Trainers - Fluid vs Mag

[deluz]

I have had a Kurt Kintetic fluid trainer for a long time.
It is really heavy (25 lbs) and difficult to move around.
One reason I got it was so we could ride our tandem on it.
But that was when we we were both working and we did not want to ride in the dark and cold after work. Now my wife is retired and I am part time retired, I figured we would not need it anymore. But last year and this year its been raining a lot which is not normal for Socal. Also I can ride only every other day due to problems with my legs not recovering. So I don't want to miss those days I do ride so I started to use the trainer again. The other day I moved it from the garage inside the the house and I had to put it on a dolly. Its not just weight, its the awkward shape. I looked for a lighter trainer and found a Saris Mag+ on local CL for $40. I was thinking my Kurt was magnetic but it is fluid. I have only spent a few minutes on the Saris but I noticed immediately that it felt different and not in a good way. I need to spend more time on it, but I have read that fluid trainers give a more realistic road feel than Mag trainers. Has anybody else experienced this? I may end up passing the Saris along and keeping the Kurt. although the Saris is much lighter and no problem to move around.. Thanks for any input.

[ssb94]

Yeah mag trainers don't feel anything like fluid trainers, that's normal. Fluid trainers provide resistance that is an exponential function of your speed (like air resistance when you're riding outside). Magnetic trainers have linear resistance curves. That's why the fluid feels more natural. If you can keep it in one spot, I'd keep the fluid. Mag is fine for mindless spinning, but it's harder to get a real workout.

[Peter P.]

I have a Kurt Kinetic fluid trainer, and have used mag trainers in the past.

While the Kurt Kinetic's benefit is it offers all the resistance anyone could ever want, replicating real world resistance curves, and is smooth, the drawback is it's TOO SMOOTH. It's akin to riding of level ground where momentum robs you of engaging your hamstrings. I would prefer to not have the flywheel effect.

I bought my sister a used Blackburn mag trainer and was amazed at how equally quiet as the Kurt it was and although the resistance curve doesn't quite match that of real world riding, there's still plenty of resistance to get a good workout. And if you can get one with a smaller, or no flywheel, you get the benefit of engaging your hamstrings to keep your momentum, much like riding up a hill.

Count me in the camp that mag trainers are just fine.

[RWL2222]

People ride a tandem on a trainer? I would have never imagined such a thing.

[.RJ]

If you can swing it, you can find an older wahoo kickr for a few hundred $ and its much nicer to 'ride'.

[deluz]

Originally Posted by RWL2222

People ride a tandem on a trainer? I would have never imagined such a thing.

Yep we did it in our garage. We bought a TV and mounted it on a wall to watch while riding. Could never make it past one hour.
At the time the tandem was all we rode, now it’s the opposite only riding half bikes.

[carpediemracing]

I have both mag and fluid trainers. KK fluid, Saris Mag. Both on KK RR trainer frames (KK and Saris/CycleOps resistance units have the same contact points to the trainer frame so they are essentially interchangeable).



I use the mag trainer with my track bike because I can adjust resistance. However it tops out pretty low, so it's a bit tricky, I can't do big efforts with the mag unit.

The mag unit also has a much lighter flywheel. Pedal stroke gets a bit choppier, as there's more dead spots in the wheel spinning. In real life you have momentum (except maybe really steep hills).

The fluid unit is much more versatile, as the resistance varies based on wheel speed and you can get the resistance really high if your wheel is going fast enough. With a geared bike it's perfect, you can shift to adjust wheel speed and get different resistance levels.

[Ewiser]

I would get a smart trainer. These old style trainers were good in their day. But their day has passed. Get a wahoo Kickr and you will feel the difference.

[Peter P.]

Originally Posted by carpediemracing

The mag unit also has a much lighter flywheel. Pedal stroke gets a bit choppier, as there's more dead spots in the wheel spinning.

That was the point in my post above. I WANT to work my hamstrings and the inertia defeats that. Consequently, when I get on the road in spring time I can feel a lack of uphill strength because my trainer and rollers have too much inertia. And no, merely riding bigger gears doesn't offset the inertia, at least in my experience.

I think back to the days of the old Racer-mate Wind Load Simulator, not for the noise but for the resistance without the inertia.

[KonaSS]

No saying that Peter P is wrong, but never heard that a ****ty trainer feel gets you a better workout.

Pre-smart trainer days, Fluid trainers were almost always preferred for their feel and ability to provide high levels of resistance. And KK trainers were always at the top of that list.

I spent many a winter on my KK (still have it in the basement in case my smart trainer dies) and I never had a problem hitting my fitness goals.

Conversely, most mag trainers barely lasted a season before they broke on me.

[AngryScientist]

Smart trainers certainly changed everything about stationary cycling, but back in the old days, yes, fluid trainers definitely had a more roadlike feel than mag trainers. They were always a little heavier and more expensive, and you paid more for them because they felt a little better. I think what the OP is describing is normal.

Unsolicited advice!

If you're a fit cyclist who can't move a 25# trainer from one room in your house to another without a dolly or much difficulty, it's time to add in some upper body and core strength work to your routine. I mean that in the most constructive way too. I know a lot of older cyclists who can outride me any day of the week, but can't do a dozen pushups. Full body fitness is important, IMO.

[deluz]

Thanks for all the feedback.
Had no idea about this when I looked for a lighter trainer.
I will probably be putting the Saris back on CL.
Those smart trainers while more advanced are pretty expensive.
Being in SoCal the only time I use it is when it rains which is maybe a week or two or riding days a year. So far lowest temperature during the day has been 57 degrees but most days low 60’s