Trailer Keel Roller Change in Diameter

[Miquel]

I am now replacing three 12-inch keel roller on the trailer for my 1978 MONTAUK [17].

The keel roller are mounted on fixed points that are welded to the frame of the trailer; there are no adjustable roller brackets. There are two bunks which are also welded straight to the frame with no adjustment.

The existing rollers are black rubber and are 3-5/8-inches in diameter. They might have been originally been 3-1/2-inches in diameter.

I have ordered new rollers of a higher-quality material that are 3-inches in diameter.

Q1: will changing the diameter of the keel rollers to 3-inches from 3-1/2-inches affect the loading of the boat?

Q2: Or, will changing the diameter of the keel rollers to 3-inches from 3-1/2-inches only have a negligible effect on the loading of the boat?

I think that the final height of the bearing surface of the keel roller would end up only being one-half of the change in diameter.

[jimh]

Q1: will changing the diameter of the keel rollers to 3-inches from 3-1/2-inches affect the loading of the boat?

Yes. The effect will be the boat will sit lower onto the trailer by 1/4-inch.

[Phil T]

The difference will be negligible.

[Miquel]

To both who replied: thank you for your opinion.

I have gone ahead and replaced [the keel rollers].

[jimh]

The boat will sit slightly lower on the trailer, but that is assuming that any bunks are not impeding that lowering. You should check the bunk heights after you change the roller size.