hub-centric question
 

Hey all

I picked up a set of cheap black steelies and snow tires from discounttiredirect.com. I remember the website saying that the wheels were not hubcentric on the Impreza, and they would include hubcentric rings.

Well, I was putting the wheels on tonight and discovered that I apparently threw away the rings with the shipping materials - I just wasn't paying attention when I unpacked them :oops:

Question. . . is it bad to run wheels that are not hubcentric? I understand the purpose of having them hubcentric, but what's the potential problem if they're not?

Does anyone know what size fitment i'd need for the impreza, and does Kragen carry hubcentric rings?

Tighten all 5 (6, heh, to make sure) in a star pattern, slowly, using the appropriate lugs, and you'll be fine. I run numerous sets (:lol::lol:) of non-Subaru bore wheels (bigger than 57.1) and I've never had an issue - don't just reef on one lug until it's tight, get them all up to the lug face then go around doing a turn at a time and you'll center them just fine.

As long as you tighten the lugs at least 90% in the air, you will be fine. Studs/lugs carry the weight, not the center bore.

Let me rephrase that.

Get them fairly tight in the air and then lower the car just enough so the tire won't spin but is not really caring weight and torque to spec before putting full weight on it.

Perfect... I popped them on and they seem fine - no vibration

thanks :)

What they said. You can buy them from Summit though, I think.

Or you can be a little dishonest and call to inform them they forgot to ship the rings with the wheels and I would bet they will send you out a set asap.
Hell, they might have actually forgot. Maybe you didn't throw them away.
I bought a set of wheels from them a few years ago and they did forget, one phone call got me a set.

Actually, the guys at discount tire direct seem pretty cool. I bet if he called them and said, "oops I threw out the hub rings, can you send me another set?" they'd be happy to, considering it probably costs them all of $2 to make a customer happy.

True this.


Also, most of my cars have been LUGcentric - the old VWs and Porsches with 5x205 pattern are all LUGcentric, and over 50 years of running like that with no issues can't be wrong.


The main thing being HUBcentric does is line the wheel up properly with the lugs, and add an extra source of clamping force for the wheels-to-hub. I wouldn't worry, especially for snows that will likely never see hard cornering.

That being said, I feel better about having my summer wheels designed to fit the 57.1 hub, and would prefer wheels intended for abuse to not use hubcentric rings to achieve that.


But like I said, if VWs and Porsches have been rocking LUGcentric wheels for 50+ years, there's not a whole lot to worry about IMHO.

Lug-centric only works for cars with wheel studs, but like Aaron explained above, if you pay attention to what you're doing there's no risk of lugnuts coming loose. I've been autocrossing on non-centric Volks for years.

Fixed?


I know of a few drag racers and off roaders using lugcentric wheels/drums/discs with wheel studs and nuts with no fail. Most of the VW drag racers are still using 5x205 wheels, all with 14mm studs pressed into their discs or drums, and 300+ whp, down into the 9s, still no problem. Just sayin, OP shouldn't have any issues ;)

Been rollin' on em since with no problems :)

I hate wheel bolts so much I have a hard time accepting the existence of the concept I guess. :lol:

Our Saab had 'em. Terrible, terrible idea. I just can't understand the point, especially since the female threads tend to strip easier than the male, and lining up the wheel on the hub is a PITA w/o lug studs... it's even worse when the brake rotor spins instead of the wheel if you rotate it to line up the holes.

Huh? The only things providing any clamp load are the lug studs & nuts (or yes, bolts if you have a retarded car).

AFAIK the only thing hub centric center bores are good for are lining things up when installing wheels. Priceless on lug bolted cars like the A4. And providing a little support in the event of loose lugs/bolts so they don't just shear off and drop the corner of the car to the ground. I can attest to the later as well having been in a car at the track with loose lug bolts.

And as far as studs vs. bolts, I think the German engineers convinced the TUV at some point that bolts had some small benefit and thus the TUV made it a standard for cars they certify or some such. Not that interested to go research it but that is what I recall when I asked back when I bought my Audi.

This is along the lines of what I was referring too, my bad.

I said clamping force, meant contact area/surface matching. You're right Austin - clamping comes from the bolts/nuts, not the surface area or shape. But having the hub lip and corresponding impression at the hub bore on the wheels match must create some sort of positive surface area/clamping area gain, no?


I can tell you without a doubt and with absolutely no actual specification or factual basis that hub-centric wheels fit tighter to the hubs than non-hub-centric wheels given the exact same amount of perceived torque on the lugs from the incredibly approximate installation of lug nuts using a spider wrench. :eek::rolleyes::huh::P



I swear both sets of hub-centric 5x100 wheels (using correct acorn/tapered nuts for each) on the Subaru fit better/tighter than the non-hub-centric 5x100 wheels on my bug (blank 4x130-style rotors drilled to 5x100 for modern 5x100 VW wheel fitment, with thread-in 12x1.5 studs, acorn nuts for OE-type seats). Referring to wheel removal - the wheels seem to like to stay in place after loosening all lugs before "falling off" when removing from the Subaru compared to the VW, which just seem sloppy and fall once the fifth nut is loosened at all.

Just sayin.

All technical with heavily researched specifications, of course. :rolleyes:



All that said, I like hub-centric simply because it's quicker when installing wheels - rather than about 10 passes for each stud to get the wheel aligned it's 3 or so.

Different bolt thread diameter, pitch and possibly required torque are probably part of your perception.

As I said before, the hub-wheel interface should carry no load on any studded or bolted wheel except in the event of a loose wheel while on the ground or some portion of the wheel weight before the lugs are tightened in the air.. On a hub centric wheels, in most cases, they will actually not be any contact between the hub and wheel at the bore once the lugs are tight. the clearance that allows the wheel to slip on easily will be equally distributed around the hub so the wheel will be clear by .0001" or more all the way around.

Yeah, the weight load/cornering load/braking load/everything else load of the car is transferred from wheel to hub by friction at the flat flanges of the wheel & hub. The torque you put on the lug nuts generates thousands of pounds of axial force (preload) in each fastener, which generates a proportional amount of friction/clamp load in the plane of the hub flange to resist any external forces, and all of that essentially 'welds' everything together at the flange interface as a rigid assembly. Like Dean said, that center hub boss and corresponding inner bore of the wheel are probably not even touching once everything is torqued down.

After attempting to read this several times, I'm feeling very much stupid :?:

I think I got it though.... torque the damn lug nuts to spec!