Wheel weight???
03-31-2006, 11:44 PM
#16
Rennlist Member
Hey, before you get all key'ed up, read the message. 1lb on the tire is like 2lbs in the car. so that 5lbs per tire is like 50lbs sitting in the car.
Its not about being right, its about helping folks not to worry about things that they wont feel , but may "think" they feel. do you know how many times ive been to the dyno after sensing something was wrong, only to see nothing is wrong?? many times!
anyway, i was just providing a rule of thumb, on a topic that is clearly misunderstood by many as well. this list gets though! 1lbs=1.4lbs on a 17" rim and near 2lbs if on the tire, as if the weight was sitting in the car vs rolling
sorry that wasnt more clear.
MK
Its not about being right, its about helping folks not to worry about things that they wont feel , but may "think" they feel. do you know how many times ive been to the dyno after sensing something was wrong, only to see nothing is wrong?? many times!
anyway, i was just providing a rule of thumb, on a topic that is clearly misunderstood by many as well. this list gets though! 1lbs=1.4lbs on a 17" rim and near 2lbs if on the tire, as if the weight was sitting in the car vs rolling
sorry that wasnt more clear.
MK
Originally Posted by tommytomaso
MARK<I don't know why your telling me like i dont know somthing, 1-3 hp is little to nothing...its also just shy of a dif between a tune-up and no tune up. so your retelling me your stats in "MATH" terms like that make you more RIGHT!!??? MArk i like 90% of our posts...but im seeing you feel a need to SEEM right.... unnesasary. and by the way, thier are many who can tell by FEEL that thier car is not running right...and i bet the HP dif is just 5hp or less. so lets not quib the little suff.. truth is alota little things can make a dif.. and knowing at what point little is alot is the game....
a spinning mass of 50lbs...WILL NOT in the REAL world react just like 50lbs sitting beside you. if you argue that point WHAT the hell computer are you using.. try not to compare your RACE car to our unrace prep cars.. thier are ALot of small mods that your car has that will balance out things that would show up more prononced in a street car. ie: 5hp to the ground in a car thats only getting 190 to the ground is ALOT! not like in a car thats getting 300+ to the ground.
a spinning mass of 50lbs...WILL NOT in the REAL world react just like 50lbs sitting beside you. if you argue that point WHAT the hell computer are you using.. try not to compare your RACE car to our unrace prep cars.. thier are ALot of small mods that your car has that will balance out things that would show up more prononced in a street car. ie: 5hp to the ground in a car thats only getting 190 to the ground is ALOT! not like in a car thats getting 300+ to the ground.
04-01-2006, 12:06 AM
#17
Burning Brakes
mark.. if your just adding the equation to help others thats great(and why i always read your posts) but you word things like your correcting.. 50lbs of spinning mass will not react just like its sitting in the car..Well mabe it will how i drive but for sure not how you drive. and just becase you dont feel it..dosnt mean that it cant be felt. My 18'' wheels feel alot differant then my 16s .... the braking takes longer and i can feel the weight dif at speed in turn responce...but alas 235 to 225 will change manythings. as will an extra 12lbs on each corner.. now if i could only figure out were the weight has changed in corospondince to the center axle i would know realy how much has changed for the differance i feel. lets not forget 50lbs spinning close to the axle is not like 50lbs spinning 1 foot from the axle. my braking may take 2-5feet longer than befor...thats a big enough dif for a "Ooo SH&t"" and a call to my insurance adjuster".. sorry i wasnt more clear.
04-01-2006, 01:31 AM
#18
Addict
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My experience from the stock GTS C2's to the 19" Forgelites...heavier. Very noticable to me. I just swapped them back for a few days recently and the GTS felt much quicker and torqueir. Resolution?...me needs more hp now! 
I am not positive about the actual weights of the wheels, because I seem to forget the exact weight as when I weighed them a week ago. I can tell you that I am within a few pounds. I DO know/remember this, The 19" wheels were 4 lbs heavier each in front and 6 lbs heaveir each in the rear. So I have added 8lbs (front) + 12lbs (rear) =20lbs total. It DOES feel different!
These are the weights I believe with the tires
C2 17"x7.5" with 225/45 =36# ea
17"x9" with 255/40 =38# ea
VERSUS
Forgelite 19"x8" with 225/35 =40# ea
19"x10" with 275/30 =44# ea
One thing to note, is that not only did I increase wheel diameter, but width increased by 1/2 inch in front and 1 inch in rear. Overall rolling diameter is within a 1/2 inch all around.
