Resistance
without Weights.
Since 1978.
Keiser manufactures training equipment where the resistance does not come from a weight stack, but from pneumatic pressure or a magnetic brake. Both allow for finer adjustment and more precise measurement than iron—the reason why the equipment is found in fitness studios, physical therapy clinics, and high-performance sports. All models are available from our Swiss warehouse.
Keiser is a family-owned business from Fresno, California, that in 1978 introduced the first exercise equipment with Air pressure resistance introduced. In the cardio area, the M-series works with a Magnetic brake without friction contact. At Fitness-Flohmarkt we carry five M3-series indoor bikes (CHF 1,990 to 2,790), the M3i Total Body Trainer, the M5i Strider crosstrainer, the Infinity-series A300 Functional Trainer with accessory kit and the matching compressor.
Basics
Two ways to generate resistance
Almost all Keiser devices can be classified by a single question: Where does the load come from? Everything else follows from this decision — how finely the weight can be adjusted, how much maintenance is required, and how reliable the displayed numbers are.
Air pressure
Instead of a weight stack, compressed air pushes against a cylinder. The load depends on pressure, not mass — which means there is no inertia to pull along during acceleration, and no impact when setting it down. The weight can be changed during the repetition without letting go of the handle.
- Resistance starting from 0.1 kg, in 100-gram increments
- Minimal impact on joints and connective tissue
- Rapid movements remain under controlled stress
- In stock: Functional Trainer A300
Magnetic brake
A magnetic field slows down the flywheel without touching it. No felt, no friction points, no adjustments—and virtually no noise. The flywheel is located at the rear, where sweat cannot reach the drive mechanism. The belt is self-tensioning.
- 24 or 72 resistance levels, depending on the model
- Wear-free: nothing grinds, nothing wears down
- Quiet enough for living spaces and basement ceilings
- In the product range: M3 Series, Total Body Trainer, M5i Strider
Indoor Cycling
The M3 Series: five models
Everything mechanical is identical on all five bikes: V-frame, magnetic brake, maintenance-free Poly-V belt, combination pedals with SPD click system and toe cages, four-way adjustable saddle, and transport wheels. There are differences in only three places — display, number of gears, and handlebar adjustment range.
M3
Without a display, 24 gears. For studio classes where the music and instructor take control — or as the most affordable entry point into the series.
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M3i Lite
The same certified power measurement as the large models, B/W display with Bluetooth. «Lite» refers solely to the handlebar: height-adjustable only.
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M3i
Like the Lite, but with 4-way handlebars. This covers heights from 147 to 213 cm — the model for households and fitness studios with very different body heights.
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M3i Studio
Color display with zone indicator, 72 gears, pedal generator instead of batteries. At 112 cm, it is the lowest bike with a color display — relevant for low basement ceilings.
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M3i Studio Plus
The studio bike with 4-way handlebars — same price, broader fit range from 147 to 213 cm. Unless there is a reason against it, this is the obvious choice.
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| M3 | M3i Lite | M3i | M3i Studio | M3i Studio Plus | |
|---|---|---|---|---|---|
| Ideal for | Studio, Budget | Onboarding + Tracking | Entry-level, all sizes | Studio, Classes | Studio, any size |
| Display | — | M Connect (B/W) | M Connect (B/W) | Studio (Color) | Studio (Color) |
| Zone display | — | — | — | ✓ | ✓ |
| Courses | 24 | 24 | 24 | 72 | 72 |
| Connectivity | — | Bluetooth | Bluetooth | Bluetooth & ANT+ | Bluetooth & ANT+ |
| Power supply | — | 2 AA batteries | 2 AA batteries | Generator | Generator |
| Handlebars | 2-Way | 2-Way | 4-Way | 2-Way | 4-Way |
| Height | 147–213 cm | 150–188 cm | 147–213 cm | 150–188 cm | 147–213 cm |
| Max. user weight | 136 kg | 160 kg | 160 kg | 160 kg | 160 kg |
| Height / Weight | approx. 39 kg | 112 cm / 40 kg | approx. 42 kg | 112 cm / 40 kg | 124.5 cm / 42.5 kg |
| Price | CHF 1,990.00 | CHF 2,490.- | CHF 2,590.00 | CHF 2,790.- | CHF 2,790.- |
Same for all models: magnetic brake · maintenance-free poly-V belt · V-frame · virtually silent · emergency stop function · hybrid pedals (SPD + toe cages) · 4-way adjustable saddle · transport wheels · footprint approx. 130 × 66 cm
The two displays in comparison
| Studio Display | M Connect Display | |
|---|---|---|
| Models | M3i Studio & Studio Plus | M3i & M3i Lite |
| Ad | Color LCD with zone color | Black and White |
| Training modes | % FTP, % Max HR, METs, Speed | none |
| Connectivity | Bluetooth & ANT+ | Bluetooth |
| Heart rate reception | Bluetooth & ANT+ | 5 kHz / GymLink |
| Personal Profile | ✓ FTP, HRmax, weight | — |
| Power supply | Pedal generator | 2 AA batteries |
Same for both displays: Watts, RPM, kCal, time, distance, heart rate and gear · Odometer and bike ID · Interval values without delay · Automatic backlight · Wireless data transmission. On the M Connect display, a color zone indicator is provided by the M Series App on a mobile phone or tablet.
