Shipping heavy auto parts and tools can be expensive, whether you run an ecommerce store or just need to send a spare car part occasionally. Items like brake assemblies and power tools often weigh dozens of pounds, which drives up shipping costs. Luckily, there are strategies to keep costs down by choosing the right carriers, services, and partners. This guide will walk you through the cheapest ways to ship heavier auto parts (5–75 lbs) without special handling needs. We’ll compare major carriers (USPS, UPS, FedEx), explore flat-rate vs. weight-based shipping, and show how third-party logistics (3PL) providers like eFulfillment Service can save you up to 80% on heavy shipments.

Common heavy auto parts to ship include:

• Brake rotors and drums: Dense metal parts (~10–20 lbs each)

• Struts and shocks: Suspension components that can weigh 5–15 lbs each

• Starters and alternators: Heavy electrical units (often 10–25 lbs)

• Tool kits and power tools: E.g. an impact wrench kit or mechanics’ tool set (20–50+ lbs)

• Engines/transmissions (partial): Smaller engine parts or assemblies (often approaching 70 lbs limit)

These kinds of items are hefty and often weight-dense, meaning shipping charges can get steep. Below, we’ll discuss how to minimize those charges.

Jump right in: The Cheapest Way to Ship Heavy Auto Parts

• Understanding the Challenges of Heavy Shipments
• USPS vs. UPS vs. FedEx – Which is Cheapest for Heavy Auto Parts?
• Saving Even More: Use Third-Party Logistics (3PL) for Heavy Items
• Summary

Understanding the Challenges of Heavy Shipments

Shipping costs generally increase with weight, distance (zones), and package size. Heavy auto parts trigger higher base rates, and if the box is large, you may face dimensional weight pricing (charged by size rather than actual weight). For example, USPS applies a “balloon” or dimensional rate if a package exceeds 1 cubic foot, which can double the price for a bulky item. UPS and FedEx also use dimensional weight for large boxes, though their thresholds and surcharges are a bit more forgiving, making them cost-effective as box size grows.

Key cost factors for heavy parts:

• Weight-based charges: Carriers charge more as package weight increases. Rates jump especially at certain weight breakpoints (e.g. above 5 lbs, 20 lbs, 50 lbs, etc.). Heavy shipments (50–75 lbs) can be several times more costly than light parcels if using standard rates. 
• Distance (Shipping Zone): The farther the destination, the higher the rate in weight-based shipping. A 50 lb box sent coast-to-coast costs far more than the same box sent to a neighboring state. 
• Package dimensions: Heavy auto parts are often compact, but if you’re shipping something like a pair of rotors or a large tool set, the box size might trigger DIM pricing. Avoid empty space in the box and use snug packaging to minimize dimensions. 
• Handling surcharges: Carriers may add fees for very heavy packages. UPS and FedEx apply “Additional Handling” or “Heavy Package” surcharges for items over ~50 lbs. These are typically around $15–$25 extra. USPS doesn’t surcharge for heavy weight specifically, but has strict 70 lb weight limits and size limits.
• Packaging needs: Heavy metal parts need sturdy boxes (double-walled corrugate) and ample cushioning to prevent damage. While packaging won’t directly change the shipping rate, it can add a bit of weight. More importantly, good packaging avoids damage that could lead to costly returns.

USPS vs. UPS vs. FedEx – Which is Cheapest for Heavy Auto Parts?

When it comes to heavy shipments, no single carrier is always cheapest. The best option depends on the package weight, size, and where it’s going.

USPS: Flat-Rate Boxes = Small, Dense, Cheap

• Sweet spot: pieces that fit a Flat Rate box (up to 70 lb). Think brake rotors, compact tool kits, alternators.

• Pricing magic: the Large Flat Rate ships coast-to-coast for roughly $20–25, whether it weighs 5 lb or 50 lb. That can undercut weight-based rates by $60 or more.

• Limits to know: over 70 lb or bigger than 12″ × 12″ × 6″? USPS taps out. Priority (by weight) also climbs fast past 20 lb and far zones, often overtaking UPS or FedEx.

• Best use case: heavy-but-small parts headed long distance. Nearby shipments up to ~20 lb are fine too. Anything bulky—or 71 lb+—needs a different ride.

UPS: The Heavy-Duty Workhorse

UPS Ground loves the 20-150 lb range and doesn’t blink at big boxes.

• Rates: routinely the lowest for hefty parcels. A 30 lb starter motor heading two states away? UPS often beats USPS by double-digits.
• Reliability: detailed tracking, guaranteed delivery windows—handy when you’re shipping pricy parts.
• Gotchas: “Heavy Package” stickers (+$ 15ish) kick in over 70 lb, and outsized dimensions draw surcharges. Remote ZIP codes can add a small sting.
• When to choose it: once your box tips the teens—or Flat Rate won’t work—UPS Ground is the go-to for speed and price.