I am not positive about the actual weights of the wheels, because I seem to forget the exact weight as when I weighed them a week ago. I can tell you that I am within a few pounds. I DO know/remember this, The 19" wheels were 4 lbs heavier each in front and 6 lbs heaveir each in the rear. So I have added 8lbs (front) + 12lbs (rear) =20lbs total. It DOES feel different!
These are the weights I believe with the tires
C2 17"x7.5" with 225/45 =36# ea
17"x9" with 255/40 =38# ea
VERSUS
Forgelite 19"x8" with 225/35 =40# ea
19"x10" with 275/30 =44# ea
One thing to note, is that not only did I increase wheel diameter, but width increased by 1/2 inch in front and 1 inch in rear. Overall rolling diameter is within a 1/2 inch all around.
04-01-2006, 11:58 AM
#19
Administrator - "Tyson"
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What happens with this topic if a 3.09 rear end is installed?
04-01-2006, 12:51 PM
#20
Race Director
Thread Starter
Hacker
Don't even start the ring gear stuff :>)
120lbs seems very heavy for one front & rear wheel/tire for the 997 lightweights... Thats almost 20lbs heavier than the aftermarket 18" turbo twists! You should weigh them to confirm...my guess is they are around the weight of the 02 lightweights!
Don't even start the ring gear stuff :>)
120lbs seems very heavy for one front & rear wheel/tire for the 997 lightweights... Thats almost 20lbs heavier than the aftermarket 18" turbo twists! You should weigh them to confirm...my guess is they are around the weight of the 02 lightweights!
04-01-2006, 12:57 PM
#21
Rennlist Member
again, say what you want about how it feels. the reality, is very simple. 4lbs per wheel spinning, with most of the weight on the outer diameter, like tire only weight, is like 8lbs if in the car. x 4 would be 32lbs in the car (vs the 16 actual on the wheel and tire). dont think anyone can feel this. you may think so, but thats easy to disprove. ive run my best times with a 1/2 tank, vs my empy laps . certainly i cant feel any diff in any way shape or form. however, i can notice, a slight difference with a full tank, thats near 100lbs.
if the weight is evenly distributed on the wheel and tire, thats more like 1.7 x as if it was in the car.
hey, dont shoot the me, shoot Newton! its his laws.
Mk
if the weight is evenly distributed on the wheel and tire, thats more like 1.7 x as if it was in the car.
hey, dont shoot the me, shoot Newton! its his laws.
Mk
04-01-2006, 12:58 PM
#22
Rennlist Member
nothing if you make the tire large enough! 
the true answer is, "it depends!"
MK
the true answer is, "it depends!"
MK
Originally Posted by Hacker-Pschorr
What happens with this topic if a 3.09 rear end is installed?
04-01-2006, 12:59 PM
#23
Administrator - "Tyson"
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Originally Posted by IcemanG17
Hacker
Don't even start the ring gear stuff :>)
Don't even start the ring gear stuff :>)
Why is that?
Originally Posted by IcemanG17
120lbs seems very heavy for one front & rear wheel/tire for the 997 lightweights... Thats almost 20lbs heavier than the aftermarket 18" turbo twists! You should weigh them to confirm...my guess is they are around the weight of the 02 lightweights!
I'm doing some work on my front brakes today, I'll weigh the fronts. Great, my wife has given me puzzled looks as I take kitchen stuff into the grage while working on the car - the bathroom scale will be something new.
04-01-2006, 01:02 PM
#24
Rennlist Member
that weight is connected to the rest of the car, no way around it. the only difference is that its effects are sligtly amplified due to the fact that it is spinning, thats it. again, 17" rim 1.4x the weight. if on the tire only, more like 2x. you are not just "stopping" the rim and tire. its is part of the entire moving mass, just the rotating stuff has a weigh value of some factor more. more. so, does 32lbs in the car increase your stopping distances (16lbs of wheel and tire weight increase?) well sure, but by how much. not measureable in my opinion, or many others.
MK
MK
Originally Posted by tommytomaso
mark.. if your just adding the equation to help others thats great(and why i always read your posts) but you word things like your correcting.. 50lbs of spinning mass will not react just like its sitting in the car..Well mabe it will how i drive but for sure not how you drive. and just becase you dont feel it..dosnt mean that it cant be felt. My 18'' wheels feel alot differant then my 16s .... the braking takes longer and i can feel the weight dif at speed in turn responce...but alas 235 to 225 will change manythings. as will an extra 12lbs on each corner.. now if i could only figure out were the weight has changed in corospondince to the center axle i would know realy how much has changed for the differance i feel. lets not forget 50lbs spinning close to the axle is not like 50lbs spinning 1 foot from the axle. my braking may take 2-5feet longer than befor...thats a big enough dif for a "Ooo SH&t"" and a call to my insurance adjuster".. sorry i wasnt more clear.
