Welcome to the Pure Motorsport Tyre Tech for Toyo Motorsport Tyres
For more infomation on Toyo's R888 tyre please [Contact us].

Sizing information:

The writing and symbols on the sidewall of your Toyo tyre can tell you a lot about the tyre itself, such as what weight it can carry and its maximum speed. This helpful guide will show you what's what, so that you can read the writing on the wall. The writing on the sidewall of your Toyo tyre is like a specification sheet - it tells you everything you need to know about the tyre. This information includes details of the tyre's country of origin, size, speed rating, type approval,loading capability, model number and much, much more. Of course, some of this data is stuff only a tyre technician will find useful, but there are several details you will find handy too.

Let's use the Proxes T1-S 265/40ZR17 96Y above as an example

PXT1-S - The Toyo pattern name.

265 - The nominal section width of the tyre in millimetres.

40 - The aspect ratio of the tyre, (the ratio between the section height and section width). If no figure is shown it is normally 82.

R - Radial construction. All Toyo’s car tyres sold in the UK are radial except for certain special tyres such as space saver spares.

17 - The diameter of the rim shown in inches.

96 - The load capacity of the tyre shown as an index. which should be looked up on the [load index table]. In this case the load capacity of the tyre at the correct inflation pressure is 710kg.

Y - The speed symbol, i.e. the maximum sustainable speed for the tyre at the load capacity given - in this case 186.4mph. [View the Speed Symbol Table]

Steel Belted Radial - as with the letter "R", this refers to the tyres construction. "Steel Belted" is a particular form of radial construction.

DOT - the type approval mark of the American Department of Transport, showing that our tyres have passed their strict testing procedures. When a tyre has passed both the American and European test programmes, you know you can have complete faith in it.

CXKA 6HY47887 - this is Toyo's production code marking, an internal code that allows us to determine exactly where and when a tyre was made.

E4 0213760 - the ECE type approval mark and number, showing that our tyres have been tested and passed as high-quality by the European regulatory authorities.

Made in Japan - the country where your Toyo tyre was made.

Size Chart:

Load Index table:

The Load capacity of a tyre determines what payload each tyre can carry. It is vital that you check with your manufacturer what capacity should be put on your car. In some cases insurance can be void if you select the incorrect tyres. The following table below shows the Load Index against actual load.

Speed Symbol Table:

Cold Inflation Pressures

Optimum cold inflation pressures are chosen to achieve optimum hot inflation pressures.

Optimum cold inflation pressures are determined by: 1. event distance, 2. vehicle weight and 3. camber settings. Pressures shown below are for inflation with compressed air.

Hot Inflation Pressures

Hot inflation pressures indicate the suitability of the cold inflation pressures. Where hot pressures are too low, start with a higher cold inflation pressure or vice-versa. Pressures shown below are for inflation with compressed air.

Hot Inflation Pressures Guide:

The hot inflation pressures shown above have a large range. This takes into account the variances in vehicle weights within the ranges shown, as well as axle weights, for example: a front-engine, rear-wheel-drive vehicle with a front weight bias will usually give best results with hot pressures that are 2-4psi higher on the front axle compared to the rear axle.

Changing hot inflation pressures by small amounts ( 1-4psi ) can be used to fine-tune handling:

Changing hot inflation pressures to change handling bias should be used for fine-tuning only. Improving overall grip levels should be done by tuning spring rates, anti-roll bars, suspension geometry etc., using lap times and pyrometer readings to asses changes.

Hot Inflation Pressures NOTE: Tyres with full tread depths used on dry tracks will have more tread flex and therefore more heat build-up compared to tyres with reduced tread depths. One result of this heat build-up is slightly increased pressure build-up. The amount of pressure build-up will decrease as tread depth decreases.

