|Side view, 101 on top|
The problem is that the shoe features a whopping big drop from the heel to the forefoot: 10mm. Due to the construction of the shoe, this was easily resolved, however. Heel-less MT100s are quite a nice option to have, especially in colder weather, or while racing.
|MT100 original ankle collar|
I will note that the soles on both shoes are functionally identical. The toe area on the 101 may be a smidge wider, but this seemed to have no effect other than to avoid feeling like the soles were a tad narrow, which did occur sometimes in the 100, especially when running down hill.
|Rear view, 101 on right|
The 101 is indeed wider across the toes, although upon trying them on they felt like they were crowding my big toe a bit. This may be a function of the fact that I've been wearing my 100s without the insole. To give my toes enough room I bought the 101s in a size 10, versus the 9.5 in the 100, so I have a comfortable fit even with the insole. This allows for a bit more protection in the heel area when racing. There is enough room in the toe to splay my toes when running down hill, and that, along with wearing the insole, allowed me to bomb down hills heedless of the rocks.
|Front view, 101 on left|
They also significantly redid the overlays on the top, and the material seems to breathe much better than the 100 did. The laces are either the same, or are so similar that I can't tell the difference.
The one welcome improvement is that the achilles-tendon slicer at the top of the heel is much reduced, and the soft liner material (light green in the picture) curves over the plastic material which was formerly so effective at gashing your leg.
I've not tried running sockless in the 101 yet, but hope to have a pleasant time of it.
To test the old and the new, I ran the same course twice, as detailed in my Paine to Pain Race Report. I won't recap that here, except to note that the modified 100 performed well in the practice run of that course.
I had only worn the 101 around for about half an hour prior to sending it to the cobbler for a heel-ectomy. I picked them up Saturday afternoon for a race on Sunday. Yes, like a fool I took a shoe that I had never even run in once to a trail half-marathon. It occurred to me while in the parking lot at the race start that I was doing this, and that I had sworn I would never do it again after making this mistake with my Bikilas. But I had no other shoes, so I really had no choice at that point.
Happily, they performed perfectly. I wore the exact same pair of socks with the 100 and the 101, and I did not experience any discomfort whatsoever with the 101. Not a blister, not a hot-spot, no break-in at all. Kudos to New Balance for that. I did stop at about mile 11 and adjust the tongue on one shoe, but that was precautionary.
So I like both of these a lot. If you can find the 100 on clearance and make the modifications I did, I think you'll be quite happy with them, while saving some money. Or buy the 101 and, after removing the heel, wear as is.
My only caveat about these two shoes is that they do have excessive cushioning. Yes, even 8mm is too much for me nowadays. The only knee pain I've ever had in my running career has been from the 100s last winter (runners' knee), and two Sundays ago (IT band stiffness). The IT band stiffness repeated the second Sunday in the 101. I don't know if this is the result of the 101s or of my weakened ankle (detailed in the race report), so I will withhold judgement. Ideally I'll do the Paine to Pain course again in the next few weeks in my Treks, and see how the knee and ankle do.
P.S. Here's my summary of my New Balance MT100 and 101 posts.
Here's my follow-up post on the knee issues I had running in the MT100 and 101s. In a nutshell, the two New Balance sneakers exacerbated an existing condition, but they did not cause it. I avoid cushioned shoes, and avoid problems.