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      08-07-2007, 04:17 PM   #1
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Disadvantages of 19's...

I'm worried that going with the 19's will make the ride too harsh for these horrible NH roads I have to drive on. Can anyone tell me if there is a huge difference in ride quality between 18's and 19's?

Thanks!
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      08-07-2007, 05:34 PM   #2
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a little bumpier..but youll regret not getting them every time you see another m3 with them. i bought mine after i purchased the car and lost tons of dollars!
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      08-07-2007, 10:39 PM   #3
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Quote:
Originally Posted by bulletproof View Post
I'm worried that going with the 19's will make the ride too harsh for these horrible NH roads I have to drive on. Can anyone tell me if there is a huge difference in ride quality between 18's and 19's?

Thanks!
I have 20's on my ML350 and they're fine. 19s look better than 18s and there is little difference in ride quality. Put snows on your 18s and you're set.
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      08-08-2007, 12:05 AM   #4
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Performance in general

In general 18s for performance and 19s for looks.

That being said the amount of performance decline you will experience with 19s compared 18s will be small but measureable. The basic reason is weight and moment of intertia. Rotating mass in a vehicle is more of a performance hinderance than non rotating mass because it takes more energy to get a rotating mass translating and rotating than to simply get a non-rotating mass translating. This obsession with rotating mass can be seen in all sort of design areas and many in cars. Engine designers are quite keen to lower rotating bodies mass and moment as well. Next thing about an objects moment of inertia is that it rises very quickly with its size - as the square of it's radius in fact (meaning double the radius = 4 times larger moment). These priciples explain the extra work brakes have to do in decelerating a vehicle as well as the hinderance larger wheels play in its acceleration.

The next area the heavier wheels (and tires) hurt you is in suspension performance. Anything that moves with the wheels is part of the vehicles so called "unspring weight". High unsprung weight is a huge detriment to vehicle suspension performance because all of that mass has a high inertia and can not respond as quickly nor as effectively to roadway force and profile inputs as a low mass/low inertia system.

OK, enough technical blah, blah, blah. Some pratical information: Wheel weight varies significantly by manufacturer and design. It is quite possible for a nice, weight consciously designed, forged 19" to be significantly lighter than a crappy 18". However again, apples to apples, with a similar design the 18 will be lighter and a lower moment of inertia.

Also to back up this claim I specifically remember an article that tested 18s vs. 19s on the M3 and they did measure better acceleration, braking and ride with the 18s.

Last but not least I personally can not stand how much the 18s pale in comparison in the looks department to the 19s, so I will comprimise. I'll go for 19s but will consider weight in my criteria. However, if I can't find a design I really like to look at I will also just eat the performance differences.

Hope that all helps.
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      08-08-2007, 05:31 PM   #5
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Quote:
Originally Posted by swamp2 View Post
In general 18s for performance and 19s for looks.

That being said the amount of performance decline you will experience with 19s compared 18s will be small but measureable. The basic reason is weight and moment of intertia. Rotating mass in a vehicle is more of a performance hinderance than non rotating mass because it takes more energy to get a rotating mass translating and rotating than to simply get a non-rotating mass translating. This obsession with rotating mass can be seen in all sort of design areas and many in cars. Engine designers are quite keen to lower rotating bodies mass and moment as well. Next thing about an objects moment of inertia is that it rises very quickly with its size - as the square of it's radius in fact (meaning double the radius = 4 times larger moment). These priciples explain the extra work brakes have to do in decelerating a vehicle as well as the hinderance larger wheels play in its acceleration.

The next area the heavier wheels (and tires) hurt you is in suspension performance. Anything that moves with the wheels is part of the vehicles so called "unspring weight". High unsprung weight is a huge detriment to vehicle suspension performance because all of that mass has a high inertia and can not respond as quickly nor as effectively to roadway force and profile inputs as a low mass/low inertia system.

OK, enough technical blah, blah, blah. Some pratical information: Wheel weight varies significantly by manufacturer and design. It is quite possible for a nice, weight consciously designed, forged 19" to be significantly lighter than a crappy 18". However again, apples to apples, with a similar design the 18 will be lighter and a lower moment of inertia.

Also to back up this claim I specifically remember an article that tested 18s vs. 19s on the M3 and they did measure better acceleration, braking and ride with the 18s.

Last but not least I personally can not stand how much the 18s pale in comparison in the looks department to the 19s, so I will comprimise. I'll go for 19s but will consider weight in my criteria. However, if I can't find a design I really like to look at I will also just eat the performance differences.

Hope that all helps.
Excellent! Thanks for the thorough explaination.
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      09-09-2007, 11:14 PM   #6
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swamp2, Is that why F1 cars have 14" wheels ? I always wanted to find an answer for this
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      10-02-2007, 12:11 AM   #7
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No the ride and the hadnling only improves wiht 19" rims. I have a bmw 328xi coupe. After i put the rims on it i was scared that the ride would be harsh but it wasnt. My friend who has the smae car as me put 20' rims on his car and he is looking to sell them know deep dish crome. Becuase he went to big and he feels liek he is in a suzuki his ride sucks... So dont hesitate wiht the 19' rims
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      11-04-2007, 04:36 PM   #8
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Isn't it just much easier to say....
18's for track/performance, and 19's for street/looks?
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      11-05-2007, 09:15 AM   #9
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Quote:
Originally Posted by BMW MotorSport View Post
Isn't it just much easier to say....
18's for track/performance, and 19's for street/looks?

