107730 HUDY Droop & Upstop adjustment tool

- Precise tool for accurate droop and upstop adjustment

- Ensures consistent and repeatable measurements

- Enables fine tuning of suspension geometry and balance

- Easy to use for quick and precise adjustments

- High quality Swiss 7075 T6 aluminium

The HUDY Droop & Upstop Set-Up Tool is a precision tool designed for the most accurate and convenient adjustment of suspension droop and upstop values.

The tool features a precision-machined measuring wheel and a clearly marked droop scale that ensures perfectly repeatable measurements.

In the world of 1/10th scale electric touring cars, droop (suspension travel) and upstop (suspension compression) are two of the most underrated, yet most effective, handling adjustments. While springs and damper oil determine the firmness, droop and upstop determine how much and how far the chassis is allowed to work.

Here you can find out how to use these parameters to optimise your setup for carpet or asphalt.

1. Droop (suspension travel): The control of weight transfer

Droop describes the distance that the suspension arms can move downwards when you lift the vehicle. It therefore limits how far the chassis "rebounds".

The effect on driving behaviour

The suspension travel significantly controls how much weight moves when braking or accelerating(pitch) and how much the car leans outwards when cornering(roll).

• Lots of droop (lots of suspension travel):

  • Effect: The chassis can move a long way. The tyres stay in contact with the ground for longer, even on uneven tracks.

  • Application: Ideal for low-grip tracks or uneven tarmac. It generates more mechanical grip, but also makes the car feel more "sluggish".

• Little droop (limited suspension travel):

  • Effect: The chassis is prevented from rebounding. The weight transfer is sudden and is stopped earlier.

  • Application: Perfect for high-grip (carpet). The car reacts more directly, bounces less and the risk of "traction rolls" (tipping over with too much grip) is reduced.

Pro tip: Droop is usually adjusted with the grub screws in the wishbones (downstops). Make sure that the value is exactly the same on the left and right, otherwise the car will pull askew when accelerating or braking!

2. Upstop (spring deflection): Protection and stability

The upstop limits how far the suspension can compress before the wishbone or damper hits a mechanical stop.

Why limit the spring deflection?

In contrast to the droop, the upstop is rarely used as an active tuning tool, but is crucial for consistency:

1. Chassis protection: It prevents the chassis from hitting the tarmac hard on bumps or hard landings.

2. Body clearance: It stops the suspension from deflecting before the tyres grind in the wheel arch and cause the car to break away abruptly.

3. Aerodynamics: On touring cars with a lot of downforce, a defined upstop prevents the front lip from touching the ground at high speed, which would interrupt the airflow and lead to a sudden loss of grip.