Predict lockup before the tire gives up
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Course: Engineer tire and brake grip that lasts
Module: Engineer brake force and bias
Estimated duration: 55 minutes
Lockup is the design limit, not an afterthought.
When you engineer brake force and bias, the question is not how much pressure the system can make in the abstract. The useful question is where each tire will stop rotating before it can keep converting brake torque into road force. A brake package can make more clamping force than the tire can use. Once the resistance at the rotating tire exceeds the tire-road traction available at that instant, the wheel stops rotating. That is lockup. For this lesson, your job is to predict that boundary before the tire crosses it, then use testing cues to confirm whether your prediction matches the car.
This sits after the lessons on converting line pressure into axle force and accounting for load transfer. Those lessons tell you how much brake force the hardware is trying to apply and how normal load moves under deceleration. This lesson uses those pieces as the lockup screen. At every important braking condition, ask which tire is closest to its usable longitudinal limit. If the answer is a front tire, the car usually gives you a stable warning through the steering. If the answer is a rear tire, the car can rotate under braking and become difficult quickly. That is why bias work is not just a performance exercise. It is a stability exercise.
The basic mechanism is simple enough to say in one sentence: a tire can only create braking force in proportion to the load it is carrying and the friction it can generate against the road, and lockup begins when brake torque demands more road force than that tire can provide. The complications are what make the skill worth learning. Load is moving forward while you brake. Load is also moving side to side if you brake while turning. Aerodynamic load can be strong at high speed and disappear as speed falls. Tire grip changes with temperature, surface friction, and slip. The driver can change the brake torque rate by how quickly the pedal is applied. A car that is stable during a straight-line test can show rear bias when the same brake force is combined with cornering.
Start with the tire, not the caliper.
The tire is the final limiting part of the brake system. Pressing the brake pedal creates line pressure. Line pressure creates pad force and brake torque. Brake torque resists wheel rotation. The road can only answer with the traction the tire can generate. If the brake system asks for less than the tire can support, the wheel keeps rotating and the car decelerates. If the brake system asks for more, the wheel speed falls too quickly and the tire slides.
That is why bigger brakes alone do not automatically shorten a stop. If the old brakes could already lock the tire, the tire was the limiter. More torque may improve heat capacity, repeatability, feel, or modulation, but the peak stop still has to pass through the tire. For bias work, this matters because you are not trying to make every end of the car lock equally. You are trying to distribute brake demand so the front and rear tires approach their available grip in a stable order.
For an intermediate driver or engineer, the useful mental model is a demand-capacity comparison. Demand is the brake torque at a wheel converted into the longitudinal force the contact patch must provide. Capacity is the tire-road braking force that tire can support at its current normal load and slip condition. Lockup prediction asks where demand reaches capacity first.
The first screen is normal load. Tires create traction in relation to how hard they are pressed into the road. A tire carrying more vertical load has more potential braking force than it had with less load. When the car decelerates, load transfers from the rear axle to the front axle. That makes the front tires more capable under hard braking and the rear tires less capable. The brake system therefore usually needs more front brake than rear brake. This is the engineering reason behind front-biased systems and the driver reason you normally want the fronts to begin locking slightly before the rears.
Use slip as a warning, not a cliff.
A tire does not go from full grip to useless grip in one instant. Longitudinal tire force rises with braking slip up to a peak, then the tire can enter an unstable region between peak friction and full sliding. Limpert gives the important control warning: once the tire moves beyond the stable rising part and past peak, the time to run through the unstable region into lockup is very short. For the driver, that means the edge of lockup is not a comfortable place to camp with clumsy inputs. For the engineer, it means a controller or driver response that waits until the wheel is already locked is late.
Some dry-road tires with a high peak relative to sliding friction may reach peak braking friction at roughly 20 to 30 percent slip. The exact optimum changes with tire and surface. Limpert also notes that the optimum slip value decreases as tire-road friction decreases. That makes low-grip surfaces less forgiving. You need less slip to reach the useful peak, and the window between effective braking and sliding can feel narrower. This is why a wet or dirty braking zone can punish the same pressure trace that worked on a warm, dry track.
Do not overfit your lockup prediction to wheel deceleration alone. Wheel angular deceleration is a useful first warning because a wheel that is slowing much faster than the vehicle is building slip. But Limpert points out that threshold wheel angular deceleration depends on operating parameters including vehicle speed, tire-road friction behavior with slip, brake torque rate tied to pedal force rate, brake system inertia, and wheel load. The possible threshold values can vary by very large ratios. In practical terms, a single magic wheel-deceleration number cannot predict lockup everywhere. You need the larger picture: speed, load, surface, slip behavior, and how fast the driver is adding torque.
