Bicycle Mechanics - Trainer speeds???

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Are all bicycle trainers designed to work only at high RPM?
Is there one with a brake ?
HillRider
12-26-12, 01:10 PM
There are trainers with variable resistance and can be set to mimic a stiff hill climb. Set the resistance high, use a high gear and you will certainly not be "going" very fast.
fietsbob
12-26-12, 01:39 PM
The speed is Zero, it's stationary after all..
Some stationary trainers add friction.. often the brake pad is Wool Felt blocks.
If by brake you mean a way if increasing resistance, there is. A mechanical brake isn't practical because couldn't dissipate heat fast enough so after a short while it would get unacceptably hot. (Imagine riding all day dragging your brakes). Instead trainers create resistance wither through magnetism, a fan, an impeller moving fluid, etc. All trainers have resistance units, and each method of resistance has advantages and drawbacks.
Some treiners allow you to change the level or resistance, while others have reisistance that increases with speed (a power curve) better simulating the natural resistance of outdoor riding.
BTW- if you do buy a trainer, invest in some training videos, or at least some other form of entertainment. Stationary training can be incredibly boring otherwise.
Put the front of the trainer on a crate of beer so you can ride uphill :)
HillRider
12-27-12, 07:04 AM
If by brake you mean a way if increasing resistance, there is. A mechanical brake isn't practical because couldn't dissipate heat fast enough so after a short while it would get unacceptably hot. (Imagine riding all day dragging your brakes). Instead trainers create resistance wither through magnetism, a fan, an impeller moving fluid, etc. All trainers have resistance units, and each method of resistance has advantages and drawbacks.
Some trainers allow you to change the level or resistance, while others have resistance that increases with speed (a power curve) better simulating the natural resistance of outdoor riding.
Actually all trainers use a "brake" of some sort to provide their resistance and the energy they absorb is dissipated as heat. Fan types just slightly warm up the large volume of air they move so the heat they generate isn't that obvious. Centrifugal friction (basically dragging friction pads), magnetic and fluid types do, in fact, get quite hot. The resistance unit on my Performance fluid trainer is far too hot to touch after a training session.
Fan and fluid trainers have non-linear resistance curves and get harder to pedal faster than the "speed" increases. They mimic outdoor riding where the required power increases with about the cube of the speed (i.e. riding at 30 mph requires almost 8 times the power that riding at 15 mph does). Magnetic and centrifugal friction types have more linear resistance and the power required is directly proportional to how fast you pedal.
There are computer controlled trainers that can simulate varied terrain and change the resistance accordingly and even tilt the bike to give the illusion of climbing and descending. These are NOT cheap.
so the wind resistance trainers are the best bang for the buck??
coupster
12-27-12, 02:30 PM
Wind resistance trainers do give you the best bang for your buck, but............
They are extremely NOISY. I opted for fluid and cut down the noise a little.
Wind resistance trainers do give you the best bang for your buck, but............
They are extremely NOISY. I opted for fluid and cut down the noise a little.
yes the typical wind trainer is very noisy. Years age there were some with larger slower fans that moved more air slower and were therefore decently quiet, but I haven't seen that recently except for a few very pricey units. One of my favorite trainers these days is the Cycle-ops Magneto. It's a progressive magnetic (power curve) unit, with a small relatively quite fan who's main purpose is to keep the trainer cooler at high wattage loads.
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