A Harken traveler car that rattles, feels gritty even after cleaning, or has visibly lost bearing balls needs a bearing rebuild kit, not just lubricant – Harken sells three kits (System A, Midrange, and Big Boat) matched to your track's width, and MAURIPRO stocks all three ready to order. This guide shows you how to tell a rebuild job from a lubrication job, measure your track to find the right kit, and see what the rebuild actually involves.
Harken traveler car rebuild kits at a glance
| Kit | Track system / width | What's included | Shop at MAURIPRO |
|---|---|---|---|
| Harken System A Rebuild Kit | Small Boat track, 22 mm (7/8 in) | End caps, car loader tool, and ball bearings for one car | Shop System A kit |
| Harken Midrange Non-Captive Bearing Car Rebuild Kit | Midrange track, 27 mm (1 1/16 in) | End caps, car loader tool, and ball bearings for one car | Shop Midrange kit |
| Harken Big Boat Car Loader Kit | Big Boat track, 32 mm (1 1/4 in) | End caps, car loader tool, and ball bearings for one car | Shop Big Boat kit |
| Harken Traveler Car, 27 mm, Shackle, 4:1 | Example Midrange non-captive car this guide applies to | One-piece aluminum car, ball bearings on Hardkote-anodized races | Shop this car |
Harken's classic traveler track lineup – Small Boat, Midrange, and Big Boat – uses cars that ride on recirculating ball bearings rather than the captive-bearing cars found on Harken's newer High-Load line. That difference matters for maintenance: a captive-ball car can usually be serviced in place with a drop of bearing conditioner, but a recirculating (non-captive) car's balls aren't retained inside the car body, so a full bearing reload eventually becomes the only real fix. This guide is written for owners doing that job themselves between haul-outs.
Does your traveler car need a rebuild, or just lubrication?
Not every sticky or noisy traveler needs a full teardown. If your car still moves but feels gritty or resists under load, start with a fresh-water rinse and the correct bearing lubricant – our traveler car lubricant guide covers that routine in detail. A rebuild kit is the next step up, and it's the right call when:
- The car rattles side to side on the track even under load, a sign bearing balls are missing or worn undersized.
- You can see or hear loose or spilled ball bearings after removing an end cap for inspection.
- Lubrication doesn't fix the grittiness because the car is a non-captive design and the balls themselves – not just their surface film – are worn.
- An end cap is cracked, missing, or won't seat securely, which lets water and grit into the bearing race.
What's the difference between a captive and a non-captive (recirculating) traveler car?
MAURIPRO's own Harken traveler car buying guide draws this line directly: a ball bearing (recirculating) car uses stainless balls that circulate through the car body for the lowest friction under load, at the cost that "bearings can spill during service." A captive ball car holds its balls in place inside the car, trading a bit of efficiency for a design that's easier to store and service without losing hardware. The System A, Midrange, and Big Boat kits in this guide are built specifically for the recirculating type – that's why Harken and MAURIPRO both label them "non-captive bearing" kits. If your car is a newer High-Load, captive-bearing design instead, a rebuild kit like these isn't what it needs; routine OneDrop lubrication in the bearing races is.
How do you know which Harken bearing kit fits your car – System A, Midrange, or Big Boat?
Harken's classic traveler track comes in a few standard widths, and the car has to match the track it rides on – a car sized for one width won't ride correctly on another. For the three non-captive rebuild kits MAURIPRO stocks, the match is straightforward once you measure the track:
| Track width | Harken system name | Rebuild kit |
|---|---|---|
| 22 mm (7/8 in) | Small Boat / System A | System A Rebuild Kit (HSB501) |
| 27 mm (1 1/16 in) | Midrange | Midrange Non-Captive Bearing Car Rebuild Kit (HMR99) |
| 32 mm (1 1/4 in) | Big Boat | Big Boat Car Loader Kit (HBB1) |
Measure the track's overall width (the outer beam, not the slot the car's toggle rides in) with calipers or a tape measure, and check that number against the table above. If you still have the car's original packaging or a part number stamped on the car body, that's the more reliable way to confirm the match – track width alone gets most owners to the right kit, but a stamped part number removes any guesswork.
What's actually inside a Harken traveler car rebuild kit?