USING NITROGEN COMPARED TO COMPRESSED AIR FOR TYRE INFLATION

Nitrogen behaves quite differently compared to normal compressed when used to inflate tyres. When subjected to heat, compressed air will expand at a greater rate compared to nitrogen. For this reason, all factors being equal, there will be less pressure build-up when nitrogen is used for tyre inflation compared to normal compressed air. For this reason cold inflation pressures should be higher when using nitrogen inflation compared to using compressed air.

The advantage of using nitrogen compared to compressed air is that cold inflation pressures are closer to optimum hot pressures. Steering feel and response will be superior with the higher inflation pressures for the first 2 - 3 laps compared to using the lower inflation pressures suitable when using normal compressed air. Nitrogen inflation also provides less variance in inflation pressures, therefore more consistent tyre performance and steering response. .

A good "rule of thumb" to determine the optimum cold inflation pressures for nitrogen inflation: 1. determine the usual amount of pressure build-up that occurs using compressed air, 2. halve that amount, and 3. add the amount from step 2 to the cold inflation pressure used for compressed air.

NOTE: When using nitrogen for tyre inflation, ensure tyres are purged of compressed air and moisture, otherwise the advantages of nitrogen inflation will not be realised.

WET CONDITIONS & INFLATION PRESSURES

For wet tracks (STANDING WATER) increase pressures by 4-10 psi compared to dry track pressures. Increasing the pressure for wet tracks makes the tyre's contact patch smaller, making the tyre less susceptible to aquaplaning.

There is less heat build-up on wet tracks, therefore less pressure build-up. This is another reason cold inflation pressures need to be higher than those used for dry conditions.

For optimum performance on tracks where there is standing water, tyres with new depth or close to new tread depth will provide optimum performance. Buffed or worn tyres (3 - 1.5mm tread depth) will be susceptible to aquaplaning where there is standing water.

It is recommended that tyres used on wet or damp tracks are given a short "scrubbing-in" session before they are used competitively to remove the layer of mould release on the new tyres. Without "scrubbing-in" the tyres will be slippery until this layer of mould release agent is worn away.

Camber Settings

Toyo motor sport radials will provide optimum cornering grip with camber settings between negative 3 and 6 degrees on steer axles. Where adjustment is possible, negative camber on drive axles will also improve cornering grip. Optimum camber angles will provide optimum cornering grip, and therefore will be an important contributing factor for improving lap times.
NOTE: On some vehicles a lack of negative camber can over-heat the outside tread shoulder causing grip levels to drop-off suddenly and in some cases cause blistering of the outside tread shoulder. Large heavy, front engine cars are most susceptible to this type of tyre damage.

CAMBER SETTINGS & INFLATION PRESSURES

Where camber adjustment is limited or class rules limit the amount of negative camber allowed, increasing cold inflation pressures is necessary to prevent the outside tread shoulder overheating. This also applies to vehicles that are used on the street as well as the track, where the camber settings are a compromise for this dual purpose. Where this is the case, adding 3 - 6psi to recommended cold and hot inflation pressures usually prevents the outside tread shoulder over-heating.

Tread Depths & Tyre Performance on wet & dry surfaces

All grooved motor sport tyres will have some tread flex. On dry surfaces tread flex reduces overall grip levels and therefore lap times. To optimise dry grip levels with grooved race tyres, tread flex needs to be minimised. The more groove area or "void" a tread pattern has, the greater the amount of tread flex there will be in dry conditions.
PROXES RA1 - This pattern has a tread depth of 6mm or >6mm when new and has enough groove area to be very effective as a "wet" with new tread depth or close to new tread depth. For optimum dry track performance, buffing will make a large difference in grip and endurance for the Proxes RA1 and is highly recommended. Buffing will also provide more even tread wear and a slower wear rate.

PROXES R888 - This pattern has 5mm of tread depth when new and minimal groove area on the tread shoulders for optimum dry track performance. Buffing the Proxes R888 will provide a small improvement for cornering grip on dry tracks.

