jdmspoonitr

iTrader: (1)

Hello,

Well after testing my new wheels out last night 15x8 +45 TE37's I was surprised to see that I needed spacers up front as well as in the rear. In the front it looks like I need 5mm to clear the piston bulges on my spoon calipers and in the rear I need 5mm to have the tire clear the trailing arm.

I am wondering if anyone has used motorsport-tech.com to make custom spacers. Pretty pricey at $180 for four, but I am wondering if it is worth it.

Currently I have two 5mm H&R spacers that I have used on the stock ITR wheels to clear the spoon calipers and have been running those on stock studs perfectly fine. But I am wondering if a 5mm spacer that is hub centric like the H&R and wheel centric (basically an integrated hub centric ring on a spacer so that the wheels are on center) would be a good idea?

This is on stock studs for now, and I think I have to also consider the wheel being thicker than the stock ITR wheel as well. I have heard anything from 4-6 full turns or that the threaded lug should be threaded down the stud at least as far as the diameter of the stud itself. I want to hear it from guys that actually track their car with spacers, rather than the folks doing it to have their wheels sticking out on the street.


Best regards,

Ken

solo-x

Hub centric spacers are not needed. Just grab another pair of standard 5mm spacers and you're set. I think I actually have an extra set of 4 H&R spacers if you're interested. PM me if you are.

JBrettHowell

I disagree. You won't die (probably) and your car will not explode without hubcentric spacers, but at triple digit speeds the balance of the wheels is extremely important, and a very slight skew can produce tremendous unbalanced force at those speeds. Moreover, the lug studs are not designed to carry the shearing load of the wheel, which is what they are doing when you are using wheels that are not hubcentric. Will the proposed setup work? Yes, and probably for a good while, but over time you will be fatiguing the studs and running the risk of the wheel being out of balance.

That being said, people do it all the time and very rarely do you hear of a failure. Over engineered lug studs FTW.

Also, the rule of thumb is that you should engage as much of the threads as the stud is wide. 4 turns may be pushing it. 6 is probably pretty good, but why not just replace the studs with longer ones (and potentially stronger, like from ARP)?

slammed_93_hatch

Not true.

The force/friction of the back of the wheel to the rotor which is then touching the hub is what actually carries all of the load.

The hub-centric/circle part doesn't carry any load, and it doesn't even center the wheel.

The lug nuts center the wheel.

JBrettHowell

Um, no, but it's your ***.

DB2-R81

Quit posting story tales you are wrong, lug studs do not carry the shearing load of the wheel!!!!

Thank you, slammed_93_hatch!

Johnny Mac

Jimmy is correct.

The stud hole diamter in the wheel is slightly over-sized compared to the studs by approximately 1.0 mm. When you torque down the wheel, the stud is now centered in the wheel with approximately .5 mm gap between hole and stud with the conical taper of the lugnut/wheel effectively centering the wheel. Now, because there is considerably friction between wheel and the brake rotor with or without a wheel spacer(s), the wheel studs will not see ANY shear loads. However, if the lug nuts are not torqued properly and the torque acting on the wheel from braking or acceleration exceeds the friction torque, then the wheel will slide on the brake rotor/wheel spacer and now the wheel studs will be in shear and in bending moment. And anyone who knows about threaded fasteners knows that the threaded portion of any stud, bolt, or screw should never be subjected to shear or bending unless a large safety factor of design is used - and even then, this should only be done when there isn't any other way to design this bolted joint.

jdmspoonitr

iTrader: (1)

Well for the front I have used 5mm H&R Trak spacers, which center on the hub, but there is no protruding piece that actually centers the wheel on the spacer and the 5mm spacer makes it so that the OEM hub does not stick out far enough to center the wheel either, so I am relying all on the lugs to center the wheel. I have never had a problem, but if a better alternative (a spacer that is hub centric and also will center the wheels) then maybe it would be an added layer of safety?

Here are the two options:

(1) Hub Centric to Vehicle Hub --> This is what the H&R are
This is a flat spacer that fits perfectly tight on the hub.

(2) Hub Centric to Vehicle and Wheel Centric to Wheel
Fits hub perfectly tight and, where wheel bolts to adapter, a custom machined adapter lip fits perfectly tight into wheel's center hole. This extra measure positively influences the ride and kills vibration. Highly recommended for newer vehicles and those which will be used for towing. ---> Now these are something I have not seen in a 5mm spacer and maybe they don't even exist.

solo-x

Like I said, hub centric spacers are not needed for the reasons J-Mac and Jimmy posted.

nsxtasy

I have never heard anyone claim that 4 full turns was sufficient. I have heard a lot of people claim 6 full turns and a lot of others claim 7 full turns.

