Best Picks

Eunorau M12 to M10 Hitch Adapter Review

A $25.99 steel adapter, Female M12 to Male M10, for rear hub motor axle nuts so a trailer can be installed without interfering with the dropout, per the page. It lists an 18mm install length and names the TWO-Wheels Hunting Trailer plus a list of Eunorau bikes.

3.5Editorial rating: 3.5 out of 5Editorial rating · research-basedUpdated October 21, 2026
$25.99Price checked October 21, 2026
Check price at Eunorau

2% off

Use this code at checkout

Our verdict

A fit for an owner of a listed bike who needs to hitch the store's TWO-Wheels Hunting Trailer to an M12 rear hub motor axle nut. Look elsewhere if you use another trailer or a bike not on the list, or want a stated weight or load rating. The main caveat is the cable-side warning, which the buyer has to read against their own motor.

Best for
An owner of a listed Eunorau bike who needs to mount the TWO-Wheels Hunting Trailer on an M12 rear hub motor axle.
Skip if
Your trailer or bike is not named on the page, or you need a stated weight or load rating.

Why 3.5/5: Held back by coverage terms that do not name this item and by a BBB profile with an F grade and unanswered complaints.

Changing a Female M12 thread to a Male M10 one is the job of the $25.99 Eunorau M12 to M10 Trailer Hitch Adapter (Hub Motor). The page says it fits on the rear hub motor axle nut so a trailer can be installed without interfering with the dropout, and lists a steel build, an M12*P1.25mm internal thread pitch, an M10 external thread and an 18mm install length.

Specifications

SpecPage says
BrandEunorau
ColorBlack
MaterialSteel
Internal Thread PitchM12*P1.25mm
External ThreadM10
Install Length18mm

Options and pricing

A single $25.99 variant is offered in black steel, with no crossed-out price on the page, and it showed as in stock when read. How many pieces are in the pack is not stated.

How it compares

The Eunorau M12 Trailer Hitch Adapter (Hub Motor) is $29 against $25.99 here, and its summary names the ONE-Wheel cargo trailer and a hub motor with an M12 nut, while this page names the TWO-Wheels Hunting Trailer. The Eunorau 190mm Hub Quick Release Skewer for E-Bike Trailers costs $29 and is listed for the ONE Wheel cargo trailer as well.

Shipping, returns and warranty

Shipping: the shipping page says accessories and batteries go by FedEx or UPS in an estimated 5 to 9 days after 1 to 3 business days of processing; orders over $100 ship free and smaller orders pay $14.99, with a possible remote-area charge. If the local warehouse is out of stock, the item ships from an overseas warehouse in an estimated 10 to 15 business days, and there may be no carrier tracking until it reaches the destination country and clears customs. Returns: an order can be cancelled for a full refund before it ships or is produced, but not after it ships; the page asks buyers not to refuse a delivered e-bike and to contact the store instead. A return must be applied for within 7 calendar days of receipt, the product must be new and re-sellable (not assembled, ridden, used or damaged) and complete with its manuals, accessories and original packaging, and the buyer ships it back within 7 days at their own cost to Eunorau's warehouses in the US, Australia, Europe or the UK. The store inspects it within 5 days and refunds in full when the fault is Eunorau's (wrong, damaged or defective item) or minus the shipping cost when the reason is the customer's. The terms page says customers are charged shipping only once, returns included, with no restocking fee, which does not match the return page's wording. Warranty: the warranty page covers original Eunorau parts and components for 24 months (manufacturing defects only, no labor) but excludes wear items, free gifts and accessories that came with a purchase, and damage from unapproved accessories or chargers; it does not name this item, so ask support whether and how it applies. It is for the original purchaser and excludes shipping damage. Disputes under the warranty go to binding individual arbitration (AAA rules, Nevada law) unless the buyer emails an opt-out within 30 days of purchase.

