Here are the specs...

2007 G35S sedan, Eibach pro kit with SPC rear camber kit.

I'm in the market for some OEM 19 inch G37S wheels and would like to pick up and install some spacers at the same time. I'm going for a super flush look with no tucking and no negative camber.

Most likely going with: 225/45/19 front & 245/40/19 rear.

I would love some recommendations on what millimeter spacer to go with. Also... what brands are best?

 

I would go with Ichiba V2 20mm allaround.

 

agreed

 

Hope u don't mindm me asking, but I heard some spacers are safer than others, can u tell me which I ones and why?

 

yeah 20 should be good

 

There's quite a bit of debate on this topic as the term "SAFE" means different things to different people. If you do some reading/research about increased shear stresses on wheel studs caused by a second "slip plane", you'll get an idea why you should care. Personally, I would not run spacers; if I absolutely had to, I would ONLY use a bolt on, hubcentric, wheel adapter type spacer with a minimum thickness of around 18-20mm. With few exceptions, for anything less than that, you're compromising the bolt attachment to your hubs. Obviously, going too much thicker than that has it's problems too, but they are more in line with the types of suspension stresses you get from improper wheel offsets in general and NOT just wheel stud specific. Here's a link for a typical of the type I'm referring to: http://www.motorsport-tech.com/wheel_adapters.html

I know it's a purist attitude, and I'll get heat on this from many people who have run spacers before without problems, but your best bet is to simply get wheels that fit.

.02

 

Thanks for the suggestions guys. I was also thinking of going with 20mm at all four corners. I'll probably put the new wheels on to see how it handles and looks then make my decision.

All at the same time spacers do make me a little nervous. Just like vqsmile noted... they can increase stress and as Eug96 posted yesterday... his broke! That's not something you want to mess with.

 

Thread from the dead, but i'd prefer not to make my own thread for a small topic.

I'm planning to get dropped on BC Racing BR + SPC full camber kit. Planning to run OEM sport wheels 225/245 stock setup. I want a flush look to it, any recomendations?

 

I'm running KW Var3 with SPC Camber kit with 18" Sport wheels. I'm running 235/255 tho, with 15mm front, and 20mm rear. Try looking into going 235/255 as well, instead of 225/245.

 

Mmmn, I'm not following this. Why are 20mm the ideal size? Wouldn't 15mm be "safer" since you are extending the rim out less. I thought the more aggressive the size the higher chance of problems?

When you say bolt on you mean the ones with out built in studs correct?

 

Edit: NO, by 'bolt on', I do mean the ones with their own (secondary) studs. I would NEVER use a simple "spacer" (because of the added slip plane), ONLY a "wheel adapter" type.

It is my understanding that the 20mm thickness allows at least two or three advantages: first, it allows for a full, uncompromised lugnut attachment to the hub (ie. no special low-profile nuts and funky socket to tighten them), second, better chance of the stock studs fitting behind the wheels without needing to be ground down or requiring wheels with cutouts on the backside, and lastly, greater depth for anchoring of the secondary studs securely into the spacer itself (remember, the spacer is aluminum, not iron like the hub).

I initially had the same impression you've mentioned, that 15 seems inherently "safer" than 20, but after reading up and looking at various makes and speaking with a reputable custom spacer manufacturer, I came to the understanding that there is actually a bit of a "sweet spot" to be had at around 18-20, where it's considered as strong as possible for a spacer, yet without extending any further than is necessary for that maximum strength. This of course, gives deference to the physical attachment strength and reliability of the wheel/spacer to the hub as being of primary concern, and not to that of the wheel bearings/ suspension/etc. that are also affected by the stress loads introduced by spacing the wheels.

 

Ahh I see. Well based on that rationale... 20mm bolt on spacers might even be safer than a spacer that uses the original stud or extended stud to mount the wheel. Since now there is additional "space" between where stud meets the wheel and where the stud meets the hub.

 

It's not a question of "might even be", it's pure physics. Any engineer can attest to the principles involved.

For your reference, and if you can stand the tech speak, here's an article I found fairly concise on the subject of adding a second shear/slip plane causing stresses on the wheel studs.

http://realbig.com/detomaso/1998-11/53.html

 

What if the wheel doesn't sit properly because of that type of spacer? Wouldn't the extended studs be a safer direction to go?

 

That's a bit of an absurd question though; of course a setup that would at least bolt down properly is safer than one that wouldn't even sit flat. But that really assumes that the wheels you have are the only possible wheels that can be used. A different set of wheels (with reliefs if need be) used with a bolt-on spacer is still better than extended studs with a free floating spacer. As I said before, I recognize that I am a purist about this, and I know people can and do "get away" with using those other spacers all the time; I'm just saying it isn't right and there is a distinct structural difference.