Which are the five lightest wheels for the 997 turbo?
#61
03-30-2010 | 10:13 PM
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Our Tech1-200 series for the Turbo are also very light.
The Tech1-210 front in 19x8.5 is 7.48 kg. Rear in 19x11.5 is 8.95 kg.
The 19x12 for the GT3 is 9.08 Kg.
We have been trying to find stocking distributors for this line.
However, in the meantime we will announce a group buy next Monday on all the Tech1-100 and Tech1-200 series wheels. Under $4k per set.
PM me if you want a quotation.
The Tech1-210 front in 19x8.5 is 7.48 kg. Rear in 19x11.5 is 8.95 kg.
The 19x12 for the GT3 is 9.08 Kg.
We have been trying to find stocking distributors for this line.
However, in the meantime we will announce a group buy next Monday on all the Tech1-100 and Tech1-200 series wheels. Under $4k per set.
PM me if you want a quotation.
#68
04-06-2010 | 03:40 PM
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guys i've tracked with my dymags a few times, our backstraight at monticello is quite long and i usually hit about 155-160mph before braking. the only unstableness i've felt was during braking from those speeds down to about 120mph, which i think is more likely the lack of rear wing on the turbo. if you really live above 180mph (yea right) then i guess you need to find out if lightweight wheels are indeed unstable and avoid. if you're like the rest of us, just set up the suspension with tons of camber and maybe go more neutral on toe, and you won't feel anything.
#69
04-06-2010 | 04:24 PM
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yeh i already made a statement on light wheels and how unstable they r .. some made me look like an idiot and some agreed, i've seen it and lived bro, the car literaly swivers as u said above 240~ KM
#70
04-06-2010 | 04:40 PM
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From an engineering perspective, there is nothing inherently unstable about lightweight wheels. Absolutely nothing.
However, if the wheels are not machined to very tight tolerances with very low runout (<0.3mm, .012 in), then the wheels can develop unpleasant harmonic vibration at high speed. This can be manifested by moderate to severe steering wheel shake. It is quite unnerving at high speed.
Multi-piece wheels like the Dymag are very difficult to manufacture with such high levels of concentricity. The more the pieces, the more difficult it is.
Not impossible, mind you, just difficult.
Forged monoblock wheels can be built with practically zero runout if one builds the proper tooling and fixtures. Not cheap, but very smooth at high speed.
However, if the wheels are not machined to very tight tolerances with very low runout (<0.3mm, .012 in), then the wheels can develop unpleasant harmonic vibration at high speed. This can be manifested by moderate to severe steering wheel shake. It is quite unnerving at high speed.
Multi-piece wheels like the Dymag are very difficult to manufacture with such high levels of concentricity. The more the pieces, the more difficult it is.
Not impossible, mind you, just difficult.
Forged monoblock wheels can be built with practically zero runout if one builds the proper tooling and fixtures. Not cheap, but very smooth at high speed.
#71
04-06-2010 | 08:26 PM
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From an engineering perspective, there is nothing inherently unstable about lightweight wheels. Absolutely nothing.
However, if the wheels are not machined to very tight tolerances with very low runout (<0.3mm, .012 in), then the wheels can develop unpleasant harmonic vibration at high speed. This can be manifested by moderate to severe steering wheel shake. It is quite unnerving at high speed.
Multi-piece wheels like the Dymag are very difficult to manufacture with such high levels of concentricity. The more the pieces, the more difficult it is.
Not impossible, mind you, just difficult.
Forged monoblock wheels can be built with practically zero runout if one builds the proper tooling and fixtures. Not cheap, but very smooth at high speed.
However, if the wheels are not machined to very tight tolerances with very low runout (<0.3mm, .012 in), then the wheels can develop unpleasant harmonic vibration at high speed. This can be manifested by moderate to severe steering wheel shake. It is quite unnerving at high speed.
Multi-piece wheels like the Dymag are very difficult to manufacture with such high levels of concentricity. The more the pieces, the more difficult it is.
Not impossible, mind you, just difficult.
Forged monoblock wheels can be built with practically zero runout if one builds the proper tooling and fixtures. Not cheap, but very smooth at high speed.
The stability comment comes from no less a big name than Ruf! I have no idea how applicable it is but I'll quote the thread here so maybe we could hear counter-points from a pro. (I hope to learn something from this.)
