Description of The Problem: The nipples connecting the spokes to the rim have partially or fully stripped edges. As a result, the spoke wrench cannot grab the nipple and rotate it to true the wheel.
Modified Nipple Driver
Regular nipple drivers are meant to be used only for the initial treading of the nipples on the spokes. Hence why they have a sticking probe in the middle. It’s there to prevent overtightening of the spokes and ensure that all spokes have the same initial tension.
One can make a modified nipple driver with the opposite structure – a cut in the middle meant to accommodate the end of a spoke sticking out of a nipple.
I made a nipple driver like that from a cheap screwdriver by filing the middle with a rotary tool. A small file will work too, but the process will take more time.
Тhe modified nipple driver can be used to tighten or untighten the nipples from the side of the rim on which the tire sits.
To do that, one will have to gain access to the nipples’ ends by removing the tire as well as the rim strip.
Note: It’s recommended to drop some oil on the nipples to reduce friction and facilitate their rotation.
If you don’t have access to new nipples, you can use this method to true the wheel somewhat, but it’s not a good long-term solution because you will have to strip down the wheel every time you need to adjust a spoke.
Pliers + Flathead Screwdriver
Another way to remove a round nipple is to use a set of pliers and a flathead screwdriver.
The procedure is as follows:
- Grab the nipple with pliers as firmly as you can while making sure that the jaws of the pliers are not in contact with the spoke. You can wrap something (e.g., duct tape) around the spoke for extra protection. Then, rotate the nipple counter-clockwise.
- Periodically, check if the nipple is unscrewing.
- After a few turns, it will be possible to unscrew the nipple from the outside via a basic flathead screwdriver.
Downsides of this method:
- The pliers may fail to untighten the nipple while also damaging it severely.
- The pliers may damage the spoke if the user is not careful
- The nipple will be completely destroyed. This may be a problem if you don’t have a spare.
Cut the Spoke
If nothing works, and the nipple is completely damaged and thus you can’t access it from either side, the only solution is to cut the spoke connected to the nipple. Once the spoke is cut, you can remove it from both ends.
The downside of this approach is that you lose a spoke. If you don’t have a spare, you won’t be able to re-build the wheel. And if the spoke is of custom length not available at a bike store, the issue worsens.
To cut the spoke, you can use a set of pliers designed for cutting brake cables and housing. They work very well for this task too.
FAQ: What causes rounded nipples?
Nipples are made from brass and aluminum instead of stainless steel to prevent galling – abrasive wear occurring when two metals are in contact with one another.
Unfortunately, brass and aluminum are soft metals and can easily be damaged by a spoke wrench made of hardened steel. If the wrong size spoke wrench is used and it slips, the nipple will be cut and will gradually round.
Tips To Prevent Rounded Nipples
One of the ways to reduce nipple damage is to work slowly. Make sure that the spoke wrench is of the right size and fully wrapped around the spoke. Only ten rotate the wrench.
Spokes and nipples get dirty. The extra grid can cause corrosion and make the nipple seize. Hence why it’s helpful to drop a bit of oil on every nipple before truing or disassembling a wheel.
High-quality Spoke Wrenches
Generic spoke wrenches like the one below grab the nipple only from two sides and can easily strip the edges.
For that reason, some manufacturers make spoke wrenches that grab 3 or even 4 ends of the nipple. As a result, the tension is spread more evenly and the chances of a spoke wrench slipping and damaging the nipple are lower.
Use Tall High-quality Nipples
The quality and height/length of nipples matter too. Avoid cheap, short nipples. The longer the nipple is, the more surface area the wrench has to work with. Consequently, the chances of damaging the nipple diminish.
Summary: What You Need To Know
Rounded spoke nipples are the result of:
- A low quality spoke wrench
- Using a spoke wrench of improper size
- Rushing the wheel building process
(When the spoke wrench slides, the stainless steel that the wrench is made of damages the soft brass or aluminum nipple.)
If the nipple is round, and you have to true the wheel or disassemble it, the options are:
- Use a modified nipple driver to unscrew the nipple from the outer side.
- Use a set of pliers to unscrew the nipple from the hub side and then unscrew the nipple with a regular flathead screwdriver from the tire side.
- Cut the spoke and replace it.
To prevent a round nipple consider the following tips:
- Lubricate the nipples before manipulating them.
- Use high-quality spoke wrenches – preferably models that grab the nipple from multiple sides
- Don’t rush the process
- Use longer, high-quality nipples