Endurance · two special cases
If the bike is not the answer
Two devices from the M-series use the same magnetic technology, but move more than just the legs — or take the strain off the joint entirely.
M3i Total Body Trainer
The same magnetic resistance system as the M3i Bike, but with moving arm levers: train the upper and lower body together or separately. The resistance is continuously adjustable, and the console displays cadence, power, calories, heart rate, time, distance, and acceleration on a single screen. Bluetooth for the M-series apps is on board.
- Mass125 × 74 × 137 cm
- Weight51 kg
- Max. user weight130 kg
- Resistancestepless, magnetic
M5i Strider Crosstrainer
The series' cross-trainer: wear-free magnetic resistance, continuously adjusted via a smooth control knob, 24 gears. The computer displays RPM, watts, calories, heart rate, time, gear, and distance; the Polar receiver is integrated. Double handles are padded and movable, and the handlebars are height-adjustable.
- Mass130 × 60 × 168 cm
- Weight58 kg
- Max. user weight180 kg
- ConnectivityBluetooth, Polar
Strength Training · Infinity Series
The Functional Trainer A300
The Infinity series was the first cable machine to work with air pressure. Because no mass needs to be accelerated, the load remains the same throughout the entire movement—regardless of how fast, at what angle, and in what direction you pull. This is precisely what makes the device equally useful for rehabilitation and competitive sports: some need 2 kg finely dosed, while others need explosive movements without inertia in the system.
Functional Trainer A300
Two independently height-adjustable arms, ten positions, free direction of pull. The resistance starts at 0.1 kg and increases in 100-gram increments — up to 48 kg on both sides or 24 kg on one side. Because the training does not take place in a fixed track, balance and the core are always engaged.
- Height150 to 226 cm
- Base width / Depth81.5 × 61 cm
- Weight59 kg
- Cable length180 cm / 365 cm
Infinity Accessory Kit
Without this set, the Functional Trainer is delivered with only the standard single handles. The kit includes seven parts: Back/Lat Strap, Pro Ankle Cinch Strap, Waist Belt, Triceps Rope, and the Keiser Chop Bar. This adds lat pulldowns, footwork, hip movements, triceps exercises, and rotations.
- Scope7 attachments
- MatchingInfinity Series
1/2 HP Compressor
The Functional Trainer is delivered without a compressor — compressed air is a requirement, not an option. Clean, dry 6.9 to 8.3 bar are required. Anyone who does not have a compressed air line in the room needs this compressor: 1/2 HP, 230 V, 50 Hz, designed to be deliberately quiet for the training room. One compressor supplies up to eight Keiser machines — so if you have multiple devices, you only need one.
- Performance1/2 HP
- annexation230 V, 50 Hz
Classification
Where Keiser makes the difference
Devices that run for twenty years
No brake pads to adjust, no belt tension to calibrate, no weight stack to slam. Maintenance is the real reason chains like LA Fitness and David Lloyd rely on the M3 Series.
- Multiple bikes simultaneously via the M Series Group App
- Comparable wattage values across all devices
- Saddle and handlebars adjusted without tools
- Virtually silent even at high cadence
load from the bottom
The functional trainer starts at 0.1 kg, and the resistance on the bikes can be reduced as low as desired. For working with patients, the fine gradation matters more than the upper limit—as does the ability to document every session.
- Resistance adjustable in 100-gram increments
- Minimal impact on joints and connective tissue
- Power and heart rate as objective progress monitoring
- Over 80 peer-reviewed studies on strength training and aging
A device instead of a floor
A bike requires around 130 × 66 cm, the Functional Trainer an 81.5 cm base width. Anyone who trains seriously at home does not buy the cheapest equipment here, but one that still delivers the same performance after ten years.
- No battery replacement for the Studio models
- Data to Zwift, Strava and comparable apps
- Suitable for rented apartments: no heavy impact noise
- on parquet or laminate a floor protection mat underneath
Before buying
What you should know
No screen, no subscription
No Keiser device includes a tablet, a screen, or a course subscription. The displays operate independently and show wattage and cadence even without a phone. Those who want to stream classes place their own device on the media tray.
The resistance is not controlled by the app
The bikes send their data to Zwift, Strava, and comparable apps — but they do not receive control commands. You choose the gear yourself using the lever. Anyone expecting smart trainer automation is looking at the wrong device.
