What are the ramifications of having undersize rotors. Minimum thickness is 8.5mm, and currently running 7.5. This is on my 1275LS.
Cheers Ron

less efficient braking and voiding of insurance

Not entirely sure of the physical ramifications (cracking etc) but the legal ramifications are BIG , if you have a prang and they're found to be under the minimum allowed then you're basically screwed , the insurance company will laugh at you while tearing up the policy and if anyones injured or killed then the charges increase in severity .

_________________

Well its just as well she's up on block waiting for rotor's

I believe the 8.5mm stated is a machining limit, not the minimum you can legally run them to.
I have also seen some S rotors with 8mm stamped on them.

I ran my old S ones down to 7mm and they still stopped OK.
Cooper 998 ones are only 6.35mm (1/4" ) thick NEW, if you think 7.5mm is thin.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The funny thing about minimum thickness for discs is that I can't find anything from BMC or Leyland stating what the minimums are.
Nobody really worried about minimums for any discs (or oversize drums) till the late 80s, but now they go overboard with them.

Dept of transport in Qld must have limits as I have been failed with 8mm rotors on the Moke Californian, same rotors as the LS. The info I have found on them states they are 10mm new and minimum of 8.5mm and when I put new rotors on, they were stamped along the edge as 8.5mm minimum machining thickness, the same applied to the 'S' rotors I got earlier this year. The improvement in the Moke braking was very noticeable with the 10mm thick rotors.

With some calipers you can jamb the pistons if they extend too far....is this likely to be a problem taking the rotor below 7.5mm, more towards the Docs 6.35mm

_________________
"Show me the Mini!"

I have seen a pad FALL OUT of a Fiat 125 floating caliper due to undersize rotors.. the pad's backplate (its facing was gone) fell out between disc and pad bracket.. then the piston hit the rotor.
Physically this can't occur with Mini opposed piston calipers, but it's an example of the perils of using dodgy brakes.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.