That is also why pedal application rate matters. If you stab the pedal, you create a high brake torque rate. The wheel can decelerate quickly, slip can rise quickly, and the tire can pass through the stable region before the driver has time to sense and correct it. If you squeeze the pedal and continue adding pressure, you give the tire time to build longitudinal force while giving yourself time to sense which end is approaching the limit. The goal is not timid braking. The goal is a fast, controlled ramp that lets you stop adding pressure before the tire is already locked.
Predict the first lockup tire.
A clean lockup prediction has four steps. First, estimate the normal load at each tire or axle for the condition you care about. Use the static distribution as the starting point, then add the load transfer caused by braking. If the car is turning while braking, account for lateral load transfer as well. Second, estimate the braking capacity of each axle from the tire load and available friction. Third, compare the brake system demand at each axle to that capacity. Fourth, ask what changes during the braking zone: speed falls, aero load may fall, the driver may turn in, the inside rear may unload, and tire temperature may move.
That fourth step is where many wrong bias decisions come from. A car does not have one lockup condition. It has a set of lockup conditions. It can be front-limited at the start of a high-speed straight-line stop and rear-limited later when speed falls and aero support drops. It can be acceptable in straight-line braking and rear-limited during brake-turning because pitch and roll together unload an inside rear tire. It can look fine on cold tires and become rear-biased once warm tires and greater deceleration create more forward load transfer. If your prediction assumes one load state and the track gives you another, the bias decision will be wrong.
The stable target is front-first, only slightly.
Both Bentley and Lopez point toward the same target: set the brake bias so the fronts begin to lock marginally before the rears. This is not because front lockup is fast. It is because it is the more stable warning. If a front tire starts to slide under braking, you feel it in the steering and the car tends to continue pointing closer to straight. If the rear tires lock first, the rear of the car can step out because the rear axle has lost the braking grip that was helping keep it aligned. Rear-first lockup under trail braking or brake-turning can become a spin mechanism.
Slightly front-first does not mean heavily front-biased. Too much front bias leaves rear braking capacity unused and lengthens the stop. The front tires do too much work while the rear tires still had available longitudinal grip. You may get early front smoke, flat spots, or an easy steering warning, but the car is not using all four tires efficiently. The useful target is narrow: the fronts should be the first end to complain, but only just. That gives a warning margin without throwing away braking force at the rear.
The opposite error is more dangerous. If the rears reach lockup first, the car may dart, rotate, or feel nervous in the brake zone. Lopez describes rear bias as something that can become very exciting once the car heats up and produces the deceleration and forward load transfer it will see in real running. The reason is mechanical, not mystical. The rear tires are losing vertical load under braking. If the brake system still asks them for too much longitudinal force, they are the tires most likely to give up first.
Bias is a prediction you must warm up before trusting.
Do not set bias from cold tire behavior and declare the car ready. Lopez warns that if bias is set when tires are cold and grip is lower than in racing conditions, the car may not show the same forward load transfer it will show when everything is warm. Once the tires come up and the car decelerates harder, the fronts carry more load and the rears carry less. A setting that looked acceptable cold can become too rear-biased when the car is actually at pace.
The correct sequence is to get the tires to operating temperature first, then test. That does not mean you test recklessly. It means your data must come from the same friction and load-transfer neighborhood in which the car will be driven. Warm the tires with normal laps. Then perform straight-line stops off line, after checking mirrors, and build brake pressure until a front or rear tire is just at the edge of lockup. If lockup occurs, release enough pressure quickly to restore rotation and avoid flat spotting. The test should teach you which end is first, not punish the tire.
This is where observation helps. In an open-wheel car, the driver may be able to see a front tire beginning to lock or see the visual pulsing effect of slip across the surface. The driver can also use mirrors aimed at the rear tires during testing to confirm rear-bias sensations. In a closed-wheel car, you may have to rely more on feel, smoke from the wheel wells, tire marks, or observers. Puhn recommends using observers or video for brake-balance tests and starting at moderate speed, around 40 mph, so the test can be observed safely. He also warns not to lock all four wheels, because that destroys the information you were trying to collect.
Straight-line testing is only the first pass.
