How to Check 90mm Tire Width and 100mm Dropout Compatibility for Camping Trailer Hub Motors

Shenzhen Jinhaixin Holdings Co., Ltd

2026-07-29

Shenzhen Jinhaixin Holdings Co., Ltd explains how to assess 90mm tire width and 100mm dropout compatibility for 6.5-inch camping trailer hub motors using a practical three-step installation check.

For a camping trailer hub motor, fitment depends on more than wheel diameter. The relationship between the 90mm tire width, the trailer frame clearance, and the 100mm dropout opening should be checked together before installation. This guide provides a practical inspection sequence for the 6.5-inch camping trailer hub motor supplied by Shenzhen Jinhaixin Holdings Co., Ltd, helping trailer manufacturers and DIY builders evaluate the mechanical match before assembly.

Confirm the Key Installation Dimensions

The referenced motor is designed for electric camping trailer applications and is identified by three important physical fitment points: a 6.5-inch wheel diameter, a 90mm tire width, and a 100mm dropout opening. These dimensions describe different parts of the installation and should not be evaluated independently.

Installation Item	Referenced Dimension	What to Verify on the Trailer
Tire width	90mm	Clear space around the tire, including frame members, fenders, guards, brackets, and adjacent components.
Dropout opening	100mm	Inside spacing between the two mounting faces that receive the motor axle.
Wheel size	6.5-inch	Available wheel-envelope space and the intended trailer chassis layout.
Axle arrangement	Dual threaded axle configuration	Whether the dropout slots, mounting hardware, and retention method suit the axle structure.

A Three-Step Compatibility Check

Measure the dropout spacing accurately

Measure the internal distance between the two trailer-frame dropout faces where the motor axle will be seated. For this camping trailer hub motor configuration, the target opening is 100mm. Take the measurement at the actual mounting location rather than at an outer frame edge, and confirm that welds, paint buildup, spacers, or brackets do not reduce the usable opening.

If the measured opening differs from 100mm, do not force the axle into position. Review the trailer design, mounting interfaces, and required hardware with the motor supplier before proceeding.

Check clearance for the 90mm tire width

A 90mm tire width requires adequate lateral clearance on both sides of the wheel. Inspect the closest points around the tire path, including the trailer chassis, suspension or support elements where applicable, fenders, body panels, cable routing, and protective covers. The tire should not contact surrounding parts during normal wheel movement or when the trailer structure is loaded.

Clearance assessment should consider the complete wheel-and-tire envelope, not only the motor housing or the axle centerline.

Verify axle seating and retention before final assembly

Confirm that the dual threaded axle can sit fully and squarely in the trailer dropouts. The mounting interface should support the intended axle orientation and allow suitable fastening hardware to be installed without interference. Before connecting the electrical system, inspect the mechanical installation for even seating, unobstructed wheel rotation, and protected cable routing.

Final installation should follow the applicable trailer design requirements and the assembly instructions provided for the selected motor and related components.

Why Tire Width and Dropout Width Must Be Checked Together

A 100mm dropout can indicate that the axle mounting width is suitable, but it does not by itself confirm that the trailer has enough space for a 90mm-wide tire. Conversely, a chassis may have sufficient tire clearance while the dropout opening or axle retention method does not match the motor. A complete camping trailer motor installation review therefore combines mounting width, tire clearance, axle interface, and surrounding structural clearance.

Practical Pre-Installation Checklist

Measure the usable dropout opening at the intended motor mounting point and compare it with the 100mm requirement.
Check that the dropout shape and mounting structure accept the threaded axle arrangement.
Inspect both sides of the 90mm tire envelope for clearance from chassis parts and accessories.
Confirm that the 6.5-inch wheel size is appropriate for the trailer layout and intended installation position.
Plan cable routing so that wiring is not pinched, stretched, or exposed to avoidable contact with moving parts.
Review the complete low-voltage drive system, including the controller and battery pack, as part of the overall vehicle integration.

Support for Camping Trailer Motor Integration

Shenzhen Jinhaixin Holdings Co., Ltd focuses on the design, development, customization, production, and supply of low-voltage electric drive systems, including brushless hub motors, drive controllers, and energy battery packs. For camping trailer projects, providing the trailer drawing, dropout dimensions, wheel-clearance information, and intended system configuration can help establish a clearer basis for component selection and installation planning.

Confirm mechanical fitment before assembly: measure the 100mm dropout opening, verify clearance for the 90mm tire width, and check the threaded axle mounting interface as one coordinated installation review.