1M Wheels Weigh 26+lbs?!?!

[Papethova]

Originally Posted by marcel b

9 (front) and 10 (back) WIDE

I hope its now clear for EVERYONE

[neech]

Originally Posted by Papethova

THAT was my point... if 13s weigh 21lbs then 1M wheels (9s and 10s) shouldnt weigh more than that.

What 19"x13" rims do you have that weigh 21lbs? I would like to know!

Furthermore, these weights for OEM street car rims are not bad at all. BMW can't put pure racing wheels that will bend and crack in 40k miles and require a warranty replacement or even worse, a law suit. Even the OEM 350z Nismo "lightweight" rims by Rays engineering are 29 lbs for a 19x10.

[Papethova]

Originally Posted by neech

What 19"x13" rims do you have that weigh 21lbs? I would like to know!

Furthermore, these weights for OEM street car rims are not bad at all. BMW can't put pure racing wheels that will bend and crack in 40k miles and require a warranty replacement or even worse, a law suit. Even the OEM 350z Nismo "lightweight" rims by Rays engineering are 29 lbs for a 19x10.

Forgeline VR1 19X10 front 20lbs 19X13 rear 22lbs (sorry I was 1 pound off).
They are 1 piece forged wheels, IIRC with tires Im under 50lbs per wheel (I wanna say 45-46, I had written it down somewhere).

I have another set of wheels for my other car again 19X13 and those may have been the 21lbers. The car isnt housed here so I cant verify that.

[heli_ben]

Originally Posted by formula M

I will eventually replace my wheels, most likely go with Neez.

Wow - very nice!

[heli_ben]

Who here is a good enough driver to feel 5lbs a corner on unsprung mass? (on a car with street / road focused suspension)

[neech]

Originally Posted by heli_ben

Who here is a good enough driver to feel 5lbs a corner on unsprung mass? (on a car with street / road focused suspension)

Well the common thought is that (at least for handling) every pound of unsprung rotational mass you shave off is equivalent to 10x that in sprung weight. so 5lbsx4 cornersx10 = 200lbs in total chassis weight. Can you feel the difference around the road course between having a passenger or not?

Now imagine shaving off 10 lbs off each corner. Yes, wheel weight is a big deal.

Unsprung weight by itself (shocks, suspension components, brake calipers) is a 4x ratio IIRC.

[blueshark]

Originally Posted by neech

Well the common thought is that (at least for handling) every pound of unsprung rotational mass you shave off is equivalent to 10x that in sprung weight. so 5lbsx4 cornersx10 = 200lbs in total chassis weight. Can you feel the difference around the road course between having a passenger or not?

Now imagine shaving off 10 lbs off each corner. Yes, wheel weight is a big deal.

Unsprung weight by itself (shocks, suspension components, brake calipers) is a 4x ratio IIRC.

Interesting.. How does the math work?

[neech]

Originally Posted by blueshark

Interesting.. How does the math work?

Well i'm not sure where the 10x comes from but the general principal has to do with the moment of inertia (MOI) / angular momentum. MOI is the amount of force required to change the angular momentum of an object about a fixed axis, or change the axis of rotation. These are what "gyroscopic" forces are.
When you accelerate/brake/turn, not only are you changing the velocity of the wheel (as if it were in your trunk) but you must change the angular velocity AND also the axis of that velocity, which both require significant energy. Think about when you're holding a spinning bike wheel by the hub, how hard it is to change the orientation... And that's 3-4 pounds at a relatively slow angular velocity.. Now take 60 lb car wheel/tires, multiply that by 4 corners, at 20-100mph... That is a significant moment of inertia.

I think the 10x is a pretty rough guesstimate though, not sure where that came from.

[blueshark]

Makes sense.. Thanks.

[heli_ben]

Originally Posted by neech

Well the common thought is that (at least for handling) every pound of unsprung rotational mass you shave off is equivalent to 10x that in sprung weight. so 5lbsx4 cornersx10 = 200lbs in total chassis weight. Can you feel the difference around the road course between having a passenger or not?

Now imagine shaving off 10 lbs off each corner. Yes, wheel weight is a big deal.

Unsprung weight by itself (shocks, suspension components, brake calipers) is a 4x ratio IIRC.

I can certainly feel 200lbs. However we've changed rims on my race car with a similar %'age mass reduction and we couldn't really see it in laptimes, and I don't think I can feel it.

I don't think it's that simple.

For sure it's always good to cut mass wherever you can, especially in rotational and non-rotation un-sprung mass... but I think on a road car, it's primary use is in the bar, not on the track! :-)

[heli_ben]

Originally Posted by neech

Well i'm not sure where the 10x comes from but the general principal has to do with the moment of inertia (MOI) / angular momentum. MOI is the amount of force required to change the angular momentum of an object about a fixed axis, or change the axis of rotation. These are what "gyroscopic" forces are.
When you accelerate/brake/turn, not only are you changing the velocity of the wheel (as if it were in your trunk) but you must change the angular velocity AND also the axis of that velocity, which both require significant energy. Think about when you're holding a spinning bike wheel by the hub, how hard it is to change the orientation... And that's 3-4 pounds at a relatively slow angular velocity.. Now take 60 lb car wheel/tires, multiply that by 4 corners, at 20-100mph... That is a significant moment of inertia.