The driving experience is different
The flywheel is deliberately kept light. Anyone switching from a heavy flywheel bike will notice this immediately: the pedal stroke carries itself less and reacts more quickly to every change in wattage. That is precisely why intervals can be hit cleanly — though you don't get the rolling momentum of a heavy bike in return.
Accessories are not always optional
On the functional trainer, the attachment determines which exercises are possible — without Infinity Kit only the single-handed grips remain. And pneumatic machines need a compressed air source in the room. It is better to clarify both before ordering than after.
Price and Perspective
Keiser is not a cheap manufacturer, and their equipment isn't cheap here either. What justifies it is the lifespan: A drive without frictional contact simply has fewer parts that wear out. For a gym, this is a calculation over years, not a single season. Anyone who only rides occasionally at home will find in our indoor cycling bike range also significantly cheaper options — we will honestly tell you which one fits your application.
Frequently Asked Questions
Emperor at fitness flea market
Which M3 series model is right for me?
Three questions are decisive. First: Do you need numbers? Without a display, it is M3 the cheapest choice. Second: Do you need a colored zone display directly on the bike and 72 instead of 24 gears? Then a studio model. Third: Is anyone taller than 188 cm? Then it has to be a model with 4-way handlebars — that M3i or that M3i Studio Plus.
What is the difference between M3 and M3i?
The M3 has no display and no connectivity, its handlebar is only height-adjustable, and the maximum user weight is 136 kg. The M3i features the M Connect display with Bluetooth, a 4-way adjustable handlebar, and a maximum user weight of 160 kg. The magnetic brake, belt drive, frame, and pedals are the same on both.
What does «Lite» mean with the M3i Lite?
Only the handlebars: They are height-adjustable, but not adjustable lengthwise. The frame, magnetic brake, belt drive, combination pedals, 24 gears, and certified power meter are identical to the more expensive models. The saddle remains adjustable in four directions. Anyone over 188 cm tall should spend CHF 100 more for the M3i.
Do the bikes work with Zwift and other apps?
Yes, all models with a display transmit power, cadence, speed, and heart rate. The M Connect display uses Bluetooth and can transmit to multiple devices simultaneously, while the Studio display also features ANT+. Zwift, Strava, and comparable apps recognize the bike directly as a power source. The app does not control the resistance—you select the gear using the lever.
Do I need clipless pedals?
No. The combination pedals have two usable sides: one with an SPD click system, and one with toe cages for normal athletic shoes. Cycling shoes provide more control during the upstroke at high cadences, but they are not necessary.
How loud are the devices and how much maintenance do they need?
The drive operates without frictional contact, which is why the bikes remain very quiet even at a high cadence. There is no brake felt to adjust, the Poly-V belt is self-tensioning and requires no adjustment. For an inspection, the drive is accessible via eight screws.
Why does Keiser use pneumatic resistance in the strength training area?
Because compressed air has no mass that needs to be accelerated. A weight stack delivers inertia peaks during fast movements and a shock to joints and connective tissue when reversing—air pressure does not. In addition, the load can be adjusted in 100-gram increments and changed in the middle of a repetition. Dennis Keiser was the first to bring this principle to exercise equipment in 1978.
Does the functional trainer need a compressor?
Yes, absolutely. The Functional Trainer works with compressed air and is supplied without a compressor. It requires clean, dry air at 6.9 to 8.3 bar — either from an existing compressed air line in the building or from the Kaiser Compressor (1/2 HP, 230 V). Good to know: One compressor supplies up to eight Keiser machines. If you are planning multiple devices, you only need it once.
What is included with the Functional Trainer?
The device itself with the standard single-hand grips. Back/Lat-Strap, Pro Ankle Cinch Strap, Waist Belt, Triceps Rope, and Chop Bar are in the separate Infinity Accessory Kit. Anyone who wants the full range of exercises plans for it from the very beginning.
How much space do the devices need?
The bikes take up about 130 × 66 cm; for getting on and off, plan for about 60 cm extra. The Total Body Trainer measures 125 × 74 cm, the M5i Strider 130 × 60 cm. The Functional Trainer takes up 81.5 × 61 cm, but requires up to 226 cm of ceiling height and space on the sides for outstretched arms.
Am I buying new goods here?
Yes, all Keiser equipment shown on this page is new and is shipped from our Swiss warehouse in Liestal, usually within 1–3 working days. Pickup is possible by arrangement. You can see whether a model is currently in stock directly on the respective product page next to the price.
Do you also advise on furnishing entire rooms?
Yes. Whether course room, physiotherapy practice, club or basement gym — write to us info@fitness-flohmarkt.ch. With multiple devices, the conversation is always worthwhile, also because of setup, flooring, and delivery.
Unsure which model?
With eight machines featuring partly identical mechanics, the choice is rarely obvious. Tell us who is training, how often, and in which room — and we will tell you which machine fits and which one you can skip.