FedEx: Neck-and-Neck with Big Brown

• Capacity: identical limits to UPS (150 lb, 108″ length).

• Cost: in many lanes, FedEx Ground is within a few dollars of UPS, sometimes a slightly cheaper. Example: a 50 lb coast-to-coast box recently priced at $96 via FedEx, edging out UPS by a whisker.

• Extra perks: marketplace deals (eBay, Pirate Ship) can slash heavy-parcel rates, think ~$40 for ~30 lb cross-country if you print the label through eBay.

• Speed: transit times mirror UPS; some shippers find FedEx a hair slower on certain routes, but differences are rarely deal-breakers.

• Bottom line: keep FedEx in the quoting mix. For any given heavy shipment, a quick side-by-side can save you lunch money.

Remember that shipping consultant’s tip: “USPS may beat everyone on a 10-pound cube, but the moment you’re lugging a 30-pound alternator, check UPS and FedEx first.”

Quick Takeaway

• Flat-rate fans? USPS wins if it fits.

• Middleweights (10–40 lb) crossing multiple zones? UPS or FedEx Ground usually steal the show.

• True bruisers (40 lb+) or oversized boxes? Ground with UPS/FedEx is almost always the smartest wallet play.

Example: Shipping a 50 lb Auto Part (Cross-Country Rates)

Rates shown are examples for a 50 lb package from New York to Los Angeles. USPS and FedEx costs are from Easyship’s live calculator for 2024. UPS Ground is estimated in the ~$100 range (UPS wasn’t the absolute cheapest in this scenario, but is usually within 5–10% of FedEx’s price for similar ground shipments). USPS Large Flat-Rate Box cost is fixed (commercial rate) and only applies if the item can fit in the 12″ x 12″ x 6″ box – it’s an outstanding value for heavy parts that meet the size limit.

As the example shows, USPS Parcel Select (Ground Advantage) was the cheapest option for a very heavy box at long distance, albeit with the slowest delivery (about a week). FedEx and UPS Ground were a bit more expensive but offer faster transit (around 5 days cross-country). Meanwhile, USPS Priority (air service) was far more expensive for that weight, and Flat Rate would have been a steal if the item could fit in the box. The lesson: always compare the available services for your package – a slower service or a flat-rate box can drastically cut costs if transit time or size constraints allow.

Flat Rate vs. Weight-Based Shipping: Which One Saves You More?

When it comes to shipping heavy auto parts, this is the question:
Flat-rate box or weight-based shipping?

Let’s break down what each one actually means — and when each makes the most sense.

Flat-Rate Shipping: “If it fits, it ships” — and saves

With flat-rate shipping, you pay a fixed price based solely on the box size — not the weight (as long as you’re under the limit).

• USPS Flat Rate is the poster child here — and for good reason. A Large Flat Rate Box (up to 70 lbs!) will run you around $20–$25 to anywhere in the U.S.

• That means a 50 lb pair of brake rotors ships across the country for the same price as a 10 lb package next door. No rate hikes. No zone nonsense.

• It’s a steal for small, heavy items like:

  • Starters

  • Rotors

  • Alternators

  • Dense tool kits

When should you use flat-rate?
Anytime you’re shipping a heavy but compact item across multiple zones (like coast to coast). Especially if you’re pushing past that 5–10 lb range.
It’s less helpful for lightweight parts or local orders, where regular ground or Priority Mail might beat it on price.

Bonus:
UPS and FedEx offer similar programs — UPS Simple Rate and FedEx One Rate. They’re not quite as flexible (typically capped at 50 lbs), but still useful if you’ve got a box that fits the spec.

Bottom line? Flat-rate is the champ for small, dense, long-haul parts.

Weight-Based Shipping: When Size and Distance Matter

Now, if your part is bulky, oddly shaped, or doesn’t snugly fit into one of those flat-rate boxes… you’re back in the world of weight- and zone-based pricing.

Here’s what that means:

• You’re charged based on two factors:

  • How much it weighs
  • How far it’s going (zones — the more zones it crosses, the more you pay)

Carriers like UPS, FedEx, and USPS all calculate this differently, but the result is the same: the heavier or farther it ships, the more it costs.

When weight-based wins:

• You’re shipping locally or within 1–2 zones

• The package doesn’t qualify for flat-rate (e.g., too big or oddly shaped)

• It’s light enough that the weight-based cost beats flat-rate (often under 5 lbs)

But — and this is a big but — beware of dimensional weight.
If your package takes up a lot of space (say, a long box for a strut assembly), carriers might charge you for the space it takes up, not the actual weight.

Pro tip:
Cut down on box size where you can. Pack it tight, lose the fluff, and keep those dimensions compact — it’ll save you from sneaky price hikes.

What About Freight?

Great question — but only if you’re shipping really big items.