Apparently it's the gyroscopic effect (Read about Gyroscope Effect on Wikipedia here.) that Ruf is talking about. A turning wheel that's heavier resists moving from straight line better; believe it's from conservation of momentum -- resisting of external torque.
>>>>>>>>>>>>>>>>>
http://www.rennteam.com/forum/thread...html#p20154550
From TB993tt:
With the 1987 onwards CTR Ruf would say that the heavy wheels made the car stable at the very high speeds in a straight line due to a gyroscopic effect - if this is true (which seems to make sense) then I guess by definition the gryoscopic effect would make the heavier wheels a hindrance when the wheels are turned for a corner......
Last edited by cannga; 04-06-2010 at 08:52 PM.
#73
04-06-2010 | 09:36 PM
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Hi Mike,
The stability comment comes from no less a big name than Ruf! I have no idea how applicable it is but I'll quote the thread here so maybe we could hear counter-points from a pro. (I hope to learn something from this.)
Apparently it's the gyroscopic effect (Read about Gyroscope Effect on Wikipedia here.) that Ruf is talking about. A turning wheel that's heavier resists moving from straight line better; believe it's from conservation of momentum -- resisting of external torque.
>>>>>>>>>>>>>>>>>
http://www.rennteam.com/forum/thread...html#p20154550
From TB993tt:
With the 1987 onwards CTR Ruf would say that the heavy wheels made the car stable at the very high speeds in a straight line due to a gyroscopic effect - if this is true (which seems to make sense) then I guess by definition the gryoscopic effect would make the heavier wheels a hindrance when the wheels are turned for a corner......
The stability comment comes from no less a big name than Ruf! I have no idea how applicable it is but I'll quote the thread here so maybe we could hear counter-points from a pro. (I hope to learn something from this.)
Apparently it's the gyroscopic effect (Read about Gyroscope Effect on Wikipedia here.) that Ruf is talking about. A turning wheel that's heavier resists moving from straight line better; believe it's from conservation of momentum -- resisting of external torque.
>>>>>>>>>>>>>>>>>
http://www.rennteam.com/forum/thread...html#p20154550
From TB993tt:
With the 1987 onwards CTR Ruf would say that the heavy wheels made the car stable at the very high speeds in a straight line due to a gyroscopic effect - if this is true (which seems to make sense) then I guess by definition the gryoscopic effect would make the heavier wheels a hindrance when the wheels are turned for a corner......
Alois Ruf is an innovator par excellence!
That said, I disagree that the gyroscopic effect contributes to stability. No road surface is smooth enough to escape all the effects of gyroscopic precession. Every force applied to a rotating body causes the "gyroscope" to precess in a direction 90 degrees from the applied force. This is one reason why heavy wheels resist turning. (The other is kinetic energy).
Unfortunately, every bump or irregularity in the road, regardless how small, causes these forces to be applied and this precession reaction to occur. The heavier the wheel, the greater the force and the greater the reaction. In addition, the heavier the wheel, the more the impact force is transmitted to the suspension and to the car itself. It's physics. And it is inescapable.
In short, gyroscopic forces are not your friend.
In contrast, lighter wheels require far less energy to accelerate and decelerate, react less to pavement irregularities, require less damping, reduce wear on brakes and suspension, and inspire more driving confidence.
They also save fuel, if anybody cares.
There are other factors that contribute to instability that are far more important. Air management over the car and under the car are critically important to stability. Aerodynamic forces, such as downforce, lift, and drag all increase at the square of the speed. So at high speed, too much lift can SERIOUSLY reduce control, traction and stability. These manifestations can easily misrepresent themselves to your brain as problems with wheels, tires, brakes and suspension.
Its why the top pros spend so much on data logging, wind tunnels, and the like.
Sorry for the long post. I hope i answered your question.
#74
04-07-2010 | 01:11 PM
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Joined: Mar 2010
Posts: 67
From: Pompano Beach, FL
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I have the utmost respect for the entire Ruf organization.
Alois Ruf is an innovator par excellence!
That said, I disagree that the gyroscopic effect contributes to stability. No road surface is smooth enough to escape all the effects of gyroscopic precession. Every force applied to a rotating body causes the "gyroscope" to precess in a direction 90 degrees from the applied force. This is one reason why heavy wheels resist turning. (The other is kinetic energy).
