Rear Triangle Alignment -- Will 6mm make a difference I can feel?

I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.

The head tube is straight, and when I put a rear wheel in, it is
centered in the triangle.

Will this offset make a difference I can "feel", or should I just go
ahead and build up the bike?

Thank you.

Jeff Rininger

On Mar 12, 2:38*pm, Jeff wrote:
I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.

The head tube is straight, and when I put a rear wheel in, it is
centered in the triangle.

Will this offset make a difference I can "feel", or should I just go
ahead and build up the bike?


What - are you kidding? Don't tell me - you bought it from an
unaccountable third party.

On Mar 12, 5:38*pm, Jeff wrote:
I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.

The head tube is straight, and when I put a rear wheel in, it is
centered in the triangle.

Will this offset make a difference I can "feel", or should I just go
ahead and build up the bike?

Thank you.

Jeff Rininger

the wheel is centered because of spacers on the axle ? how did you
measure to determine the offset ? care to name the manufacturer of the
frame ?

On Mar 12, 2:47*pm, wrote:
On Mar 12, 5:38*pm, Jeff wrote:

I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.
[snip]

the wheel is centered because of spacers on the axle ? how did you
measure to determine the offset ? care to name the manufacturer of the
frame ?

I used the rear wheel from my current road bike. The rear spacing on
the carbon frame is correct (130mm) so the wheel goes right in and is
centered left/right in the triangle. Looks to me like the whole rear
tirangle was laid up wrong (jigging error) at the factory...

I measured the offset using a Park frame jig that grabs the frame at
the BB and has an adjustable "slider" arm (similar to the one on the
Park rear derailleur hanger tool) that you can adjust to pick up the
desired part of the frame. The you reverse the frame (without
changing the slider arm setting) and pick up the same point on the
other side of the frame. This is a nice heavy-duty stand that makes
coldsetting steel frames as easy as that operation can get. (I'm not
sure Park makes that stand any longer -- couldn't find it on their
website.)

I guess I could take my current steel frame and introduce a similar
6mm misalignment to see if I can feel the offset when I ride it, but I
was hoping that someone would say "Nah, you won't feel it" or "Yeah,
it will be unrideable" to save me the work and mental anguish of
coldsetting an error into a perfectly good frame...

On Mar 12, 7:26*pm, Jeff wrote:
On Mar 12, 2:47*pm, wrote:

On Mar 12, 5:38*pm, Jeff wrote:

I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.
[snip]

the wheel is centered because of spacers on the axle ? how did you
measure to determine the offset ? care to name the manufacturer of the
frame ?

I used the rear wheel from my current road bike. *The rear spacing on
the carbon frame is correct (130mm) so the wheel goes right in and is
centered left/right in the triangle. *Looks to me like the whole rear
tirangle was laid up wrong (jigging error) at the factory...

I measured the offset using a Park frame jig that grabs the frame at
the BB and has an adjustable "slider" arm (similar to the one on the
Park rear derailleur hanger tool) that you can adjust to pick up the
desired part of the frame. *The you reverse the frame (without
changing the slider arm setting) and pick up the same point on the
other side of the frame. *This is a nice heavy-duty stand that makes
coldsetting steel frames as easy as that operation can get. *(I'm not
sure Park makes that stand any longer -- couldn't find it on their
website.)

I guess I could take my current steel frame and introduce a similar
6mm misalignment to see if I can feel the offset when I ride it, but I
was hoping that someone would say "Nah, you won't feel it" or "Yeah,
it will be unrideable" to save me the work and mental anguish of
coldsetting an error into a perfectly good frame...

yep, sounds like you know your s**t- it will be ridable, your brakes
will be a pain to center, your tire will wear offside too. you paid
good money for your frame I presume, the frame alignment is a visible
deficency you discovered, how do you feel about the possible unseen
deficency within ? wouldn't it be easier to exchange your frame now or
after ?

Jeff wrote:
On Mar 12, 2:47�pm, wrote:
On Mar 12, 5:38�pm, Jeff wrote:

I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.
[snip]
the wheel is centered because of spacers on the axle ? how did you
measure to determine the offset ? care to name the manufacturer of the
frame ?

