Truing Wheels

[camzh]

So I bought a new bike,
And its arrived with a 'slight wobble in the rear'
The 'slight wobble' makes me think the rim is stuffed.

But I'm curious to know if its possible to have it trued back to shape.
The rim is 7mm off at the biggest deflection.
It's suffered an impact at the center of the deflection and has a pretty good dint in it.

thoughts ?

 

[Urban DH]

sure you can pull it true probably have a little bit of up and down but if she's got a good dint it will have a flat spot also and might be annoying, you can pull it true and ride it fine for a while but dont put it off too long

 

[The Duckmeister]

You'll never get it properly true if the rim is dented. You can probably pull it straight laterally, but you'll never get it properly round. The spokes will be unevenly tensioned, so you're fairly likely to suffer frequent spoke breakages.

Your best bet is to replace the rim & have it built onto your existing hub & spokes.

 

[MTB Wanabe]

You'll never get it properly true if the rim is dented. You can probably pull it straight laterally, but you'll never get it properly round. The spokes will be unevenly tensioned, so you're fairly likely to suffer frequent spoke breakages.

Your best bet is to replace the rim & have it built onto your existing hub & spokes.

+1 on this. I will also go a bit further and say that it would be a good idea to also replace the spokes and nipples whilst you are changing the rim. Reason being is that you don't know how long the previous owner has been riding the wheel like this and the spokes will probably be unevenly fatigued also which will lead to premature spoke failure in the new build. If you don't go with the same rim, there is a chance that the spoke lengths could be different anyway, but this is beside my point.

My assumption here is that the ding is quite noticeable and would result in a massive variation in spoke tensions. If the tensions don't vary that much, say around 10% from the average, then you should be able to get away with just truing it for a while.

 

[camzh]

This is the major dint.

Doesnt look so bad in the picture.

I like the idea of tossing it along with the spokes and nipples and rebuilding the whole lot.

From the spoke calulator on the DT Swiss site, using a rim from CRC they reccomend 265mm on one side, and 266mm on the other.
But on CRC the spokes available are 264mm or 266mm

Longer or shorter ?
I'm erring on longer. Can always make something longer shorter...

 

[T-Rex]

That's not a bad ding, but dings are mostly cosmetic. First thing to do is check the spoke tension of the spoke immediately adjacent to the ding, and the the spokes either side of it. Also check for any cracks propagating from the spoke hole in the rim.

Next thing to check is if the rim is flat spotted. This means the rim has been pushed out of round, and its a bigger issue than a ding. Close your eyes and run your finger tips over the ridge of the rim next to the spokes. You will feel if its been pushed in.

As others have said, if its been bent sideways 7mm, you won't straighten it. But a loose spoke could put it out 3-4mm, so you might be able to get it back to something acceptable.

If you decide to relace it, new spokes are a good idea. If the calculator comes up with an odd number, eg 265 mm, go down to 264, not up to 266, as you could run out of thread when tensioning it.

If you can get a rim with the same ERD as your existing rim, you can just use spokes the same length as those that you have.

 

[The Duckmeister]

Next thing to check is if the rim is flat spotted. This means the rim has been pushed out of round, and its a bigger issue than a ding. Close your eyes and run your finger tips over the ridge of the rim next to the spokes. You will feel if its been pushed in.

That's flat spotted. Look at the difference in the curve where the dent is compared to a bit further to the right; you can see it tighten towards the edge of the pic.

 

[driftking]

As others have said get the other stuff checked as mentioned.The dint is nothing bad, Iv got a few of those in my rim one which has cracked horizontally at the dint. Its fine.

 

[camzh]

Thanks for the feed back.
I took the wheel to Blackmans at Blacktown on Friday arvo.
I hadn't noticed a crack that was radiating out on both sides from a different impact. :tape:

I've had a quick go at truing it myself knowing it was toast anyhow.
Its probably within 5mm now.

I straightened this dint out a little as the tyre wasn't seating correctly.
Rode it today around OMV with no issues, but not sure how long it would last.


just to be safe I have a new rim, spokes and nipples on the way from CRC.

 

[camzh]

The crack looks like this if anyone is interested.
Same on both sides.

 

[T-Rex]

The crack looks like this if anyone is interested.
Same on both sides.

That will be ok until your new rim arrives, I've seen much worse. You can ride a rim that's cracked clean through, the opposing spokes will hold it together, provided you don't hit anything big. The main issue with a little crack like that is it can open up when you tension the spoke, so go easy with the spoke key.