S-Prihadi

Hi All,

Just wanna share.

I decided to buy BBS CH-R Nurburgring Edition. https://bbs.com/en/products/performa...ition-engl.php
18" ET47, 8.5J all around, so can't do 9J rear like my current OEM staggered set up.
I choose ET47 to be as close as to original ET48 front and rear if non staggered set up. There is no 9J for 18" btw.

BBS website configurator showed I can choose ET47 as an E400 variant. So I assumed all cool.
The wheel is special order from Germany, not stocked at the local dealer. So it was air shipped yada yada.

To my suprise, my front brake caliper hit the spoke of the BBS...dang, how can having extra 1mm clearance and wheel still hit the brake caliper ?
Note for those who does not understand offset. ET48 vs ET47 means, an ET47 wheel/rim will poke out to to the fender or distance itself more from the strut by 1mm ( assuming both are 8.5J ).

The E400 344mm rotor and caliper is fat and protrude a lot above ( outward of ) wheel mounting point on hub/rotor.


So, in my case, the OEM wheel, AMG type by Ronald design the spoke as below :

The 2 red circles is the collision point of wheel to caliper

I hate needing spacer and changing OEM specs, but in this case I had no choice.
I simulated with rings for bolts to create a spacer like gap and got 5mm spacer as minimum and I will get 2.2ish millimeters of clearance of caliper towards the collosion zone with wheel spoke.
I called BBS dealer and Eibach dealer for 5mm spacer. No stock, need to air-freight in again....

So I made locally the 5mm spacer. The accuracy sucks in terms of even-ness of the thickness. 0.2mm was the tolerance, NOT ACCEPTABLE !!!

Red lines are where I measure. Numbers are all in millimeters.


Then come another problem. If I use spacer, I need extra long wheel bolts.
The included in the kit with centering adapter too, the BBS wheel bolt was 100% same thread engagement as the OEM one, but it is cone 60 degrees ( tapered )
and M14 x Pitch 1.5 is not common in my country and more so at 35mm thread length.
Call BBS dealer, got only 10 pcs because it was from a spacer kit. Not bad, still got 10 pcs chrome version, not black one.
Called Ray Engineering dealer, they got pitch M12 x pitch 1.25...bloody hell. At least I got their tire valves....
It is the number 49 https://www.rayswheels.co.jp/product...s=0&t=0&page=2
BBS does not supply air valves, they assume we owners get TMPS from our OEM. Its tire valve hole diameter is 11.4mm for your record.

OEM bolts compared to tapered ( 60* cone )



Rule of thumb ( with engineering calculation ), thread engagement for any bolts must be at least equal to its diameter to fully get the strength ( for steel )
So M14 = 14 millimeters thread engagement. Pitch 1.5 means 1.5mm. 14/1.5 = 9.3 turns of the thread/bolts.
https://www.nord-lock.com/insights/b...a-tapped-hole/

Do remember that measuring bolts protrusion length ( for thread engagement ) from a wheel/rim must take into consideration thickness of rotor material, because the female thread is at the hub only.


.


Centering bore is 66.4mm


Will continue...................

S-Prihadi

Not happy with the poor accuracy locally made spacer, I ordered 4 pcs from Eichback Poland/Europe because they can do international shipping.
Local Eibach dealer dont stock spacers, lots of spings though.

Finally landed in 7 days and 33% import taxed etc etc.

Germans are **** indeed. These spacers thickness accuracy tolerance is 0.05mm as worst case. Holy cow.

They even shank the bolt holes..... my my, what an art form this spacer is



The center bore of the spacer is damn accurate too as such I need to clear all micro rust on the hub centering bore and it fits so snugly, it will not spin out of position.
I marked all spacer position to find its 12 o'clock. The reason is for on-wheel balancing repeatability when I change wheel set to OEM-Ronald one for the fun at the track.




With the 5mm Eibach spacer, I get 2.29 millimeters clearance with confidence.



With 5mm spacer and ET47 wheel, a 6mm pops out compared to OEM ET48.



Will continue................

S-Prihadi

This time I experiment tire size for more comfort.
I could have choosen 245/40 at the back to be similar with the front, but I decided I want more side wall "meat" for rear tire.

OEM for rear was 265/35 which gave me 93mm side wall height, with 9J rim/wheel.
Front with 8.5J rim/wheel 245/40 got me 98mm.
So rear OEM was less "meat" compared to front.







Now with rear tire using 8.5J same as front, I decided to choose 255/40 to get 102mm side wall height, which should be more comfy for me.
So compared to OEM I am 11 millimeters taller rear tire now and 5mm taller compared to front tire.


255 is the suggested max limit for an 8.5J.
I think the side wall looks nicer, kinda flat and not donut shape like if a 245.