I used the rear wheel from my current road bike. The rear spacing on
the carbon frame is correct (130mm) so the wheel goes right in and is
centered left/right in the triangle. Looks to me like the whole rear
tirangle was laid up wrong (jigging error) at the factory...

I measured the offset using a Park frame jig that grabs the frame at
the BB and has an adjustable "slider" arm (similar to the one on the
Park rear derailleur hanger tool) that you can adjust to pick up the
desired part of the frame. The you reverse the frame (without
changing the slider arm setting) and pick up the same point on the
other side of the frame. This is a nice heavy-duty stand that makes
coldsetting steel frames as easy as that operation can get. (I'm not
sure Park makes that stand any longer -- couldn't find it on their
website.)

if it's the tool i think it is, are you measuring to the outside or the
inside of the drops? if you're measuring to the outside, you can easily
measure a difference, yet the frame is perfectly straight. different
thickness drops, etc. what matters is that the two wheels are centered
wrt each other, and that's measured on the *inside* of the drops.




I guess I could take my current steel frame and introduce a similar
6mm misalignment to see if I can feel the offset when I ride it, but I
was hoping that someone would say "Nah, you won't feel it" or "Yeah,
it will be unrideable" to save me the work and mental anguish of
coldsetting an error into a perfectly good frame...

fwiw, i've seen frames with different thickness rear drops set
"centered" for their outside, not their inside, and thus they were
off-center. apparently it's a simple mistake to make.

and yes, it does make a difference to ride.

On Mar 12, 4:38 pm, Jeff wrote:
I just bought a new carbon road bike frame, and when I measured the
rear triangle, I found it offset 6mm to the left.

The head tube is straight, and when I put a rear wheel in, it is
centered in the triangle.

Will this offset make a difference I can "feel", or should I just go
ahead and build up the bike?


6mm is a huge amount for a frame to be off. Return it. If it was steel
and cold settable, I'd still return such a bent thing. There's also a
real possibility of the crankarms striking the chainstays with such a
bend. Honestly, it sounds like a bike that got backed into in a
garage--that's sort of a classic description you gave.

On Mar 12, 10:29*pm, landotter wrote:
.. There's also a
real possibility of the crankarms striking the chainstays with such a
bend.

that's a really really good point to consider.

On 2009-03-13, jim beam wrote:
Jeff wrote:
[...]
I measured the offset using a Park frame jig that grabs the frame at
the BB and has an adjustable "slider" arm (similar to the one on the
Park rear derailleur hanger tool) that you can adjust to pick up the
desired part of the frame. The you reverse the frame (without
changing the slider arm setting) and pick up the same point on the
other side of the frame. This is a nice heavy-duty stand that makes
coldsetting steel frames as easy as that operation can get. (I'm not
sure Park makes that stand any longer -- couldn't find it on their
website.)
[...]
fwiw, i've seen frames with different thickness rear drops set
"centered" for their outside, not their inside, and thus they were
off-center. apparently it's a simple mistake to make.

and yes, it does make a difference to ride.

Even if you re-dish the wheel? Which makes me wonder if having the rear
triangle translated to the right a bit might actually be a good idea--
then you could have less dish on the wheel.

Ben C wrote:
On 2009-03-13, jim beam wrote:
Jeff wrote:
[...]
I measured the offset using a Park frame jig that grabs the frame at
the BB and has an adjustable "slider" arm (similar to the one on the
Park rear derailleur hanger tool) that you can adjust to pick up the
desired part of the frame. The you reverse the frame (without
changing the slider arm setting) and pick up the same point on the
other side of the frame. This is a nice heavy-duty stand that makes
coldsetting steel frames as easy as that operation can get. (I'm not
sure Park makes that stand any longer -- couldn't find it on their
website.)
[...]
fwiw, i've seen frames with different thickness rear drops set
"centered" for their outside, not their inside, and thus they were
off-center. apparently it's a simple mistake to make.

and yes, it does make a difference to ride.

Even if you re-dish the wheel?

not if you re-dish the wheel - but that would be a huge no-no - you
couldn't use a different wheel, and that wheel would be exclusive to
this machine.


Which makes me wonder if having the rear
triangle translated to the right a bit might actually be a good idea--
then you could have less dish on the wheel.

sure - if every other manufacturer did the same thing!