Can Upgrading Axle Weight Capacity of Bigfoot 25B25FB Prevent Axle Failure

Updated 07/19/2020 | Published 04/29/2019

Products Featured in This Question

Electric Trailer Brake Assembly - Self-Adjusting - 12" - Left Hand - 5,200 lbs to 7,000 lbs

(382)

$80.07

Dexter Trailer Hub and Drum Assembly - 7K E-Z Lube Axle - 8 on 6-1/2 - Pre-Greased - 1/2" Stud

(331)

$169.95

Question:

I have a bigfoot 25B25FB travel trailer....It is rated at GVWR of 7500 lbs. I have replace the 3500 lb axles once because they were bent and causing uneven tire wear....After I replaced the axles one of them broke.... They were Dexter axles.....I want to upgrade to either the 5200 lbs axles or the 7500 lb axles....I was told that unless the trailer frame was a 4 in frame that the 7500 lbs axle would bend the frame....Can this be true? My trailer is not at my house so I am not sure of the frame size. Im not sure that the 7500 lb axle would even fit with the 8 lug tires.... What is the difference in the axle diameter between the two and what is the weight difference? Any recommendations as to axle size? thank you

asked by: Jim S

Expert Reply:

The bigger issue you should be considering is if you are exceeding the weight capacity of your trailer. If you are bending and braking axles that are designed for the weight capacity of your trailer you most likely are exceeding the trailer capacity and going to a higher capacity axle would simply allow something else to be the weakest link. That possibly would be the frame. If you are using the full GVWR of 7,5000 lb of your trailer and you only had 7k axle capacities then this would be a problem and going to a higher capacity axle setup would be ideal.

A 5,200 lb axle with a 3 inch diameter would be a great solution. We only have a few of them, but I attached a link to all of the 5,200 lb axles we carry. To pick out the correct size will require you to measure the distance between the hub faces of the axles and the spring seat centers.

There are hubs with 8 lug bolt patterns that fit 5,200 lb axles like the # 42866UC3-EZ.

expert reply by: Jameson C

Jack H.

7/19/2020

I have the same Bigfoot 25B25FB trailer and experienced the same problem with uneven tire wear caused by bent axles when riding at the trailer's 7500 lb weight limit -- easy to do in a fully optioned trailer with gear for two people on a long trip. First time, replaced the 3500 lb axles with larger 3" medium wall tubes and 3500 lb spindles so I could retain the hubs and 5 on 5.5 wheels. Installed Monroe shock absorbers, later upgraded to ST load range E tires inflated to 60 psi (to match the wheel rating). Fast forward 8 years, again poor tire wear (fortunately nothing broken), replaced the 3500 lb axles with 89" hub face 5200 lb axles, 6 on 5.5 5200 lb hub and drum assemblies, 12" 7000 lb backing plates and 6 lug 15" wheels (axle spacing too tight for 16" wheels). Inspected and retained the 3500 lb springs (longer 5200 lb springs require a new perch). 3000 miles later all ok, time will tell... Important to note: the larger brake assemblies improve braking performance and the 6 lug wheels (and stems) are rated 80 psi to match load range E tires (the original aluminum mod wheels are stamped 65 psi max).