All three kits share the same basic contents, sized for their track: a set of replacement end caps, a small bag of Torlon ball bearings, a plastic car loader tool used to control the balls during the swap, and a printed compatibility chart cross-referencing Harken traveler car part numbers to the correct kit and ball count. Each kit services one car.
How do you rebuild a non-captive ball-bearing traveler car?
The mechanics are similar across all three kits; only the size of the parts changes. In general terms:
- Confirm your kit matches your track using the width table above before you start – and have the full kit on hand, since a recirculating car's balls can spill and scatter once an end cap comes off.
- Remove the traveler car from the track and take off one end cap to expose the bearing race.
- Use the plastic car loader tool supplied in the kit to control the ball bearings as the old ones come out and the new ones go in – it's shaped to guide the balls into the race without losing them, which is the main point of failure in a DIY rebuild done without one.
- Load the new bearings from the kit into the race using the loader, following the ball count on the kit's compatibility chart for your specific car model.
- Reinstall the end caps and tighten the fasteners fully so they don't work loose under repeated cycling.
- Reinstall the car on the track and cycle it end to end by hand before reloading the mainsheet, checking for smooth, even rolling with no grinding or side-to-side play.
Harken's own kit contents vary slightly by exact car model, which is why the printed compatibility chart in each kit – not just the track width – is worth checking before you begin.
How often does a traveler car need a full bearing rebuild versus just cleaning?
Neither Harken nor MAURIPRO publishes a fixed mileage or calendar interval for a full bearing rebuild – it's a condition-based job, not a scheduled one. Rinse and lubricate first at spring commissioning and whenever the car feels gritty; reach for a rebuild kit only once you've confirmed the issue is worn or missing bearings rather than dirt and dried-out lubricant. A well-maintained recirculating car on a cruising boat can go seasons between rebuilds; one on a boat that's raced hard or left un-rinsed after saltwater sailing will wear its bearings faster.
Frequently asked questions
How do I know if my traveler car is a captive or non-captive design?
Check your car's model listing or the part number stamped on the car body. As a rule of thumb, Harken's classic Small Boat, Midrange, and Big Boat traveler cars use recirculating (non-captive) bearings, while the newer High-Load line uses captive bearings that stay retained in the car during routine lubrication.
What size track do the System A, Midrange, and Big Boat kits fit?
System A fits 22 mm (7/8 in) Small Boat track, the Midrange kit fits 27 mm (1 1/16 in) track, and the Big Boat kit fits 32 mm (1 1/4 in) track. Measure your track's outer width to confirm before ordering.
Can I reuse the old ball bearings instead of buying a full kit?
It's not a reliable fix. Once bearings are worn or have spilled during a prior service, reusing a partial or mismatched set typically leaves the car running rough again quickly – the kits exist because a full, correctly sized set restores even rolling.
Does a rebuild kit fix a car that's rattling side to side?
Usually, yes, if the rattle is caused by missing or worn bearing balls rather than a bent track or a damaged car body. Inspect the track and car body for physical damage first; if those check out, a bearing rebuild is the next step.
Do I need anything besides the kit to do this job?
The kits include the end caps, bearings, car loader tool, and threadlocker needed to service one car. Basic hand tools to remove the car from the track and its end-cap fasteners are the only things you'll need to supply yourself.
Recommended gear
- Harken System A Rebuild Kit (HSB501) – for 22 mm Small Boat track cars.
- Harken Midrange Non-Captive Bearing Car Rebuild Kit (HMR99) – for 27 mm Midrange track cars.
- Harken Big Boat Car Loader Kit (HBB1) – for 32 mm Big Boat track cars.
- Harken Traveler Car, 27 mm Midrange, Shackle, 4:1 – an example non-captive car this rebuild process applies to.
Shop all Traveler & Genoa Car Accessories & Spares →
You may also be interested in
- What Lubricant Should You Use on a Sailboat Traveler Car Track?
- How to Use a Mainsheet Traveler on a Sailboat
- Harken Traveler Cars: Smooth, Efficient Mainsail Control (Selection Guide)
About the author: Written by the MAURIPRO Rigging Team – MAURIPRO Sailing has outfitted cruisers and racers since 2003, and our rigging specialists spec and maintain deck hardware, including travelers, tracks, and genoa cars, on boats in the 30–45 ft range. Facts in this guide are drawn from Harken's and MAURIPRO's own product listings for these rebuild kits.
Last updated: August 19, 2026