Bike vs car again...
Discussion
kawasicki said:
Bikes can generate more than 1G lateral. You don't need downforce to do that, just nice tyres!
Shane
Shane
I don’t think so! The only thing that stops a bike from tipping over to the outside of the bend (from the centripetal force) is the weight of the bike and rider moving the C of G the appropriate distance the other direction. There is only the weight of one bike and one rider (thus 1g max). Assuming the tyres grip then more than 1g lateral force would simply ‘pull’ the bike over!
Looking at the front of the car, think of it as a rectangle, with the long side being the cars width and the short side being the cars height. If all the weight is evenly distributed throughout the car then the centre of gravity will be exactly in the middle of the rectangle. The ratio of the distance across the car to the C of G over the distance up the car to the C of G will give an approximate maximum lateral G force for the car. (Assuming the tyres give infinite grip.) If the C of G is lowered then the lateral G ratio will increase allowing for faster cornering speeds.
All of that is all very simplistic as tyres don’t have infinite grip and the rectangle doesn’t stay horizontal during cornering, which will both have an impact on maximum lateral G.
With cars it’s the limits of the tyres grip that tend to determine the maximum cornering ability rather than the risk of the car toppling over. Hence the reason that aerodynamics are used to increase the downward pressure on the tyres to stop them loosing grip so soon, allowing the car to corner faster and generate significantly more than 1 lateral G.
All of that is all very simplistic as tyres don’t have infinite grip and the rectangle doesn’t stay horizontal during cornering, which will both have an impact on maximum lateral G.
With cars it’s the limits of the tyres grip that tend to determine the maximum cornering ability rather than the risk of the car toppling over. Hence the reason that aerodynamics are used to increase the downward pressure on the tyres to stop them loosing grip so soon, allowing the car to corner faster and generate significantly more than 1 lateral G.
I took the bike to Tesco's the other day to buy a french stick - The car would've been much better on that occasion!
Whether cars are outright faster than bikes and vice versa can be argued all day. However I dont think anyone will fail to agree that on real roads, bikes are faster from A - B.
My opinion, for what its worth, is that going by smiles per mile a bike (any bike) will very definitely come out on top.
black-k1 said:
kawasicki said:
Bikes can generate more than 1G lateral. You don't need downforce to do that, just nice tyres!
Shane
Shane
I don’t think so! The only thing that stops a bike from tipping over to the outside of the bend (from the centripetal force) is the weight of the bike and rider moving the C of G the appropriate distance the other direction. There is only the weight of one bike and one rider (thus 1g max). Assuming the tyres grip then more than 1g lateral force would simply ‘pull’ the bike over!
That makes no sense at all. They can generate the same lateral G as their tyres have Mu. Mu is not limited to one, and I never really understand why people think it is. It is simply the ratio of frictional force to vertical force. Sticky rubbber on a decent surface can go a good way north of 1.0.
Edited to say, you can get a very good measure of the G force on a bike by the lean angle. G is the tan of the angle the bike is away fro mthe vertical.
If a bike goes over at more than 45 degrees 9which is admittedly quite a long way) then it is pulling more than one lateral G. Again, good typres and a confident rider, and 45 degrees is not some magic angle beyond which they cannot go.
What do you think happens when they get to 45 degrees, and tip that little bit more in?
Edited by northernboy on Monday 19th February 23:20
northernboy said:
black-k1 said:
kawasicki said:
Bikes can generate more than 1G lateral. You don't need downforce to do that, just nice tyres!
Shane
Shane
I don’t think so! The only thing that stops a bike from tipping over to the outside of the bend (from the centripetal force) is the weight of the bike and rider moving the C of G the appropriate distance the other direction. There is only the weight of one bike and one rider (thus 1g max). Assuming the tyres grip then more than 1g lateral force would simply ‘pull’ the bike over!
That makes no sense at all. They can generate the same lateral G as their tyres have Mu. Mu is not limited to one, and I never really understand why people think it is. It is simply the ratio of frictional force to vertical force. Sticky rubbber on a decent surface can go a good way north of 1.0.
Totally agree but with a bike it’s not the tyres that are the limiting factor. While you will often see cars at speed ‘sliding’ sidways while cornering as the grip from the tyres has been overloaded you will not see that on a bike unless it’s induced through use of brake or throttle (thus forcing the tyres well beyond normal cornering load).
northernboy said:
Edited to say, you can get a very good measure of the G force on a bike by the lean angle. G is the tan of the angle the bike is away from the vertical.
