Drive each spoke tenon into its hub mortise with firm, square mallet blows until it bottoms out tight, then check the dish by laying a straightedge across the spoke tips: all tips must touch it together. A tilt error of only 1 degree shifts the tip of a 50 cm spoke sideways by 8.7 mm, so a spoke that fails the straightedge is re-seated or replaced before any felloe goes on.
Part of Wheelwright Craft
Driving is the seating of a shaped spoke tenon into a hub mortise, and fitting is checking and correcting the spoke’s angle and tightness before the rim goes on.
A Spoke Cannot Be Fixed After The Felloes Are On
Once the felloes are pinned on the spoke tenons, an error in one spoke is locked into the rim and fixable only by taking the wheel apart. So all the checking is done at this stage, with the spokes standing free in the hub.
What You Need
- Spokes shaped and test-fitted (Spoke Shaping)
- A hub with finished mortises (Mortise Cutting) on a stand that keeps it level
- A heavy mallet and a softwood block to cushion the spoke end
- A straightedge, long enough to span the diameter of the spoke tips
- A strip of hardwood veneer and hide glue for shimming (Hide Glue)
Method: Drive, Check, Correct
Step 1: Line up Align the tenon with its mortise square to the hub. A tenon started crooked splits the hub.
Step 2: Drive in a balanced order Drive spokes in opposite pairs, one and then the one across the hub, then the next pair, not around the hub in order. Spoked Wheels describes the same alternating order, to even out the driving stress on the hub. The carrier does not specify an order.
Step 3: Seat tight Drive each spoke home with firm, square blows. The tenon should bottom out in the mortise with a tight fit and the shoulder should sit against the hub with no gap.
Step 4: Check the dish Lay the hub flat on its stand with the spokes radiating outward and rest a straightedge across the tips of two opposite spokes, then rotate the straightedge round the wheel to check every opposite pair. All tips should touch it simultaneously; any tip standing off is a tilt or length error. Measure the distance from the straightedge to a fixed point on the hub face for each pair. The reading should be the same all round.
Step 5: Correct If one spoke is high or low, drive it a little further or lift it back out and check the mortise, rather than bending it into line.
Step 6: Treat a loose spoke If the tenon is loose in its mortise, glue a hardwood veneer shim on the tenon and drive it again. The carrier allows animal glue or none, trusting the tire to hold everything.
How Small An Error Shows
Tip offset from a tilt error = spoke length × sin of the error.
| Tilt error | Offset on a 50 cm spoke |
|---|---|
| 0.34° | 500 mm × 0.0059 = 3.0 mm |
| 1° | 500 mm × 0.01745 = 8.7 mm |
A third of a degree is already 3 mm, the upper end of the 2-3 mm out-of-round tolerance that Spoked Wheels sets for the rim, so a straightedge across the tips will show a bad spoke before any measuring instrument does. The 50 cm is an assumed round length, the same one used in Engineering Principles.
Common Mistakes
- Over-driving — hammering a tight tenon past its seat splits the hub between mortises; stop when the shoulder meets the hub.
- Bending a crooked spoke straight — it springs back after the tire goes on and the wheel goes out of true.
- Driving around the hub in order — builds up wedging stress on one side; use opposite pairs.
- Checking only a few spokes — test every opposite pair.
Safety
Heavy mallet work
Swinging a heavy mallet over a hub on a stand puts hands and eyes at risk of a glancing blow or a flying splinter. Stand clear of the line of the swing, wear eye protection, and make sure the hub cannot tip off its stand while you drive.
What’s Next
- Learn next: Felloe Construction — the rim that goes on these spokes
- Combine with: Engineering Principles — why the dish is checked