Magura QM 44 Brake Caliper Adapter PM 180 to 203 mm

The Magura QM 44 is a genuine brake caliper adapter that moves a caliper from the Post Mount (PM) 180 mm position up to the 203 mm rotor position. It is built for mountain bikes, electric mountain bikes, S-Pedelec speed e-bikes, city bikes and e-moto conversions. Every box holds one QM 44 adapter and two mounting bolts.

This adapter does not replace your caliper or your brake system. Instead, it repositions the existing caliper so it lines up exactly with the larger Ø203 mm rotor. Therefore you can step up from a 180 mm disc to a 203 mm disc while keeping the calipers you already run.

The extra stopping power and improved cooling come from the 203 mm rotor itself. The QM 44 is simply the part that makes fitting that rotor possible. As a result, braking distances shorten and brake fade appears less often on long descents.

Key Benefits

• Precise PM to PM step-up – the adapter lifts the caliper from the 180 mm position to the 203 mm position.
• No caliper swap needed – your existing Post Mount standard brake calipers stay on the bike.
• Genuine Magura part – the QM series is Magura’s factory line of caliper mounting adapters.
• Rigid construction – machined alloy means it does not flex under braking loads.
• Correct factory spacing – the caliper centres over the 203 mm rotor without shims or washers.
• Front or rear fitment – suitable for both wheels when the frame or fork allows a 203 mm diameter.
• Broad compatibility – works with Magura calipers and Post Mount calipers from other manufacturers.
• Bolts included – two mounting bolts ship in the box.

Who Is This For?

The QM 44 suits mountain bikes (MTB), electric mountain bikes (E-MTB), S-Pedelec class speed e-bikes and city bikes. It is also used in e-moto conversions, since those builds run bicycle-standard Post Mount calipers and rotors.

Riders who tackle steep descents or carry extra weight gain the most. On heavier electric bikes, a 203 mm rotor holds more heat than a 180 mm rotor. For that reason the QM 44 is often the first step in a brake upgrade. Note that it works only with a Post Mount 180 mm caliper position. IS standard forks and frames need a different QM series part, and the frame or fork must be rated for a 203 mm rotor before fitting.

What Is in the Box?

• 1× Magura QM 44 adapter
• 2× mounting bolts

Technical Specifications

Why Choose the Magura QM 44?

Magura is a German hydraulic brake manufacturer founded in 1893 in Bad Urach. The QM (Quick Mount) series is its factory line of caliper mounting adapters. Consequently, QM 44 spacing matches the same factory dimensions as Magura MT series brakes.

Unlike universal adapters, the QM 44 is a strictly single-purpose part: PM 180 mm to PM 203 mm. You therefore avoid choosing between several shim or washer kits. The caliper settles into one exact position. It also pairs well with Magura MDR-P and MDR-C 203 mm rotors, and it accepts non-Magura calipers that meet the Post Mount standard. Above all, it is a clean way to increase rotor diameter without buying extra parts.

Frequently Asked Questions

Does the Magura QM 44 work with a Center Lock hub?

• The QM 44 changes only the brake caliper position, not the hub type.
• It has no effect on how the rotor attaches to the hub.
• With a Center Lock hub, use a separate Center Lock to 6-bolt rotor adapter if needed.

Is the QM 44 compatible with any 203 mm disc?

• Yes, provided the 203 mm disc suits your brake system.
• The frame or fork must also be approved for a 203 mm rotor diameter.
• Magura MDR-P and MDR-C 203 rotors are a natural match.

Will it fit non-Magura brake calipers?

• Yes, any caliper built to the Post Mount standard fits.
• The caliper must be designed for the PM 180 mm position.

Can I use the QM 44 on an IS standard fork?

• No. The adapter works only with a Post Mount 180 mm caliper position.
• IS standard forks and frames require a different QM series part.

Does the QM 44 fit e-moto conversions such as Sur-Ron or Talaria builds?

• Yes, e-moto conversions commonly use bicycle-standard Post Mount calipers and rotors.
• The build must present a PM 180 mm caliper position and clear a 203 mm rotor.

Front or rear – where does it mount?

• Either wheel, as long as the frame or fork permits a 203 mm rotor.

Do I need to buy bolts separately?

• No. Two mounting bolts are supplied with the adapter.

Does it increase braking power on its own?

• No. The larger 203 mm rotor delivers the added power and cooling.
• The QM 44 is the part that allows that rotor to be fitted at all.

For riders moving from a 180 mm to a 203 mm disc, the Magura QM 44 is the direct factory solution. It keeps the existing Post Mount calipers, sets the correct spacing over the larger rotor and arrives complete with the two bolts required for the job.