Reformer Spring Colours Explained: A Brand-by-Brand Guide
Reformer springs are the whole machine. The carriage, the straps and the footbar give you positions; the springs decide how hard each one is. And yet there is no shared colour code in Pilates. A red spring on one brand is not a red spring on another, and yellow can mean the lightest spring in one studio and a medium one in the next.
This guide sets out how the major reformer brands colour their springs, what the colours mean in practice, and how to translate a setting when you move between machines. It is written for clients who train across studios, instructors who teach on more than one brand, and anyone who has ever been told to "go to a red and a blue" and wondered which red and which blue.
The Short Answer
Each manufacturer chose its own colours. The table below shows the standard order from lightest to heaviest on the brands you are most likely to meet in UK and EU studios.
| Brand | Lightest | Heaviest | ||
|---|---|---|---|---|
| Balanced Body | Yellow | Blue | Red | Green |
| Align-Pilates | Yellow | Blue | Red | Green |
| Merrithew (STOTT PILATES) | White / Yellow | Blue | Red | Black (where fitted) |
| Peak Pilates | Blue | Yellow | Red | — |
| BASI Systems | Yellow | Blue | Red | — |
Two patterns are worth remembering. Red is a full or near-full spring on almost every brand. Yellow is the one that moves — very light on Balanced Body and Align-Pilates, medium on Peak Pilates.
Brand by Brand
Balanced Body
The most common reformer in boutique studios. The standard set runs yellow (very light), blue (light), red (medium to full) and green (heavy). Many Balanced Body reformers ship with three reds, one blue and one yellow and no green at all, which is why so many instructors treat red as the heaviest spring in the room.
Align-Pilates
A UK manufacturer, and common in home setups and newer studios. The colour order matches Balanced Body: yellow, blue, red, green. Align-Pilates is one of the few brands to publish resistance ranges in kilograms, which makes it a useful reference point when converting settings.
Merrithew (STOTT PILATES)
Red is the full-tension spring, with blue and lighter springs stepping down from there. Merrithew labels springs by percentage of a full spring, but those labels are approximate — treat them as a guide rather than a measurement. Exact spring sets vary between models such as the SPX and the studio-grade reformers.
Peak Pilates
The main source of confusion. On Peak, blue is light, yellow is medium and red is heavy. A client trained on Balanced Body who reaches for "a yellow" on a Peak machine will get noticeably more load than expected.
BASI Systems
Yellow, blue, red, from light to heavy. BASI reformers also use a gear system that changes the starting tension of the springs, so the same spring combination can feel different depending on the gear setting.
Why the Same Setting Feels Different
Colour is only part of the picture. Three other factors change what a spring setting actually delivers.
Gear or bar position. Moving the spring bar or gear changes how stretched the springs are before you start. A higher gear means more pre-tension and a heavier feel.
Spring age. Springs lose tension with use. A studio that replaces springs on schedule will feel heavier than one running older sets on the same nominal setting. Manufacturers publish replacement intervals — typically every two years in a commercial setting — and they are worth following for safety as much as consistency.
Range of movement. Springs get heavier the further they stretch. A long-legged client pushing the carriage out further on footwork will meet more resistance than a shorter client on the identical setting.
How to Convert a Setting Between Brands
There is no exact conversion, but there is a reliable method.
Convert by role, not by colour. Ask what the spring is doing. A full spring is a full spring on any machine. If a programme calls for "two reds and a blue" on Balanced Body, the equivalent elsewhere is two full springs and one light-to-medium spring, whatever colour those happen to be.
Start light. When moving to an unfamiliar brand, start one step lighter than your usual setting and add load once you have felt the machine. It is easier to add a spring than to recover control of a carriage that is moving faster than expected.
Watch the light springs. The biggest errors happen at the light end, where yellow, white and blue swap meanings. Heavy settings tend to translate more cleanly because red is consistent.
Write settings down by brand. Instructors teaching across studios save time by noting settings as "BB: 2R 1B" or "Peak: 2R 1Y" rather than relying on colour alone.
Common Settings by Exercise Type
These are starting points on a Balanced Body or Align-Pilates reformer, not prescriptions. Every body, machine and teacher will adjust from here.
| Exercise type | Typical starting range | Why |
|---|---|---|
| Footwork | Three to four reds | Large leg muscles, closed-chain pushing |
| Hundred, arm work supine | One red, or one blue and one red | Smaller muscle groups, control over load |
| Rowing and arm work seated | One blue or one yellow | Shoulder stability matters more than load |
| Long stretch, plank series | One red, or one red and one blue | Spring supports the carriage; lighter is harder |
| Knee stretches | One or two reds | Speed and control against moderate load |
| Jumpboard | One to two reds | Lighter springs reduce impact and increase hang time |
Note the plank row. On many reformer exercises the springs assist rather than resist, so a lighter setting makes the work harder. This is the most counter-intuitive part of the machine and the reason new clients sometimes add springs to make an exercise "easier" and find the opposite.
Stability Is Part of the Setting
A carriage on a light spring moves quickly. Footwork on the bar, standing work on the platform and lunges against the frame all depend on your feet staying exactly where you put them. Bare feet on a sweat-dampened footbar slip. This is why most studios require grip socks for reformer classes — not as a dress code, but because the springs only work as intended when the contact points do not move.
Reforman pilates grip socks are built for exactly that: a full-sole grip pattern, a gender-neutral fit, and a design that works in the studio and outside it.
Frequently Asked Questions
What is the heaviest spring on a reformer?
On Balanced Body and Align-Pilates, green is the heaviest. On most other brands, red is the heaviest standard spring. Many studio machines are not fitted with a green spring at all.
Is a yellow spring light or heavy?
It depends on the brand. Yellow is very light on Balanced Body, Align-Pilates and BASI, and medium on Peak Pilates.
Can I convert spring settings exactly between brands?
No. Colours, gear systems and spring age all vary. Convert by the role of each spring — full, medium, light — and start one step lighter on an unfamiliar machine.
Why does a lighter spring make some exercises harder?
In planks, long stretch and many kneeling exercises, the springs help hold the carriage in place. Less spring means less assistance, so your body does more of the stabilising work.
How often should reformer springs be replaced?
Follow the manufacturer's guidance for your machine. Commercial studios commonly replace springs around every two years, or sooner with heavy use or visible wear.
This guide is a general reference. Spring settings are starting points and vary by machine, model and condition. Always follow your instructor and the manufacturer's guidance for your equipment.