The OEM rims/wheels I will use for fun at the track only. I use this tire and stick to OEM size.
https://www.tyrereviews.co.uk/Tyre/G...AMPIRO-SX2.htm
This is low cost tire and local users claimed for its price it is very good. Let see at the track how it will do.
I totally don't mind if the dry traction is not as good as Michelin PS4 I am using, it will be more fun if I get to skid more

My OEM rims/wheels, 3 of them are already minor damaged. Not visible at all ....but when spinning at the balancing machine, to the trained eyes ( the tire shop guy ),
he pointed out to me that minor "deformation". I did not get to measure it using dial gauge, but indeed when spinning it can be seen.

I know where I got the wheels damaged.
This is Jakarta/Indonesia typical problem. Not only crappy roads, but all bridges joints will either sank or bulge.
Its low quality work and material and over loaded truck using the roads.
I hit this depression and humps only at 60 KM/H, but the right wheel sound ( louder than left wheel ) when impacting that hump is so METALLIC...



The pattern on the GT Radial Champiro SX2.



Now all wheels get marked for right side (2) and its 12 o'clock or ZERO position when re-installed. Since the on-wheel balancing ( some called it finishing balancing ) was done for best accuracy,
I practice this marking to ensure the wheels get back to original position in relation to the hub when I swap between the BBS and OEM set.
The reference is the small star/torx bolt on the rotor. Depending on which side of the car, it can be on the left or right side of the wheel bolt female thread.


.


For tire yellow and red dot info : https://www.yokohamatire.com/tires-1...match-mounting

For newbie who never seen on-wheel balancing/finishing balance, see below.
First the common OFF-WHEEL balancing is done, and then tire installled on the car and finishing balance performed.
Depending on which tire front or rear ( with differential ), the spinning is 1,200 RPM for front or approx 148 KM/H.
Rear is heavier to spin due to me using Quaife ABT differential. https://www.quaife.co.uk/quaife-prod...-differential/
Rear get 1,000 RPM or approx 121 KM/H.


Will continue.............

kajtek1

Long topic, so maybe I overlook it, but looks like your spacers lack center flange? It is crucial on MB to avoid vibration.
When it comes to wheels fitments - nominal sizes are just that - nominal.
Not only tires come with very loose tolerances and just becouse they have the same molded sizing, doesn't mean they measure the same, but as you experience the rims can have bigger or smaller ribs.
Years ago I had 2 sets of wheels for ML55. The same ET, the same tire width, yet 1 set would rub the fender under load, the other would not.
I finally got tape measure and the 1st set had tire crown full 10 mm wider than the 2nd, regardless same nominal size.

S-Prihadi

Hi K,

I don't need the center flange if for a 5mm spacer.
The rotor itself still has "enough" of the flange to zero-in by wheel/rim center bore adapter and wheel can stay put nice and accurate without bolts.




I have not measured the tire dimensions to the millimeters yet, but I tracked their out of balance-ness when new.
I got one tire of the Champiro SX2 265width, at insane 95 grams off for its outer side on the OEM wheel. I will try to measure its dimension against its opposite.

S-Prihadi

On-wheel finishing balancing is really good. It can balance all spinning components attached to the wheel.
Example brake rotor, bearing hub and for rear wheel drive car, rear wheel shaft + differential.

In the 80s, my 1983 MK2 Supra if not balanced on-wheel/finishing balancing, will have a very very slight wobble at 100 MPH / 160 KM/H.
This E400 so far okey without on-wheel balancing , but after I ruined the previous Michelin PS4 at the track, the rear tires which did not go bald had so much
"wear memory" on them from the track use, only on-wheel balancing can cure its vibration at 140-160 KM/H. However there was some tire noise which can not go away.
Its quite common for tires to have what I call "wear-memory" after say 10,000KM of use or hard use on the track.
Anyway, I threw away those rear tires and got the Champiro SX2 for the OEM wheels.

With 6mm protrusion (outward) of front wheel due to 5mm spacer and 1mm from offset, I was worried front tires could scrub the fender while in a tight corner and while cornering hard and with sudden braking/nose dip.
So I simulated the best I could with front tire being pushed up using jacks.
Being a macpherson strut system at the front, the outside tire get extra negative camber under heavy cornering load...so most likely tire will not scrub fender ( cross my fingers ).
Let see at the track next time.







End of Report.

nota_amg

Just curious and I mean no disrespect, but would it not have been less expensive, not to mention FASTER, to just shave/file down the brake calipers where the wheel was hitting them and then repaint/refinish them while they were still on the car???

S-Prihadi

Hi Nota,
No worry, that is a good conversation/thoughts.
The need to shave down will be approx 3.x millimeters minimum, that is a lot and it seems it is very close to the hydraulic fluid path region if not directly below the piston. It is very risky.