A straight-line stop tells you whether the front-to-rear brake split is close under pure longitudinal demand. It does not prove the car is safe under combined braking and turning. Once you add steering, the tire budget is shared. The same tire may need to brake and corner. The inside rear can become substantially unloaded. Lopez notes that a bias setting that is perfect in straight-line braking can be too far rearward for comfort under simultaneous braking and turning. That is the condition where rear bias reveals itself.
The sequence should therefore move from straight-line to brake-turn testing. First, get a straight-line front-first margin. Then test the car under a controlled combination of braking and turning, not at race aggression on the first attempt. You are looking for rear nervousness, darting, or rotation as the brake is held into the beginning of steering. If that appears, the rear axle is probably being asked for more braking than its reduced load can support in that combined state. Move bias forward in small steps and retest.
This is also why the lesson belongs in a brake-force and bias module rather than only a car-control module. The driver feels the symptom, but the engineer explains it. During brake-turning, pitch and roll change the normal load at each tire. The rear axle is already lighter from braking. The inside rear is lighter again from roll. If rear brake demand remains high, that tire can reach the lockup boundary before the front tires. A car that looked balanced on a straight road can become rear-limited at corner entry.
Predict speed effects through the braking zone.
Speed matters in more than one way. In Limpert's control discussion, threshold angular deceleration depends on vehicle velocity and wheel speed. In cars with aerodynamic devices, speed also changes normal load. Puhn's rear-wing sports racer example is the one to remember: at high speed, the rear wing improves rear-tire traction for braking, but as speed drops, downforce drops, increasing the chance of rear-wheel lockup when braking for tight corners.
That means a car can need different bias margins at the beginning and end of the same braking zone. At the high-speed start, the rear may be supported by aero load and tolerate more rear brake. Later, when the car is slower, rear downforce is lower, and the same rear brake demand may be too much. If the driver also turns in near the end of the zone, the rear tires lose still more available longitudinal capacity. A fixed bias setting must be conservative enough for the worst part of the zone, not just the highest-speed part where the car feels planted.
This is the engineering reason driver-adjustable bias can be valuable in racing cars. Lopez describes a driver-adjustable knob connected to the bias bar as a way to make changes during one outing instead of repeated pit trips. The point is not to twist the knob casually every lap. The point is to test a hypothesis efficiently once the car is warm: if the car is rear nervous under brake-turning, move the balance toward the front and see whether the symptom reduces while straight-line braking remains strong. If the fronts lock too early and the rear feels unused, move cautiously toward more rear contribution and retest.
Treat lockup evidence as data.
A lockup prediction becomes useful only when it can be checked. The checks are sensory, visual, and recorded. Through the steering, front lockup feels like the front tires have stopped obeying the intended path as cleanly. Through the seat, rear lockup or excess rear bias can feel like the rear of the car darts or begins to rotate. Visually, an open-wheel driver may see which tire is starting to lock. Observers may see whether front or rear locks first. In a closed-wheel car, smoke puffs from a wheel well can be evidence. Tire inspection can show flat spotting. Data can show a wheel speed dropping faster than the others or decelerating faster than the vehicle speed trend supports.
Use the evidence to answer a specific question: which tire or axle reached the limit first, and under what condition? A lockup at the beginning of a straight-line stop is not the same problem as a lockup at turn-in near the end of the zone. A single inside rear lock while turning is not the same as both rears locking in a straight line. One front tire locking before the other can indicate side-to-side conditions or setup asymmetry, but for this lesson the key is still the same: the first tire to give up tells you where brake demand exceeded available tire force.
The recovery action is also part of the skill. If a wheel locks during testing or driving, reduce pedal pressure enough to restore rotation and full braking traction. Do it quickly to save the tire and regain control. Continuing to drag a locked tire creates flat spots and provides less useful test information. You need to learn the edge, not grind through it.
Separate three limits that drivers often mix together.
The first limit is brake system torque capacity. This is whether the caliper, pad, rotor, and hydraulic system can create enough torque. If the system cannot lock the tire under the target condition, the brake hardware may be the limiter. The second limit is tire-road capacity. This is the useful braking limit for performance and bias work. The third limit is control response. This is whether the driver or ABS can prevent a wheel from passing through the unstable slip region into full lock once it approaches peak braking friction.
Do not solve the second limit with a first-limit answer. If the tire is locking, the system does not need more brake torque at that wheel in that moment. It needs less demand, better distribution, better modulation, or a different tire-load condition. Do not solve the third limit with a static bias number alone either. A car can have the right average bias and still lock if the pedal is applied too abruptly, if the surface changes, or if the driver carries too much brake into a combined cornering state.
