Frame alignment issue i dont understand
Moderator: robbosmans
Frame is a ritchey Swiss cross
Did the string test from one rear dropout, around the head tube to the other dropout.
There is a 5-6 mm difference at the seat tube towards the NDS.
The rear wheel is properly dished. Checked with dishing tool, and flipping the wheel in the rear dropouts.
It sits just about perfectly center in the rear triangle.
The shifting is flawless
One thing I can't determine is if the rear wheel is in a straight, parallel, and on-center alignment with the front wheel, or the front triangle.
I've never had any handling issues at high speeds (40mph+). Wobble, shimmy. Very stable handling
Is this 5 mm discrepancy between DS and NDS due to compensating for space needed for chain rings?
Did the string test from one rear dropout, around the head tube to the other dropout.
There is a 5-6 mm difference at the seat tube towards the NDS.
The rear wheel is properly dished. Checked with dishing tool, and flipping the wheel in the rear dropouts.
It sits just about perfectly center in the rear triangle.
The shifting is flawless
One thing I can't determine is if the rear wheel is in a straight, parallel, and on-center alignment with the front wheel, or the front triangle.
I've never had any handling issues at high speeds (40mph+). Wobble, shimmy. Very stable handling
Is this 5 mm discrepancy between DS and NDS due to compensating for space needed for chain rings?
i flipped the bicycle over, took off the wheels. reinstalled the skewers and then tied the string from the center of the rear skewer to the center of the fork skewer (measured between the inside face of the dropouts).
and the string looks like its off centerline of the bottom bracket shell by about 4 mm, with the gap being on the drive side. which doesn't seem consistent with the above string test showing the gap towards the NDS.
i can even see that the chain stays aren't equidistant from that centerline
there's a bike shop about 1.5 hours away that said they would look at it.
and the string looks like its off centerline of the bottom bracket shell by about 4 mm, with the gap being on the drive side. which doesn't seem consistent with the above string test showing the gap towards the NDS.
i can even see that the chain stays aren't equidistant from that centerline
there's a bike shop about 1.5 hours away that said they would look at it.
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If there's no problem, what's the problem?
High strength steel alloys can be risky to cold set. When I worked for Bill Holland, he stopped bending frames and changed to thermally aligning them, adding a pass of weld here and there to pull the frame into perfection. Of course that was before paint.
I would seriously consider not doing anything, just ride and enjoy.
High strength steel alloys can be risky to cold set. When I worked for Bill Holland, he stopped bending frames and changed to thermally aligning them, adding a pass of weld here and there to pull the frame into perfection. Of course that was before paint.
I would seriously consider not doing anything, just ride and enjoy.
Damon Rinard
Engineering Manager, Road Bikes
Cycling Sports Group, Cannondale
Ex-Kestrel, ex-Velomax, ex-Trek, ex-Cervelo
Engineering Manager, Road Bikes
Cycling Sports Group, Cannondale
Ex-Kestrel, ex-Velomax, ex-Trek, ex-Cervelo
that's basically what my local shop said to me.DamonRinard wrote: ↑Thu Jun 21, 2018 12:27 amIf there's no problem, what's the problem?
High strength steel alloys can be risky to cold set. When I worked for Bill Holland, he stopped bending frames and changed to thermally aligning them, adding a pass of weld here and there to pull the frame into perfection. Of course that was before paint.
I would seriously consider not doing anything, just ride and enjoy.
i'm just curious as to what's going on with this frame. maybe there IS a problem that i'm just not aware of? could be the reason i'm doing my local hill-climb in 17:12, instead of 14:38?
ya never know... HA!!!
Are you suspecting that both dropouts have "traveled" laterally by 5-6mm?
Has the frame ever been in an accident?
Can you ask the frame builder if this is correct or not?
I don't think setting the frame up in some kind of jig and moving the dropouts by 5mm will damage the frame but you also won't get any free speed by doing so either.
/a
Has the frame ever been in an accident?
Can you ask the frame builder if this is correct or not?
I don't think setting the frame up in some kind of jig and moving the dropouts by 5mm will damage the frame but you also won't get any free speed by doing so either.
/a
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If the OP is reporting a possible frame misalignment issue at the back - wheel not lining up straight - the only thing I would advise is having the frame checked with dropout alignment gauges.
If it is badly out and the frame is new you make a warranty return, but if older you have the droput(s) properly aligned - assuming, possibly wrongly, that the Ritchey Cross is steel.
If it is badly out and the frame is new you make a warranty return, but if older you have the droput(s) properly aligned - assuming, possibly wrongly, that the Ritchey Cross is steel.
So the wheel sits in the bike perfectly, the bike rides perfectly, and the two different 'tests' you have tried have given you two completely different answers?
Do you not think the most likely answer is that the frame is right and you've tested it wrong?
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The front triangle can still be off and the dtivetrain will work perfectly.
I'm honestly not sure what the second string test is, but it sounds like the string is resting on the bottom bracket shell. It could be explained by head tube twist, maybe the fork not being straight, skewers not seating in the dropouts and the BB shell itself being angled and pushing the string. The string should have only two fixed points of contact per run to be worth anything.
I'm honestly not sure what the second string test is, but it sounds like the string is resting on the bottom bracket shell. It could be explained by head tube twist, maybe the fork not being straight, skewers not seating in the dropouts and the BB shell itself being angled and pushing the string. The string should have only two fixed points of contact per run to be worth anything.
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