I’ve got a question. Perhaps it’s answered above, but just watching a moto gp bike go through a turn with the rider basically on the ground got me questioning the difference between road cornering and mountain bike cornering. Is there a difference?
Mountain bike cornering, at least according to a few videos I’ve watched seems to exaggerate the weight and body shifted to the outside of the corner with the inside arm being mostly straight forcing the outside arm to be bent and requiring knees to point to the corner to give the bike top tube room to lean over given the disconnect between the bike and the body.
Pictures of road cornering look somewhat different to me. Perhaps the same concept, but just to different degrees. I’m hoping someone can say, it’s the same or it’s not.
This picture of JA shows weight on the outside foot, but his body is not overly shifted over to the ouside. His arms seem mostly neutral and it looks clearly different than the mountain bike photo. But is it really the same? Does the traction on the road make the severity of the bike/body disconnect less needed on a turn like the one JA is taking? If the turn were sharper, would he look more like the mountain biker? I can’t say I’ve ever seen a road racer look like the mountain bike picture.
However, this does look suspiciously closer. Is it just that the turn PS is making is sharper, so therefore he’s doing it more? and the fact that he’s in aero position kind of hides the fact that his inside arm is extended?
Sorry for the elementary question, just seems like the moto gp bike, road bike, and mountain bike are all doing the same thing, but differently. Or are they?
I could be completely wrong but I reckon that the surface and weight of the bike has a large part to play in it, so the technique will be specific to the discipline. A mtb on an ideal surface probably would be closer to a road bikers position and a motorbiker has a completely different weight distribution beneath them.
When going into a corner, the bike wants to go in a straight line and stay upright. A fast, heavy bike like the motorbike needs a lot of rider weight to force it into a lean and go round the corner. Much lighter push bikes require much less weight shift from the rider.
Not entirely true on the mass. Use of “counter-steering” along with how the motorcycle is designed makes them relatively easy to commit to a turn, especially a sport bike. You actually leverage the mass to work for you with the right technique.
Discussing cornering and mixing moto and pedal bikes is not ideal as there are some differences when you really dig into it. The core ideas are similar, but differences in power production, tire contact and such lead to some differences.
Okay, so I was mainly including the Moto in the discussion because it almost seemed to me to be the antithesis of biking guidance. What about the differences between the road and mountain technique. Is there a difference?
The idea of a racing line, braking, trail braking, loading the outside pedal / peg are similar, but there are some underlying dynamics / mechanics that are way different as well.
You also need to consider the g force motorcycle road racers are experiencing. They do look like BAMFS backing it into a corner from a 190mph straightaway though.
It just depends. You don’t corner a dirt bike like a sport bike. Sport bike you’re leaning off to the inside some. Dirtbike, your body stays upright while the bike leans below you.
Some of it is the cornering forces… dirt just just way less, some of it is geometry, etc. Mostly it’s the traction… Supermoto riders lean their dirtbike based bikes over, but they’re on asphalt.
Road and Mountain Bike cornering technique differences are largely due to surface condition differences. Generally speaking, you lean a bike to corner (along with steering input that people don’t always notice, and sometimes neglect). But most of the difference in techniques comes down to the surface, not the bike type specifically.
Firm surfaces allow more lean angle consistency between the rider and bike. When everything is right, you can often draw a straight line between the bike frame and rider body.
Loose surfaces still require bike lean, but the lower level of traction requires the rider to be more “upright” and not “inline” with the bike. This is a bit of the “bike / body separation” that is often discussed with cornering.
Both the above benefit from strong weighting of the pedal on the outside of the bike, to maximize force (and therefore traction) of the bike with the surface. Another aspect is the “camber” which is the basic surface angle relative to the horizon. Methods change a bit between dead level, off-camber, and “bermed” surfaces because of how the tire loads those surface angles.
As you get looser surfaces, that outside force is still important, but you can’t get your body as leaned to line up with the bike, because that shifts the entire center of mass too far from the contact patches, and leads to “low side” falls if/when you break traction and the tires slide out.
The main key in cornering is that traction aspect, and the balance of your speed, turning input (lean and steer), and your body position. Clear as mud?
