I think I'm running the wrong belt as the failure rate is ridiculous.
Please advise: 2006 R52 JCW with a 2% crank. what size belt should I run? Need to order asap.

 

What size SC pulley and current belt length, and what kind of time frame/mileage are you considering ridiculous?

Could be a misaligned or damaged pulley. I’ve also seen posts where a small rock got stuck in a pulleys grooves and broke the belt.

Detroit Tuned belt recommendations can be found in the description here: https://www.detroittuned.com/mini-cooper-belts/

 

6 months.

Thanks for the link. Looks to be a failed tensioner which is also 6 months old, maybe 1500 miles. No track but very spirited. That made me start thinking that maybe the belt is a bit short and is over stressing the tensioner.
Again, thank you for the link.

 

if that crank pulley is a solid version, I would recommend changing it to ATI or PRW brand that has the fluid damper on it...solid pulley will eventually end up destroying your engine bearings on the crankshaft

Bryan