Leaning over a mtb compared to a motorbike

On a motorbike you put pressure on the inside foot peg and move your body right over to the inside. You can’t do that on a mob because of the pedals

offroad motorbikes have side knobs, road bikes don't. road bikes count on friction between the tyre n ground just like a road bicycle. Offroad is the same as MTB.

More mass, more speed, more surface area , gripper more even substrate

Excellent points... helps solve a debate with my bro. Thank you!

Funny I was watching a video on exactly this earlier today. It's a motorbike based video. But it get the point across.

It's the complete opposite on a road motorbike Vs an off-road MTB.

On a road motorbike you keep the bike as upright as you can by hanging off, if you don't do this you'd end up running out of tyre, and the contact patch is the biggest at a moderate lean angle. Also the bike naturally want to stay upright due to the rotating wheels and engine.

Throw in how speedway riders corner just to confuse your discussion with your brother.

What's more you run out of ground clearance if you don't keep a road (motor)bike more upright. Scraped engine cases look cool until the oil falls out or they lever the tyres up off the road mid corner.

I only initiated turns with weight on the inside peg, after that I used to unweight it so the road didn't rub the boot so hard.

Supermoto bikes on the other hand...

This pressure on the insude pegs thing is nonsense.

Keith Code actually says weight the outside one.

Interting article.

https://lifeatlean.com/weighting-the-pegs-and-body-steering-on-a-motorcycle/

My dog corners better than a motorbike.

In both cases there are quantum strings that support you. If you lean over too far the strings get entangled and will trip you up.

Yes weight through outer peg, like on a ski, but your mass moves to the centre of the corner. Countersteering forces the bike down on its side (try it on an mtb it’s phenomenal).

The outer sections of a motorbike tyre will often be made with a really sticky compound that starts to smear itself over the sidewall when abused and melds into the road surface like a bit of bluetac. It’s so sticky it can rip bits out of the surface and throw them down the road. You’ll get more lean out of a motorbike on grippy tarmac than we can manage without berms. Even a bungling halfwit like me can exceed 45°. 60° should be possible.

I had a right time unlearning sports bike cornering when I packed it in and went back to mtb a decade ago. Had loads of front wheel slides and a few crashes from dropping my inside shoulder and leaning to the inside of the front wheel. Occasionally still have to remind myself not to do it even now

road/race motorbikes try and stay upright in corners as the effective circumference of the wheel/tyre decreases as the bike is leant further over needing increased engine speed for a constant given road speed

The centre of mass for a motorbike and rider is lower than for a MTB and rider. On a motorbike, say the Triumph Tiger, the weight of the bike and rider is around 350kg, The bike is 250kg of that and it's centre of mass is 650mm from the road. The riders centre of mass is around 1000mm from the road. That makes the combined centre of mass around 750mm. On a MTB, the combined centre of mass is around 975mm from the road, so for an equal angle, you're putting far more of the tyre into shear. Coupled to the fact that MTB tyres are around a 1/4>1/5th the size of a MTB tyre and still with around 30% of the mass, the motorbike will have much more grip at an equivalent lean angle and an equivalent speed, even assuming similar tyre profiles.

My hunch is there are two things going on

We have camber thrust steering. That’s the effect where a wheel lent over will tend to move in an arc because the inside edge of the contact patch is moving slower than the outside edge. This is is because the outside of the contact past is further from the hub and moving in a larger radius circle

We also need to move the centre of gravity of the rider and bike inside the contact patch to counteract the moment created by force of the tyre pushing towards the centre of the corner below the centre of gravity. Or to put it another way the force from the tyre needs to act through the centre of gravity of the bike rider system

I think that roughly speaking the camber thrust steering requires the wheel to be at a certain angle to the ground for a particular radius of turn, regardless of speed. The distance you move the centre of gravity inside the tyre is determined by speed. For a certain radius turns the faster you travel the further inside the contact patch the centre of gravity must be

So when a motor bike and mountain bike go round the same radius turn they both want there wheels at the same angle to the ground. But the motor bike has more speed and grip and travels faster. So the rider hangs inside the bike moving there centre of gravity well inside the tyre contact patch. The slower mountain bike rider is above the bike as they don’t need there centre of gravity as far inside the the contact patch

More based on physics than riding so might be bobbins

 there are quantum strings that support you. If you lean over too far the strings get entangled and will trip you up

At least there'll be another version of you that stays upright

Have we brought up counter-steering yet?
Works a treat.

I think that the main reason the MTBer's body might be more upright is that you are prepared for the wheels to slide and dab your foot, and you can only do that if you are more upright. Speedway racers do this on motorbikes because they are sliding and need the foot. Road bike racers, who are depending entirely on the tires, don't do it. And road motorbike racers can hang off the inside of their bike to move the centre of mass further inwards - this must surely increase cornering force?

At least there’ll be another version of you that stays upright

Yes, but if you fall over and stop, the other guy will retain all the momentum but have no idea where he is. Think I'd rather be the one who fell over.