JBrettHowell

One of several sources that support my statement. I guess all of them, the manufacturers of hub-centric wheels, centering rings, and myself are all wrong. Where you are wrong and I am right is when the wheel face does not contact the hub face perfectly flat (due to surface rust or dirt) and the lug studs start carrying the shear load. The problem is it is very difficult to see with the naked eye if the fit is not perfectly flat. Now you have an unbalanced wheel and the studs are carrying the shear load. This may not result in an immediate failure, but it does start fatiguing the studs.

Ever have a wheel come off at 110 mph? I have not but I have witnessed it happening to a friend. It is a brown short moment to be sure.

It's your ***. Put as much emphasis on avoiding catastrophic failure as you feel is appropriate, but don't tell me I'm wrong without offering proof to back up your claim. That's just rude.

Stinkycheezmonky

Not that I'm necessarily starting beef here, but was there a way to verify his lugs were properly torqued prior to the incident? I'm assuming it was the studs that failed (and not the hub) since you posted it in this discussion.

JBrettHowell

During a later course walk We found 2 of the 4 lug nuts with the studs still in them (never found the other 2), and they sheared off even with the hub, and no wear on the wheel at the lug holes. Not conclusive proof, but we found a crack in one of the other studs on the other front corner, and these were ARP studs that were less than a year old, and the lugs nuts on that corner were tight. He did notice a vibration at about the point he crossed under the starter's stand at Mid Ohio and it let loose as he was braking for the turn at the end of the straight (is that turn 1 - never can keep that straight in my head since the start and finish lines are at different places on that track).

From my first post in this thread I have said that using lugcentricity to center a wheel does not mean the studs will fail, but if the wheel and hub surface aren't nearly perfectly smooth, it can lead to forces on the studs that they are not designed to take.

Believe this or consider it an urban myth, that's your choice.

FWIW, my autocross wheels are not hubcentric, but I keep a close eye on the status of the studs, clean the wheel and hub mating surface diligently, and assume that even if a wheel were to come off, at autox speeds it would not be nearly as big of a deal as it would heading through turn 12 at Road Atlanta.

That is all.

Johnny Mac

Sorry to inform you, but the hub centric ring will have no effect if the mating surfaces aren't perfectly flat. How can they? Remember, the load from the preloaded wheel studs acts predominately at the wheel face in the vicinity of the holes in the wheel. So, the compressive stress in the wheel and by virtue of Newton's Third law at the mating surface of the brake rotor/wheel spacer is a maximum right adjacent to the stud and then this compressive stress in the wheel mounting face decreases as you move away from the stud holes. The hub centric ring face, which is often plastic - or even if it is aluminum must not protrude out from the recess in the wheel to actually contact the brake rotor/wheel spacer. All the hub centric ring does is to help centrally locate the wheel before the lug nuts are tightened. That is it. You don't have to believe me but I've done my share of bolted joint engineering and fatigue testing of critical helicopter parts to fully understand what is physically happening at the wheel/hub interface of automobiles.

Oh, and giving us information printed in Modified Magazine doesn't make it correct.

And by stating that your friend lost a wheel at 110mph proves absolutely nothing. I had a wheel come loose on a racecar that I rented for my SCCA Super school because the hub failed which had nothing to do with studs. I believe you are misinformed and do not understand this topic very well. Nor do you seem to learn from what has been discussed on the basics in engineering that are at work with regard to lug nuts/studs wheel spacers, ect.

It's my *** and I can feel confident in my non-hub centric wheels with wheel spacers and rust on the rotors and aluminum lug nuts on my race car and they have been just fine.

beanbag

As has been mentioned earlier, the interface between the wheel (+ spacer) and rotor carries much of this shear stress. That's because, the forces pushing these surfaces together come from 4 or 5 lug nuts tightened to 120 ft lbs, plus the helix angle of the threads, leads to a... ummm... very large, but calculable force between these surfaces. Then times some reasonable coefficient of friction, and you get a very large number for the force that it would take to make this junction slip. I think the short answer is that it won't. Further, this junction has a higher stiffness than the sideways flex of the wheels studs, so when combined as a system, the stiffer junction will take the majority of the load.

