Yes. Zero drop or minimalist shoes put a tremdous amount of stress on one's achilles and calfs. That is why one should always take it easy when moving from a regular running shoe to a minimalist shoe. Even then, minimalist running is not for everyone. Studies show that for every person that minimalist shoes help there is another that it hurts. Bottom line, they are not for everyone, despite what minimalist enthusiasts would want you to believe. If you have been using them for a while and your calfs still hurt, then stop. Go back to a regular running shoe that does not cause you to hurt yourself.

Neither of those shoes are zero drop shoes. The Nimbus is 12mm and the Triumph is 8mm. Even though they aren't zero drop you are still going from 12mm drop to 8mm.

I run in Brooks Ghost 6s (12mm) right now and also have a pair of Netwon Gravitys (3mm). My calves always get more of a workout in the Newtons.

I loved the Triumphs when I ran in them, great light feeling shoes.

I wasn't saying that hers were zero drop. I was just relating my experience of going from "regular" shoes to zero drop shoes as there may be parallels as she is changing the drop in her shoes. I don't know at what point it makes a big difference.

I have had the Triumphs for about 2 weeks, I have done 6 runs in them. I switched because the last model Nimbus really hurt my foot where I fractured it/tore my tendon.

But now the Triumphs make my calves sore. But that should go away, right???!!

My calf soreness after switching to a different drop went away after a couple of weeks.

I agree with the above posters.

You should try to build up your mileage gradually with your new shoes. Rotate using your 8mm and 12mm drop shoes for a while.

Meanwhile you can do some calf raises and other exercises at the gym to help with the transition.

For the record I usually run in 0mm drop shoes. I can tell a big difference in how they feel compared to my 4mm drop shoes. I am not at all surprised to hear your experience about the big difference between 8mm and 12mm drop shoes.

Going from a 12mm to an 8mm and also going to a 0mm drop gave me sore calves for a couple weeks in both cases. That's perfectly normal.

(I am such a paranoid freak about pains now. I ran for a good couple of months with a pain in my heel, went to the dr, and had strained my Achilles right up to the point of rupture. I was new to running and just thought it was supposed to hurt, lol. Had to wear a boot for a few weeks with no activity. Now any ache or pain has me worried!)

You're right on target with the new pain but to me there are two different categories. Tendon and joint pain and then sore muscle pain. Muscles have great blood flow and will heal much faster. They can take a beating. Of course don't torture yourself but I still think that some general muscle soreness isn't too much to worry about.

As for phasing them in, maybe every other run until I stop feeling the pain during those runs? Then all the time? Is that how you guys did it?

My calves felt a little sore during the runs but mostly it was later during the day or the next morning when they would feel really tortured. Typically the soreness would be only minimal once I was warmed up. It subsided gradually each day till it was totally gone. When I switched to these zero drop Merrell shoes I even wore them around the house some just walking around to try to get used to them in a more casual manner on days I didn't wear them running. To me that seemed to help lessen the time spent adjusting to them.