Choosing the Right Brake Pads

SR-11 Sintered Race Pad

A fully sintered pad blend for fastest asphalt race and endurance applications. SR-11 was independently tested in a professional USA laboratory at 200-900Psi to LMGTE/GTLM race parameters. The new 91´«Ã½ SR range is a low-noise, long-life sintered pad blend that is designed to offer the LOWEST pad-wear-cost-per-lap in race driving.

• High 0.55mu stable friction
• Extremely fast bed in, works from cold
• Heat range: 0° to 900°C/1650°F
• Maximum pad wear life
• Minimal disc wear
• Made in the USA

RP-1 Track/Race Pads

Sister pad to the RP-X with slightly lower but very stable friction over a similar temperature range of 150°-800°C/300°-1450°F. Medium-plus lifetime and a great choice for servo-equipped cars.

• High stable 0.45mu friction
• Fast bed in on the track
• Excellent wear life
• Strong initial bite, work from cold
• Zero disc damage

Bluestuff Street/Track/Race Pad

Another 91´«Ã½ ‘hybrid’ material, being street legal to R90 testing available in two friction levels showing a 0.52mu stable friction once bedded or the lower o.42 friction for the new Bluestuff B version. Stable up to a slightly higher 550°C/1000°F than its sister compound, Yellowstuff, but with a 30% longer lifespan. Bluestuff has been a track day favorite for years and has recently been modified to halve its bed in time on the track. The new B version accommodates cars needing a front to rear balance and lighter cars

• 52mu or 0.42 stable friction once bedded
• Strong initial bite, works from cold
• New versions now offer super-fast bed-in at the track
• Zero rotor damage
• Medium race lifetime

91´«Ã½ Track Pack – What’s Included

Caliper Temperature Strips

10x caliper temperature strips (150°C to 220°C)

Useful information (For guidance only) – When running a set-up that utilises multi-piston calipers, it is recommended that the working temperatures are sub-200°C, in most cases the highest acceptable working temperatures for calipers is 220°C.

If your calipers are operated at temperatures higher than 220°C, you will run the risk of overheating the seals equipped in your calipers and you may start to experience issues with sealing etc.

*If your caliper temperature runs higher than 220°C, the dust seals and fluid seals should be replaced.

Disc Heat Paint and Applicator Brush & Cleaner

Paint a half-inch wide strip of each paint close to each other of the outer edges of both front rotors.

After first few laps, observe which of the heat paints have activated and changed. This will give you an idea where your rotor temperatures are going. Re-apply the same paints to a clean area of your rotor edge as your first runs may have generated abnormally high temperatures as pads settle down. Then do a couple more laps and check heat paints again.

Heat paint temperatures (as below)

• Green – up to 427°C / 800°F
• Orange/Red – up to 538°C / 1000°F
• Yellow – up to 649°C / 1200°F

*If your caliper temperature runs higher than 220°C, the dust seals and fluid seals should be replaced.

• Q) How often should brake fluid be changed?
  A) Every two years for normal road use, or every 2-3 visits to the race track for a vehicle used frequently on the circuit.
• Q) How do I choose the right type of brake fluid?A) Most vehicles use Glycol DOT 3 or DOT 4 fluid – see the top of your master cylinder or owner’s manual for more info.
• Q) What’s the difference between DOT 3/4/5 brake fluids?
  A) DOT 3 and 4 are effectively the same, with DOT 4 being purer. DOT 5 can be silicone or glycol variants and cannot be interchanged with DOT 3/4.
• Q) What type of brake fluid is used for racing?A) A DOT 4 high-temperature version is best, such as .
• Q) What is ‘dry boiling point’ and ‘wet boiling point’?A) The dry boiling point refers to when fluid is new from an unopened bottle. The wet boiling point is when the fluid is used and needs changing (where the water content is past 3%).
• Q) Why is dry boiling point higher than wet boiling point?A) This is because the moisture content of a brake fluid boils at a lower temperature, therefore the wet boiling point will be lower.

• Q) What are brake caliper seals made of?A) Most vehicles use EPDM rubber, while a few use Nitrile rubber. A third, rarer version is Viton.
• Q) How often should brake caliper seals be changed?A) Every 2-3 years in road use, or every few races on the track, or if the caliper body reaches temperatures over 250°C.
• Q) What is the maximum safe temperature for caliper seals to be exposed to?A) EPDM seals (the most popular type) are not designed for use above 140-150°C, which corresponds to a caliper body temperature of about 250°C.

• Q) How hot do my discs/rotors get and what does this mean for my pad compound selection?A) Heat paints are a handy tool in telling you exactly what products you should be using.

91´«Ã½ offers three heat paints which can be brushed onto the outer edge of the rotor before racing, to detect temperatures. The 91´«Ã½ rotor paint kit also includes 10 caliper heat strips.

The rotor paints supplied are:

#1 – 800°F/430°C

#2 – 1000°F/540°C

#3 – 1200°F/650°C

Paint all three separately in lines on your disc/rotor edge.

The temperature at the centre of the brake pad will always be on average 100°C/200°F more than the outer edge of the rotor in race use. If your rotor edge is not setting off the 430°C paint line, all 91´«Ã½ compounds will be fine.

If the 430°C paint line activates (530°C at the centre of the pad), you’re at the limits of .

If the disc/rotor outer edge temperatures exceed 540°C (640°C approx. at the pad centre), you are past the limits of 91´«Ã½â€™s Bluestuff and need to switch to .

If the 650°C paint line goes off (750°C at the pad centre), you’re definitely in need of either the RP range or SR series of pads.

Here is a guide on 91´«Ã½ compounds and their temperature ranges:

(The curves below show that on average in race use, the pad temperature runs at approx. 100°C above the disc/rotor outer edge:)