Good old fashioned wire nails would do the trick and could be bent up in a bench vice with pliers and heads clipped before being installed. One size thicker then the original hole and you are laughing. Should the hole be a touch too enlarged, soaking the wood within the bore of the hole with warm water for an hour or so then installing the nail should work well. Wood swells when allowed to. And most wheels seem to be made from Maple or Birch for their tight uniform easily machined smooth grain. Which consequently swell considerably more then other hardwoods when wet, go figure. If you know anyone with a sandblast cabinet just remove the old wire hooks, clean them up and reinstall. I suggest it because that's how I'd handle it...having such a tool available is remarkably handy at times like this. LOL Semi-Synthetic motor oil is a great lubricant as it breaks up old soil and dirt and doesn't have that unpleasant odor conventional oils have. If you buy it for Diesel it has extra detergents and will clean up the old bearings all by itself through useage alone. Use liberally but don't let it run all over, and mop up the old oil with paper towelling. Which can be masking taped or elastic banded in place while the wheel is moving if you need spare hands this trick works until the oil desticks the tape gum or eats the elastic band. Usually time to change the paper towel by then anyhow! Tricks I use in restoring old motors for sewing machines, electric fans etc.. old bearing surfaces are old and contaminated regardless of what they are attached to. And diesel semi synthetic motor oil works wonders. Avoid ANYTHING to do with linseed oil or ANY cooking grade oil as they all go gummy. Mineral oil is great if that's all you have. It's what was used way back when because it is stable and doesn't gum. But it doesn't clean the parts or lubricate like the semi-Syn. will. Any auto parts store will sell you a liltre/quart for a not too steep price.
*NOTE: Older nails are WAY BETTER as most common nails today are manufactured in China and the steel is CRAP! Cleaning up a slightly surface rusted nail is prefered to purchasing a newer shiny nail of inferior quality...try framing a roof sometime with the China made crap available on the market today! Highly frustrating! I finally resorted to using all my grampa's old framing nails that were well rusted into a box in the basement and when I ran out I switched to screws! And I'd do it again vs. purchase chinese nails!