It may be easier to say that, but it isn't as thorough and as informative -for those not in the know- as Swamp's explanation.
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      11-05-2007, 12:16 PM   #10
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Any beautiful-looking serious aftermarket 18''?
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      11-05-2007, 12:57 PM   #11
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Quote:
Originally Posted by swamp2 View Post
In general 18s for performance and 19s for looks.

That being said the amount of performance decline you will experience with 19s compared 18s will be small but measureable. The basic reason is weight and moment of intertia. Rotating mass in a vehicle is more of a performance hinderance than non rotating mass because it takes more energy to get a rotating mass translating and rotating than to simply get a non-rotating mass translating. This obsession with rotating mass can be seen in all sort of design areas and many in cars. Engine designers are quite keen to lower rotating bodies mass and moment as well. Next thing about an objects moment of inertia is that it rises very quickly with its size - as the square of it's radius in fact (meaning double the radius = 4 times larger moment). These priciples explain the extra work brakes have to do in decelerating a vehicle as well as the hinderance larger wheels play in its acceleration.

The next area the heavier wheels (and tires) hurt you is in suspension performance. Anything that moves with the wheels is part of the vehicles so called "unspring weight". High unsprung weight is a huge detriment to vehicle suspension performance because all of that mass has a high inertia and can not respond as quickly nor as effectively to roadway force and profile inputs as a low mass/low inertia system.

OK, enough technical blah, blah, blah. Some pratical information: Wheel weight varies significantly by manufacturer and design. It is quite possible for a nice, weight consciously designed, forged 19" to be significantly lighter than a crappy 18". However again, apples to apples, with a similar design the 18 will be lighter and a lower moment of inertia.

Also to back up this claim I specifically remember an article that tested 18s vs. 19s on the M3 and they did measure better acceleration, braking and ride with the 18s.

Last but not least I personally can not stand how much the 18s pale in comparison in the looks department to the 19s, so I will comprimise. I'll go for 19s but will consider weight in my criteria. However, if I can't find a design I really like to look at I will also just eat the performance differences.

Hope that all helps.
What you said makes a lot sense intellectually, but consider this.

Since we all know RS is the performance version of standard Audi cars. And the CSL is the performance driven version of a standard M3. Why would BMW put 19" wheels on an M3 CSL if 18" wheels would perform better?
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      11-05-2007, 10:53 PM   #12
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cast or forged?

Does anyone know if the 19' and 18' wheels are cast or forged? Mine is 18' and a mechanic at a shop here says both weigh similar. He has already dealt with a few 92M3. Thanks.
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      11-06-2007, 09:30 AM   #13
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Does anyone know if the 19' and 18' wheels are cast or forged? Mine is 18' and a mechanic at a shop here says both weigh similar. He has already dealt with a few 92M3. Thanks.
"In the standard version, the cast 18" 'M' double spoke wheel (style 260) is available for the E92 M3, with the forged and polished 19" 'M' double-spoke wheel (style 220) available as an option. These are weight-optimized M3
light alloy wheels.

The tyres are also specifically selected for the M3. The Michelin Pilot Sport (PS2*) is currently fitted."

BMW Aftersales Training Information

So, yes, it is likely they weigh about the same, with the forged probably being stronger.
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      11-06-2007, 12:35 PM   #14
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Good question

Quote:
Originally Posted by K3N R3D View Post
What you said makes a lot sense intellectually, but consider this.

Since we all know RS is the performance version of standard Audi cars. And the CSL is the performance driven version of a standard M3. Why would BMW put 19" wheels on an M3 CSL if 18" wheels would perform better?
The only answer I can think of is perhaps the availability of the special tires used on the CSL. I guess it could be only a question of aesthetics as well. A small sacrifice in performance for those killer looks. south? enigma? any input?
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      11-06-2007, 05:22 PM   #15
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Quote:
Originally Posted by K3N R3D View Post
What you said makes a lot sense intellectually, but consider this.

Since we all know RS is the performance version of standard Audi cars. And the CSL is the performance driven version of a standard M3. Why would BMW put 19" wheels on an M3 CSL if 18" wheels would perform better?
Because far too many people like the 19" wheels (I don't) and the market demands them.
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      11-06-2007, 06:09 PM   #16
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Quote:
Originally Posted by K3N R3D View Post
What you said makes a lot sense intellectually, but consider this.

