i dropped my bike...

Message

Kal · #141 Unread post by **Kal** » Wed Aug 09, 2006 9:26 am

VermilionX wrote:i said, it got smoother.

Which implies that your cornering in a normal riding style isn't as smooth as it should be.

#142 Unread post by **Big B** » Wed Aug 09, 2006 9:28 am

Kal wrote:
VermilionX wrote:i said, it got smoother.
Which implies that your cornering in a normal riding style isn't as smooth as it should be.

yeah, because riding around on the streets and actually working on cornering is soooo boring

VermilionX · Wed Aug 09, 2006 9:29 am

again, im not asking for riding form tips. i already got the advice i need regarding that.

like i said... i'll ask for tips if i want them. i don't mind you guys giving tips i don't ask for, but don't take it on me if i don't agree w/ you guys.

VermilionX · Wed Aug 09, 2006 9:32 am

kellanv wrote:this is why "how to" books should be banned from most people

your sig befits you.

Kal · #145 Unread post by **Kal** » Wed Aug 09, 2006 9:43 am

Right to be honest with you Verm there are two reasons I get on your case

The first reason is that I like you and don't want you to be a statistic

The second reason is, well I only really see two types of bikers or riders...

The first type of rider is all the gear and no idea passing phase thing, where they ride because its cool for a couple of seasons and then never ride again.

The second type of rider is the lifers, like wizzard and XJR_John who continue to ride until their hands are prised off of the handlebars and their licences taken away.

If I can be totally honest here I want you still to be riding in ten years and more. I am afraid that riding will be like your martial arts though - something you were completely wrapped up in for a few years and then forgotten when you find something new and 'more exciting' to do.

So yes I get on your case but I feel I have good reasons.

Posthumane · Wed Aug 09, 2006 9:50 am

VermilionX wrote:
1. more tire contact patch, so more traction. let's say both riders go 40mph on the same tight turn... the guy not hanging off might be in the edge of the tires traction limit... but the guy hanging off is not since he has more contact patch.

The guy hanging off does not have any more contact patch. Motorcycle tires have a round profile for a reason. When you lean over, the contact patch moves across the tire, but does not change is size significantly (unless your tires are completely squared off...). In fact the contact patch will be roughly equal to the normal force on that tire divided by the air pressure inside the tire, with a slight difference due to the rubber's slight resistance to deformation. So if you are wheelieing the bike down the main drag and your 500 lbs is all on the rear tire, and you have 50psi pressure in that tire, your contact patch will be roughly 10 square inches. The exception to this was noted in my last post, when a rider exceeds the critical lean angle and rides right off the edge of the tire.

Also, more contact patch does not equal more traction, at least not in all circumstances. You can let most of the air out of your tires and have a huge contact patch, but your traction would not improve at all. What would change however is that your tires would slip a lot more (not slide!) because the tire would not be stiff enough to resist excessive deformation due to side loading.

VermilionX wrote: you can take the same speed w/ less lean angle. so the guy hanging off has more traction points to spare for earlier acceleration out of the corner, leaning more, or braking if needed.

Leaning off does indeed produce less lean of the bike, but that doesn't mean the cornering force is reduced. As I said earlier, both methods move the Cg of the bike/rider combo towards the inside of the corner the same amount for a give corner at a given speed. This means that the lateral acceleration of the bike is the same, and the lateral force on the tire is the same (just applied to a different portion of the tire). The amount of traction you have available is based on the force placed on the tire, not the lean angle, and since the force is equal if you are leaning off or not, your available traction does not increase by leaning off...

VermilionX wrote:
2. hanging off is one of the steering aids along with putting weight on the pegs.

True, but since you way significantly less than the bike and are actually only shifting a small part of your weight (your butt is not that heavy) over a small distance, the effect is minimal. It is also completely unneccesary unless you are trying to achieve the highest rate of lean (ie, go from no lean to full lean in 0.x seconds). This however is offset by the time it takes you to move your body. You can lean very fast just by countersteering.

Now I'm not criticising per se, ride how you want. I'm just trying to have a discussion about the physics of what is happening. If you do not want to discuss motorcycles and the way they work, please let me know and I will leave your thread alone.

VermilionX · Wed Aug 09, 2006 9:50 am

Kal wrote:Right to be honest with you Verm there are two reasons I get on your case

The first reason is that I like you and don't want you to be a statistic

The second reason is, well I only really see two types of bikers or riders...

The first type of rider is all the gear and no idea passing phase thing, where they ride because its cool for a couple of seasons and then never ride again.

The second type of rider is the lifers, like wizzard and XJR_John who continue to ride until their hands are prised off of the handlebars and their licences taken away.

