May 242019



*See the end of this log for terminology used*

In February, one of our two dollies had a tire bulging out the side; the bead had been cut by the rim. We use this dolly to transport large loads of firewood inside the house, among other things. While searching for a new tire assembly (instead of replacing the entire dolly), we let some air out of the tube to decrease its pressure and the amount of strain on the tube and tire. I was later was informed by Con that the tire had been cut by from being improperly installed by hand, and was not cut be the rim.

In order to look for a new wheel assembly, we needed several measurements: axle diameter; length from outer edge of one side of cart to inner edge of split pin on same side of cart (split pins hold wheels on axle) divided by 2 (equaling max width of each new hub, including width for 2 washers per wheel and space for wheel so its not flush against cart); overall tire height; and tire width and rim size from tire label. Tire dimensions are generally labeled as “height/width – rim size”, but do not always include rim size. Labeled height is not the overall height, but from the inner edge (against the hub) to outer edge (touching the ground) of the tire.

A lesson I learned through this process was to ask “what is the basic function of this part, and what does it need to complete this function?” before any work is done. If any of the dimensions we measured were not met by the new wheel assembly, the dolly would not be able to function efficiently, or at all. If the new hubs were too wide, they could sit flush against the cart and split pins. At best, they’d create increased friction and wear, at worst they’d be too tight and the wheel wouldn’t rotate. If the new tires were too short, the tray would drag on the ground.

Each tire assembly was replaced individually; while doing the first, we left the old tire on the other side to help balance the cart. The axle was wiped of any grease/oil and dirt before replacing each, and re-oiled afterward.


wheel – circular metal piece onto which a tire is fitted

tire – rubber covering that is inflated or surrounds an inflated inner tube and is placed around a wheel to form a flexible contact with the ground

bead – edge of tire that sits on wheel

rim – outer edge of wheel that holds tire

tube – inflated, fits inside tire

hub – attaches wheel assembly to axle

axle – rod passing though center of wheel