Since we all know RS is the performance version of standard Audi cars. And the CSL is the performance driven version of a standard M3. Why would BMW put 19" wheels on an M3 CSL if 18" wheels would perform better?
There is nothing wrong with 19" wheels but only if the car's suspension set-up was originally designed to run with said wheels. The reason why we are even having this debate is the fact that BMW decided to offer the M3 with two differing wheel size options and the reason is as goldminer said namely money, almost everyone will prefer the look of the 19" alloys on the car and are willing to for go a little of the balanced handling to have the looks. The kind of people who keep the standard rims are the kind who are only interested in the performance, the car could be made out of flower patterned Carbon Fibre and they wouldn't care less as long as it benefited the performance, same goes for the rims.

So what I am trying to say is you can only truly optimise a car for one wheel size, so this explains why the CSL was able to run 19" wheels and perform amazingly and yet in the M3 it always felt like a compromise.
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      11-06-2007, 07:04 PM   #17
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Quote:
Originally Posted by footie View Post
There is nothing wrong with 19" wheels but only if the car's suspension set-up was originally designed to run with said wheels. The reason why we are even having this debate is the fact that BMW decided to offer the M3 with two differing wheel size options and the reason is as goldminer said namely money, almost everyone will prefer the look of the 19" alloys on the car and are willing to for go a little of the balanced handling to have the looks. The kind of people who keep the standard rims are the kind who are only interested in the performance, the car could be made out of flower patterned Carbon Fibre and they wouldn't care less as long as it benefited the performance, same goes for the rims.

So what I am trying to say is you can only truly optimise a car for one wheel size, so this explains why the CSL was able to run 19" wheels and perform amazingly and yet in the M3 it always felt like a compromise.
The thing is 18" wheels are not an option on the M3 CSL. Only the 19" CSL wheels from BBS that we all know very well. And as far as I know, ( and I could be wrong) the Standard M3 was designed on 18" wheels.

Let's say the following statements are true. (18" wheels perform better than 19" wheels, and the CSL is the performance brand for BMW's M division. CSL owners are more interested in performance than standard M3 owners.)

If it were merely a matter of sacrificing aesthetics for performance, why not give the option for both?

I submit that there is always the exception in every case and I'm hardly an expert, but this one seems to fall right in that category.
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      11-06-2007, 09:36 PM   #18
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18s vs. 19s

Quote:
Originally Posted by K3N R3D View Post
What you said makes a lot sense intellectually, but consider this.

Since we all know RS is the performance version of standard Audi cars. And the CSL is the performance driven version of a standard M3. Why would BMW put 19" wheels on an M3 CSL if 18" wheels would perform better?
With ultra high performance tires, there is little difference between the handling potential of either 18s or 19s. The weight difference is negligible, as well, especially if, as on the E92, the larger wheels are forged. The larger wheels give more room for larger brakes. The smaller sizes have the advantage of a greater R-comp tire selection.
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      11-07-2007, 08:39 AM   #19
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Quote:
Originally Posted by K3N R3D View Post
The thing is 18" wheels are not an option on the M3 CSL. Only the 19" CSL wheels from BBS that we all know very well. And as far as I know, ( and I could be wrong) the Standard M3 was designed on 18" wheels.

Let's say the following statements are true. (18" wheels perform better than 19" wheels, and the CSL is the performance brand for BMW's M division. CSL owners are more interested in performance than standard M3 owners.)

If it were merely a matter of sacrificing aesthetics for performance, why not give the option for both?

I submit that there is always the exception in every case and I'm hardly an expert, but this one seems to fall right in that category.
Sorry mate, I think you didn't understand what I was meaning. Basically a car can only truly be set-up for one wheel/tyre size, the fact that BMW didn't offer any other option on the CSL proves as much. But in the standard M3 we were given a choice and because of this that is why we are debating the merits of each.
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      11-07-2007, 09:41 AM   #20
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Quote:
Originally Posted by GregW / Oregon View Post
"In the standard version, the cast 18" 'M' double spoke wheel (style 260) is available for the E92 M3, with the forged and polished 19" 'M' double-spoke wheel (style 220) available as an option. These are weight-optimized M3
light alloy wheels.

The tyres are also specifically selected for the M3. The Michelin Pilot Sport (PS2*) is currently fitted."

BMW Aftersales Training Information

So, yes, it is likely they weigh about the same, with the forged probably being stronger.
BMW has made a lot of hoopla over how light their wheels are.....I believe the 18s are around 20 lbs or slightly lighter.......yes, sick. Before this car the only really light weight wheels came from the aftermarket.

BTW: nice write-up swamp.
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      11-07-2007, 10:08 AM   #21
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Quote:
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BMW has made a lot of hoopla over how light their wheels are.....I believe the 18s are around 20 lbs or slightly lighter.......yes, sick. Before this car the only really light weight wheels came from the aftermarket.
I'd like to see confirmation of that. The 18s on the E46 M3 are 24 lb. front 26 lb. rear, if I remember correctly (or is it 26 & 28?).
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Last edited by GregW / Oregon; 11-07-2007 at 10:29 AM.
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      11-07-2007, 12:23 PM   #22
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I will never buy cast wheels, ever. New Orleans' shitty roads *demand* forged wheels. My E46 19" wheels have taken some serious abuse....
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