Doggus

I peeked in on one of our local spin classes and noticed EVERYONE was on a magnetic trainer. There wasn't a fluid trainer to be seen amongst the ~20 spinners. What is the deal with using a fluid trainer at a spin class? I keep hearing stories of fluid trainers making mush of even seasoned strong racing veterans. I'm wondering, is it an ego problem and they won't down shift? Or is it the fact that as the flluid heats up the resistance increases at an exponential rate? I posed the question on our local board and this is the response from one of the guys who runs the class:

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"Their are a few that use them but they are alot of work. Work in the wrong way. The idea behind most of the spin classes is to spin. That is hard to do on a fluid. Yes you can gear up but then you are not doing the same gears that are on the work out. Kinda like motor pacing, yea you can do 35 mph after a down hill but it's not the same as being behind a motor at 35 mph on flat ground. Does that make sense. I can explain it better than write it. Fluids also tend to get harder the hotter they get. I've watched guys end up in the small ring for half a class.
Mags that adjust give more options. Depending on how you feel or the work out thats up on the board like a couple of weds ago. I hurt just thinking about that one."
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This guy is a local coach in the area and knows what he's talking about. I think I'm just too stupid too understand what he's trying to tell me. Can anyone translate into laymans terms?

I'm thinking as long as I'm keeping my cadence at a certain level, I could care less what gear I'm in. Some people are working harder than others anyway and they're all working off the same cue sheet.

frisco_rider

Doggus, I might join you at RBM with my fluid trainer.. we will just get a better workout then the rest

Doggus

At least I won't look like the only idiot there

When you going? Wifey might go too and I'll rent her a magnetic trainer.

toshi

Interesting observation, one I've noticed as well. Most pros warm up using mag trainers, if you keep your eye on pre-race photos. And within indoor cycling clinics where there are other racers (many of whom have personal coaches), I see more mags than fluids.

frisco_rider

What days are they? Tues/Thurs? Anyway, it will be next week before I can make it out.

Doggus

November 1 through March 29
Monday - Thursday
6:30 pm - 7:30 pm

RBM Spin Classes

I find it amusing that the picture on that page shows a fluid trainer?!? Or it may be a wind trainer for all I know.

frisco_rider

looks like a fluid trainer in the pic to me.

froze

There are two types of suppose mag trainers...at least from CycleOps, the lowest price one is called Mag and the better one is called Magneto. The Magneto is a very good and capable trainer for a reasonable price that would satisfy most riders. The Cycleops Fluid2 is more for someone who is training as a professional. That is why the local spin class mostly rode Magneto's or maybe the Mag, because the local yokos are not capable of exceeding their limits.

DMF 

Trainers? We use stationery bikes with big-assed flywheels with a friction brake. You set you own resistance, from light to so-tight-you-can't-turn-the-crank.

msheron

I have a magnetic trainer and it works just fine. I think it is personal option by the consumer. I chose mag due to fact I have heard that fluid trainers are sometimes prone to leak!

roadwarrior

Not in the six years I've owned mine.

msheron

Just reporting what others who own them have told me. Which one do you have?

thomspins

yeah just use a mag; you'll only be buying a fluid soon there after..

I have a personal coach (granted I am training for racing) but you can easily overpower a mag trainer (magneto is the one i had from cycleops). Also, if you're doing high resistance work a mag trainer is all but useless.

in a spin class if you're spinning at the preferred cadence what does it matter what gear you're in? If you want to make it easier or harder (wattage load) just play with the gears.. i.e. when i'm on a mag trainer 240 watts would have me in the 53-13 at 90 rpm, on the fluid it could be the 39-14 to get the same ..

roadwarrior

Cycleops Fluid2

Many years ago, the first ones that Cycleops/Saris made did have a seal issue. Saris replaced all of them no questions asked.
In the last three years, I'd guess I've sold 500 of these and not seen a single one come back.

msheron

Sweet. One day I may upgrade but for now the magnet will do.

Doggus

I already own a Cycleops Fluid2. They now have me worried that I really should have bought a magneto.


