James R.

Well guys / gals...it's been a tough two weeks...I've gone back and forth on what new wheels I wanted...as a result of all my indecision I've ended up with 3 sets of wheels. I'm out a sizeable chunk of money in shipping and handling...re-stock fees and the like. I figure...when life hands you lemons, you make lemonade. Soo for the benefit of all Audiworld patrons I found an opportunity to pull something good out of all this. An objective comparison of these three wheels in the area of weight...claimed Vs measured, as you will see these two values don't even come close to what most people claim their wheels weigh...with the exception of ONE...the PES Gran Prix. Tony of PES said it weighs about 21 lbs...and it does. The BBS CH is not CH for Challenge...but rather CHunky. And the Oettinger RE long criticized for needing to lose a few pounds proves that old adage, "Don't believe the HYPE!!!"

<img src="http://pictureposter.audiworld.com/227/thefamily.jpg">

First for the test equipment...we have the trusty postal scale, calibrated on a regular basis...and intrinsically temperature compensated by design. Capable of measuring up to 100 lbs in 4oz increments...

<img src="http://pictureposter.audiworld.com/227/thetestrig.jpg">

Ok...first wheels to hit the ol' scale, the PES Gran Prix hailing from www.pes-tuning.com coming it at a price of $315 and with a claimed weight of 21 lbs...18x8 ET35

<img src="http://pictureposter.audiworld.com/227/pesscale1.jpg">

Let's take a closer look at the weigh in...looks like this wheel is fighting in the right weight class per the manufacturer claims. Just a shade over 21 lbs...possibly attributable to scale error...or this is in fact what the wheel weighs. Point is it's very close to claimed weight...

<img src="http://pictureposter.audiworld.com/227/pesscale2.jpg">

Next contender to step up to the plate...the vaunted BBS CH the biggest hoax of a lightweight wheel ever. Hailing from Germany...made by BBS measuring in at 18x8.5 ET35 with a frequently quoted weight of 22 lbs...sometimes 23. Sir would you please step onto the scale ;-)

<img src="http://pictureposter.audiworld.com/227/bbschscale1.jpg">

Ohhh nooo it seems someone has been fibbin' about their weight...looks like the BBS CHunky are not in fact, "light weight" wheels after all...see below, they tip the scales at a svelte hair under 26 lbs.

<img src="http://pictureposter.audiworld.com/227/bbschscale2.jpg">

Next up we have the Oettinger RE...a wheel hailing from Germany measuring in at 18x8 ET35 with an average claimed weight of 25 lbs. Again another wheel which was within a pound of claimed fighting weight ;-)

<img src="http://pictureposter.audiworld.com/227/oettrescale1.jpg">

Let's take a closer look...my lord it's freaking uncanny...the CH and the RE appear to have been separated at birth, yet they look so much different. Turns out these two wheels are within oz's of each other...there's no longer anymore excuse not to run the Oetts than there is to run the CH...because the CH light weight claim is a FARSE.

<img src="http://pictureposter.audiworld.com/227/oettrescale2.jpg">

Now for those doubters...yes I can't verify the accuracy of the scale in the absolute sense. Though I did back to back weigh items on our Digital Pitney Bowes postal scale which can read up to 6 lbs...as follows X lbs. XX.XX oz it's pretty precise...and what I measure there jives with the old school mechanical scale.

What I can prove is that the scale has high intrinsic linearity. What this means is...if you had say 5 things which in total weighed 100 lbs...and you put them on the scale and it read 200 lbs (which is off by a factor of 2:1) As you removed them...4 items on scale reads 160 lbs...3 items on scale measures 120 lbs...2 items on scale measures 80 lbs...one item on scale measures 40 lbs. The idea being that the scale indicates...despite having an absolute error that is it linear...each item which is known to have 20% of the total weigh results in a 20% change in reading when it's added to or removed from the scale.

Paper is a tightly controlled product and works well to illustrate this concept...I have many more data points...but I'll show you two.

<img src="http://pictureposter.audiworld.com/227/inlstack4far.jpg">
<img src="http://pictureposter.audiworld.com/227/inlstack4near.jpg">

You'll notice that 4 reams of paper weigh an indicated 20 lbs 8 Oz...

Next we cut this down to 2 reams...we expect if the scale is linear...aka not accurate in absolute terms...but linear as described above the scale should measure 10 lbs 4 oz...

<img src="http://pictureposter.audiworld.com/227/inlstack2far.jpg">
<img src="http://pictureposter.audiworld.com/227/inlstack2near.jpg">

My lord...it's nearly spot on. This proves the scale is linear...and therefore TOTALLY reliable for relative comparisons of weight. The absolute values you can argue all you want (despite my digital scale Vs analog scale test proving at least to me that the analog scale is in fact accurate) but I can safely say Rim X weighs more than or less than or the same as Rim Y etc. If one person can use a more accurate scale to measure ONE of these wheels we can calculate the precise weight using these measurements with an error scale factor.

So all this goes to show...people believe what they want to believe even if it's not true. Or that too many people are operating with no application of or respect for basic scientific principles...they take measurements for granted...esp if they're in their own favor.

So in light (pardon the pun) of these findings...I encourage anyone who was afraid to buy the Oettinger RE wheels...cause you thought the CH would be SOOOOOOO much lighter and have SOOOOOO much less rotational inertia...don't worry, buy away...it's every bit as heavy as the BBS CHunky ;-) This pushes home the idea that what's good for the rigors of the street probably aren't fit for the track...light wheels...esp cast ones give up strength in exchange for weight (unless exotic treatments are applied...heat and chemical). What looks good...may not weigh what you want.

Wheels for street and wheels for track...I think that's what I'm going to do. In the mean time I'm going to enjoy my new 18 Oettingers and my newfound brake clearance ;-)

For those of you interested in the RE DTM Autohaus has an excellent deal running on them right now...give em a ring...

If you're looking for a set of BBS CH give me a ring...I'm blowing them out at a ridiculous price.

Regards,

"so you're foofighter"

Great work there James...I personally still like the CH's but the PES wheels are growing on me!

GPO - Needs a car!

I'm not flaming you but damn if you aren't crazy to do this!

CMC

What are you doing with the PES wheels?

BiZzAro ThAi

can you weight some SSR comps for me ? )

James R.

Got the PES wheel..love the weight, but had an issue or two which I didn't approve of.

Got the CH...then realized that I don't want to roll my fenders...and I hate the idea of rubbing...so they must go.

Got the RE and I'm sticking with it...and now I don't feel so bad knowing the CH was just as fat a pig as the RE.

Yes it was expensive...I just hope every one can learn from the stuff I post here ;-)

Regards,

James R.

BTW - Thanks for the compliment...uhh I think.

James R.

;-) before they hit my pocket book. I ordered enuf wheels...time for someone else to pay...ahem.

Regards,

James R.

James R.

But do it soon...cause they're going back tomorrow...the PES that is. I'm stuck with the CH's methinks, but they should be easy enough to unload for $350 a wheel...when T-Rack is sellin' them for $415 a wheel.

Regards,

James R.

CMC

Oh yeah, have you decided on tires yet?

CMC

May I ask what "issues" did you have with the PES wheels?