Just a bit of a warning, they are very soft mine have already deformed slightly where the hull is resting on them, they don't seem to want to spring back into shape afterwards..
tim i also used towshores brackets on mine but i understood them to be a universal size.. hence why i may trade up to the nylon ones when the funds allow..
I have an indispention (hallmark) roller coaster trailer. I need 7 replacement rollers. Indispention only make one size, and they are totally over priced. Im hoping I can use these instead as they are slighty more economical!
Finally after a bit of googling I have found my answer in the form of this rather good picture. Seems they will fit so thats a load of money I've just saved
Indespension have 2 types of ribbed rollers.
The NA010 which is 115mm dia and the NA012 which is 125mm dia.
Make sure they have the nylon bushes with them from towsure.