Hard - medium suspension spring ø medium

Balance between firmness and absorption: the suspension spring that makes a difference in setup

The TT951 from Tectime is a medium-hard suspension spring with a medium diameter, sold in a pack of 4 units. A small component with a direct and measurable impact on the car's behaviour on the track.

Function and performance

The suspension of a slot car directly affects traction and cornering stability. A spring that is too soft allows the chassis to sag excessively under acceleration or in fast corners; one that is too hard transmits every irregularity of the track and reduces the effective contact of the tyre with the rail.

The medium-hard point of the TT951 represents an intermediate-high hardness: the chassis maintains a controlled working height, the guide does not lose contact during changes in elevation, and the response to acceleration is firm without losing grip. It is the usual starting hardness for wooden or plastic tracks with a good surface finish, where top speed is sought without sacrificing stability.

Assembly and preparation

The assembly is not particularly difficult, but it is advisable to pay attention to some details:

• Ensure that the spring seat in the chassis is clean and free of burrs before installing the new part.
• Check that the free length of the spring is uniform across the different points of the suspension to avoid height differences between sides.
• Combine the TT951 with other suspension adjustments (preload, chassis height) before validating the setup on the bench or on the track.
• The pack includes 4 units, allowing for the preparation of two complete axles or having immediate spares during a racing session.

Compatibility

This section directly depends on the specific application for which the TT951 is designed within the Tectime catalogue. The medium diameter directs it towards chassis that use standard-medium size spring seats. Consult the technical documentation of your chassis or compare with the original springs before placing the order if you have doubts about the exact measurement.

Common mistakes

• Installing springs of different hardness on opposite sides: this creates traction imbalances that cannot be corrected with other adjustments.
• Not checking the free length: two springs from the same batch may have slight variations; measuring them before assembly is good practice.
• Changing only the spring without reviewing the rest of the suspension: the setup is a whole; changing the hardness of the spring without adjusting the preload or height may not yield the expected result.

Ideal for…

Preparers and club drivers who methodically work on suspension setup and need to have various hardnesses on hand to adapt to different tracks and conditions. Also for those who maintain several cars in preparation and want to unify the stock of suspension spares with a reliable product.

Frequently asked questions

What is the difference between a medium-hard spring and a soft one?

A soft spring absorbs track irregularities better but can cause excessive roll and loss of guide height in fast corners. The medium-hard offers greater stiffness, resulting in a more direct response and less pitching, at the cost of some sensitivity on imperfect tracks.

How many units does the TT951 include?

The pack contains 4 units.

Can I mix this spring with others of different hardness in the same car?

In principle, it is not advisable to mix different hardnesses on the same axle, as it introduces asymmetry in behaviour. If different hardnesses are used between the front and rear axles, it is a deliberate tuning decision; never between the right and left side of the same axle.

How do I know if I need a harder or softer spring?

If the car tends to "lean" in corners or the guide loses contact during elevation changes, try increasing hardness. If the car bounces or loses traction on an uneven track, decrease hardness. The adjustment should always be validated on the track, not just on the bench.

Is it compatible with any slot car chassis?

Compatibility depends on the inner diameter and length of the spring seat of each chassis. Compare the measurements of the TT951 with those of the original spring of your car before purchasing if you do not have prior reference with Tectime products.

The Tectime TT951 is a medium-hard suspension spring with medium diameter, sold in a pack of 4 units. Designed for slot car setup and tuning, it offers a firm yet balanced response ideal for wood or plastic tracks. A must-have spare for club racers and serious hobbyists looking to fine-tune chassis behaviour, improve guide contact and optimize rear traction. Compatible with slot car chassis using standard medium-diameter spring seats.