MR33 Circle Droop gauge V2 Review

Droop is one of the most powerful setup values in on-road RC racing. Long gone are the days when we had to slide O-rings over shock shafts to adjust it... unless you’re still running stock TT-02 or TT-01 chassis! These days, droop adjustment is quick and precise, and it plays a crucial role in how the car shifts weight under acceleration, braking, and cornering.

What is Droop?

In simple terms, droop refers to how far the suspension arms can extend when the car is lifted off the ground. It controls how much weight can transfer from one end of the car to the other when driving.

• More droop allows the suspension to extend further. This lets the car roll more in the corners, improving grip on bumpy or lower-traction surfaces.
• Less droop limits extension, keeping the chassis flatter and more stable on smooth, high-grip tracks.

Tuning droop is one of the most effective ways to fine-tune balance: more front droop can increase steering on corner entry, while more rear droop can add rear grip on corner exit.

Measuring Droop and Downstop

Over the years, racers have used many different methods to measure droop. These days, we don’t usually measure droop directly, but instead use downstop values.

The most common method involves placing the car on droop blocks and using a gauge to measure under the suspension arm. You simply slide the gauge under the lowest point of the arm and record the value.

This works well, but it’s not always perfect. Suspension arms wear, manufacturers may use slightly different moulds, and two sets of arms that both read “5mm” might not actually give you the same setting on track.

Introducing the MR33 Droop Gauge V2

The new MR33 droop gauge addresses these issues by measuring at the axle height instead of the suspension arm. This eliminates variation caused by arm wear, hub tolerances, or different wishbone designs.

The gauge comes with two integrated aluminium measuring wheels that are 34.8mm in diameter, The measurements a range from 21.0 to 25.0mm in 0.2mm increments, ideal for precise setup work.

Using it is simple

1. Place your chassis on 10mm droop blocks.
2. Thread the measuring wheels onto your axles.
3. Slide the gauge block under the wheels until it touches, then note the reading.

Because it measures at the axle, this method is inherently more accurate and repeatable than arm-based measurement.

Transitioning From Old Measurements

If you’re used to the “classic” downstop numbers, it’s easy to translate. For example:

• A 6.0mm front downstop typically equates to 23.4mm axle height on the MR33 gauge (a 17.4mm offset).
• A 5.0mm rear downstop works out to around 22.4mm axle height.

Roll Centres and Droop Together

It’s also worth considering how droop interacts with roll centres, another key chassis geometry setting.

The Roll centre is the virtual point around which the chassis rolls in a corner. Lowering the roll centre allows more chassis roll, which can increase grip but may feel less responsive. Raising the roll centre reduces roll, giving sharper steering and a more direct feel.

Droop adjustment affects how weight transfers around that roll centre. For example, more front droop allows the chassis to roll more relative to the front roll centre, giving better mid-corner steering. Less rear droop can stabilise the rear end under braking by reducing how much weight shifts forward.

When you tune droop and roll centres together, you unlock one of the most powerful combinations for fine-tuning balance and grip.

Final Thoughts

The MR33 droop gauge isn’t cheap, but it’s very well made, easy to use, and delivers consistent, accurate results. For me, the big appeal is simplicity—measuring droop is now faster, more reliable, and one less thing to second-guess in setup.

And when it comes to race day, anything that makes life easier is a win.