If I can be totally honest here I want you still to be riding in ten years and more. I am afraid that riding will be like your martial arts though - something you were completely wrapped up in for a few years and then forgotten when you find something new and 'more exciting' to do.

So yes I get on your case but I feel I have good reasons.

thanks kal... im sure you know i don't take things too personal.

and you know... before riding, i was obsessed w/ video games for as longa s i can remember. i never thought i'd find some other hobby that will be better.

now that i found riding... i love it better than video games.

so who knows... the only other thing i can think of that is better than riding is flying.

i still play video games but not as much as i used to.

so maybe if get the chance to get into flying... i'll definitely ride less.

VermilionX · Wed Aug 09, 2006 9:52 am

Posthumane wrote:
VermilionX wrote:
1. more tire contact patch, so more traction. let's say both riders go 40mph on the same tight turn... the guy not hanging off might be in the edge of the tires traction limit... but the guy hanging off is not since he has more contact patch.
The guy hanging off does not have any more contact patch. Motorcycle tires have a round profile for a reason. When you lean over, the contact patch moves across the tire, but does not change is size significantly (unless your tires are completely squared off...). In fact the contact patch will be roughly equal to the normal force on that tire divided by the air pressure inside the tire, with a slight difference due to the rubbers slight resistance to deformation. So if you are wheelieing the bike down the main drag and your 500 lbs is all on the rear tire, and you have 50psi pressure in that tire, your contact patch will be roughly 10 square inches. The exception to this was noted in my last post, when a rider exceeds the critical lean angle and rides right off the edge of the tire.

Also, more contact patch does not equal more traction, atleast not in all circumstances. You can let most of the air out of your tires and have a huge contact patch, but your traction would not improve at all. What would change however is that your tires would slip a lot more (not slide!) because the tire would not be stiff enough to resist excessive deformation due to side loading.

VermilionX wrote: you can take the same speed w/ less lean angle. so the guy hanging off has more traction points to spare for earlier acceleration out of the corner, leaning more, or braking if needed.
Leaning off does indeed produce less lean of the bike, but that doesn't mean the cornering force is reduced. As I said earlier, both methods move the Cg of the bike/rider combo towards the inside of the corner the same amount for a give corner at a given speed. This means that the lateral acceleration of the bike is the same, and the lateral force on the tire is the same (just applied to a different portion of the tire). The amount of traction you have available is based on the force placed on the tire, not the lean angle, and since the force is equal if you are leaning off or not, your available traction does not increase by leaning off...

VermilionX wrote:
2. hanging off is one of the steering aids along with putting weight on the pegs.
True, but since you way significantly less than the bike and are actually only shifting a small part of your weight (your butt is not that heavy) over a small distance, the effect is minimal. It is also completely unneccesary unless you are trying to achieve the highest rate of lean (ie, go from no lean to full lean in 0.x seconds). This however is offset by the time it takes you to move your body. You can lean very fast just by countersteering.

Now I'm not criticising per se, ride how you want. I'm just trying to have a discussion about the physics of what is happening. If you do not want to discuss motorcycles and the way they work, please let me know and I will leave your thread alone.

nope i don't mind, that's a very informative post. thanks.

do you race?

Posthumane · Wed Aug 09, 2006 10:00 am

VermilionX wrote:
do you race?

Not motorcycles. But I have done a bit of car racing here and there (mostly AutoX) and some race car desing in school (Formula SAE). I am an engineering student with a great interest in cars, bikes, planes, etc. so I try to learn as much as I can about how/why they work. A lot of that is from reading, some from observation and deduction.

Anyway, good luck with the racing. I would suggest you take one day, and try riding your canyon route without moving your butt off the seat at all, just try to lean the bike as much as you can. Try this for an entire day to get the feel of it. I'm guessing at the end of this day you will find you are much smoother even without leaning off the bike than you were before.

VermilionX · Wed Aug 09, 2006 10:00 am

BIKE DAMAGE UPDATE!

so i went to my trusty mechanic to check my bike...

he said the frame is fine and he fixed my frame sliders... he said i don't need a new one.

he was able to mask some of the scratches but the othes are deep he said. so there's not really much he can do besides a repaint.

he also, checked how it rides... he said it's fine... brakes, suspension everything is fine.

anyway... he told me he'll have this great deal on parts unlimited in a few weeks so he told me to let him know what i need. i asked him about tires and he liked the dunlop qualifiers the best. so i'll go w/ that. after all, the qualifiers is my 2nd choice. he said he can gett a good deal on the tires from parts unlimited. so yay for me!