corynardin

I have a wheel set and the rims are shot but spokes, nipples and hubs are fine. I am pretty sure that any new rim would need shorter spokes (but I will check before buying of course) than the current wheels. Is there any reason why I can't just grind off the excess length and cut new threads? If so is there a stanard thread spec or better yet would you point to a cutting die?

Shimagnolo

Spoke threads are rolled, not cut.

https://www.youtube.com/watch?v=gDer5HJpbHA

AlphaDogg

AFAIK, whenever building a wheel, you have to start out with new spokes. Old spokes have flexed a lot in their lifetime and it would be ill-advised to use them.

Dan Burkhart 

Spoke threads must be rolled (formed) not cut. Most bike shops have some sort of spoke threading machine such as Hozan or Cyclo for doing limited numbers of spokes, or high end machines like Phil Wood for production runs.
Labour to rethread spokes will likely run as much or more than new straight gauge spokes, so the advantage is negligible.
Also, you can't really know how close the spoke elbows are to failure due to fatigue, so re using old spokes is not advisable, in my opinion at least.

dsbrantjr

No argument with the above comments, but since you asked the thread is 2-56 UNC.

corynardin

Thanks for information. It makes sense that the threads are rolled not cut since they will be much stronger that way. And thanks for the callout.

Doohickie

This. Lots of people re-use hubs. Rims get beat up. Spokes get fatigued, which eats into their life but is not visually identifiable. Spoke nipples get somewhat abused by truing wheels with crappy spoke wrenches. Hubs tend to avoid all that trauma and can be re-used, unless there are visual indications of damage.

If spoke nipples aren't abused they can be reused, but LBSs around here include them with new spokes, so I don't see any reason to re-use old ones except for when I am doing what I call a "reconditioning"- where I take everything to total slack, then tension and re-true the wheel.

HillRider

As Doohickie notes, good quality hubs can be reused and can outlast several rims. However, the economics of bicycle wheels being what they are, it's usually possible to buy equivalent quality complete wheels for less cost than having an existing hub relaced to a new rim with new spokes, even if you do the building yourself. If you have an LBS do the work, it's even less attractive.

That said, many riders do indeed build or rebuild their own wheels despite the cost penalty for the experience and pleasure of doing it themselves.

Doohickie

Indeed!

Shimagnolo

Then others of us just do the work ourselves because of miserable past experiences with the LBS *and* a supposedly-reputable well-known online shop. The former was too incompetent to even true a loosened factory-built wheel, and the latter cranked the tension so high the rims were cracking then refused to warranty their work.

When I build my own, I know the job was done correctly.

BCRider

Many a wheel has been rebuilt by buying a rim with the same ERD and mounting it to the old rim with masking tape and transferring the ends of the spokes to the new rim followed by regular tensioning and tuning. Around here it was apparently not uncommon to do this two or three times back before disc brakes when avid and frequent riders rode up and down the muddy west coat "Shore" trails and wore out a couple of rims a year due to the mud and rim brakes.

And doing it this way you ensure that the spokes all stay in their original positions so no new bends are needed. The only key is to find out what the ERD of your present rim is and buy a new one which matches it or is not different by more than 2 mm's to what you have now.

On the other hand if you're looking at going from a box section to deep section rim then get new spokes for all the reasons mentioned.

Looigi

When I build my own, I know who screwed it up.

HillRider

I guess I've been more fortunate than you. My favorite LBS has a very competent wheel builder and my experience with several sets of pre-built wheels from Colorado Cyclist has been nothing but positive.

corynardin

Doohickie, thanks for the pictures. I don't remember reading anything on sheldon brown about the use or beer in wheel building. It does seem like a key element however and perhaps it souls be updated to include it.

JohnDThompson 

You've heard of "spoke prep?" That thar is "builder prep" and just as important.

fietsbob

Hozan makes a thread rolling die, practical in a shop,
for making a few spokes from longer ones.

64 or 72? just buy some new ones.

Dan Burkhart 

The Hozan is a nifty little tool and I've gotten a lot of use out of mine. It's presumably not meant for doing large lots of spokes, but I've done many wheel's worth with mine, and only replaced the rollers a couple of times.
The thing to watch with this tool is to be sure you get the rolling head meant for stainless spokes, and it will last much longer. The base machine comes with the cheaper head for steel spokes unless you specify the upgrade.

Dan Burkhart 

Yeah, but as with any good thing, too much will ruin the result.