# Trainers: Fluid or Mag

I'm looking at getting a trainer because I have next to no time to get on the road and want to start up with Carmichael's Time Crunched Training Program. Part of the program is to ride do high intensity intervals at low RPM. I like the idea of a fluid trainer being the quietest due to training at night with a young one in the home. Also that I don't have to modify the resistance as I'm riding, but my concern is whether I can do high intensity training at low RPM on a fluid trainer. I've read that the resistance increases when the fluid thickens. And that the fluid thickens by the speed of the wheel in the chamber, so I assume that spinning at a high gear would allow for this, but I just want to ensure this is possible before ordering one.

• I haven't looked at the specifics of the TCT high intensity low rpm workout. How high is high intensity, how is it measured, and how low is the rpm? May 17, 2014 at 3:55
• Also, in order to give a good answer to your question, it would be good to know what speed you can maintain when climbing, the slope of that hill, your cadence on that hill, and your total weight. Knowing those things will help to determine whether a fluid (or magnetic) trainer can provide the appropriate load. May 17, 2014 at 4:54
• Good points! I would be ideally riding at, or just below lactate threshold. As for climbing, depends on the slop. 15% grade would be about 12kph (yeah, not that fast) at about 75rpm. In this case, I'm shooting for 60-75 RPM. My regular spinning cadence is 85-95 RPM. I'm about 165" @ 6'1". I haven't weighed the bike, but I suspect it's around 17 lbs
– BenK
May 17, 2014 at 5:01
• OK, thanks. The short answer is you're going to have a hard time finding a fluid trainer that will provide that kind of load at low rpm (and you won't be able to find a magnetic trainer that can provide that load at all). I'll do the calculations and provide a more complete answer tomorrow -- unless someone else wants to do the calculations and write-up and I'll upvote that. May 17, 2014 at 5:35