Before you buy

The page shows 1 customer review with 0% of them five-star in the store's own widget, which we could not verify; several product pages show the same review counts or lists, so the figure may not belong to this item alone. Reputation: Eunorau E-Mobility USA Corp has an F grade on the Better Business Bureau, is not BBB accredited and has 2 complaints on file, both marked unanswered: a December 2025 request for proof that a bike sold as new was new, and a May 2025 report of a battery cover that would not latch, which the buyer attributes to a frame defect. A web search on 21 October 2026 found no Trustpilot page for Eunorau. The store says it has specialised in e-bikes since 2009 and designs its bikes in the US and manufactures them in Shanghai, while the BBB lists a business start date of 12 December 2019; the eunorau-ebike.com domain was registered on 27 July 2016.

What we liked

  • Lists both thread sizes: Female M12 with an M12*P1.25mm pitch and Male M10
  • States an 18mm install length and steel material
  • Names a trailer and bikes: DEFENDER-S, UHVO, DEFENDER, G30-CARGO, Rear-drive Flash and Flash AWD
  • Includes a mounting warning about the side of the hub motor cable

Worth noting

  • No weight, load rating or pack count is given
  • The compatibility list is framed for owners of the store's Hunting Trailer and says little about other trailers
  • The side-mounting warning about the motor cable is the only installation guidance

Questions before you buy

Which trailer and bikes does the page name?

It names the Eunorau TWO-Wheels Hunting Trailer and says owners of that trailer can install the adapter on the DEFENDER-S, UHVO, DEFENDER, G30-CARGO, Rear-drive Flash and Flash AWD. It also says it is compatible with an M12 rear motor axle on an e-bike.

What are the thread sizes?

Female M12 to Male M10, with an internal thread pitch of M12*P1.25mm, an external thread of M10 and an install length of 18mm.

Does the side of the motor cable matter?

The page says that if the adapter is mounted on the left side of the motor, the hub motor cable cannot be at the shaft center left, and likewise on the right. The page text gives no further explanation.

How are Eunorau accessories and batteries shipped?

By FedEx or UPS, an estimated 5 to 9 days after 1 to 3 business days of processing; free over $100, otherwise $14.99. If local stock is out, the item ships from an overseas warehouse in an estimated 10 to 15 business days, possibly without tracking until it clears customs.

What is the return window?

The return page gives 7 calendar days from receipt to apply. The item must be new, unused and complete in its original packaging, and the buyer pays the return shipping to Eunorau's warehouse; the refund is full only when the fault is Eunorau's. Orders can be cancelled for free before they ship.

What does the warranty cover?

The warranty page covers original Eunorau parts for 24 months but excludes wear items, free gifts, accessories bundled with a bike and labor, and it does not name this item, so ask support whether it applies.

Sources & verification

What this review is based on and the day we last read it. Specs and claims from the maker are the maker’s own; the verdict and the rating are ours.

From the store

  • Eunorau M12 to M10 Trailer Hitch Adapter (Hub Motor) product page: specs, options and price (the buy buttons go there)Specs, options and the listed priceRead October 21, 2026
  • Eunorau shipping informationFree FedEx/UPS to the lower 48 from Las Vegas; accessories free over $100; overseas-warehouse fallbackRead October 21, 2026
  • Eunorau return policyCancel before shipment; 7 calendar days to apply for a return; customer pays return shippingRead October 21, 2026
  • Eunorau warranty page (24-Month+ Limited Warranty)Frame 10 years, battery, motor and electronics 24 months; manufacturing defects only; exclusions; arbitrationRead October 21, 2026
  • Eunorau FAQClass 1-3 definitions, weight capacity, battery life and charging, design and manufacturing locationsRead October 21, 2026
  • Eunorau terms of servicePrices can change without notice; says customers pay shipping once, returns included, and no restocking feeRead October 21, 2026
  • Eunorau About pageSays Eunorau has specialised in electric bikes since 2009 and sells in the US, Australia and parts of EuropeRead October 21, 2026
  • Eunorau contact pageOrder, customer service and after-sales emails and phone lines; California showroom addressRead October 21, 2026

Independent

What we couldn’t verify

  • The page gives no weight, load rating or pack count, and no installation steps beyond the motor cable side warning.
  • The compatibility list is written for Hunting Trailer owners; the page does not say whether the adapter suits other trailers.
  • The return page says the buyer pays return shipping, while the terms page says customers are charged shipping only once, returns included, with no restocking fee.

Spotted an error or something out of date? Tell us and we’ll fix it and update the date.