[Closed] Downforce in track cycling

Speeds aren't high enough for it to be an issue. Max torque is at pretty much zero mph, corners are heavily banked. Any noticeable/significant downforce at track/race speeds would lead to relatively large amounts of drag.

That's what I think too.

It's come up because of something in an A-level PE syllabus, referring to 'downforce' in F1 and track cycling. I think it's a mistake, it should be 'aerodynamics'.

Surely they mean centrifugal force? That's what sticks you to the banking.

Surely they mean centrifugal force? That's what sticks you to the banking.

CENTRI[b]PET[/b]AL

You hit the corner (or the olympic hammer tries to fly in a straight line away fro the thrower) and the banking pushes you in (the rope pulls it in a circle), that's the centripetal force acting to the center.

Centrifugal force is the inertial force (also known as imaginary force), it's what balances the equation, it's like trying to push a car (brakes off) down the road, you push on it, it doesn't push back but you do feel it pushing back because the car's inertia is balancing your pushing. If the car's brakes are on, or the road was uphill then it would be pushing back.

Maybe it's leading into a 'compare and contrast' type question?

F1 cars on a flat track sacrifice drag for downforce, track riders have too little power to want to sacrifice any, and are held in place by the banking and centripetal force.

Grip isn't an issue on the track though apart from if you are using new michelin tubs and are going very slow on the banking where you would never be able to generate any at 5mph. Obviously aerodynamics is a big thing.

Often wondered about the tyres though as all the trackies I know run silly high pressures on 22c, the surface is smooth unlike Tarmac but would a larger tyre at lower pressures be faster due to carcass deformation?

Often wondered about the tyres though as all the trackies I know run silly high pressures on 22c, the surface is smooth unlike Tarmac but would a larger tyre at lower pressures be faster due to carcass deformation?

Thinner is always going to offer less aerodynamic drag, the trend on the road for wider rims/tyres is because on real roads the wheels rarely need to be aerodynamic straight on (how often do you have a perfect head/tail wind?), wider sections trade off frontal area for a drop in drag at ever other angles. They also deform better over rough surfaces, tyre deformation still takes energy, but less than bouncing over a piece of gravel.

Track riders don't need the same grip (try and make the back wheel spin in 50-13), there's no wind, and any tyre deformation is sapping energy. So higher pressures are almost always going to be better.

Centrifugal force is the inertial force (also known as imaginary force), it's what balances the equation

Ah.. depends on your frame of reference...

thisisnotaspoon - Member
Surely they mean centrifugal force? That's what sticks you to the banking.
CENTRIPETAL

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Felt have released a "wrong side" track bike for a lower centre of gravity.

Felt have released a "wrong side" track bike for a lower centre of gravity.

Not lower, but "better", and apparently marginal aero gains around the corners. Strikes me as mostly gimmick considering the cost of doing this, but I'm sure there'll be some marginal gain so why not.

It will be a lower COG when in the banked turns.

lower drag as all the sticky out driveline bits will travelling slower round the track, drag is proportional to the square of speed.

Why does it cost? You could just fit the drivetrain on the other side couldn't you?

molgrips - Member
Why does it cost? You could just fit the drivetrain on the other side couldn't you?

You have to make parts with all the threads etc. reversed. In practice not as expensive as full on prototype parts, and they have made a new frame anyway, but it will cost more than just chucking normal stuff down the production line.

Ghostly-Surely the drive line parts are doing the same lap time as the non-drive side so must be travelling at the same speed?

Molgrips - the only thing that maybe different is the pedal threads, can't work out if they will be the right way around. The track cog thread will still tighten when pedalling if the wheel is flipped.

What a gimmick; considering half of a velodrome is straight.

Ghostly-Surely the drive line parts are doing the same lap time as the non-drive side so must be travelling at the same speed?

No - point is they are going further, round the outside - but in the same time. Therefore moving faster.

You have to make parts with all the threads etc. reversed

Tandems have been doing this for years 😉

Most cross-over drivetrains only have one standard crank.

Therefore moving faster

I think you'll find the delta isn't exactly huge though 250 m track,111 mm bottom bracket shell - gives a ratio of about 111/40000 ~ 0.3%.

You can switch drivetrains over to the other side on track bikes just fine. Pedal axles need switched so your clipless pedals point the right way. Technically it's pretty hard on your hub lockring, but I did it once for a bike messenger just for a laugh, and he ran it that way for years with no problems...