Why do road cyclists take flat corners differently than MTBs?

Exhibit A, the road cyclist going around a corner on a descent:

Exhibit B, the mountain biker going around a similarly flat corner:

In MTB, coaches teach “bike and body” separation especially in flat cornering drills. I believe the idea is to get the majority of your weight over the side of the tire where it makes the most contact with the ground, which is basically directly perpendicular on a flat, non-banked turn. A lot of times this is accomplished by leaning the bike towards the inside leg and rotating the hips into the turn.

This keeps your tires from slipping out, as opposed to being directly perpendicular over the axles, which would put all your force into the bottom of the tire which is at an angle in relation to the ground.

However, when watching road cyclists go around turns and hairpins, it seems like they are not leaving the saddle at all, nor are they leaning the bike towards their inside leg. The road does not look anywhere near banked enough to want to remain perpendicular over the axles, yet they still do. What is the difference in technique due to?

And lastly, how should corners be taken on gravel bikes and dirt road surfaces? Should they be treated as flat corners in MTBing?

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Other than the obvious which is that there is just loads more grip on a road bike on dry pavement then on your typical MTB turn. I think the biggest difference is the bumps. The road racer doesn’t to absorb any (or any big ones usually) bumps while cornering. However, on an MTB you usually have suspension. Except when you are leaned over in a corner the forces of the bumps are now no longer in the path of your suspension travel and you have to use your legs and arms to absorb those bumps in the vertical plane.

You see similar differences if you look at how motorcycle road racers corner vs flat track or dirt bike racers. You don’t see road bike racers hanging off the inside like MotoGP though because of the weight distribution but the idea is similar.

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Yea, that’s pretty much it ^

It’s the relationship between cornering angle and balancing angle, and the techniques on those bikes are generally to optimize the available speed and traction available. The street bike vs. dirt bike example is a great way to think about it. The road bike vs. MTB is the same concept but with less extreme angles at work with less speed and traction.

I grew up on slippy roads thus my instinct is to corner like a MTB even though I am on a road bike. Touch wood it means I have stayed upright when others have come off but it also means I am pants compared to other roadies at going round bends :rofl:

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Leaning the bike engages the big side knobs on a MTB tire.

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If more roadies cornered like mountain bikers, there would probably be a lot less crashes on the road…

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Isn’t it also to do with the pedal position? MTbers use level pedals but because of the road bike geometry you need to have the outer foot down or the front foot could interfere with the wheel turning

The outer foot down is to get more weight down over the contact patch of the tire. You’ll almost never have toe overlap issues while riding. That’s usually only and issue with slow speed turning like a U-turn or in a parking lot.

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The angle from contact patch to center of mass send the same

Cornering on gravel IMO is harder than cornering on a MTB. The quality of the road surface can vary significantly - sometimes you can corner like on a road, and other times it feels like even with a modest turn you’re going to slide out.

I’ve found the best way to corner on gravel is to work the features on the road. If there’s a slight rut or camber, use the slope in your favor as a kind of banked turn. If the gravel is patchy, find a bare spot, overweight the front, and get “more turning” done in that spot. When it’s loose over hard, try to take the turn at a consistent radius (no sudden changes), and just get comfortable sliding a little.

I have gravel tires with pretty good side knobs. So when it makes sense, I lean it like a MTB. But that works only so-so, as the side knobs are much smaller than MTB.

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If you are turning anywhere near that much at any kind of decent speed your going to end up on the deck. As above that only comes in to play doing very sharp turns, no bike lean and less than 3 - 5 mph.

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And at the rear, how NOT to go around a corner on a descent.

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There are certainly differences and I agree with most of what’s been written above, but if you look at the angle of the wall on the right and the building on the left it’s also clear that this photo is nowhere near horizontal! Taken from the back of a motorbike that would also have been leaning through the corner, looks to me to be off by maybe 30 degrees. This is a better representation of what a roadie cornering actually looks like:

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That’s not the point that’s being made here. The lines are intended to indicate that a road rider corners with bike and body generally in line with each other, whereas the mountain biker has their body above the line of the bike.

Mike

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*In both cases you’re weighting the outside foot however.

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Also worth noting on this subject:

Road tires have roughly the same shape as motorcycle tires (rounded profile). This means that the contact patch increases with lean angle. I recommend watching a youtube video of the subject, from a motorcycle racing point of view. In fact you see roadies use a similar knee out - lean in technique as in motor cycle racing.

For mountainbiking the tire profile is different, and it’s all about getting those side knobs to “dig in”. So you lean the bike over, and keep your weight to the outside, to maximize downward pressure over the knobs. Also this position gives you a lot more opportunity to “save it” if you lose traction compared to if you were leaning in.

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Don’t neglect the differences between how you shift your weight from front to back on an MTB compared to a road bike. Road bikes have a much shorter wheelbase and different front to back weight bias than an MTB.

Especially with the longer/slacker bikes these days, I had to really adjust my riding style to be “over” the front more during non-bermed turns. I find that I’m shifting my weight around, front to back a lot more.

This is incorrect. Motorcyclists lean off of their bike so that the bike is at a lesser extreme angle to increase contact patch by altering the COG. If you do that on a road bike you’re in the weeds. On a road bike it may appear that they’re doing the same thing but they’re actually weighting the outside foot, the knee is just a side effect.

Additionally, knee out on a motorbike is for riders to feel the ground and in turn lean angle; the significant action is the body position off the bike.

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Piggybacking off how this is incorrect, the whole point of leaning off the motorcycle is to maximize the contact patch by keeping the bike UPRIGHT as possible. The more you lean as opposed to the bike, the more the bike can stay upright through the turn.

Track day novices stroll in with a similar notion that “dragging knees” can be accomplished by just leaning the bike further into the turn. That’s a quick recipe for a lowside crash.

Notice how Marquez nearly has his entire body off the bike, with the elbow jutting into the pavement. By dangling his body off the bike, he’s modifying the CoG such that the bike is able to stay further upright through the turn at speed. If the riders could, they’d dig themselves into the tarmac to get more lean angle - alas the riders’ body itself is obstructing that.

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Yes, you’re correct. That was a mistake on my point. The point of the contact patch still stands, up to a certain degree. It does get larger with initial lean angle. Obviously when you’re Valentino Rossi you have to decrease the bike lean as much as possible due to the speed carried in the corner.