The Acura Legend & Acura RL Forum - View Single Post

**B+O** · 02-11-08, 02:22 AM

very complicated question you pose there. I'll try not to tangent of the given subject too much. And i'll touch on the drive wheels point as well.

At lower speeds F1 cars are incredibly light and as such rely heavily on their tires for grip...especially in corners. At speed however they rely on downforce. the downforce effectively multiplies the force the tires have to break away water forces. That said, street cars themselves have a large amount of weight so the force acting on the tire is more Gravity and Mass than artificial mass of "downforce" as downforce is just artificial "weight" added to the car.

So in essence, yes the Legend and other street cars rely on weight to effectively keep tires on the pavement. The legend in specific has a generous weight envelop and would have substantial gripping potential (not as high as a W140 Mercedes but you get the idea). So it's less likely to hydroplane on any tire it uses as compared to say a Civic or a something lighter.

That all said, it is imperative that as the weight starts going up, you have more rubber on the road, especially in wet conditions. This is why I made the point earlier that if a thin tire was the answer to hydroplaning we'd all be skating on Wagon wheels. The thinner the tire, the more traction is required out of a smaller area. this gets increasingly complicated when you add to the problem with a slick surface. This is why F1s use are large tire in the rain, traction isn't based on a tire's buoyancy. It's based on its performance.

I looked up the Tires you're running Fred. The Ecsta SPT bears a stricking resemblance to the Hankook RS2.

The RS2 and the SPT are both something like the Perelli Asimmetrico

one of my Favorite tires (aside from the RE540S and A048).

The Asimmetrico Was an awesome dry weather tire but its tread design was outclassed when it came to wet weather traction. the problem is that only a portion of the Tread was devoted water evacuation. If you look at the tire's tread pattern, there's unbroken treads bands. These are pretty useless when it comes to wet traction, but in the dry it helps regulate and stabilize the tire's temperature. Also the parts that are dedicated to dispersion are pretty blocky. They're not smooth at all and this builds hydraulic pressure effectively stopping flow.

Moving on to the RS2 from Hankook...

The Hankook is my new favorite Attainable tire (Still have a crush on the now discontinued 540S and the Asimmetrico but they're hard to find). this tire is amazing in the dry, but its wet traction is, at best, mediocre. Problem with this tire is the same as the asimmetrico. The solid tread blocks are non beneficial to evacuation of water. and the tread that is available for evacuation doesn't really push the water out from under the tire. it kinda just moves it over a bit allows the tires to sink a bit more into the water.

Now to the SPT...

Now they said they used a new tread compound to "improve" wet traction. You know...that's all well and good but there's just one thing. The tire can have newly chewed bubble gum for a tread compound, but if it can't reach the road, it's all for naught. here we have the same problem. The tread isn't designed with water evacuation in mind. Looking at it, there is a better tread design for wet weather than the RS2, but not much...This is the root of your hydroplaning problems.

Now as far as the Drive wheels. The drive wheels in this particular instance (inclement weather) play a big role in stability more so than traction. given 50/50 weight distribution for a front drive and a rear drive of equal weight, the front drive car will have superior performance. The reason is that in basic kinematics, it's more efficient to pull a mass than it is too push a mass. when pushing a mass, energy tries to escape. it will go to the easiest path, and to the side is always easier than pushing forward (this is what you'd call dog trotting) a common occurrence in big tire smoking, showboating antics with RWD cars. With a front drive vehicle, the energy has no where else to go but where it's directed. there's no chance for it to move to the side to bypass the system.

In essence think of pushing a log up a hill. when pushing that log up the hill. the front will want to move around and not go exactly straight up the hill. so you'll have to walk sideways to keep the front end going up that hill. now take that same log and drag it up the same hill with when pulling it up the hill from the front of it, the energy is coming from the front. everything in the system behind the energy has to follow it. It's only been since the affordable implementation of traction control, stability assist, fuzzy logic transmission controllers and ABS, has RWD become a desired drivetrain again. RWD is an inherently unstable platform and the need for lots of electronics and safeguards need to be implemented, especially on higher HP platforms.

What is a good tire design???

Well there's a few...

The KDW is one.

Though not the prettiest tire, it's design is very functional. The WIIIIDE siphons that trail a LONG ways up the tread going straight out the shoulders allows for maximum evacuation of water from under the tire. The lack of extraneous groves allows the maximum amount rubber to still be planted for the best grip.

Yokohama AVS Sport

This was, and is a VERY good tire. its design is straight forward, simple and strong. The tire was good in both the wet and dry, but it could have used a softer compound. It was pretty sticky and fun to use, but excellent in the wet and dry.

Goodyear F1 GSD-3

This is a GREEEAAAT tire for the rain. The design of the tire is specifically optimized to reduce hydroplaning at high speeds. the large amout of openspace however compromises the effective contact patch, but dry handling is still crazy because of the advanced compound it uses. This tire is a really good tire.

