Rotors, 1" or 1.25" ?
 

Looking to get a drop kit for my 1977 GMC 15 in the black Friday sales but it is asking me if the rotors are 1" or 1.25"". Is there a way I can tell without having the truck here (its on its way to the UK but I haven't got it yet)

Re: Rotors, 1" or 1.25" ?
 

thing is you can upgrade but its inner bearing & race if i recall correctly / rotor / caliper / possible hose if you get the 1.25 and only have the 1.0 thick rotor .

i just checked www.rockauto.com and in 77 if it was baby inline 6 / 292 inline 6 or 350 thay all show only a 1.25 rotor for new thickness spec . not saying there 100% correct or your truck is 100% original . hope this helps you make a choice .

Re: Rotors, 1" or 1.25" ?
 

Not enough detail to know for sure.

Need to know either the brake system (JB3 or JB5) or the GVW rating.

K