• If your part creeps toward 70–150 lbs, it’s worth checking rates for ground vs. freight.

• UPS and FedEx both offer freight and “hundredweight” programs for larger or bulkier shipments.

• But for most auto parts in the 5–75 lb range, standard ground shipping is faster, cheaper, and easier to manage.

Unless you’re shipping something like an engine block or full transmission, freight’s probably overkill.

The Quick Wrap-Up

Key takeaway:
Start with flat-rate if you can. If that’s not an option, compare UPS and FedEx Ground for anything heavy — and always, always pack smart to dodge dimensional fees.

Saving Even More: Use Third-Party Logistics (3PL) for Heavy Items

If you regularly ship heavy auto parts, consider partnering with a third-party logistics (3PL) provider. 3PL fulfillment companies handle warehousing, picking & packing, and shipping for you – and because they ship in volume, they can secure deeply discounted shipping rates. These savings are often passed on to you, meaning you get cheaper shipping than you could get on your own.

Benefits of using a 3PL for heavy parts:

• Bulk shipping discounts: 3PLs negotiate rates with carriers or use aggregate shipping volumes to win discounts. They can often ship at commercial rates far below retail. For example, some third-party providers like advertise up to 91% off carrier rates by leveraging their volume.
• Carrier selection and optimization: A good 3PL will choose the cheapest or best carrier for each order automatically. They might use USPS for one order and UPS for another based on algorithms, so you always get the best deal without having to compare each time.
• Experience with heavy shipments: 3PLs are used to handling odd-shaped or heavy products. They’ll pack your brake rotors or tool kits securely (saving you potential damage costs) and may use techniques like multi-weight consolidation (combining packages to one destination) or zone-skipping to lower costs.
  
• Streamlined fulfillment: Beyond just shipping cost, a 3PL takes the fulfillment task off your plate. While you focus on selling auto parts, they handle the heavy lifting (literally). This can be a huge relief for small businesses shipping heavy items, as packing and hauling 60 lb boxes to the post office gets old fast.

Spotlight: Save Big with eFulfillment Service’s SaverShip Program

Let’s say you’re sending a 20-, 40-, even 70-pound auto part several states away — and you’re watching the shipping cost eat your profits alive.

You’re not alone. That’s exactly the problem eFulfillment Service’s SaverShip was built to solve.

What is SaverShip?

SaverShip is a special shipping program from eFulfillment Service, a Michigan-based 3PL that caters to ecommerce sellers. It’s laser-focused on heavier items — specifically 5 to 75 lbs, which puts it smack in the sweet spot for auto parts, power tools, gym gear, and more.

And the numbers? They’re pretty impressive.

• A 20 lb package? 67% cheaper than USPS.

• A 50 lb package? 80% cheaper than FedEx’s published rates.

• One seller even shipped a 9 lb item for under $8 — beating Shopify’s and Pirate Ship’s cheapest options.

We’re talking about turning a $100 shipment into $20 — consistently.

How Does SaverShip Pull This Off?

One word: consolidation.

Instead of pricing shipments individually like traditional services, SaverShip bundles heavy orders from lots of small businesses and ships them in bulk. That unlocks massive volume discounts — the kind usually reserved for retail giants.

And because eFulfillment Service ships everything from their central warehouse in Traverse City, Michigan, packages don’t get penalized with coast-to-coast zone pricing. You avoid those nasty distance surcharges without sacrificing delivery speed.

Oh, and SaverShip also reduces or avoids:

• Dimensional weight pricing tricks

• Extended delivery zone charges

• “Heavy package” handling surcharges

You know… all the usual nickel-and-dime fees that sneak up on sellers shipping big stuff.

No Strings, No Surprises

SaverShip isn’t just cheap — it’s seller-friendly too.

• ✅ No setup fees

• ✅ No long-term contracts

• ✅ No order minimums

• ✅ Easy integration with Shopify, Amazon, WooCommerce & more

That means you can ship once a day or once a week without jumping through hoops — and still get access to ultra-low rates typically reserved for enterprise players.

Why It’s a Big Deal for Auto Part Sellers

Auto parts are a tricky category: they’re often dense, heavy, and oddly shaped, but not big enough to go freight. That puts most shipments squarely into the expensive “grey zone” for carriers.

SaverShip bridges that gap. It’s like having a commercial shipping contract — but without the volume requirements or fine print. For small and mid-sized ecommerce sellers, that’s rare.

And sure, other 3PLs exist. Red Stag Fulfillment, for instance, is well-known for handling oversized items with care and offers strong FedEx deals. But eFulfillment Service stands out for its low-cost model and focus on small businesses — especially those who sell heavy but manageable products.

In one industry roundup comparing top heavy-shipping 3PLs, eFulfillment Service ranked #1 for affordability and flexibility — and SaverShip was a big reason why.