#tyres

[thunderstruck9]

Titina Maselli (Italian, 1924-2005), Camion [Lorry], 1976. Oil on canvas, 72.5 × 92 cm.

[viejospellejos]

[its-where-the-wild-things-are]

[colonellickburger]

Wim Wenders. When Martin Scorsese Had a Flat Tyre II, 1977. Utah

[nonbinarylewishamilton]

a rough guide to grips and tyres:

A Rough Guide to F1 Tyres and Grip (shorter version)

What is grip?: Grip is the friction available between a tyre’s contact patch and the road surface, and often determines how hard you can brake, how fast you can corner, how aggressively you can put the power down. Basically, grip is how well tyres hold onto the road. 

Grip comes from three places. Mechanical grip is what the tyres and suspension can do on their own, independent of speed, crucial on low-speed circuits like Monaco where aerodynamics barely contribute. Aerodynamic grip is the indirect benefit of downforce: wings and diffusers press the car into the track, giving the tyres more load to work with, which lets them generate more lateral force through corners. Thermal grip concerns whether the tyre is at the right temperature to work at all.

Why rubber is weird (and why it matters): Rubber is a viscoelastic material. When you deform it, it doesn’t spring back immediately. During that delay, energy is lost as heat, a property called hysteresis. This is why tyres warm up during a lap even when you can’t see any obvious sliding: the rubber is constantly being loaded and unloaded against the microscopic roughness of the track surface, and that internal friction generates heat throughout the whole compound, not just the surface.

This gives tyres two distinct grip mechanisms. Adhesion grip works like molecular velcro: rubber molecules bond temporarily to the road surface, and as the tyre rolls those bonds are stretched and broken, creating a friction force. Hysteresis grip comes from the energy lost in the rubber’s deformation cycle itself. The useful quirk here is that hysteresis grip isn’t affected by contaminants like oil or water, which is partly why wet-weather compounds are designed with high hysteresis built in.

The working range: Every Pirelli compound has an optimal temperature window. Below it, the rubber goes cold and brittle; it can’t conform to the track surface, the contact patch shrinks, and you get graining as chunks of rubber shear away like rubber eraser crumbs. Above it, the rubber overheats and essentially boils, producing blisters where large chunks separate from the surface.

Pirelli’s current range runs from C1 (hardest) to C5 (softest). Softer compounds warm up quickly and suit cooler conditions and smooth tracks; harder compounds need high-speed corners and rough surfaces to generate enough heat, but are much more robust at high temperatures. For each race weekend Pirelli nominates three of the five as Hard (white), Medium (yellow) and Soft (red).

Alongside the slicks, Pirelli supply intermediates (green) for damp or drying conditions and full wets (blue) for heavy rain. Both are deeply grooved to channel water away from the contact patch. They lean more heavily on hysteresis grip than slicks, which is why they maintain traction even on a flooded surface where adhesion grip is largely wiped out.

Tyres and Temperatures:  Tyre temperature is central to how grip is produced. Warmer rubber is softer and more pliable, which increases the contact patch area and strengthens the adhesive bonds with the road. But there’s a narrow window (think soft tyres and why they typically don’t last).Getting the tyres into and staying within their working window is a large part of what separates the top drivers. During a safety car, drivers typically  weaving on straights to keep tyre temperatures up. Before a qualifying lap, drivers run an out-lap and a prep lap specifically to bring all four corners to temperature evenly. Brake bias adjustments are used mid-stint to route more heat through the wheel rim and into the carcass; in F1, a 10°C rise in rim temperature translates to roughly 1°C in tyre carcass temperature, which can be enough to flip a tyre from underperforming to fully alive.

When to use which tyre:  Compound selection happens at two levels. Before the weekend, Pirelli pick the three compounds available based on track characteristics: harder choices for circuits that generate high tyre loads (fast sweeping corners, abrasive asphalt, high ambient temperatures) and softer choices for smooth or slower tracks where getting heat into the tyre is harder. Monaco and Singapore get the softest end of the range; Spa and Silverstone tend toward harder options.

Then teams make their own calls within the weeken. The soft is almost always the qualifying tyre because it gives maximum grip, short life, fine for a single flying lap. For the race, teams weigh how long each compound will last against the lap time it gives up. A typical approach is to start on the medium or hard and preserve track position, then switch to a fresher, grippier compound later when it matters most. Starting on the soft is riskier but can work if the team can jump rivals in the first stint before the rubber goes off. Weather changes the equation a bit because when it does rain, the team shifts to intermediates (tyres with green stripes). And if it gets heavier, the team go for full wets (tyres with blue stripes; rarely used). 

Degradation and strategy (the fun part and not so fun part): When a tyre exceeds its working range, it starts sliding more. Sliding generates more heat. More heat causes more sliding. The feedback loop kicks in fast. A typical F1 tyre stint lasts roughly 300 km at best, compared to the 64,000 km you’d get from a road tyre. During each race weekends, each driver receives 13 sets of dry-weather tyres for a standard race weekend and must use at least two different slick compounds during a dry race. There typically is a mandatory stop, which varies race and track. 

Tyre degradation is a quite crucial variable in race strategy because if deg is high, you lose time quickly but if deg is low, staying out and banking track position makes more sense. Teams primarily  model tyre degradation curves from practice data and pre-plan multiple race scenarios. During the race, drivers are told to “switch to plan B” when tyres are degrading differently to expectations, which also tells them to hit pre-defined lap delta targets to make the rubber last. The driver who can manage tyre temperatures without losing lap time too quickly often wins races that looked otherwise settled on paper.

sources (in no particular order): x x x x x x x (my fave one of these- its really good. please read if you can) x x x x x x

[slack-wise]

Rowan Smith. Untitled (Tyre), 2012. Bass wood

[vintagepromotions]

'The best and the cheapest bicycle tyres - Michelin'

Poster advertising Michelin bicycle tyres, featuring the company's mascot Bibendum riding a bicycle while smoking a cigar and throwing tyres at the viewer (c. 1910). Artwork by H.L. Roowy.