Why Are Wheel Pilot Hole Measurements Taken in Decimals and Not Fractions.

Question:

Hi, I am trying to determine what wheel and tire combo I would like to order. In watching the videos that reviewed the possible choices I have in the 4 on 4 category, I was wondering if you could give a better number on the pilot hole measurement than that of 2.65… Its rather hard to figure out exactly what that would translate to when most of the folks would have only a measuring tape at hand and not a micrometer. If it were close to something like 2 5/8 or 2 11/16, this might help a bit more on the consumers end. My only fear is that I would get it wrong and then have to pony up for a return shipping. That would kinda defeat the purpose of buy from etrailer and the great prices you have on everything in stock. Way better than the big stores around the corner.

asked by: Joe

Helpful Expert Reply:

The wheel pilot hole will only matter if A) the wheel centers on the hub and uses wheel bolts, nut lug nuts, to secure to the hub or B) if the hole is too small on a hub that uses lug nuts.

If your wheels secure to the hub using lug nuts then the pilot hole can be larger than the part of the hub it fits on.

Why we use decimals and not fractions is because when a wheel does install with wheel bolts, the pilot hole has to be exact. Fractions are not accurate enough and someone can easily misread a tape measure or ruler. Plus hub centers taper towards the end and are wider at the base where the wheel sets. You could not get a tape measure or ruler down there to take that measurement with any degree of accuracy.

2-5/8 inches is too small and 2-11/16 inches is too big. 2.65 inches is closest to 2-21/32.

So the first step is to determine if your wheels attach to the hub using lug nuts or wheel bolts. Then you can look at the wheel and tire combos accordingly. You will want to match or exceed the trailer capacity when choosing tires. Going with higher capacity tires does not increase the trailer capacity. There should be a sticker or plate on the trailer frame somewhere that says the capacity and might also say what tire size you should be using.

expert reply by: Michael H