Tread Temperatures

As for most motor sport tyres, Toyo motor sport radials can be slippery when cold. Caution needs to be exercised until the tyres have had some time to warm-up. Grip levels will be low when the tread temperature is less than 55 degrees Celsius.

Optimum operating temperatures for Toyo motor sport radials is between 75 and 95 degrees Celsius. Over 100 degrees Celsius, grip levels drop-off rapidly.

Rim widths and tyre performance

Toyo motor sport radials will provide optimum performance where the rim size allows the sidewall to have little or no protrusion from the rim flange.

Where possible, use of minimum rim widths should be avoided. For most sizes, optimum tyre performance will be provided with rim widths that are from the mid point to the maximum in the range of approved rim widths shown.

See [sizing chart] for recommended rim widths.

Tread Compounds

Proxes R888: All Proxes R888 tyres held in stock are "GG" tread compound. The "GG" is a versatile medium soft tread compound, suitable for a wide range of applications.

The Proxes R888 is available with the "SG", ultra-soft tread compound in a small range of sizes from Toyo motor sport dealers by indent order only. No "SG" tyres are kept in stock due to a short shelf life of this tread compound. The "SG" tread compound is suitable for a narrow range of applications only, and has a faster wear rate compared to the "GG" compound. Suitable applications for the "SG" compound will include lightweight vehicles used for short competition such as Hillclimbs or Sprint events.

The temperature range for the "SG" compound is narrower and will overheat or "go off" much quicker than the "GG" compound.

The tread compound of each Toyo Proxes R888 tyre is marked on the sidewall.

Street use

All three Toyo motor sport radial patterns are legal for use on public roads but recommended for competition or use on closed circuits. Grooved, street legal race tyres are designed for users who need to drive their vehicle to and from the circuit, and / or where the class regulations specify that street legal tyres must be used.

When compared to high performance or ultra-high performance tyres, when used on public roads, Toyo motor sport radials will:

1. have comparatively poor ride comfort. Toyo motor sport radials have a steel sidewall ply to minimise sidewall deflection for optimum cornering grip.

2. be susceptible to "tram-lining" / "tracking". The casing stiffness provided by the steel sidewall ply and wide belt packages used on Toyo motor sport radials make them susceptible to tram-lining caused by road irregularities common on public roads.

3. have faster tread wear. The tread compounds used on Toyo motor sport radials provide much higher grip levels compared to high performance or ultra-high performance tyres rather than long tread life.

4. be slippery when cold. Due to the tread compounds & construction types, grip levels will be low until the tyres have had some warming-up. This will be especially noticeable in cold and / or rainy conditions.

5. be susceptible to aquaplaning when used with low tread depths (3 -1.5mm) on wet roads, especially in heavy rain conditions. Users need to exercise caution in these conditions with careful monitoring of vehicle speed to avoid aquaplaning. The Proxes RA1 pattern is the exception. The Proxes RA1 has a void ratio that makes it resistant to aquaplaning, where tread depths are >4.5mm. For more information on wet road grip and aquaplaning, click here.

Using different tyre types and patterns on one vehicle

Mixing high performance street tyres and motor sport tyres on one vehicle: Some users try to address a lack of grip on an axle by fitting motor sport tyres to the axle that has a grip deficiency, and using high performance street tyres on the other axle. This practise is not recommended as it creates a grip imbalance. The fastest lap times will be achieved by addressing the oversteer or understeer problem by suspension and chassis tuning. The exception to this is drifting, where it is common to use motor sport tyres on the front axle and high performance street tyres on the rear axle to promote progressive oversteer.

Mixing different brands and / or patterns of motor sport tyres on one vehicle: This should also be avoided where possible to avoid handling imbalance. Different casing constructions and tread compounds provide different grip levels, warm-up times and handling characteristics. Having tyres of the same tread compound & construction type on both axles will promote balanced handling.

References:

Toyo Australia

Toyo Tire UK