just a fear that they might occur?

The person who built one of our Al frames has already said
they are happy to respacing for us (I believe that it had
already been respaced from the standard width when I bought
it). I've also ridden another Al frame with the wrong sized
hub for a year or two, but for that one the diffference is
only 5mm nominal, probably slightly less in practice. In
both cases, I suspect that the combination of force and
precision required to cold set the frame accurately is a
greater problem than any long-term weakening.

I await numerous reports of respaced frames that failed...

James
--
If I have seen further than others, it is by treading on the
toes of giants. ne.jphomeOpen ↗

the required heat treatment of Al frames does indeed
suggest it's not a good idea. I don't think you'll get many
reports as I don't think too many people would want or be
game to try it.

"James Annan" <[email hidden]> wrote in
message "]news:[email hidden]...

Quoted message said:

Jay Hill said:

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear
dropout width

measures

Quoted message said:

Quoted message said:

Quoted message said:

126mm. How much damage will I do to the frame if it is
spread out to about 137mm?

Sheldon doesn't recommend it for al. From sheldonbrown.comgloss spOpen ↗
ss.html#spacing:

"Re-spacing is not generally feasible with aluminum,
carbon fiber or titanium frames."

So he says, but I am not aware of respacing Al frames
causing many problems in practice. Of course his
experience is rather greater than mine...but is this
actual experience of problems, or just a fear that they
might occur?

The person who built one of our Al frames has already said
they are happy to respacing for us (I believe that it had
already been respaced from the standard width when I
bought it). I've also ridden another Al frame with the
wrong sized hub for a year or two, but for that one the
diffference is only 5mm nominal, probably slightly less in
practice. In both cases, I suspect that the combination of
force and precision required to cold set the frame
accurately is a greater problem than any long-term
weakening.

I await numerous reports of respaced frames that failed...

James
--
If I have seen further than others, it is by treading on
the toes of giants.
ne.jphomeOpen ↗

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear dropout
width measures 126mm. How much damage will I do to the
frame if it is spread out to about 137mm? I imagine that
spreading the dropouts to install the wheel each time
stresses the frame and I'm guessing that riding it stressed
is not good for it either.

That's a whole lot of respacing. Half as much would be okay
to just stick the wheel in without any modification.

What model mountain bike do you have that's spaced 126mm?
I'm not sure any ever were, especially not in this
millennium.
--
Rick Onanian

On Wed, 23 Jun 2004 10:52:16 GMT, "Gary in VA" <[email hidden]>

Quoted message said:

I've got a al mtb frame (2001 model) that the rear dropout
width measures 126mm. How much damage will I do to the
frame if it is spread out to about 137mm? I imagine that
spreading the dropouts to install the wheel each time
stresses the frame and I'm guessing that riding it stressed
is not good for it either.

While going from 126mm to 130mm with an aluminum frame
has worked for me, I'd hesitate to try to reach 137mm (or
even 135).

jeverett3<AT>earthlink<DOT>net
home.earthlink.net~jeverett3Open ↗

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear dropout
width measures 126mm. How much damage will I do to the
frame if it is spread out to about 137mm? I imagine that
spreading the dropouts to install the wheel each time
stresses the frame and I'm guessing that riding it
stressed is not good for it either.

MTB frames since about 1990 should all be 130mm (rare) or
135mm, so yours is a bit weird. Anyway, no - you shouldn't
stretch an Al frame this much.

If you must have more gears then sell it and buy
another bike.

Gary in VA said:

I've got a al mtb frame (2001 model) that the rear dropout
width measures 126mm. How much damage will I do to the
frame if it is spread out to about 137mm? I imagine that
spreading the dropouts to install the wheel each time
stresses the frame and I'm guessing that riding it
stressed is not good for it either.

What frame is this? You sure you didn't measure it wrong?

MTB frames have all been 135 mm rear spacing for 15 years
now, so the fact that a 2001 model frame is 126 mm is
suspect. Even road frames have been 130 mm since 1993, when
8 speed became standard.

nick said:

the required heat treatment of Al frames does indeed
suggest it's not a good idea. I don't think you'll get
many reports as I don't think too many people would want
or be game to try it.

