Duragrouch

Hey, simpler is always better. Sometimes I'm over-cautious about potential variables. I made my living in industries where "failure is not an option", so performed enormous Failure Mode and Effect Analyses, on (hopefully) every conceivable way that a part or system can fail. So I tend to think of more possibilities than most folks. Often, not needed. It's just hard to get out of that mode after decades. I tend to be most alert on things involving safety, or in a repair where there is a risk of permanently bollixing up the part.

pdlamb

The answer is kind of like "how many men does it take to fix a pothole?" One, of course, but a dozen or more (a) BF people "helping" or (b) truck drivers, flagmen, backhoe operators, and supervisors.

grumpus

If you peel away the layers of sniping and tangential pondering the necessary information is there, I think. But there's a distinct whiff of ADHD about the whole discussion.
Parallel.

FBinNY 

You say tomahto, I say tomayto.....

FWIW -I was referencing the screw axis.

In my world, we'd often say square to mean either parallel or perpendicular, or both.

grumpus

I know exactly what you meant, I was just getting into the spirit of things by adding an unnecessary irrelevant comment that was.likely to cause thread drift.

Duragrouch

And the word for today is... rhombohedron. I just like to say rhombohedron.

BTinNYC 

By this time John M has learned MIG welding and it doesn't matter if the hangar snaps off.

Trakhak

Still, he should take all the time he needs before attempting the repair. I'd recommend the equivalent of medical school plus residency.

wheelreason

Or convert to Hinduism and come back as Sheldon Brown...

john m flores 

Finally got a chance to work on this! Made some initial progress with the Park Tool Derailleur Alignment Gauge, the older chrome one.



Things were going pretty well until the rear wheel fell out. It was then that I realized that the hanger had been pulled back, opening up the dropout...



Bike Friday advised me to use a crescent wrench (positioned in line with the dropout and frame) to bend the dropout forward again, using an axle keep from pulling it too far. It worked great.



I then remounted the rear wheel and continued to use the DAG. I'm pretty close now.



I'll be doing the final alignment soon and then mounting a new RD and putting the bike back together.

For those that have used the DAG - how precise do you need to be? 1mm between measuring points? 2mm? more?

Thanks everyone for your help!

FBinNY 

Consider the 12" length of the beam vs. 1or 2mm variation, then glance at a sine chart and it'll be obvious that the method is far more precise than necessary. Either is more than fine.

Moe Zhoost

To answer your question: I generally try to get it within a mm. but don't sweat it if it's 1-2mm. The test is if you've resolved shifting problems.

About this thread: I had a hard time reading all of the 'over-the-top' advice given here, but accept that it was given in the spirit of helpfulness. The fact is that with the alignment tool, the job is quickly and easily accomplished. No need to over-complicate it with hydraulic presses, bench vises, etc. It does take a bit of finesse to determine the right angle for bending, but gentle nudges on the tool arm get you there nicely. Most first time users want to crank on the tool and go too far.

Duragrouch

"Close enough for government work." - Dad

smd4

Seems like there’s an “S” bend in there. How did that thing get so jacked up?

Duragrouch

It's a Bike Friday All-Packa, designed for off road. Go look at the original post (#1), I hadn't recalled seeing pics until today. Massive mud, including the chain.

Kai Winters

1-2mm variance using three points of contact...bottom to set the gauge, top is the Y axis and left side of the wheel is the X axis, perpendicular to the Y axis...is great.
Good job especially fixing the dropout...I've had to do that in the past and it is not a lot of fun and there really aren't any specific tools to fix it other than a good Crescent wrench.
Well done, chapeau...

Kontact

Great job!

grumpus

You seem to have missed the point - the dropout was bent, it wasn't just a hanger alignment problem.

Moe Zhoost

Nope, didn't miss it. That's a minor issue relative to the alignment, but it does have to be addressed first.

john m flores 

Thanks again everyone for your help and support! The All Packa is back on the road!


The Advent Super Short is a 1x but I'm currently running a 50/34 2x front. The derailleur works great with the 34T. If I try with the 50T, I can only use the smaller end of the cassette. I may try swapping out the 50T for a 42T or something and see if it works. We'll see.

smd4

If nothing else, at least you cleaned your drivetrain.