bing tracking image
Q & A Icon

Difference Between Idler and Braking Axle  


Whats the difference between a brake axle and a idler axle, also I have a single axle dual zieman jet ski trailer that I would like to increase the axle capacity to 3500lb rating, which axle do you recommend for direct bolt on.thanks


Expert Reply:

A brake axle would have brakes, either electric or hydraulic drum or disc brakes while an idler hub would have no brakes. Many times, a tandem axle trailer will have one braking axle and one idler axle.

The 3500 lb capacity # 35545I-EZ-89 axle you were looking at comes with idler hubs, but because it has brake mounting flanges, brake assemblies and hub/drums could be added at a later date if necessary.

To find a replacement axle, you'd need to measure the hub face to hub face dimension (A) and the spring center to spring center measurement (B) from your current axle. You'd then choose a replacement axle with the same dimensions. I've provided a diagram showing how to take the measurements.

Keep in mind that in addition to increasing the capacity of the axle, you'd also need to ensure that the suspension and wheels/tires were upgraded to upgrade the trailer capacity to match the capacity of the axle.

expert reply by:
Mike L
click to enlarge

Rob T.


Hi, I’m in the process of acquiring a Load rite single axle boat trailer with 5 lug drum brakes.Can I put a new set of hub assemblies on spindle and eliminate the drums? The boat is light and used in salt water and I don’t need the drum headache, my Shoreline trailer with a bunch of good replacement parts is just about done. Does spindle length differ or can I just unbolt backing plates, etc and install new hubs? Thank You

Etrailer Expert

Chris R.


As long as you truly don't need the brakes, there's not an issue replacing hub/drums with idler hub assemblies - as long as you choose the right replacement. In order to ensure it will fit your spindle you'll need to note the inner and outer bearings used for your existing hubs (the numbers will be stamped right inside the bearings themselves). Also make sure the new ones match the axle capacity. If you can tell me this info I would be happy to make a specific recommendation.

Product Page this Question was Asked From

Q & A Icon

Continue Researching

See More Q&A Expert Answers >>