*bump*
Found this thread searching for other tales of achilles woe.
I discovered I had a leg length difference while looking at my leather saddle and seeing it had taken on quite a different shape L:R. Long story short, I lowered all my saddles by about 10-15mm to suit my shorter side and have been blown away by the improvement in comfort. I used to frequently get saddle sores on my LHS (short side) which i now know is because i was grinding it into the seat.
Did a long-ish ride a few weeks ago and had a few jabs of pain from my right achilles in the late stages, didn't think an awful lot of it. This weekend I did a 2, 3 then 7hr ride on consecutive days and from the off yesterday I could feel a tightness/tenderness of my right achilles again. The dull pain would come and go, to the point i would forget all about it. Then I would stop for a break/check map etc, set off and there it was again.
It was very sore getting out of bed this morning, so i've started looking into it.
The general advise seems to be that your saddle is too high, but I having recently lowered mine, I'm wondering if I'm getting excessive heel dip on my longer leg now. My other half commented on one of the early rides (at the new saddle height) that one ankle/foot was alot more mobile than the other.
Anyway, a quandary - I have been building up for a 2 day ride across Wales with friends this coming weekend. RICE in the immediate term, I was wondering about moving the cleat on my right shoe back. I have some KT tape kicking round too, so could try supporting it a bit.
But if the forecast is crap, I could legitimately cry 'injury' and not go. But having created the route for it, I will be sick with envy seeing them do it without me.