Aluminum frames require heat treatment after _welding_, not
after cold-setting.

It's just metal, albeit with less elongation before failure
than steel. It still bends. If the rear stays are of
relatively modest external size, you can bet that the wall
thickness is generous and the rear end will be agreeable to
minor adjustment. Handlebar-thick stays such as on older
Cannondales might prove difficult simply because of the
large forces required to make them yield.

Chalo Colina

nick said:

the required heat treatment of Al frames does indeed
suggest it's not a good idea. I don't think you'll get
many reports as I don't think too many people would want
or be game to try it.

Also, stretching them this much (10mm) will put the dropouts
and the rear mech hanger quite out of parallel.

"Bill Lloyd" <[email hidden]> wrote in message >
What frame is this? You sure you didn't measure it wrong?

Quoted message said:

MTB frames have all been 135 mm rear spacing for 15 years
now, so the fact that a 2001 model frame is 126 mm is
suspect. Even road frames have been 130 mm since 1993,
when 8 speed became standard.

It's a 2001 Fisher X-Caliber 29er frame that was never built
up. The rear triangle has been checked to make sure that
it's still in alignment and it is according to Fisher's
specs. I'm measuring it between the dropouts where the axles
fit into them without a wheel in place. And you do have to
spread the dropouts to get a 135mm hub in place.

Gary in VA

Rick Onanian said:

What model mountain bike do you have that's spaced 126mm?
I'm not sure any ever were, especially not in this
millennium.

Most if not all pre-Hyperglide MTBs were 126mm between
dropouts. There were a lot of mountain bikes made between
1981 and 1988, and most of them have other characteristics
unavailable in up-to-date MTBs, like long chainstays and
slack parallel angles, that make them desirable even now.

Chalo Colina

Chalo said:

Rick Onanian said:

What model mountain bike do you have that's spaced 126mm?
I'm not sure any ever were, especially not in this
millennium.

Most if not all pre-Hyperglide MTBs were 126mm between
dropouts. There were a lot of mountain bikes made between
1981 and 1988, and most of them have other characteristics
unavailable in up-to-date MTBs, like long chainstays and
slack parallel angles, that make them desirable even now.

What's desirable about slack head angles? 68 degree head
angles, which were quite popular then, are fine on downhill
bikes but I'm more than happy that they're a little steeper
these days.

Greg
--
Destroy your safe and happy lives Before it is too late The
battles we fought were long and hard Just not to be consumed
by rock'n'roll

Chalo said:

There were a lot of mountain bikes made between 1981 and
1988, and most of them have other characteristics
unavailable in up-to-date MTBs, like long chainstays and
slack parallel angles, that make them desirable even now.

I used to ride a Schwinn Cimmaron MTB that met your
description -- long stays, slack angles. I hated the
handling of that thing with a passion. So the old saw
applies: YMMV.

--
Dave dvt at psu dot edu

"nick" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

the required heat treatment of Al frames does indeed
suggest it's not a good idea. I don't think you'll get
many reports as I don't think too many people would want
or be game to try it.

It's messages like this that make me suspect that the "don't
re-space Al" advice is indeed nothing more than FUD.

James

G.T. said:

Chalo said:

There were a lot of mountain bikes made between 1981
and 1988, and most of them have other characteristics
unavailable in up-to-date MTBs, like long chainstays
and slack parallel angles, that make them desirable
even now.

What's desirable about slack head angles? 68 degree head
angles, which were quite popular then, are fine on
downhill bikes but I'm more than happy that they're a
little steeper these days.

What makes those old bikes desirable today is that you can't
buy such a thing new anymore. Not everybody likes sub-70-
degree angles; but then not everybody likes the ubiquitous
71/73 geometry that is effectively your only choice in a
rigid MTB today.

If you could buy a bike with 68 degree parallel angles and
18.5" stays at your LBS right now, then the old stuff would
lose a lot of its appeal.

As for me, I like slack angles and high BBs enough that I
usually stick longer-than-stock forks on my bikes. That lets
me use manly crank lengths and offers a hint of the in-the-
groove handling qualities I enjoy in my motorbike.

Chalo Colina