Unfortunately, every bump or irregularity in the road, regardless how small, causes these forces to be applied and this precession reaction to occur. The heavier the wheel, the greater the force and the greater the reaction. In addition, the heavier the wheel, the more the impact force is transmitted to the suspension and to the car itself. It's physics. And it is inescapable.
In short, gyroscopic forces are not your friend.
In contrast, lighter wheels require far less energy to accelerate and decelerate, react less to pavement irregularities, require less damping, reduce wear on brakes and suspension, and inspire more driving confidence.
They also save fuel, if anybody cares.
There are other factors that contribute to instability that are far more important. Air management over the car and under the car are critically important to stability. Aerodynamic forces, such as downforce, lift, and drag all increase at the square of the speed. So at high speed, too much lift can SERIOUSLY reduce control, traction and stability. These manifestations can easily misrepresent themselves to your brain as problems with wheels, tires, brakes and suspension.
Its why the top pros spend so much on data logging, wind tunnels, and the like.
Sorry for the long post. I hope i answered your question.
Alois Ruf is an innovator par excellence!
That said, I disagree that the gyroscopic effect contributes to stability. No road surface is smooth enough to escape all the effects of gyroscopic precession. Every force applied to a rotating body causes the "gyroscope" to precess in a direction 90 degrees from the applied force. This is one reason why heavy wheels resist turning. (The other is kinetic energy).
Unfortunately, every bump or irregularity in the road, regardless how small, causes these forces to be applied and this precession reaction to occur. The heavier the wheel, the greater the force and the greater the reaction. In addition, the heavier the wheel, the more the impact force is transmitted to the suspension and to the car itself. It's physics. And it is inescapable.
In short, gyroscopic forces are not your friend.
In contrast, lighter wheels require far less energy to accelerate and decelerate, react less to pavement irregularities, require less damping, reduce wear on brakes and suspension, and inspire more driving confidence.
They also save fuel, if anybody cares.
There are other factors that contribute to instability that are far more important. Air management over the car and under the car are critically important to stability. Aerodynamic forces, such as downforce, lift, and drag all increase at the square of the speed. So at high speed, too much lift can SERIOUSLY reduce control, traction and stability. These manifestations can easily misrepresent themselves to your brain as problems with wheels, tires, brakes and suspension.
Its why the top pros spend so much on data logging, wind tunnels, and the like.
Sorry for the long post. I hope i answered your question.
Champion Motorsport has designed and manufactured 1 piece forged aluminum as well as Mg. wheels for many years now, the tolerances are very tight, and on road cars as well as purpose built racing cars, the lightweight forged wheel has always shown substantial performance improvements.
Tomorrow we will debut a new product. I will post it here first.
Thank you again..
#75
04-07-2010 | 04:08 PM
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Joined: Dec 2006
Posts: 3,116
From: Palos Verdes
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That said, I disagree that the gyroscopic effect contributes to stability. No road surface is smooth enough to escape all the effects of gyroscopic precession. Every force applied to a rotating body causes the "gyroscope" to precess in a direction 90 degrees from the applied force. This is one reason why heavy wheels resist turning. (The other is kinetic energy).
Unfortunately, every bump or irregularity in the road, regardless how small, causes these forces to be applied and this precession reaction to occur. The heavier the wheel, the greater the force and the greater the reaction. In addition, the heavier the wheel, the more the impact force is transmitted to the suspension and to the car itself. It's physics. And it is inescapable.
In short, gyroscopic forces are not your friend.
In contrast, lighter wheels require far less energy to accelerate and decelerate, react less to pavement irregularities, require less damping, reduce wear on brakes and suspension, and inspire more driving confidence.
Unfortunately, every bump or irregularity in the road, regardless how small, causes these forces to be applied and this precession reaction to occur. The heavier the wheel, the greater the force and the greater the reaction. In addition, the heavier the wheel, the more the impact force is transmitted to the suspension and to the car itself. It's physics. And it is inescapable.
In short, gyroscopic forces are not your friend.
In contrast, lighter wheels require far less energy to accelerate and decelerate, react less to pavement irregularities, require less damping, reduce wear on brakes and suspension, and inspire more driving confidence.
)So... are you saying:
1. Yes gyroscopic effect is a problem, but the heavier wheel is not at an advantage because:
2. With road irregularities, the force on the heavier wheel is larger, and therefore it suffers just as much from precession?