Uneven tire wear

[Rob Roy Macgregor]

I recently replace a tire on my Mac trailer. The old tire had worn unevenly and I see that the wheel is not perpenicular. Instead, it is slightly slanted outwards causing more wear on the inner aspect.
Can I adjust this alignment myself or should it be taken to an automotive repair shop?

[kmclemore]

I had this exact problem on both my wheels on the Mac's trailer... it comes from having a bent axle.

I fixed it using a rather crude method, but it worked a treat... I put the Mac and trailer on a level, flat surface... then I placed a floor-jack under the center of the axle and raised it up, with the boat fully loaded on the trailer.... as I raised the jack I measured the camber (tilt) of the wheels using a bubble level (the kind you use for lining up carpentry in your home)... when they got just slightly past level (tilted in a wee bit at the bottom) I lowered the jack... after a few rounds of this I got just enough bend in the axle to make the wheels perfectly perpendicular to the road surface when fully laden. Once you think you have it just right, roll the trailer for about 30 feet or so, then re-measure to be sure it took.

End result - no more strange wear pattterns!

[Night Sailor]

Kevin, that's the kind of solution I like: knowing the laws of physics, then applying them with what you have on hand at the time.

Most boat axles and stubs are soft iron so you can bend them on purpose or accidently. It pays to avoid curbs and slow down for potholes as much as you can.

[Rob Roy Macgregor]

I had thought of using a jack and dismissed it as too simple a solution. However, now I know it can be done, I will give it a try. Now that we have a wee bit snow on the ground, this will need to be a spring project...............the list is growing.

[kmclemore]

That's fine.. but be sure BOTH are off-camber in the same amount before you start. If one is bent but the other is not, this won't cure your problem.

[Rob Roy Macgregor]

Hmm, looks like I need to re-think this, as only one is affected. Perhaps I should call MacGregor and see if they have any suggestions. I may end up taking the trailer to one of our local trailer dealers once I launch my boat at the marina in early May.
Oh my, May is still 4 1/2 months away. Looks like I will have to dream of sailing until then.

[Catigale]

Rob - monitor the new tire for a bit before you start making axle bends..you might find the wear pattern acceptable for your uses without using the brute force approach. If you dont know the history of the trailer - someone could have put an old tire on it even...

[Rob Roy Macgregor]

It is definitely wear. After I had bought it, I noticed the spare tire had uneven wear on it. Getting it home after a 1300 mile trek, I noticed the left tire had the same wear pattern.
I have replaced the tire on the trailer and now using the one I took off as a spare. On looking at the tire from in front of the trailer there is an outwards deviaton of a few degrees at ground level.
We now have about 3 inches of snow on the ground and it is too cold to be crawling under the traier to see if I can see what is causing the problem.
I had a small 8x4ft utility trailer which had a bent axle. When I brought it to a welding shop, they up-ended it, heated the axle with an oxy-acetelene welding torch and hammered it back into shape. However, the Mac trailer is would be a lot heavier than the utility trailer, so I doubt if it could be up ended easily.
I know that one local company carries stock axles that could replace the one I have. However, it sounds like it could be pricey as the have to do the brake work etc as well.