For engineering work, the design limit is the first tire to lock in the worst credible condition. You do not set maximum brake force by the tire with the most load. You set it by the tire that will run out first. In a straight-line stop, that may be a rear tire if rear brake demand is high relative to rear load. During brake-turning, it may be the inside rear. On a rear-wing car, it may appear later in the zone as speed and downforce fall. On a low-friction surface, the optimum slip is lower and the margin can narrow.
The intermediate driver's workflow.
Before the session, know what you are trying to learn. You are not just trying to brake later. You are trying to find the first-lockup condition. Review the predicted load state. Ask whether the car is likely to be front-limited, rear-limited, or condition-dependent. If there is aero, ask whether the answer changes as speed falls. If the braking zone includes turn-in, ask whether the straight-line prediction is enough. If the tires are not yet warm, do not treat early stops as final evidence.
During warm-up, bring the tires into the range where the car will actually be driven. Then test away from traffic. For the first straight-line stops, squeeze the brake and add pressure until you are near the edge. Keep the steering straight so you are not mixing variables. If a front begins to lock just before the rear, and the car remains stable, the first pass is close. If the rear locks first or the car darts, you have a rear-bias problem for that condition. If both ends lock together because you overdid the pedal, the test did not isolate the bias. Back down and repeat with a more controlled pressure ramp.
After the straight-line pass is close, test brake-turn behavior. Do this only with room and at a controlled pace. Hold enough brake into the initial steering phase to reproduce the combined condition, then feel whether the rear becomes nervous. If it does, that is not a reason to drive around the problem with bravery. It is evidence that the rear tire capacity in the combined state is lower than the brake demand being placed on it. Move the hypothesis toward more front bias and test again.
After the session, write down the setting, temperature context, observed lockup order, and condition. Puhn's instruction to record adjuster turns matters because bias work can otherwise become paddock folklore. You need to know not just that you changed the car, but how much and in what direction. If a later session has different grip, different tire temperature, or different fuel load, your notes let you separate a real setup change from a changed condition.
The standard of success.
You are improving when your predictions become condition-specific and your corrections become smaller. Early on, you may only know that the car locked a tire. Then you learn which end. Then you learn whether it happens straight, at turn-in, late in the braking zone, or only when the tires are cold. Then you can predict it before it happens: this straight-line stop should show a slight front-first warning; this brake-turn test may expose rear bias; this rear-wing car may need caution as speed drops.
On track, good lockup prediction feels boring in the right way. The car slows hard without surprises. The front tires are the first warning if you exceed the limit. The rear stays aligned under straight braking and does not dart when you add steering. Your pedal trace, whether recorded or simply felt, becomes a purposeful ramp rather than a jab. Your tire wear shows fewer flat spots because you are catching the lockup boundary before the wheel is dragged. Your bias changes are small, documented hypotheses rather than large guesses.
Cross-reference the earlier skills when you need numbers. Use the line-pressure lesson to convert master-cylinder pressure, caliper piston area, pad friction, rotor radius, and tire radius into wheel braking demand. Use the load-transfer lesson to estimate how normal load changes with deceleration, center of gravity height, wheelbase, and combined cornering. Use the bias-as-hypothesis lesson to turn symptoms into controlled adjustments. This lesson gives you the boundary condition those calculations must satisfy: no tire should be asked for more braking force than it can provide, and if one must reach the edge first, it should be the front, slightly, under the test condition that matters.
Worked example: Formula car straight-line lockup screen
Lopez's Formula car example gives you a clean numerical way to think about the first-lockup tire. The car is described with 1000 lb of mass distribution at rest: 400 lb on the front pair and 600 lb on the rear pair. That static distribution is not the braking condition. Under maximum deceleration, the example transfers 250 lb onto the front tires, leaving 650 lb on the fronts and 350 lb on the rears. In that hard-braking condition, the front pair has about 65 percent of the available traction and the rear pair about 35 percent.
The lockup prediction follows directly. If the brake system is still asking the rear axle for anything close to the static rear share, the rear tires are being overworked under braking. They no longer have the 600 lb static support that made the number look reasonable in the pit lane. They have only 350 lb in the example condition. A rear axle that looked powerful and appropriate when the car was parked can become the first lockup axle when the car is decelerating hard.
