Measure from the spoke nipple hole to the spoke tip
To find the correct spoke length, measure from the inside of the rim (where the spoke threads into the nipple) to the end of the spoke. Place your ruler or caliper at the hole in the rim where the spoke enters, then measure straight across to the spoke's threaded end. This distance is your spoke length, and it is what you order when you need replacements.
The measurement matters because spokes come in half-millimeter increments — a 290 mm spoke is different from a 292 mm spoke. If you order the wrong length, the spoke will either not thread far enough into the nipple to hold tension, or it will bottom out before you can tighten it properly. Either way, the wheel will not be rideable.
You do not need expensive tools. A ruler, measuring tape, or digital caliper all work. The caliper is fastest and most accurate, but a ruler taped to the spoke works fine if you are careful to measure perpendicular to the rim.
Key Takeaways
- Measure from the inside of the rim hole (where the nipple sits) to the very end of the spoke's threaded portion.
- Spokes are sold in 2 mm increments, so a measurement of 291 mm rounds to either 290 mm or 292 mm depending on your rim and hub.
- A digital caliper gives the most accurate reading, but a ruler or measuring tape works if you hold it perpendicular to the rim.
- Measure at least two spokes on the same wheel to confirm the length, because some wheels have mixed spoke sizes.
Gather the right tools for an accurate measurement
A digital caliper is the fastest tool for this job. It measures to the nearest millimeter and takes the guesswork out of reading a ruler. They cost between $10 and $25 and are worth having if you work on bikes regularly. Open the caliper jaws, slide one jaw into the spoke nipple hole in the rim, and close the other jaw against the spoke's threaded end. Read the display.
If you do not have a caliper, a ruler or measuring tape works just as well, though it takes more care. Lay the ruler flat against the spoke so it crosses the rim hole perpendicularly — not at an angle. Mark where the spoke's threaded end meets the ruler, then read the distance from the rim hole to that mark. A metal ruler is easier to read than a cloth tape measure.
Some people use a spoke length gauge, a small metal tool with notches for common spoke sizes. You slide the spoke into the notches until it fits snugly, and the notch tells you the length. These are inexpensive but only work if your spoke length matches one of the standard sizes the gauge covers.
Measure multiple spokes to catch mixed sizes
Measure at least two spokes on the same wheel, preferably on opposite sides of the rim. Some wheels — especially older ones or those that have been repaired — have spokes of different lengths. If you measure only one spoke and it happens to be the odd one, you will order the wrong size for the rest of the wheel.
If you find two different lengths, measure a third spoke to figure out which is the standard size. The length that appears more often is the one you need. Write both lengths down and keep them for future reference.
If you are replacing a single broken spoke, measure the unbroken spokes around it, not the broken one. A broken spoke may have been bent or shortened in the crash, so its measurement will not tell you what length to order.
Account for the difference between rim and hub measurements
Spoke length depends on both the rim diameter and the hub flange diameter. A wheel with a larger hub needs shorter spokes because the hub flanges are farther from the center. A wheel with a smaller hub needs longer spokes. This is why you cannot use a spoke length from one bike on another bike without checking — even if both rims are the same size, the hubs might be different.
When you measure the spoke, you are already accounting for both the rim and hub because you are measuring the actual spoke in the actual wheel. That is why direct measurement is more reliable than trying to calculate spoke length from rim and hub specifications. Measure the spoke that is already in the wheel, and order the same length.
Common mistakes that lead to wrong measurements
The most common error is measuring from the wrong point on the rim. Some people measure from the outer edge of the rim instead of from the inside of the nipple hole. This adds several millimeters to your measurement and gives you a spoke that is too long. Always measure from the inside of the hole where the nipple sits, not from the rim's outer surface.
Another mistake is measuring at an angle instead of straight across. If you tilt the ruler or caliper, the measurement gets longer. Hold the measuring tool perpendicular to the rim — at a right angle — so the measurement is straight from the hole to the spoke tip.
A third error is measuring the spoke's total length instead of just the threaded portion. The spoke has a bend near the hub (called the elbow), and you measure only from the rim hole to the end of the threads, not all the way down to the elbow. If you include the elbow in your measurement, you will order a spoke that is too long.
What to do if you cannot measure the original spoke
If the spoke is too damaged to measure, or if you do not have the original wheel, you can order a spoke and test it. Buy a spoke that is close to what you think you need — within 2 mm — and try threading it into a nipple. If it threads smoothly and has at least 3 to 4 mm of thread left when fully tightened, that is the right length. If it bottoms out before tightening, you need a shorter spoke. If it does not have enough thread to hold tension, you need a longer one.
This test-and-order method costs a bit more in shipping, but it is faster than trying to calculate spoke length from rim and hub measurements, especially if you are not sure of those measurements.
Frequently Asked Questions
Do I need to remove the spoke from the wheel to measure it?
No. You can measure the spoke while it is still in the wheel. In fact, it is easier that way because the rim hole stays in place and gives you a fixed starting point. You only need to remove the spoke if it is so damaged that you cannot read where the threads end.
What if my measurement is between two standard sizes?
Round down to the smaller size. If you measure 291 mm, order 290 mm. A spoke that is slightly too short will have more thread in the nipple, which is safer than a spoke that is slightly too long and bottoms out before tightening.
Can I use the same spoke length on the drive side and non-drive side of the wheel?
Usually yes, but not always. Most wheels use the same length on both sides. Some wheels — particularly track bikes or wheels with very high spoke counts — use different lengths on each side because the hub flanges are different distances from the center. Measure both sides to be sure.
How do I know if a spoke is the right length once I install it?
When the spoke is fully tightened in the nipple, you should see 3 to 4 mm of thread still visible above the nipple. If the thread disappears completely into the nipple, the spoke is too short. If the spoke bottoms out and will not tighten further, it is too long.