Chainsets and heel clearance
I currently use SRAM Rival crank/chainset, with no problems. I have a heel-in pedalling style (confirmed with a sports therapist) to alleviate knee pain. This means that my right shoe is not far from touching the rear mech cable alongside the chainstay when pedalling through the upstroke.
I had in mind to go for Ultegra on my next bike. However, I've been reading reviews of a bunch of compact crank/chainsets in Cycling Plus this month. There is a mention of the 'heel clearance' provided by each product, but can anyone tell me how this is defined? Presumably the measurement is agnostic of different sized feet etc? The SRAM offerings seem to offer considerably more clearance than Shimano or indeed any of the other manufacturers (19mm for one of the SRAM components, versus a measly 4mm for Ultegra), which makes me think I might have to stick with SRAM, or be very cautious about a third-party offering.
I'd hate to splash out on, for example, Di2, only to find that my knee problems return. Any thoughts from anyone with similar issues?
Cheers for any help.