Dimensional Differences [brake Calipers]

[RAC68]

I was told and would like verification that the front brake calipers on a BJ8 P2 are larger in overall size then those on a P1. Additionally, is it true that the wire wheel offset for a P2 is greater then that which is necessary for wires on a BT7?

I appreciate that the piston diameter of a P1 is greater then the piston diameter of a P2 but always though the overall caliper size were identical and the calipers could be interchanged. Also, I was under the opinion that the wire wheel offset needed for a BT7 was the same as a P1 and assumed a P1 was identical to a P2.

So, are my understandings and assumptions in error and if so, where?

Thanks,
Ray (64BJ8P1)

 

[Jeepster]

I believe you are correct that the two callipers have different external dimensions.

When I first had my phase 2 I was informed it was a phase 1 ( due to the single flashers) so ordered new callipers for a phase 1. They didn't fit so had to send them back and work out why they didn't fit.

 

[British_Recovery]

Later BJ8 calipers are #16 and the bolt holes are 3.5" center to center. Earlier cars with disc brakes use #14 calipers and the spacing is 3.25". The rotor on the later cars is thicker as well.
As far as wheels, the 60 spoke, 4.5" wheels will clear both calipers ( as will the 48 spoke, 4" wheel ). The problem with rubbing comes up with certain optional wheels. For example, a 72 spoke, 5.5" wheel, # 480, will clear the #14s, but rub on the #16s.
Bob

 

[steveg]

Welch sells what I believe is an early '70s Triumph caliper which has the larger piston and pad of the BJ8 P2, but on the 3.25" bolt centers.

Just to muddy the waters - I'm using 5.5" 72-spoke Daytons having about 1/2" clearance on Toyota calipers on BJ8 P2 spindles. My wheels originally fit my drum-braked BN6. It's hard to believe the BJ8 calipers wouldn't fit. I'd call Hendrix to get the scoop. Their website specs are a little hard to understand.

 

[Healey Nut]

My 67 BJ8 P2 has original calipers and 72 spoke 5.5 Chrome stainless spoke Daytons on it . I can get my pinkie finger in between the top outside edge of the caliper and the inner circumference of the rim . The gap between the spokes and caliper as the spoke pass the caliper is about 3/4 to 7/8 ".

 

[Keoke]

My 66 BJ8 P2 has original calipers and 72 spoke 5.5 Chrome stainless spoke Daytons on it . I
do not have any clearance problems with the calipers either.