What's the limit of what can be "trued" on an aluminum rim, and how to check?

[Nitori]

Backstory: I've got a 19" Pro Wheel spoked rim that I got for free. Came off of someone's mid 2000's Yamaha TTR125L.

Never really got around to looking at it too hard because it had a broken spoke, sat on the "I'll deal with this someday" pile.

I took the tire and tube off today, and it's one hairy SOB under there- mismatched nipples, some bent spokes in addition to the broken one, and as I was delacing it the tightness was all over the place.

Question is, how much of a wobble can be "worked out" in the lacing and truing process? It doesn't appear visibly damaged in any spot, but put it on the floor and give it a push and it will wobble and flop over. It appears to lay flat on the floor (floor isn't perfectly flat to check, but the "short side" doesn't follow when you rotate the rim 180) and looking at it edge on I sure as heck can't see much wrong.

What I thought I'd do is get it powdercoated all pretty and re-laced with some fancy new spokes, good as new. I just don't wanna throw money at something that can't be trued properly because of hamfisted PO shenanigans.

 

[DohcBikes]

This could be debated but really the only way to know is to go for it. I've seen some bad wheels be trued to .002" tolerance. Not by me ;D

If it is flat spotted or the spoke holes are stretched just can it.

 

[jpmobius]

Unless it is actually bent - like from hitting something, or is locally twisted - again like from hitting something, very likely it can be trued up fine. One critical thing that people forget or overlook is the fact that the tire itself will tend to even out small local irregularities. Many rims have a rather dreadful bump - depression-bump where the two ends of the extrusion are welded together. If you run an indicator on the outside of the rim, this is not so bad, but can be very misleading when truing. I like to use the inside of the rim, where the bead of the tire will rest. The bad spot where the weld was ground down is much worse, but much more localized so getting the average good there makes the tire be in the right place. I will often use a file to touch up localized high spots. Like dohc says, you really have to try it. If your rim looks curved like a potato chip, you still have a pretty good chance to true it up compared to if it has an actual bent spot. Spokes can very powerfully move the center line of the rim anywhere you want, but can't move the edges around if they have been bent from their relation to that center line. .002"? Certainly doable on a lot of rims, but better than really needed. I have seen some pretty obviously more out of round rims than that that drove just fine. Like I said, the tire will average out a lot - not that you should plan on it having to.

 

[datadavid]

Re: What's the limit of what can be "trued" on an aluminum rim, and how to check?

My stock thruxton rim had some 4-5mm ovality, that was possible to true. Not sure if its a good idea to true rims that have been forcibly bent, but they are rarely 100% to begin with.

 

[hillsy]

You'll be best off doing a mock-up before you send anything away to get PC'd.

 

[Nitori]

I cleared some space off of my "mostly flat" workbench (I checked it the other day and it was inside of 0.5 mm but not perfect) and laid the wheel flat. It is sort of potato-chipped but not by a lot.

(That's a .8mm feeler in there, not the actual measurement but there for scale.)

I'm on the fence about just getting a new rim. PC'ing an old and icky rim is certainly cheaper, but ~$80 for a polished turd is now just... an expensive turd. And paying someone to attempt truing it beforehand might be a wash versus a good deal on a new one.

Speaking of polished turds, I also got around to delacing my CB/CL100 rear rim, which was an adventure- apparently this PO was of the "if I can't see the rust anymore it doesn't exist" school of thought and rattle-canned over it. It's pitted a bit but should PC up quite nicely.

It's steel and straight as an arrow. Clunk, on the workbench it sits with no wobble. Heavy, though.