What Hub Do I Need for My Old 16ft Aluminum Boat Trailer?

Updated 03/11/2025 | Published 02/23/2025

Question:

I have a very old trailer that needs new hubs. The tapered axel diameter size is 1.55 1 9/16 to 0.77 with a total length of 7.5 3/4. I need two 5 x 4.5 hubs. I carry a 16ft aluminum boat on the trailer that is no more than 2000lb. Could you please advise on what idle hub kit I can buy that will fit this. I can provide more measurements and pictures to assist if required. Many thanks for your help

asked by: Simon

Expert Reply:

Hello Simon,

Happy to see if we have a hub that will work for you. I am going to need some better measurements from you. I attached an image of what part of the spindle to measure for the inner and outer bearing, using a digital caliper like # PTW80157 will give you the most accurate measurement. You could wash the grease of your current bearings and get the bearing number directly off them. Once I get better measurements, or the bearing numbers I can see if we have something that will work.

I really do appreciate your time, and I look forward to hearing back from you.

expert reply by: Kate F

Where to measure spindle to get bearing sizes.
(click to enlarge)

Simon

2/26/2025

Hello Kate, Here are the measurements you requested: A: 39.2 mm (1.543”) (1 9/16) (length 2") B: 30.1 mm (1.185”) (1 3/16) (length 1") C: 27.9 mm (1.098”) (1 1/8) tapers from 24.1 mm (0.948”) (15/16) (length 2.25") D: 19.4 mm (0.763”) (3/4) (length 2") E: 18.1 mm (0.71”) (23/32) F: 50.8mm (2.0”) Large bearing inner diameter is 29.72mm (1.17”) wording on bearing as far as I can tell is 15118 Timken USA Small bearing inner diameter is 19.05 mm (0.75”) wording on bearing as far as I can tell is BT0907A Bower USA I can send you pictures of the setup too if needed. There used to be a very old breaking system on it that was dilapidated so I am replacing it with the idle hub instead. Many thanks for your assistance Simon

Kate F.

2/26/2025

@Simon Thank you for getting that information to me Simon. I have an answer, but it is not the one you were hoping for, and for that I am very sorry. They no longer make a hub with inner bearing 15118 and outer bearing 09074 (the 4 must have looked like an A). Your best bet is going to be to replace the whole axle, given the age and not being able to find the right parts for it. If this is the route you choose to take it will require some more measurements to ensure that we get you into the right one. You will need the hub face to hub face, and the spring center to spring center. I attached a help article on how to measure your axle as the measurements need to be precise. Of course we would need to know your axle capacity as well, which I am guessing you will need the 2,200 pound. For example, the Dexter Trailer Axle with Idler Hubs # 35545I-ST-89 has a 3,500 lb capacity, with an overall width of 89 inches from hub face to hub face and 74 inches from spring center to spring center. Similarly, the Dexter Trailer Idler Axle with Hubs # 20545I-EZ-72-10 has a 2,200 lb capacity, measuring 72 inches from hub face to hub face and 58 inches from spring center to spring center. I am sorry to be the bearer of bad news. A few years ago I had to replace the axle on my Ranger boat that we don't even carry, it ended up being a custom order job and cost a pretty penny so I feel your pain. Feel free to comment what measurements you come up with so I can see if we have the right fit for you.

Helpful Links

faq-how-to-measure-trailer-axle.aspx

Simon

3/9/2025

@KateF Hi, thanks for the information and advice. I kind of thought that might be the answer, it is what it is! I have finally been able to measure the axel. I measured break flange to break flange as there is only 1 hub on the trailer now. I was 61 inches. The aluminum boat will not be more than 2000lbs so from the information with an additional 7 inches added, the axel will be about 68 inches. Are you able to tell me what axel I will need to buy to sort out the trailer from this measurement? Many thanks in advance for all your help and support :) Regards Simon

Kate F.

3/10/2025

@Simon Hello Simon, I am very sorry but we do not have an axle that will work for you. Our sizes jump from 60" hub face to 72". If you Google "axle 68" hub face to hub face" there will be plenty that pop up. The first company that pops up tends to have a way larger selection when it comes to trailer axles. I am very sorry we do not have what you need this time.