Is the heel in the Nimbus much softer than the 2140? If so, the relative instability combined with additional heel softness in the Nimbus could cause achilles problems. Were you having problems in the 2140s? If not, I'd definitely get your gait re-checked. From 2140 to Nimbus is a fair old jump down in stability.
Has anyone had any problems with the Asics Nimbs 12 - I've recently switched from the 2140 to the 12's after a gait analysis and I'm finding I'm getting a very sore heel/achilles area - I'm thinking it may be cause by the tighter/higher back of the shoe. It's only on one foot as well. Anyone else had any issues - looks…