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View Full Version : Rollers and trainers. Summary



jdura65
02-21-2000, 02:14 AM
Dear members of the forum,
My original question was:
I am looking for information about rollers and trainer for
bicycles.
Advantages and disadvantages.
-Rollers vs. trainers.
-Magnetic vs. fluid.
-Feasibility for training.
If you are user of this equipment, personal opinion will be welcome.
This is the summary of the different opinions and comments that I received
from two forums: Biomech and Sports Enigeering. Thanks to all.
If you have more opinions or comments, I will complete the summary
in the future
Advantages of rollers


 Good for warming up


develop good co-ordination


You will also have found your natural cadence, which you can then use on
the road to tell you when to change gears


 On rollers is where I really learned bike control


Disadvantages of rollers


can offer little resistance


require skill and attention when riding


is as boring as watching cement set


the newer grooved aluminium rollers, use touring tires- those things eat
racing tires for lunch


too much resistance and the bike/rider would ride off the front of the
rollers


Advantages of trainers


More stable ride


several types of resistance (fan, constant magnet, variable magnet, fluid
in order from cheaper)


Expensive models can be connected to a PC to run a simulated program of
variable resistance, race against an imaginary opponent or even connect
to the internet


Trainers are easier to learn


probably safer


they are smaller and more portable.


Disadvantages of trainers


is as boring as watching cement set


SYSTEMS & NOTES


Fluid supposed to be better than magnets which supposed to be better than
fan


to simulate actual road cycling you need a flywheel that has equivalent
rotational inertia as the linear inertia of a cyclist. i.e. 60-80kg. The
cheap units are hardly ever heavy enough to do that


The air resistance needs to be simulated as well. Air resistance is cubic
in nature as is water. i.e. the faster you want to go the force required
increases cubically not linearly. This is normally done with air turbine
fans (but rarely is it done correctly. i.e. pedal speed at a given gear
offers the right resistance). This is not simulated by magnetic or belt
brakes or electrical brakes ( gym equipment), which tend to be linear in
nature


Fluid trainers are smoother and resistance increases exponentially. 
Most magnetic trainers give the sensation of "pulses" coming from the rear
wheel.  Fan assemblies are also popular, but are noisy.  As in
fluid trainers, the resistance increases as velocity increases.


Wind resistance is used with both trainers and some rollers. It is loud
yet can be used to create a cooling breeze very desirable when in a sealed
room. No different resistance settings yet accurate exponential increase
in resistance with speed. Same speed/resistance relationship as outdoors.


magnetic resistance has variable resistance but it's not speed dependant.
Much quieter than wind


fluid resistance is quiet has variable resistance as well as speed dependant
resistance. Supposedly the cadillac of trainers but I don't think there
too much better than mag trainers.


fans generate a lot of noise


the noise that may be created by the fans or the magnetic unit are in my
opinion not a big deal


ROLLERS: also I wanted to get aluminum and not PVC drums


--
************************************************
Juan V. Durá - Instituto de Biomecánica de Valencia
http://www.ibv.org
Tel. +34 - 961366032       Fax. +34 -
961366033
 

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