I think you will have to figure that out with either a calculator, a ruler or a test fit.

 

anyone can guide me picking a set of spacer?
my z running 19" 9.5 +15 and 10.5 +15 Gnosis GS4
now i want to put a spacer to flush them.
8mm front and 15mm at the back.
was going to get Project kics.

but seem like 15mm project kics hub size is diff to 350z's hub(66.1mm)?
i see sponsor shop have a option for getting kics hub ring.
but other brand like Ichiba V2 (66.2mm?)or H&R doesnt (66.1mm?) seem to have rings for 350z.

so is it better to get spacer that have perfect hub size? rather than spacer + hub ring?
but i kind of like the look on the edge of project kics.
anyone can give me an idea what to pick? depend on quality? fitment?

 

Buy hub centric. Project kics and h&r are good brands. I wouldnt trust ichiba personally.

Inb4lock/merge

 

9.5 and 10.5 +15 your already flush, actually your wheels stick out. Look into Z1 motorsports spacers, they are high quality billet and are available with APR studs. Much better than the GayDM Kics crap.

 

yea, i found a few broken stud report for ichiba ...
i rolled my fender and pulled abit, so it is not flush now.

whats the main purpose for hub centric?
my frd is using project kics on his G, but didnt use hub centric
he said u dont really need one

 

Read/search here, your question can be answered probably in the first few posts

I'm not sure why you want a spacer at +15 though, you're already plenty aggressive?

 

I am of the opinion that hub centric spacers are snake oil. If the wheel is not centered properly on 5 properly torqued studs/lug nuts then a plastic or aluminum ring really isn't going to matter much. I do think you need to be careful when your torque the lug nuts being careful to do them incrementally and in the right order.

The other side of the argument is that the rings are cheap so why not. And that's a good enough argument. However I've seen several sites/makers that want $35 for four plastic rings. And that is just idiotic. They should bundle them with grounding kits and charge double for both.

 

My back wheel



closer look



it has about 20mm gap(back wheel) and 15mm gap(front) between the inside of fender to tires

 

Logic dictates that you would want a 20mm spacer in the rear and a 15mm spacer in the front. You may want to check my math on that however.

 

cant 100% tell by the angle, but I think Itll look terrible with a spacer, dont do it. Go lower or get a fatter tire if you dont want the gap.

 

if 15mm and 20mm, tires will touching fender , and i got vinyl wrap on it.

 

anybody know the answer to this question?

 

Yes

 

no

 

Actually your missing the main part of being hub centric. The load from the wheel is actually on the hub, not the 5 studs. The hub is designed to take a lot more force than the stud can. When properly setup, the only thing the studs to is hold the wheel on.

 

If that is the case then the hub centric rings that are available make no sense. Most, if not all of the ones I have seen are made of polycarbonate or cheap aluminum. Neither of these is strong enough to withstand distortion even from the forces exerted by the pressure of the lug nuts, much less the horizonatal and vertical forces transmitted through the wheel itself. The hub is made of steel. The polycarbonate rings I have can be distorted just by squeezing them with your hand. How are they supposed to support the wheel and all the huge forces transmitted through it (as in hitting a bump at speed)?

And, the studs have to withstand rotational (acceleration/braking) and angular forces (cornering) whether the wheel is hub centric or not. So the studs do a lot more than just holding the wheel against the hub.

Granted, the factory studs can fail under track (and even street) stress....but they fail even on the OEM wheels.

Probably a good set of studs (ARP) to go with the aftermarket rims is more important than rings. Just a guess.

 

Your definatly not an engineer. So they distort in you hand, slide it over the hub and see how much you can distort it, push it into the wheel and see how easy is is to distort, put it inbetween the wheel and hub and see how much you can distort it.

Rotational force is nothing compaired to sharp impact. Rotational force is also reduced on studs from the friction of the wheel to hub face. You get that friction when the studs are tightned. (some drag stuff is a different story)

BTW the ring are made out of the same stuff most newer guns are made of, its not weak crap.

 

Correct.

Of course I can't make it distort with my hand while its on the hub or the wheel. The forces the car will exert on the ring will obviously be greater than what I can apply.

Right, but it is not insignificant. The forces are still quite large, especially when you take braking into account.

Yep, and that same friction applies to all other forces applied to the wheel/hub.

Polycarbonate is a great material. Not arguing that. I'm just skeptical that in this application it really does what some folks claim that it does.

But, as I mentioned before, they cost $10 so there isn't much reason not to use them. And if they are as critical as you suggest, folks who chose not to use them will pay the price with broken studs and wobbly wheels.

 

Even with careful hand torquing in a star pattern, I still had some wheel vibration at 75-80 mph. Purchased some aluminum rings and it solved my problem. Also gave me some peace of mind when others are putting my wheels back on, that they are centered correctly.

 

Where did you take your materials science and statics/dynamics courses? Just wondering.