Trimming Spoke excess length off ends
 

Hi wondering how to trim off excess spoke length off wheels built with double wall rims. I normally just grind the ends off with a small angle grinder on a single wall rim, but these ones are down 9mm holes.

I have tried a small grindstone in a drill chuck but that made no visible progress.

Is there some sort of millling cutter or chuckable file that I can use, or maybe needlenose plier type cutters? I don't fancy taking the spokes out to trim them. Regards Bill P

Pardon my asking, but if its below the 2nd wall, why trim them? They shouldn't be much more than a millimeter or so above the top of the nipple if properly sized anyway.

Hi Maxx, They're at or +/- 1mm at the upper wall, i prefer to have them end as close as possible to the nipple, which is 4mm down the hole. (The spokes are sized for single wall rims).

Might have to take them out and chop them

so the spokes protrude 5mm from the nipple? Something isn't right there. Spokes aren't sized differently for single or double walled rims.

Ummm, try building the wheel with the correct length spokes?

Um... sorry but yes they are. At least typically they would be. It all depends on the rim and what diameter it sits the nipples at. But typically a single wall rim, just a basic U channel shape really, will hold the nipples at a larger diameter than on a double wall rim. So you need shorter spokes for a double wall rim compared to a single. It's all based on the Effective Rim Diameter (ERD) spec that's used to size the spokes along with the crossing number and the hub diameter.

BillP, there's no need to break down the wheel and cut them down. If you grind down the ones protruding through the holes in the inner wall that's all you need to do. Otherwise if you're going to break down the wheel you'll have to completely despoke it, cut the spokes and trim the ends to smoothen the entry of the threads so they go back in the spokes. At that point you'd be far better off buying new spokes in the correct sizes. It'll cost a little but save you a whole heap of time.

The amount sticking out isn't doing any harm at all other than the bits sticking up into the inner tube area. If you trim those ends it's all good.

Um, If I were hypothetically building two identical wheels, except that one had a double wall rim, and one had a single wall rim, but both rims have the same ERD, (remember hypothetically here, we can discuss the technicalities of this until we are blue in the face, but it really wont do any of us any good) the wheels will have the same length spokes.
Sizing spokes is has nothing to do with whether the rim has a single wall, double wall, or 100 walls, its all based on the ERD.

If the spokes are sticking out of the top of the nipple 5mm, there is a problem. The spokes are too long, and the nipples dont have many threads left to grasp on the spoke.

All that extra rotating weight !!!

You must have had a heck of a lot of threads to start with to have that much come out the other end of the nipple.

Thanks BC Rider for the considered response. I'm running pretty thin tubes and I'm sure they will want to jam themselves down the hole just to impale themselves on the spoke ends. Think I'll use some stiffer rim tape. Bill P

Yes, if the ERD is the same then yes they would use the same spokes. But generally the sections used for double wall rims will have a smaller ERD than single wall rims just due to their design since the outermost wall will be pretty close to the single wall center and the second part of the double wall has to be located further inwards to form the cavity between the two walls.

In fact since his wheel has the spokes sticking up generally to the lower portion of the outer center trough I'd be willing to put money on the idea that a previous owner had a single wall rim on there and it got damaged and so he bodged on this double wall using the original spokes and that's why they are sticking out so far from the nipple ends but only up to the outer wall which is roughly where the single wall rim would have been.

SPot On BC rider. The original single wall rolled steel rim ERD is about the same dia as the outer wall of the new extruded al rims. The bodger is me however. And proud of it.

We might be getting some terms mixed up here. There's BSD - bead seat diameter. That's the ETRTO size you see in fine-print on the tyre. If you look at the Sutherland's manual in the wheel-building section, there's a correction for rim-depth of various models. These range from -3mm to -50mm or more depending upon how deep the rim is. Basically ETRTO minus rim-depth = ERD effective rim-diameter. That's the diameter where the nipple-heads would lay.

Yes, it's called an end-mill.

What I want to know is how they managed to spin the nipples down far enough so that there's 5mm sticking out above? Most nipples would bottom out with 2mm sticking up.

Nothing wrong with bodging. It's making the best of what you've got. A time honored tradition.

Danno is right though. I'm also surprised that you were able to make those spokes work. They must be bottomed on the threads by now or even worked down a hair past them. Perhaps even some of the tension you felt was the nipples running out of thread and screwing onto the unthreaded portion.

Ummmm.... how many crosses are there? You haven't calculated for 3X and done a 2X relace, have you? Just asking in a polite way.

Thanks Danno, Had a look at an small end mill earlier today at a hardware store. Just wondered how much it would dance around in a handheld drill chuck.

I've got heaps of threads and the lacing pattern is the same. Maybe going 4x would use up a bit.

Seems to me that going to double walls is always going to require shorter spokes unless the nipples can be seated on the outer wall.. . Now there's a thought... might check those eyelets ! Bill P.

According to some calcs I did on some 700C rims I did a couple of weeks ago, going the extra cross would soak up around 5mm +-, but that was 3X compared with 2X. The extra cross, assuming the hubs can take the angle, might be a very cost efficient and speedier solution.

Just back from the shed. (Cadel's on TdF ) I've hit the spoke ends with a 4" grinder and they're now 0.5mm or 0.75 below the outer wall. I reckon that might be ok. I've also run a length of fibreglass tape around the rims (gyprock stuff) , underneath a beefy rim tape. D'ya think i'm home?

Sounds like you've done a fine job! No worries about the spokes poking through. Although I still wonder about mangled nipple threads having been forced over the solid portion of the spoke by 3-4mm...