There are two types of forces that cause shear stress (pushing sideways) on the wheel studs. One is the wheel trying to get pushed off center (as when landing after catching some big air) and the other is rotational, from the monster torque that your 4 cyl engine generates. Since the hub centering is not a press fit, it can't counteract either of these types of forces. Unless you have really loose lug nuts and land after doing a really big jump, then the hub centering will slip a fraction of a mm and then stop. Hurray, you've been saved!

Whether the mounting surface is perfectly flat or clean is not a big issue, since the frictional force will be comparable, albeit the stiffness may be a touch lower. That is,
unless the dirt that you are referring to is a couple of ball bearings and grease.

The main benefit I see to a hub centering setup is that it makes it less likely to tighten the wheel on crooked, thus pre-stressing the studs. Thus, do not have the weight of the car on the wheel while you are tightening the nuts.

Anyway, I just made all of this up right now. I've never worked in a helicopter factory, so I have no direct experience with bolted junctions.

Johnny Mac

Actually, for most applications the lug nut torque spec. is 80-85 ft-lbs. not 120 ft-lbs.

descartesfool

I've been running wheels with and without spacers on my turbo ITR on track for years and years without any of those pesky wanna-fall-out hub-centric rings on OEM and H&R studs and have never had an issue due to not having hub-centric rings installed.

However I ordered a set of new Team Dynamics wheels and had them custom bore them to the correct hub size and add some steel inserts in the stud holes, since that makes for easier and faster installation, with less galling of the aluminum around the wheel nut faces. As for rusted hubs, that is a no-no in terms of minimizing vibration, so I always keep hubs and disk and wheel faces clean, as much as reasonable.

So what is the force a clamped wheel to hub joint can take based on a bolt torque of 80 lbs and 5 studs? At very low wheel nut torques, most of the force is taken in bending of the studs from the wheel surface pushing on the wheel nuts. Then the more you clamp by increasing nut torque, the higher the frictional force, until at some point, forces are equal, and after that the frictional force becomes the dominant component. A big truck or bus uses much, much higher wheel stud torques and many more studs.

Some good info here in MIL-HDBK-60 on fasteners and torques: http://www.mechanicsupport.com/manuals/mil-hdbk-60.pdf

Stinkycheezmonky

<--- Accidentally torqued mine to probably ~120 ft-lbs recently (turns out my torque wrench is busted), broke a goddamn lugnut in half when I tried to loosen it. Getting the still-stuck half off was not fun.

jdmspoonitr

iTrader: (1)

I was about to say here...uhhh 120ft lbs is alot LOL. It turns out with the wheel I am running it is very borderline as far as how far down the thread the lug is going. It is barely the same distance as the diameter of the stud and that worries me. I will be looking at installing TL studs which are about 0.375" longer.

Stinkycheezmonky

If you're going with TL studs, might as well go ARP.

solo-x

ARP are overkill and $$$$. I've done longer studs on both my civic and my ITR and finding a slightly longer OEM stud got me extended studs for under $15 vs. over $100 for the ARP bits.

Stinkycheezmonky

I sure didn't spend $100 on ARP doodles... It wasn't $15 (closer to $40-50), but for the spacers/wheels I was using at the time, the TL was pushing it for not being long enough. Now it wouldn't matter, of course

Atmosfear

iTrader: (18)

Same here. I just bought a set of 16 for $52 even. New hubs are next.

GSRCRXsi

yup i think i spent like 50-60 shipped for all 16. just pressed them all in too. im glad cause i hadone about to fall out in the front and one in the rear that was the incorrect stud and only pressed in halfway.

and i got the extended ones with extended lugs. now i can run virtually any wheel spacer id ever need, and still have plenty of thread engagement, plus the ARPs are stronger. its a small price to pay for insurance IMO.

descartesfool

My OEM ITR front studs have never broken. Bought car new in 1999. And it's done a whole lot of track work. 300 WHP. Who needs ARP studs. All you need is a torque wrench (that's working as it should of course). While I have H&R extended studs in the rear to run spacers to clear the trailing arm with fat-*** Hoosier 225/45/15's, I didn't change the rear studs because of strength concerns. OEM ones are plenty strong enough for whatever my turbo can throw at them. Best to worry about other things than Honda fasteners. (I also run OEM Honda head bolts, as who needs ARP studs there as well).

In Honda I trust.