Now turn that into a test target. If the car is warm and you perform a straight-line stop, the stable target is a slight front-first lockup tendency. That means the 65 percent front traction condition is being respected closely enough that the front tires give the first warning. If the rear locks first, your brake demand is not matching the load-transfer state. If the front locks much too early, the car is stable but underusing rear capacity. The exact pressure numbers belong to the line-pressure and load-transfer lessons; this lesson's point is the screen: compare brake demand against the tire capacity after the load has moved, not before.
Worked example: Rear-wing sports racer into a tight corner
Puhn's rear-wing sports racer example is the reminder that the first-lockup tire can change during the braking zone. At high speed, the rear wing improves rear-tire traction. That can make the rear feel secure early in the stop and can allow more rear braking than the same car would tolerate without aero load. But as speed drops, rear downforce drops as well. The rear tires now have less vertical load available while the brake system may still be asking for the same proportion of braking effort.
That creates a specific failure pattern. The car may be stable at the first hit of the brakes, then become rear-sensitive later as speed falls, especially when braking for a tight corner. If the driver starts to add steering near that lower-speed point, the rear tires are asked to do even more with less. A bias setting chosen only from the high-speed beginning of the stop can therefore be too aggressive at the low-speed end.
The prediction is not simply that aero cars need front bias. The prediction is conditional. Ask where rear normal load is greatest and where it is least. Early in the stop, rear aero load may be helping. Late in the stop, the wing is helping less, forward load transfer is still present, and turn-in may be starting. That late-zone condition can be the design limit. If you test only the first half of the braking zone, you may miss the condition that actually locks the rear tire.
Worked example: Bias that passes straight-line testing but fails brake-turning
Lopez separates straight-line bias testing from brake-turn bias because the two conditions do not load the tires the same way. Once the bias is close in straight-line stops, the next test is simultaneous braking and turning. The reason is that pitch and roll happen together. The rear axle is already unloaded by braking, and the inside rear tire is unloaded further by cornering. Rear brake drag can then help the rear of the car slide more than the front.
Imagine a car that gives a clean straight-line result: front tires approach the edge first, rear feels calm, and the stop is strong. If you stop there, you might call the bias finished. But then you enter a corner while still braking and the rear starts to move. That is not a contradiction. The straight-line test measured a pure longitudinal condition. The brake-turn test measures a combined condition. The inside rear tire now has less capacity than it had in the straight-line stop, so the same rear brake demand can become excessive.
The practical correction is to treat the brake-turn result as its own evidence. If the rear darts or begins to rotate while braking and turning, move the bias toward the front in small increments, then repeat the test. Do not wait for a race start or a crowded session to discover it. The whole purpose of the test situation is to find the unstable condition before it finds you.
Common mistakes
Mistake one: setting bias on cold tires. Cold tires produce less grip than the car will have once it is at pace, and the lower deceleration can hide the load-transfer condition you are really setting for. What good looks like: warm the tires first, then use the lockup order from the warm car as the evidence.
Mistake two: treating a straight-line stop as the whole answer. Straight-line braking is necessary, but it does not test the inside rear under combined braking and turning. What good looks like: first get a stable straight-line result, then confirm the setting under controlled brake-turning.
Mistake three: aiming for all four wheels to lock together. Puhn warns that this makes the brake-balance test meaningless because you no longer know which end reached the limit first. What good looks like: approach the edge gradually enough that you can identify the first tire or axle to complain.
Mistake four: accepting heavy front bias because it feels safe. Front-first is the stable target, but too much front bias compromises total braking because the rear tires are not contributing as much as they could. What good looks like: the fronts begin to lock only marginally before the rears.
Mistake five: ignoring speed-dependent rear load. A rear-wing car can feel rear-secure at high speed and become rear-lock prone as speed and downforce fall. What good looks like: evaluate the whole braking zone, especially the lower-speed end before turn-in.
Mistake six: using pedal aggression as a substitute for brake capacity. A hard stab can drive wheel slip through the stable region too quickly and create a lockup that tells you more about input rate than usable bias. What good looks like: a firm, fast squeeze that lets the tire build force and lets you identify the edge.
Mistake seven: failing to record changes. Bias adjustments without notes become guesses. What good looks like: write down the adjuster position or turns, track condition, tire state, test type, and observed first-lockup end.
Drill: Three-pass first-lockup map
Purpose: build a condition-specific map of which tire or axle reaches lockup first, without using tire damage as the measuring tool.
