do tyre treads affect braking performance?

Question

the question asked was that whether there will be any differwnce in the braking performance of a bald tyre and a treaded tyre....i thought it would....my instructor thought otherwise...special relevance to aircraft tyres and operations..

Answer 1

You can't generalize based on car tires the way many people are. Car tires are made to last thousands of miles, many Americans expect car and truck tires to last 80,000 miles. In Europe I was used to using high performance tires that would be very unlikely to see 20,000 because Europeans expect braking and handling instead of speed and long life.

Aircraft tires are made in a different way from different materials, there are broad similarities, but aircraft tire life could be measured in miles rather than thousands of miles.

Most aircraft tires appear to be bald, but what you are looking at is the layer of soft rubber that forms the outer layer of the tire. For commercial aircraft this layer will be replaced many times before the carcase of the tire reaches the end of its life.

It would be much more accurate to describe aircraft tires as slicks rather than bald. You don't want a tire that could pick up a stone and fling it into the bottom of the aircraft or wing at 100mph.

The tread on tires does make a difference, it helps clear water and mud in poor conditions. They also have better grip on ice due to the sharp edges. The tread blocks also deflect more easily than solid rubber, so they make the tire behave as if it were made from a softer compound, this is part of the reason you lose dry grip as your tires wear. But grip also equates to drag, the last thing you want when trying to get airborne.

Narrow tires will cut through water at higher speed than wider ones, that's why racing cyclists don't aquaplane in heavy rain, no matter how fast they go their tiny little contact patch still grips the road. You'd have to do over 100mph to get a high pressure racing bike tire to aquaplane. Aircraft tires tend not to be very wide in comparison to their load and speed, it's a complex equation. Fast jets will still aquaplane at high speed on wet runways though.

Anyway, all other things being equal a treaded tire of the same composition as an untreaded one grips better.

Answer 2

I think it all depends on the aircraft type. I fly as much as I can my own Kitfox taildragger with big smooth tundra tyres and braking is never an issue since it should only be used when taxiing.
Since I live in Norway and fly during the winter too, one thing I can tell you is that there has been days when it was pretty unsafe to drive my car to the airfield because the roads were so slippery. But it was nothing to take off or land from the same slippery runway. Keep your feet away from the toe brakes and you're fine - winter or summer.

Answer 3

The purpose of the tread is to give more adhesion in wet conditions. If the runway is dry, a bald tire puts more rubber on the pavement, so it would be better, in a perfect world. If you ever plan on landing in the rain, however, the tread will help displace water on the pavement, and increase the amount of braking power you can use without hydroplaning or locking up the wheel.

Answer 4

Well, since most aircraft tires do not have a "tread" like automobile tires do, I guess your debate would be kind of pointless. Aircraft tires are mostly "bald" with only two or three medium depth grooves running around the circumference of the tire. Larger aircraft do not depend on tires and brakes to slow down after landing... That's what the thrust reversers are for.

Answer 5

You have to remember your not driving on your aircraft tires. A bald tire has more of a risk of blowing out on touchdown. On dry pavement a bald tire will do the same a one with tread. In wet conditions the bald tire will not have the performance of one that has thread.

Answer 6

1

Answer 7

bald tire will slide/ slip.
Full thread tire will not slide

Answer 8

only when there is rain on the runway

Answer 9

Sure, same as with your car.