If a bike goes over at more than 45 degrees 9which is admittedly quite a long way) then it is pulling more than one lateral G. Again, good tyres and a confident rider, and 45 degrees is not some magic angle beyond which they cannot go.
What do you think happens when they get to 45 degrees, and tip that little bit more in?
If a bike goes over at more than 45 degrees 9which is admittedly quite a long way) then it is pulling more than one lateral G. Again, good tyres and a confident rider, and 45 degrees is not some magic angle beyond which they cannot go.
What do you think happens when they get to 45 degrees, and tip that little bit more in?
Again agreed but road bikes do not lean significantly beyond 45 degrees. While you may just about achieve a little more than 1g it will be an insignificant amount more than 1g compared to what a car can do.
The advantage the bike has in the corner is it’s width. Because a car is wider then any given corner will have an apparent lesser radius for the bike as the outside to inside to outside move can uses more track.
996 sps said:
Fergus be honest not to interested in grammar lessons, on a bike and car web-site not an English lesson if I was handing in work for a sports therapy degree then fair enough, It always makes me wonder how interesting someones job is when they have the time to look closely into grammar and spelling, get your head down!
Preformance bikes have recorded Ring times in January issue where my timings where from, actually get it on CD Rom rather than hard copy then you can spell check it yaaaawwwnn!
A bit off topic but I'm with Fergus on this. 996 sps - to follow your reasoning you would only ever do something correctly if you were being examined so if, for example, you were a single fig. golfer you'd only bother to go round in under 82 in a competition, happily going round in 100plus - or in your case 200plus Preformance bikes have recorded Ring times in January issue where my timings where from, actually get it on CD Rom rather than hard copy then you can spell check it yaaaawwwnn!
- at all other times. Presumably you are also happy to ride you bike really badly unless someone who knows what they are doing is watching. You don't have to "look closely" into bad spelling or grammar, it's just there in front of you, plain as day! Rather like bad riding or driving in fact! Back on topic - thanks to the people who have recognised that my original post had nothing to do with saying that cars are quicker than bikes or visa versa. Yet again got held up on Sunday by a whole gaggle of bikes on my local 'bikers' road. All the usual gear, latest machinery, knees out - but nowhere near down, heads behind the bubble thinking 130mph is fast. The frightening thing is that not one of them thought there would be anything trying to get past - no life savers, nothing. Got past eventually and got the finger. Why - because the idiots was blissfully unaware I was there and got a fright. I'll say again, what feels fast on a bike often isn't. Also, again, I believe that a huge percentage of guys with superbikes can't ride them properly. It's their life I guess but me, I'd be more interested in trying to learn the skills to keep me alive than that! I know there are those out there that can ride well and they have my huge admiration. Even more so when I get my bike in a few weeks time!
kawasicki said:
Pugsey
There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
How does that fact - which I completely agree with btw - lessen the relevance of my comments on bad bike riders? A poor rider is of MUCH greater risk to himself than a poor driver and my point was you'd think it would be in these guys own interests to try to do it properly. Discuss. Your comment seems to be merely another "he's had a go at bikers so I'll have a go drivers" type comment. How does that move the discussion along? There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
Pugs.
Edited by Pugsey on Tuesday 20th February 08:36
kawasicki said:
Pugsey
There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
I think all we've really established is that cars are more flattering of operators with average ability There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
rsvmilly said:
kawasicki said:
Pugsey
There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
I think all we've really established is that cars are more flattering of operators with average ability There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
Pugsey said:
kawasicki said:
Pugsey
There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
How does that fact - which I completely agree with btw - lessen the relevance of my comments on bad bike riders? A poor rider is of MUCH greater risk to himself than a poor driver and my point was you'd think it would be in these guys own interests to try to do it properly. Discuss. Your comment seems to be merely another "he's had a go at bikers so I'll have a go drivers" type comment. How does that move the discussion along? There are also a huge proportion of sports car drivers who can't drive properly, so I don't really see how your argument really moves the discussion along.
shane
Pugs.
Edited by Pugsey on Tuesday 20th February 08:36
Pugsey said:
Yet again got held up on Sunday by a whole gaggle of bikes on my local 'bikers' road. All the usual gear, latest machinery, knees out - but nowhere near down, heads behind the bubble thinking 130mph is fast. The frightening thing is that not one of them thought there would be anything trying to get past - no life savers, nothing. Got past eventually and got the finger.
130mph on the road IS fast, it matters not what vehicle you are on/in at the time. That you still felt the need to pass them at that speed is more telling of you than them imo. And a car passing at you at those speeds is bound to be unnerving, so I'm not really surprised they took umbrage (altho giving the bird is still not really called for).
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