Pass one is the moderate-speed observation pass. Use a safe test area or appropriate track session procedure, away from traffic. Start around the moderate-speed range Puhn recommends for the first brake-balance test, about 40 mph. Make three straight-line stops. In each stop, squeeze the pedal and increase pressure only until you are close to the edge. The success criterion is that you can identify whether the front or rear approaches lockup first without locking all four wheels.
Pass two is the warm straight-line pass. Bring the tires to operating temperature with normal laps, then perform four off-line straight-line stops from a higher speed appropriate to the venue and rules. Check mirrors first. Add brake pressure progressively until a tire is just at the edge. If a wheel locks, reduce pedal pressure immediately enough to restore rotation. The success criterion is a repeatable slight front-first tendency. If the rear locks first or the car darts, record the condition and move the bias forward before repeating. If the fronts lock much too early, record that the car is stable but likely underusing rear braking capacity.
Pass three is the brake-turn confirmation pass. Once the straight-line result is close, perform three controlled brake-turn entries at a pace that leaves margin. Carry enough brake into the beginning of steering to reproduce the combined condition, then feel for rear nervousness or rotation. The success criterion is that the rear remains aligned while the front remains the earlier warning end. If the car is stable straight but rear-sensitive in this pass, treat the brake-turn result as the design limit and adjust toward more front bias.
After the drill, write a short lockup map: tire temperature state, bias setting, straight-line first-lockup end, brake-turn first symptom, and any speed-dependent pattern. Repeat only after a real change in setting, tires, surface, or conditions. The goal is not to make lockups happen. The goal is to know where they would happen first.
When prediction gets weak
Lockup prediction is strongest when the surface, tire state, speed range, and driver input are repeatable. It gets weaker when any of those change. Limpert's ABS discussion explains why a single threshold is not enough: threshold wheel angular deceleration varies with vehicle speed, tire-road friction behavior with slip, brake torque rate, and system inertia, and the range of possible thresholds can be very large. That is the engineering version of what drivers feel on track: the same pedal pressure can be clean in one condition and too much in another.
Low-friction surfaces are one weak point because optimum slip decreases as tire-road friction decreases. The useful slip window can become smaller, so the driver has to be earlier with pressure reduction and smoother with the ramp. Tire construction is another weak point. Some tires have a high peak and a more meaningful drop toward sliding friction; others show less decrease between peak and sliding. That changes how much warning the tire gives and how much braking force is lost after the peak.
Aero cars add another weak point because speed changes normal load. Brake-turning adds another because the tire is no longer spending its whole grip budget on braking. In these conditions, do not ask one test to answer every question. Use the straight-line test, the brake-turn test, and the full-zone speed picture together. The design limit is the earliest tire to run out in the condition that matters, not the condition that was easiest to test.
Author Review
No quiz questions are attached to this lesson.
Sources
| # | Document | Chunk | Pages | Score | Collection |
|---|---|---|---|---|---|
| 1 | Going Faster Mastering the Art of Race Driving - Carl Lopez | 329f32ca-8ced-733f-e17c-6e0bae8bdb06 | 219 | 1 | uio_books_raw_v1 |
| 2 | Going Faster Mastering the Art of Race Driving - Carl Lopez | 400d34e7-28f8-89ba-4742-f8c200ff541d | 220 | 1 | uio_books_raw_v1 |
| 3 | Going Faster Mastering the Art of Race Driving - Carl Lopez | 161a4041-de57-1e41-faec-81bc25f141c6 | 49 | 1 | uio_books_raw_v1 |
| 4 | Brake Design and Safety Rudolf Limpert | b9880fc4-310c-51a6-0db5-dd4015874416 | 340 | 1 | uio_books_raw_v1 |
| 5 | Speed Secrets Professional Race Driving Techniques Ross Bentley | 2c65fbd7-40f5-68b5-f4d5-5c65a45c49ab | 27 | 1 | uio_books_raw_v1 |
| 6 | Brake Handbook Fred Puhn | 6267d588-b702-87ea-7112-11e0b935f799 | 116 | 1 | uio_books_raw_v1 |
| 7 | Going Faster Mastering the Art of Race Driving - Carl Lopez | 07618ee4-43f3-5de7-8fb1-6a50de32eb16 | 47 | 1 | uio_books_raw_v1 |
| 8 | Going Faster Mastering the Art of Race Driving - Carl Lopez | 01db454a-e23f-3062-7078-beadca3b679e | 50 | 1 | uio_books_raw_v1 |