so...what is an acceptable rim runout?

[3Q Jay]

my 'new' 18X8 +40's from an 03 FX35.all 4 measure between 0.006" and 0.008" radial.

baseline LF rotor hat was 0.0015 pre-wire brush, and <0.001 post wire brush. obviously, indexing does not appreciably change the runout and the inboard/outboard bead lips read about the same (rim is parallel) with the same inboard/outboard extrema following the rim as it indexes. This is without tires.planning to run either 235/45 or 245/40 if it matters.

[Q45tech]

After runout measurements put the wheel on a balance machine without tire and set to FINE RESOLUTION...........treat [select on balancer] the wheel like it has inner and outer channels for clip on weights.

No more than 5 grams inside and 10 grams outside to balance the wheel to 0.0/0.0 grams...................a very tough spec.

[3Q Jay]

thanks, tech for the reply. Please help me understand- besides less balance weight being better (intuitive), are you saying that the rims are no good if they dont meet the 5, 10gram? it sounds like you are not fussed by the runout as stated, as long as the balance is close.one other point--i agree it would be nice to know what the rim balance is all by itself, but if the whole rim/tire assy gets radial balanced on a hunter 97xx, is the rim really significant by itself?

[maxnix]

if the whole rim/tire assy gets radial balanced on a hunter 97xx, is the rim really significant by itself?

Yes, because it is your base. If it is off, even a Michelin won't help.

I am sure you know your tire sizes are a little short. There are some very good 245/45-18 our there with 100 load rating.

[szh]

I am sure you know your tire sizes are a little short. There are some very good 245/45-18 our there with 100 load rating.

Yup!

And, I would not recommend being short in this area of tire load index.

Z

[3Q Jay]

thanks for the replies. i'm now leaning toward the 245/45, but the 235/45 is not 'short' at 26.3 compared to factory 215/65/15 at 26.0-26.1 why would you two assume i'm skimping on load index? 235/45/18 come in 98w (csc2's and ecsta spt)ps2's in 245/40 come in 97y (if you ask for it).factory was 95v, so that is my minimum criterion.

i'm liking the zro nero in 245/45 with a 96w--but $1000 out the door--sheesh.btw--i'm not finding ps2 in 245/45/18

[maxnix]

1.) thanks for the replies. i'm now leaning toward the 245/45, but the 235/45 is not 'short' at 26.3 compared to factory 215/65/15 at 26.0-26.1 2.) why would you two assume i'm skimping on load index? 235/45/18 come in 98w (csc2's and ecsta spt)ps2's in 245/40 come in 97y (if you ask for it).factory was 95v, so that is my minimum criterion.

3.) i'm liking the zero nero in 245/45 with a 96w--but $1000 out the door--sheesh.

4.) btw--i'm not finding ps2 in 245/45/18

1.) Either should work, but I would still do the 245/45

2.) There are definitely benefits in performance and wear by maximizing the load index. REad Q45tech's posts on slip angles. Also on Kumhos. Don't know what CSC are.

3.) Zero Nero is good, but look at the top Goodyears that z likes. For a good 18" tire, you will have to pay.

4.) PS2 is 255/40-18 99Y, about $265 ea. from Costco, a little more from TR. AZhitman had the same size Rosso Asymmetrico on 18x8, but I think an inch in from vertical on that short a profile is not optimal for sidewall flex and bead seating angle.

Don't go cheap, unless you wnat to spend twice when the tire wears out prematurely or fails you in a critiacal situation, or is just a plain POS while driving and to balance.
Modified by maxnix at 6:34 AM 5/19/2006

[3Q Jay]

went to Zuby's today to have the bare rims checked for balance on their hunter 9712.

they repeated my radial and lateral runout measurements within 0.002 on each of the 8 measurements--so i thought that was valid.

none of the 4 rims meet Q45tech's stated criteria (no surprise to me really).two are close: the best was 0.0 oz inner and 0.75 oz. outer (about 21 grams). next best was 0 inner and 1.50 oz outer. third was 0.75 inner and 2.50 outer. worst was 3.75 inner and 4.50 outer. this particular rim is not the worst in terms of lateral or radial runout. the balance weight locations are 180° out, and i noted while spinning that the inner spoke machining surfaces 'wobbled' (but not the bead seats).

so there it is facts and data. makes me feel good that rims are not bent. will buy tires and have force matched and see what we see.

side note for any OC, CA locals--Zuby's is the right place to go. he noted immediately my car was an 'a' and asked about the active suspension. he also showed me that pict of another Q45 with the rotor problem (Q45 forum on 'abused Q').

[maxnix]

Interesteing Jay. That last one sounds like a real loser.

Can't quite understand how the rim can be true on the one with the wavy spokes.

[Q45tech]

A smart technologists would grind [safely] the balance pads on the wheels to bring them into perfection......assumming they are radially and axially true and close in balance .........say 1 ONE OUNCE.

BUYING AN OUT OF BALANCE WHEEL IS A SERIOUS ERROR.....you can pay $150 each to get them straigthened but be sure to test them after the proceedure because most people are not very demanding or smart enough to test their work quality.

Typical street is ounces, in NASCAR and Formula they speak in single GRAMS

[Q45tech]

People complain about VIBRATIONS and little do they know they bought and paid for the added vibrations..............chromed wheels are the ABSOLUTE WORST THING ever sold to a vehicle owner.