04-01-2006, 01:40 PM
#26
Race Director
Thread Starter
I found this site
http://www.944racing.de/reload.php?u...elweights.html
Lists the weights of all the common porsche wheels.....the flat dish wheels are very light at about 77lbs per set (lighter than I thought!)....even the "lightweight" 02 carreras are 86.24lbs per set...almost 10lbs heavier than the flatdish....but thats on an 18" wheel....whats really interesting is the difference between the true hollowspoke and the solid spoke turbo II's....94.82 vs 116.16lbs...21.34lbs lighter!!! Big difference....even the factory 17" cup II's are 10lbs lighter than the Milla Migla aftermarkets.....
http://www.944racing.de/reload.php?u...elweights.html
Lists the weights of all the common porsche wheels.....the flat dish wheels are very light at about 77lbs per set (lighter than I thought!)....even the "lightweight" 02 carreras are 86.24lbs per set...almost 10lbs heavier than the flatdish....but thats on an 18" wheel....whats really interesting is the difference between the true hollowspoke and the solid spoke turbo II's....94.82 vs 116.16lbs...21.34lbs lighter!!! Big difference....even the factory 17" cup II's are 10lbs lighter than the Milla Migla aftermarkets.....
04-01-2006, 03:34 PM
#27
Interesting topic... Mark how are kineses???
Interesting topic...
I will eventyually go to the 996 lightweight cast rims... very sexy...
I got my 16 X 7" forged disks refurbed... I though they were ugly but they have grown on me a lot and will suffice until I am ready for a flashy brake and wheel uprade... they seem to have held strong for the first 20 years...
Before that I was looking at the SSR GT3 rims but found they were like 26 lbs each... sure there may be less tire blah blah blah...
The stock forged disk 16" rims weigh like 17.5... or at least i read this somewhere...
But what really counts is rotational moment of inertia... not actual weight i.e if the weight is on the outside or more to the inside... more inertia = slower to speed up and slow down...
The topic is valid if you are the kind or person who is counting improvement in increments of 5 pounds of sprung weight here or there and are considering an upgrade anyway... may as well get something that looks good, is lighter and hopefully fits the budget...
Mark, how much do those Kineses weigh with tires... My wife and I loved them at the Sf autoshow... she may even allow me to get a pair.
LO
I will eventyually go to the 996 lightweight cast rims... very sexy...
I got my 16 X 7" forged disks refurbed... I though they were ugly but they have grown on me a lot and will suffice until I am ready for a flashy brake and wheel uprade... they seem to have held strong for the first 20 years...
Before that I was looking at the SSR GT3 rims but found they were like 26 lbs each... sure there may be less tire blah blah blah...
The stock forged disk 16" rims weigh like 17.5... or at least i read this somewhere...
But what really counts is rotational moment of inertia... not actual weight i.e if the weight is on the outside or more to the inside... more inertia = slower to speed up and slow down...
The topic is valid if you are the kind or person who is counting improvement in increments of 5 pounds of sprung weight here or there and are considering an upgrade anyway... may as well get something that looks good, is lighter and hopefully fits the budget...
Mark, how much do those Kineses weigh with tires... My wife and I loved them at the Sf autoshow... she may even allow me to get a pair.
LO
04-01-2006, 04:20 PM
#28
Burning Brakes
when moving up in size/weight of wheels"""IN my Opinion"" you should concider how well your bushings and bearings are, if thiers any play adding more weight will wear things out quite faster.
Increments of HP gains have to work in % of total hp. so 5hp gains in a car thats only making 220 is a fair gain,....or loss Iv Mark is losing 5hp from weight in his car(RACE CAR) it will be far less noticable % loss.
Increments of HP gains have to work in % of total hp. so 5hp gains in a car thats only making 220 is a fair gain,....or loss Iv Mark is losing 5hp from weight in his car(RACE CAR) it will be far less noticable % loss.
04-01-2006, 11:36 PM
#29
Drifting
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Did you guys notice from that link that there's an oem Porsche cup 2 wheel that's 9x17 et70??
A 928er could run all 4 wheels the same with some 1" spacersin the back and run 255/40/17 all around, and be able to rotate the tires to get more even wear out of them. I know they would be a lot of money, but they'd be pretty original ('94-'95 GTS) wheels and look right. With perfect offsets.
part# 993.362.128.01
A 928er could run all 4 wheels the same with some 1" spacersin the back and run 255/40/17 all around, and be able to rotate the tires to get more even wear out of them. I know they would be a lot of money, but they'd be pretty original ('94-'95 GTS) wheels and look right. With perfect offsets.
part# 993.362.128.01