Ordering windscreen wipers for a classic vehicle is easy when you measure the right things. For accurate results, it’s essential to measure windscreen wipers precisely. This step-by-step guide is designed for classic style wipers, old school wipers, hot rod wipers, and Kit Car Windscreen Wipers where fitment matters.
WHAT YOU NEED
- Tape measure (or ruler)
- Smartphone camera
- 5 minutes
STEP 1 — MEASURE BLADE LENGTH
Measure each blade end-to-end. Many classics use different driver/passenger lengths, so measure both sides.
Tip: If your current blades contact trim or the windscreen edge at full sweep, go shorter.
STEP 2 — CONFIRM THE CONNECTOR AND ARM WIDTH (5.2mm vs 7.2mm)
Classic bayonet setups typically use:
- 5.2mm arm width (bayonet)
- 7.2mm arm width (bayonet)
Examples here: Wiper Blades – Universal Archives – Classic Wipers and Mirrors
Tip: A blade that “almost fits” often indicates the wrong arm width. Measure the arm width at the bayonet end, as it’s part of how you measure windscreen wipers correctly.
STEP 3 — IDENTIFY YOUR DRIVE SIZE (COMMON CLASSIC SPLINED OPTIONS)
Many classic systems use splined drives and plain shafts. Three common references you’ll see are:
- 9/16″ (14mm) splined drive (often referenced as Lucas style)
- 5/8″ (16mm) splined drive
- 1/4″ (6.5mm) plain shaft
Tip: If you’re replacing arms, confirm your splined or plain shaft drive size as well as your bayonet/arm width.
STEP 4 — PHOTOGRAPH THE MOUNTING STYLE
Take photos of:
1) The arm base where it attaches to the post
2) The post/spindle with the arm removed
This prevents the most common ordering errors on old Holden wipers, old Ford wipers, and old Chrysler wipers.
STEP 5 — MEASURE ARM LENGTH (CENTRE-TO-TIP)
Measure from the centre of the mounting point to the blade attachment point. This helps confirm reach and park position. Additionally, always measure windscreen wipers from centre to tip for best fitment.
STEP 6 — CHECK CLEARANCE AT FULL SWEEP
Confirm:
- No contact with windscreen rubber, trim, bonnet edge, or mouldings
- No collision between blades
- No binding or stalling
STEP 7 — HOT ROD / KIT CAR SETUPS: CONFIRM THE SYSTEM PLAN
Custom builds vary. If you’re running hot rod wipers or Kit Car Windscreen Wipers, confirm the wiper arrangement, mounting style, sweep requirements, and desired park position before buying. If you’re also installing wiper switches, decide switch location and wiring route early—before trim and paint go on.
TIPS & TRICKS
- Don’t order by “model name” alone—measure first.
- Confirm 5.2mm vs 7.2mm arm width early; it’s one of the biggest causes of incorrect fitment.
- If the wipe is uneven, arm tension and alignment may be the true problem.
FAQ
Q: What measurements matter most before ordering wipers?
A: Blade length (each side), bayonet/arm width (5.2mm or 7.2mm), drive size (if splined), and clearance through the full sweep. As a rule, before buying, always measure windscreen wipers carefully to avoid fitment headaches.
Q: Do classics often use different blade lengths left and right?
A: Absolutely. Just about every classic vehicle is different, but most manufacturers share the 5.2mm and 7.2mm width bayonet/blade attachement
Q: What’s the difference between 9/16″ (14mm) and 5/8″ (16mm) splined drive?
A: They are different splined drive sizes; confirming the size helps ensure the arms seat correctly on the post.
Q: Why does bayonet width matter so much?
A: If blade and arm width don’t match, the fit can be loose and wiping performance suffers.
Q: Should I think about wiper switches during planning?
A: Yes—switch placement and wiring is best decided before final trim, especially on kit cars and custom builds.
