Cycling UK Forum

If you are breaking nipples its usually because the spokes are too short. There needs to be a good length of spoke inside the nipple, (ideally it should come to the bottom of the screwdriver slot in the nipple) and the strength of the spoke supports the load, not the nipple.
If the nipples are "pulling through the rim" then the rim has failed and you can't repair it simply by replacing the nipple.

In any case, multiple failures in under a year is "not of merchantable quality" and you should be offered either total replacement or a competent repair, at your option, I believe, but I'm not expert in consumer law.

horizon wrote: ↑31 Jan 2024, 11:25pm The ERD of the Exal is 601 (Spa Cycles), the CR18 620 (https://www.bikeforums.net/bicycle-mech ... m-erd.html). So I presume you mean that is 10 mm on either side of the rim. That seems quite a lot for similar rims - does that make the Exal a rather shallow/weaker rim?

I'm presuming that while a small difference could have been taken up by the spokes, 10 mm is way out and will require new spokes.

Your link is talking about 27 inch rims and 620mm ERD .

Presumably an old Maillard hub, I think it’s a long time since they were made?
So why subject old hub flanges to stresses they weren’t designed for?
I would be tempted to build 3 cross to protect the flanges; then you will need to address the angle where spokes enter the rim.

Tape the new rim to the old one and move the spokes across.
Snag is likely to be that you get spokes crossing where the valve is, because you need to line up the angle of the spoke nipples NOT the valve hole.

What rim is it currently?
To straighten a bent rim you need to take it past “straight “ so that it takes a set at “straight” …. Just the same as straightening anything else.
If you haven’t taken it to bits, I have had success slackening all the spokes, making a trestle to support the rim while I hook the bent bit under the workbench top and lean down on the wheel

I think the spokes are all the same material. Working the material to a blade shape won’t change the properties of the wire at the elbow, which is why I wonder if the flat spokes flex where flat not at the elbow

NickJP wrote: ↑18 Dec 2023, 4:28am When building wheels with blade spokes I use the DT Swiss Squorx (Torx head) nipples and the Squorx driver, which means there is no spoke key to interfere with using a slotted tool to hold the end of the bladed section of the spoke to prevent wind-up.

That should work.
Sapim( I think) used to have on their website a comparison of how many fatigue cycles their various spokes would last before failing, on a test rig.
The cynic in me wonders if the outstanding performance of their bladed spokes in this test was because the spokes flexed in the blade rather than at the elbow.
Bladed spokes are something I have never tried.

3x Rohloff is OK with Rigida Andra, because the rim drillings are angled to suit 3x and a big hub.
Rims with “ordinary” drilling are better with 2x because 3x spokes approach the rim at an unhelpful angle.

rareposter wrote: ↑29 Nov 2023, 10:41am

Pinhead wrote: ↑29 Nov 2023, 9:04am This post is really confusing, just what is it about spokes ?

I have never had one break, even bend, when did I last need to tighten one, never, change one, never am I alone ?

I wouldn't worry about it, this forum has a few folk on it who could discuss really really arcane and largely theoretical aspects of spokes, wheels and wheelbuilding not only until the cows come home but long after the cows have all gone to bed!
And they'd probably still be chatting about spoke tensioning when the cows woke up for breakfast.

Arcane and theoretical until you are on a moving-on tour and your wheel becomes unusable.
If your longest ride is 20 miles from home you probably haven’t come across this.

The old idea with 40 spoke rear wheels was 4 cross so that spokes were fully tangential to the (small ) flange.
However, with a big hub (eg electric) spokes fully tangential to the flange approach the rim at an unhelpful angle, so 2 cross for example is a better compromise.

The current normal practice is to “tuck under” the last crossing, but I don’t see why it makes any difference

I have to say I’m conflicted over this; Spa’s way of building wheels on touring width rims is to use 13/14g spokes driveside, and double butted elsewhere, so I have built plenty of wheels like that, and they didn’t come winging back with broken spokes.
Brucey says stress relieving 13g spokes effectively is problematic, and I think he probably knows.
I think 14g spokes (or14/16 butted) can be properly supported at the flange, provided you get the spoke line right, get a reasonable match between spoke elbow length and flange thickness ( or use washers) and stress relieve effectively.
I have dis-assembled a few wheels which have been built and stress-relieved but not ridden (eg because the rim joint is poor) and the spoke elbow has already bedded - in and created it’s own dent in the flange , so I think that’s as well “supported” as it can get?

iandusud wrote: ↑27 Nov 2023, 3:27pm …………For this reason where I feel a stronger spoke is warranted (tandem for example) I prefer to use single butted spokes to get the extra strength at the hub, which is the weak point. …….

That’s one of those things which sound right………
However, spokes fail at the elbow due to fatigue.
3stages of fatigue;
Crack initiation
Crack propagation
Failure
The long phase is crack initiation. More metal to go at will make crack propagation take longer, but (as far as I know) won’t delay initiation.
In fact, it’s probably more difficult to get the spoke line just right with the thicker spokes.

It’s pretty easy to get a good idea of the spoke length in an assembled wheel. Nipple length is pretty much a constant across brands of spoke, so the length of nipple visible outside the rim shows you how much nipple is inside the rim; usually not much more than the round head of the nipple in normal rims, and you probably won’t be getting exotic rims.
Counsel of perfection is the spoke end should reach the bottom of the screwdriver slot in the nipple; people report nipples failing if spokes aren’t inserted far enough, it’s pretty rare in my experience. Offer up a spoke, I think too short is better than too long; the spoke you want should probably extend a millimetre or so into the rim.

To put on a duvet cover, first turn it inside out; then put your hands inside the cover at the two top corners; grasp the two top corners of the duvet and shake the cover over the duvet.
This method attributed to Liverpool school for the blind.

Mixing butted spokes and plain gauge (14) spokes is unlikely to make any difference in the real practical world.

It’s possible to straighten a bent rim without taking the wheel apart. It’s best to slacken the spokes in the affected area before you bend the rim, otherwise you alter the spoke tension at the same time.
However I have approximately straightened a wheel at the side of the trail, by carefully controlled jumping on the wheel