This is what I'm trying to figure out. Why can't I just spin a lower gear. I don't give a **** what gear anyone else is spinning as long as I'm doing the same cadence.

I think I'm headed for the spin class tonight.

thomspins

yeah man a fluid 2 is better.. just put it into a gear that lets you get to the proper cadence...
for me spinning at 110 rpm w/ 50watts resistance is nothing=no workout, but 110 cadence w/ 175watts starts getting fun.. watch your h.r. and use that as a gauge as to what gear to push at the cadence everyone else in the class is spinning. if you go over 85% MHR i'd say you're in too big a gear for a spin class.

froze

That's an odd statement, let me explain, all things break! The old Cycleops Fluid trainer had some issues with leaking, but most of those leaks did not start occuring after about 7 to 8 years of almost daily use. The new version, the Fluid2 has supposely answered that problem. But regardless all Cycleops trainers come with a lifetime warranty that the company actually honors without hassles. Does that mean the new Fluid2 won't ever leak? I doubt it, in fact since it uses fluids and has seals eventually it will probably leak...at least that would be my guess.

If the Mag trainer breaks are you not going to buy it? Oh wait, breaking and leaking are two different things, if that's your argument then sell your car and buy an all battery car because you car is going to at sometime start leaking something.

The Fluid2 has about 250 watts (750 watts total) more capabiltiy then the Magneto which is about 150 more watts capable then the Magnetic. So your purchase decision should be based on what level of a rider you are and what level you want to achieve, and not based on fear.

whitemax

That's just rubbish. The fluid has a more roadlike feel to it. You can spin as lightly as you want or you can shift up for a more difficult workout. I've had the wind, mag and fluid trainers and the fluid is the best. Don't let some guy who trains couch potatoes steer you in the wrong direction. If you were considering the fluid, then go ahead and get it. There are several brands with good reputations to choose from. Happy trainering.

dekalbSTEEL

Anybody use a rim-drive trainer?

froze

This is just my own personal opinion; but I test rode about 3 years ago the rim drive Minoura, as well as Cycleops Wind, Magnetic, Magneto and the Fluid2. The Minoura Rim drive was about the same as the Magnetic but not as smooth as either the Magneto or the Fluid2; but the LBS talked me out of it due to supposely excessive tire wear on the sides.

But if your looking for a trainer that is not as expensive as the Fluid2 then get the Magneto-not the Magnetic. The Magneto is about $100 less then the Fluid2, has a very good smooth feel to it, and unless your a professional rider your never going to exceed it's capabilities.

Doggus

Update:

Anyone got a magnetic trainer for sale? I was clearly the only one in severe pain last night. Ended up with a pool of sweat beneath my bike. Others had sweat droplets on the floor but I was creating a pool, and thats with a towel catching lots of it and a sweat band. Started out in the same gear combos, quickly moved to the small ring after the third set. Unfortunately that was too late, I got spit off the back...in a spin class even. There was one other guy there with a fluid and he was clearly 'doing his own thing' too.

Fluid trainers are definitely not made for 'spin' classes unless you're an animal. I would like to 'get with the program' like all the others in the class. So - learn the hard way was the way I chose. I'll leave the fluid trainer at home for short power and sprint training sessions, not hour long pain fests.

I found a wattage graph last night for different trainers. The Fluid2, warmed up, at 53x12 - 100 RPMs required something like 1400 watts. Sheesh. I'll post the graph if I can find it again. It's in my history on home 'puter for now.

ReedZ

Here are the Kurt Kinetic Fluid curves;

https://www.kurtkinetic.com/pdfs/Power_Curves419.pdf

Kuer Kinetic web Page:

"Many people buy a bike trainer to simulate an outdoor ride indoors. The Kinetic Road Machine is the only trainer specifically calibrated to replicate the resistance encountered on an outdoor ride. We have worked with Tom Compton at www.analyticcycling.com (perhaps the most knowledgeable person on the planet regarding the forces a cyclist encounters and produces) to create a mathematical relationship between power and speed while riding our trainers. These relationships are graphed in this PDF (2.59 MB).