So i guess to beat a dead horse, I would imagine that speed exacerbates the surface conditions. And if the mountain biking technique pictured above on loose surfaces provides more traction, why wouldn’t you use the same on smoother surfaces to be able to go faster? Is there some kind of a balance between aerodynamics and the position required to get maximum traction that makes it undesirable to use the mountain biking form on a smoother surface to go faster?
Did you not read my response above, the surface is a large difference. If you want to add another the bar leverage/ starting riding is substantially different too.
If you ignore surface camber, cornering at the tire is all about coefficient of friction between the rubber, tire shape (block size, height, etc.) and the vectors of the forces resulting from the actual cornering direction input. It all gets messy and WAY over my head, but I have been involved in many discussions since this is essentially the foundation of how sophisticated driving and racing simulations model tire dynamics in their software. Slip angle is one aspect of that whole dynamic and is largely ignored in cycling (for good reason really).
It relates to your speed aspect. The faster you go, and the harder you want to corner, the lower you really want your center of mass. It’s a bit chicken/egg, but you can’t corner super fast while staying high and upright.
In the best scenario (like Moto GP), you lean as far and hard as possible. This helps keep your center of mass low (good for cornering) and it placed it closer to the center of the corner arc (also good for cornering). It’s a bit more complicated, but that is the essence.
In super loose conditions, especially as speed increases, you still need to keep from the low slide slip, so you can’t get your center of mass that low or that far towards the inside of the corner.
Overly simplified:
Good traction = Rider & Bike aligned in lean
Bad traction = Rider more upright, while Bike is leaned
Speed matters, but has the same basic impact where the faster you are moving, the more you likely need to lean as you try to make a tighter corner.
Many (many) years ago, I attended a Wolverine Cycling Camp over Spring Break…coached by Mike Walton. That club has produced a LOT of great riders (including Frankie Andreu).
They advocated a completely different cornering technique (road) where you kept the bike more upright, shifted your body inside adn then turned the HB in the direction of the turn. Your outside arm was then somewhat extended, and the inside arm bent, since your were turning the HB into the turn.
The problem with that technique is that no one else does it and you have a completely different line than anyone else in a corner…and hence it is kinda dangerous (leaving aside whether or not it is efficient).
That said, I have started to use that technique more on gravel…you keep a wider contact patch since the bike is upright and you are less prone to sliding out as a result. Add in a bit of hip rotation towards the inside of the turn and you can actually carve a pretty nice line on gravel.
Having grown up on more slippery roads I have the habit of keeping the bike more upright, it doesn’t seem to conflict with others. When I am constrained by a group I fluidly go with it, but do tend to drift when I’m not constrained and that probably explains why I am sh1te in corners on a solo TT
I’ve just ordered a gravel bike so hopefully at least it’ll keep me in good stead for that.
I’d wager that in most cases, cyclists are not pushing the absolute limit of cornering traction. As such, line selection and actual technique can and do vary. People can use a range of practices and “make it work” when you are not as close to the limit of traction where the consequences are often “controlled into crash” in a short moment.
In auto and moto racing, they are more often pushing the absolute limit for cornering traction and speed. When you do, there is often only one or two “good lines” that make sense with the aim of carrying the most speed through that corner (with consideration to how that exists relative to the features before and after that specific corner). So, that means they start applying very similar techniques because notably different ones fail to meet the speed of others.
Those motorsports all goes down a very different road (sorry for the pun) than we see in most cycling. Stuff like crits get a lot closer in the sense of cornering approaches, but much of cycling is less repeated features with split second control accuracy needed. The room for variation is usually a bit wider by comparison, allowing more different approaches that “work”, even if they may not be “ideal”.
I will add, that just because something works in one case, doesn’t make it “good”. I bet we have all experienced a moment where we misjudged the surface condition and related traction of a corner, to experience partial or complete slip that becomes an instant alert that we have exceeded the conditions with our speed and/or technique. Point being that we can likely benefit from a potential safety aspect by “over performing” in cornering practices, to be ready for those unexpected moments.
This is where practice, drills and such can pay dividends. They can helping us learn the best techniques, by experiencing what works and doesn’t when we meet and exceed the limits of traction relative to our speed and cornering application. Knowing what it feels like as you get closer to those limits in ideal and terrible conditions helps when our plan or expectations are not what really happen.
