The design, manufacture and maintenance of MAX Grip tyres from Scalextric Car Restorations
IntroductionScalextric Car Restorations has uniquely designed, developed and manufactures the MAX Grip range of tyres for the Scalextric range of cars. All the Scalextric tyre types and cars are covered by this range of tyres. This article explains how this was accomplished and the best way to look after your MAX Grip tyres.
The need for MAX Grip tyresIt became very clear early on that the tyres originally fitted to the Scalextric range of cars have a finite life. The tyres can simply wear out, they dry out and become hard, they can crack and in the worst case, fall apart. Also, with the introduction of the Sport track system the older Scalextric cars without a strong Magnatraction magnet couldn’t be used as the Sport track surface is much smoother than the classic track it replaced.
With these strong reasons it was necessary to introduce replacement tyres for the Scalextric range of cars. This new range of tyres also needed to give more track grip than the original tyres to allow the older Scalextric cars to be used on the Sport track without the addition of a Magnatraction magnet.
Another common problem is identifying which tyres are fitted to which cars. At the time of writing there are 137 different tyres available to fit 1675 different Scalextric models from 1960 to 2014, and they are all black and round. At the time “Which tyres fit my Scalextric car” was around half of the questions we used to receive at Scalextric Car Restorations. Some information was available via the Scalextric Service Sheets but very little information was available for the older cars.
Developing a Scalextric tyre databaseAt this time we already had a database of Scalextric cars produced based on the original Scalextric catalogues from catalogue 1 in 1960 up to the present. We simply added 2 new fields to the database, one for the front tyres and one for the rear tyres. For each new tyre identified a Master Sample was selected and stored, a 3 digit tyre identity code was assigned. This code was added to the database for each application. To populate the tyre database we used several methods:
During this period there were hundreds and hundreds of older Scalextric cars here at Scalextric Car Restorations so we were able to start to populate the database with the tyres fitted to these cars.
- Reviewing all the published Scalextric Service Sheets allowed cars and tyre sets to be identified, cross reference and matched.
- Tyre sets were purchased based on the Scalextric Service Sheets and the tyres identified.
- Axle sets were purchased where replacement tyres weren’t available and the tyres identified.
- Targeted Scalextric cars were purchased and their tyres identified.
- Customers kindly sent their tyres to us to be reproduced in the MAX Grip material. These tyres where also identified.
- All tyre applications were reviewed with crowd source data techniques where possible.
- To date we have identified, coded and referenced 137 different tyres for the Scalextric cars produced from 1960 to 2014.
Developing the MAX Grip tyreWith the tyre database coming along and master samples of all the Scalextric tyres also underway, the MAX Grip tyre material was identified. Only the material was of concern as the shape and size of each replacement tyre was already given by the master sample. After much research a 29 Shore A hardness cold cure rubber material was identified and considered the best option. In addition the “stickiness” of this material could be adjusted in the tyre production process.
The tooling process was selected based on the expected volumes of tyres needed. A flexible mould material was selected that is compatible with the previously selected rubber tyre material and predicted production volumes.
A method to quickly and easily produce the production tools was developed and trailed. After a few refinements a reliable method to produce the production tools was established as well as a way to add tool identity markings.
With the material for the MAX Grip tyres selected some prototype tools were made and sample tyres produced. Several problems were identified and solved. This included completely filling the mould cavity, setting the right “stickiness” for the MAX Grip range of tyres and generally developing a reliable production process capable of producing tyres at the rate of around 1000 tyres every few months.
Each production tool has one cavity and can make one complete tyre at a time. Where higher production volumes are needed additional production tools are produced. Some of the higher volume tyres can have up to eight production tools.
Manufacturing the MAX Grip tyreProduction starts by weighing out the correct amount of raw material for the batch size, generally enough for 20 to 30 individual tyres in one batch. The material is thoroughly mixed and degassed in a vacuum chamber until all air bubbles are removed.
Each production MAX Grip tyre mould is filled by hand ensuring the mould cavity is completely filled with no air bubbles or voids. The Moulds used for the MAX Grip tyres are “closed moulds” which give 100% tyre detail including the inside tyre wall. Once the tyre is fully cured the mould is opened and the new tyre removed, any flash removed, the tyre is inspected and placed into stock. The production tool is inspected, cleaned and put ready for production use again. Production tools can be used 100s of times over to produce 100s of production MAX Grip tyres.
All MAX Grip tyres are produced by hand in the UK by Scalextric Car Restorations.
Maintaining MAX Grip tyresMAX Grip tyres are designed to give the best overall levels of grip on both the Classic track surface and the Sport track surface. There are some points to take into account when using MAX Grip tyres:
MAX Grip tyres are sticky and will pick up dust and debris from the track surface. A specific test carried out was to race a Scalextric car fitted with MAX Grip tyres on a visibly dusty track. After several laps the performance of the car dropped away considerably, clean tyre track lines were visible on the track surface and the MAX Grip tyres were covered in dust.
The best grip is obtained when the MAX Grip tyre material is in contact with the plastic track surface. MAX Grip material to plastic gives very good grip, dust to dust gives very poor grip.
- Maintaining MAX Grip tyres is really all about keeping them clean and free from dust, dirt and debris. To do this each tyre must be wiped over with a damp cloth prior to a race. The track should be kept clean, again use a damp cloth the lift the dust, dirt and debris from the track and kitchen paper or similar to dry the track immediately.
- MAX Grip tyres are soft and will wear over time just like real car tyres.