As you might imagine, many variables affect a rider’s speed. The most obvious is the weight of the rider and bike. Tom specializes in the less obvious factors like frontal area and air density. With extensive use of differential equations and advanced numerical methods, Tom has created proprietary software to accurately estimate the cumulative effect of 16 different interactive forces that determine a rider’s speed. Visit the following site for more information: www.analyticcycling.com

With Tom’s help, we have been able to create an “average” rider assumed to be 165 lbs, riding a 23 lb bike with 170mm crank arms up a 1% grade, at sea level with no wind on rough asphalt... etc. The “outdoor ride” that we reference in the PDF is based on this “average” rider. Tom was then able to calculate how much power it would take for our average rider to maintain a given speed.

We then used our robot cyclist, Crank Armstong, to measure the power needed to maintain a given speed while riding the Kinetic Road Machine. By altering the viscosity and the amount of silicon solution in the fluid chamber, we were able to match the data from our “average” rider to the data produced by Crank. The end result is a very accurate power curve and the most realistic indoor simulation.

It should be noted that the power curves in the PDF are not raw data. Because so many measurements are taken and the patterns within each experimental trial can be erratic, the raw data is often unintelligible. Tom relies on Mathematica (a computer program) to fish out a mathematical model from the raw data. This model is an average of the collected data. Surprisingly, the power curves are based on a simple formula.

Remember algebra? Good. The formula for the Cyclone and the Road Machine turns out to be a cubic function. If we let S stand for “speed” in miles per hour, and P stand for “power” in watts, the formulas are as follows:

Kinetic Cyclone:
P = (6.481090) * S + (0.020106) * S3

Kinetic Road Machine:
P = (5.244820) * S + (0.01968) * S3

For example, to calculate how much power is produced at a speed of 16.1mph while riding the Kinetic Road Machine, plug 16.1 in for “S.”

P = (5.244820) * (16.1) + (0.01968) * (16.1)3
P = (5.244820) * (16.1) + (0.01968) * (16.1) * (16.1) * (16.1)
P = 84.4416 + 79.9935
Power = 164 watts

The Kinetic Road Machine power formula is accurate for all riders because the variables experience on an outdoor ride are controlled indoors. We are so confident in the accuracy of the Kinetic Trainer; we encourage you to try this test. Complete a 20 minute time trial on the trainer using a rear mount bike computer or Kinetic PC (Power Computer) Complete a similar ride on a flat course with a neutral wind. The distance covered will be within a range of + /- 3%. "

matthew_deaner

Thanks for posting the data about the Kurt Kinetic.
I've been wondering how the resistance of the Fluid 2 compares at various speeds.

A couple of weeks ago, someone posted power data for a Cyclops fluid 2 trainer. They used a powertap to determine the watts of resistance from a warmed up Fluid2 at various speeds. The tire used was a Michellin Carbon, with the spindle tightened to the rim per spec, 2 and a half turns past the point the spindle touches the tire.

I used this data to do a linear regression in order to get a power equation for the Fluid 2.

Here is the original data:
Speed Watts
14 130
15 145
16 160
17 185
18 210
19 235
20 265
21 295
28 600
30 700

The above data yielded a very high coefficient of correltation
r2 value = .9963 (1 is perfect correlation)

Here is the power equation:
Y=.3074x^2.2651

Where:
Y=watts resistance
X=speed

Here are the results of plotting wattage resistance at various speeds using the above equation:
Spd Watts
14 121.2825939
15 141.7973694
16 164.117932
17 188.275459
18 214.2997254
19 242.2192442
20 272.0613861
21 303.8524816
22 337.6179103
23 373.3821779
24 411.168984
25 451.0012824
26 492.9013341
27 536.8907546
28 582.9905565
29 631.2211879
30 681.6025668

As you can see - the equation is close, but not perfect.

Maybe there is a statistician or mathematician on the forum that could do a better job on the regression than I did...

Doggus

Here is the graph I was refering to.

According to the graph, 53x12 at 100 RPM would be ~1400 watts...





Lots of good graphs here.