Replacing cracked road rim?
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Replacing cracked road rim?
Hello all,
I've recently discovered cracks in my rear road rim. My question is, If I get a replacement rim with the same number of spoke holes, Can I keep the same spoke length if I reuse the hub? Anything else I should be aware of?
I've recently discovered cracks in my rear road rim. My question is, If I get a replacement rim with the same number of spoke holes, Can I keep the same spoke length if I reuse the hub? Anything else I should be aware of?
#2
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Only if the ERD (Google it) is the same.
#3
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There's no good reason to merely keep the same spoke length. If you actually mean can you reuse the spokes, it's not merely a question of length, but of what condition they are in. Also, if your rim cracked around the spoke holes you may need a complete wheel with more spokes. The tendency toward fewer spokes and more brittle rims has led to many more cracked rims than before.
Last edited by cny-bikeman; 10-01-18 at 08:58 AM.
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Taking into consideration cny-bikeman's post above ^^, you can replace just the rim with a new one of the same ERD. Tape them together, lining up the spoke holes (especially if they're offset)
Loosen each spoke, then transfer to the new rime. Tighten & true.
Loosen each spoke, then transfer to the new rime. Tighten & true.
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I have replaced 4 or 5 rims while reusing the original spokes. Ridden each wheel thousands more miles (so far) with no spoke failures.
You of course should check the spokes, but mostly spokes bvreak from fatigue, wire quality control, or imperfections in the crystal grain structure at the elbow of the spoke.
When a rim fails by cracking, usually that means spoke tension was on the high side - and spokes are more likely to fail from fatigue if tension is too *low*. Also, a wheel which has been ridden over plenty of miles has probably weeded out spokes that were going to fail from imperfections crystal grain structure.
As noted above, this only works if your new rim matches (or is very close to) the ERD of the old rim. Ideally spoke should thread all the way into the spoke nipple, and if your spokes are on the long or short side, you may be able to use a rim with slightly larger or smaller ERD, respectively.
It's also worth noting that the benefits aren't that great. The conveniences are just (a) not having to buy new spokes, and (b) not having to re-lease and re-seat the spokes. I have a wheel with nice 2.0/1.8/2.0 butted spokes that look to be in good shape (friend gave me the wheel after rim cracked on him) but I couldn't find a replacement rim in modern wider width that fits the E.R.D. So I bought new spokes to use on a rim with different ERD, and just re-used the beautiful Dura-Ace hub.
You of course should check the spokes, but mostly spokes bvreak from fatigue, wire quality control, or imperfections in the crystal grain structure at the elbow of the spoke.
When a rim fails by cracking, usually that means spoke tension was on the high side - and spokes are more likely to fail from fatigue if tension is too *low*. Also, a wheel which has been ridden over plenty of miles has probably weeded out spokes that were going to fail from imperfections crystal grain structure.
As noted above, this only works if your new rim matches (or is very close to) the ERD of the old rim. Ideally spoke should thread all the way into the spoke nipple, and if your spokes are on the long or short side, you may be able to use a rim with slightly larger or smaller ERD, respectively.
It's also worth noting that the benefits aren't that great. The conveniences are just (a) not having to buy new spokes, and (b) not having to re-lease and re-seat the spokes. I have a wheel with nice 2.0/1.8/2.0 butted spokes that look to be in good shape (friend gave me the wheel after rim cracked on him) but I couldn't find a replacement rim in modern wider width that fits the E.R.D. So I bought new spokes to use on a rim with different ERD, and just re-used the beautiful Dura-Ace hub.
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