02-11-08, 02:22 AM	#21 (permalink)
B+O The Mac vs. The Mack Join Date: Mar 2002 Location: VSC Moderator Posts: 12,424 Car 1: why? iTrader: (1)	very complicated question you pose there. I'll try not to tangent of the given subject too much. And i'll touch on the drive wheels point as well. At lower speeds F1 cars are incredibly light and as such rely heavily on their tires for grip...especially in corners. At speed however they rely on downforce. the downforce effectively multiplies the force the tires have to break away water forces. That said, street cars themselves have a large amount of weight so the force acting on the tire is more Gravity and Mass than artificial mass of "downforce" as downforce is just artificial "weight" added to the car. So in essence, yes the Legend and other street cars rely on weight to effectively keep tires on the pavement. The legend in specific has a generous weight envelop and would have substantial gripping potential (not as high as a W140 Mercedes but you get the idea). So it's less likely to hydroplane on any tire it uses as compared to say a Civic or a something lighter. That all said, it is imperative that as the weight starts going up, you have more rubber on the road, especially in wet conditions. This is why I made the point earlier that if a thin tire was the answer to hydroplaning we'd all be skating on Wagon wheels. The thinner the tire, the more traction is required out of a smaller area. this gets increasingly complicated when you add to the problem with a slick surface. This is why F1s use are large tire in the rain, traction isn't based on a tire's buoyancy. It's based on its performance. I looked up the Tires you're running Fred. The Ecsta SPT bears a stricking resemblance to the Hankook RS2. The RS2 and the SPT are both something like the Perelli Asimmetrico one of my Favorite tires (aside from the RE540S and A048). The Asimmetrico Was an awesome dry weather tire but its tread design was outclassed when it came to wet weather traction. the problem is that only a portion of the Tread was devoted water evacuation. If you look at the tire's tread pattern, there's unbroken treads bands. These are pretty useless when it comes to wet traction, but in the dry it helps regulate and stabilize the tire's temperature. Also the parts that are dedicated to dispersion are pretty blocky. They're not smooth at all and this builds hydraulic pressure effectively stopping flow. Moving on to the RS2 from Hankook... The Hankook is my new favorite Attainable tire (Still have a crush on the now discontinued 540S and the Asimmetrico but they're hard to find). this tire is amazing in the dry, but its wet traction is, at best, mediocre. Problem with this tire is the same as the asimmetrico. The solid tread blocks are non beneficial to evacuation of water. and the tread that is available for evacuation doesn't really push the water out from under the tire. it kinda just moves it over a bit allows the tires to sink a bit more into the water. Now to the SPT... Now they said they used a new tread compound to "improve" wet traction. You know...that's all well and good but there's just one thing. The tire can have newly chewed bubble gum for a tread compound, but if it can't reach the road, it's all for naught. here we have the same problem. The tread isn't designed with water evacuation in mind. Looking at it, there is a better tread design for wet weather than the RS2, but not much...This is the root of your hydroplaning problems. Now as far as the Drive wheels. The drive wheels in this particular instance (inclement weather) play a big role in stability more so than traction. given 50/50 weight distribution for a front drive and a rear drive of equal weight, the front drive car will have superior performance. The reason is that in basic kinematics, it's more efficient to pull a mass than it is too push a mass. when pushing a mass, energy tries to escape. it will go to the easiest path, and to the side is always easier than pushing forward (this is what you'd call dog trotting) a common occurrence in big tire smoking, showboating antics with RWD cars. With a front drive vehicle, the energy has no where else to go but where it's directed. there's no chance for it to move to the side to bypass the system. In essence think of pushing a log up a hill. when pushing that log up the hill. the front will want to move around and not go exactly straight up the hill. so you'll have to walk sideways to keep the front end going up that hill. now take that same log and drag it up the same hill with when pulling it up the hill from the front of it, the energy is coming from the front. everything in the system behind the energy has to follow it. It's only been since the affordable implementation of traction control, stability assist, fuzzy logic transmission controllers and ABS, has RWD become a desired drivetrain again. RWD is an inherently unstable platform and the need for lots of electronics and safeguards need to be implemented, especially on higher HP platforms. What is a good tire design??? Well there's a few... The KDW is one. Though not the prettiest tire, it's design is very functional. The WIIIIDE siphons that trail a LONG ways up the tread going straight out the shoulders allows for maximum evacuation of water from under the tire. The lack of extraneous groves allows the maximum amount rubber to still be planted for the best grip. Yokohama AVS Sport This was, and is a VERY good tire. its design is straight forward, simple and strong. The tire was good in both the wet and dry, but it could have used a softer compound. It was pretty sticky and fun to use, but excellent in the wet and dry. Goodyear F1 GSD-3 This is a GREEEAAAT tire for the rain. The design of the tire is specifically optimized to reduce hydroplaning at high speeds. the large amout of openspace however compromises the effective contact patch, but dry handling is still crazy because of the advanced compound it uses. This tire is a really good tire. Last edited by B+O : 02-11-08 at 02:51 AM.