I think the 10x is a pretty rough guesstimate though, not sure where that came from.

For sure your theory is right... it would be good to know the real numbers! Test anyone :-)

[IS3andME]

Originally Posted by maxnix

Mackin imports Rays from Japan. Some BBS are made in Japan.

Forged wheels for the 1M should weigh no more than 20 21 lbs. BMW evidently just doesn't care. Well, at least there is an LSD.

Sorry that's what I meant. They import the wheels. 0-60 Magazine seems to really like the lightweight Advans, Yokohamas, and Volks.

Odd how the 18" G-Spyder rims from Lexus weigh 25 pounds, but look to be less. I've been searching for "Y" spoked rims that are similar to the Neez or BBS CSLs, but not CSL knockoffs...it is hard to find fitments in that design for the IS300.

[gatorfast]

People put way too much emphasis on wheel weights. Ive switched from "heavy" factory wheels to lighter after market wheels and noticed no difference.

[M3 Adjuster]

Originally Posted by Papethova

THAT was my point... if 19 x 13s weigh 21lbs then 1M wheels (19 x 9fronts s and 19 x 10 rears) shouldn't weigh more than that.

Two ridiculous statements. Show me the first 19x 10 wheel that weighs 21 pounds that also has a 4 year 50k mile warranty and also is TUV certified. Wheel standards are much more stringent in germany than in the US.

[Papethova]

Originally Posted by M3 Adjuster

Two ridiculous statements. Show me the first 19x 10 wheel that weighs 21 pounds that also has a 4 year 50k mile warranty and also is TUV certified. Wheel standards are much more stringent in germany than in the US.

I dont know anything about TUV certification, but the 18 inch version of that wheel was tracked regularly by many people in high HP applications.

[Papethova]

Originally Posted by formula M

Forgeline doesn't even list the wheels weight, I sent them an email.

The wheels have been discontinued, but there are old links stating the weight...

http://www.wheelkinetics.com/html/forgeline/

http://forums.viperclub.org/new-prod...lus-tires.html

Contact Forgeline on Monday, they have live chat on their site and Im sure they can verify the weight

AND no, I wasnt talking about Viper drag racing, but ya numerous people have dragged those wheels.

[M3 Adjuster]

Originally Posted by Papethova

I dont know anything about TUV certification, but the 18 inch version of that wheel was tracked regularly by many people in high HP applications.

A little bedtime reading for you.

http://www.kulchawheels.com/alloy_wh...n/standard.php

At any rate.. Neech said it exactly.. any wheel BMW puts on a car has to have a warranty behind it for 4/50K miles, and be subjected to all sorts of abuse, as well as pass more stringent specifcations than what an aftermarket supplier has to do. So it's really easy to see why going with super light wheel is NOT something a manufacturer is going to lose a lot of sleep over doing. If you feel the stockers aren't light enough, sell them and get an aftermarket wheel. These days, it seems like you can't find an E46 M3, E9x M3. or other cars like the Nissan 370Z with a set of stock wheels on them anyway since so many owners go aftermarket anyway.

[Papethova]

Originally Posted by M3 Adjuster

A little bedtime reading for you.

http://www.kulchawheels.com/alloy_wh...n/standard.php

At any rate.. Neech said it exactly.. any wheel BMW puts on a car has to have a warranty behind it for 4/50K miles, and be subjected to all sorts of abuse, as well as pass more stringent specifcations than what an aftermarket supplier has to do. So it's really easy to see why going with super light wheel is NOT something a manufacturer is going to lose a lot of sleep over doing. If you feel the stockers aren't light enough, sell them and get an aftermarket wheel. These days, it seems like you can't find an E46 M3, E9x M3. or other cars like the Nissan 370Z with a set of stock wheels on them anyway since so many owners go aftermarket anyway.

Thanks

[///1M]

So if the 19" 1M stock wheels are 26 lbs each, what's a good 18" lightweight alternative for the street?

[-Z-]

Style 219m is pretty good i have it for winter setup

[MightyMouseTech]

Originally Posted by neech

Personally i like some of the Enkei racing series rims.. Enkei has 2 lines, their "street" line which is your average ricer jap rim, then their "racing" line which is actually pretty good for the price.. The RPF1's are only in a 19" for 5x120 and weigh 21lbs for a 19x10, and are about $500 a rim which is a good deal. I know some guys personally which ran they as daily and never bent one. .

+1 recommendation on the RPF1's. They are a VERY common track wheel. I have had five sets of them for both my track car and my lapping/instructing car. Great bang for the buck.

On a side note, it is very cool when a truck shows up at your house and delivers a PALLET of rims...

[M3 Adjuster]

Originally Posted by ///1M

So if the 19" 1M stock wheels are 26 lbs each, what's a good 18" lightweight alternative for the street?

Apex Arc-8 and the Apex Ec-7 are a couple of light and strong 18" wheels. Check other threads for weights but I believe 18x10 is right at 20 lbs . They are both in high demand both new and used. There is a group by going on now for Ec-7 I believe.