How critical is it to have hubcentric rims?

[Patman]

The aftermarket chrome wheels on my Corvette are not hubcentric, and since I've had this car I've never been able to get a proper balance on them. The tire shop has one of the real good Hunter balancers, and they get it pretty close, but they keep telling me it's going to be almost impossible to get a perfect balance with rims that are not hubcentric. They've also mentioned that the last two sets of Pirellis I've had have been slightly out of round. So I'm hoping with my next pair of front tires (which will be Kumho ASX, just like I put on the back of my car last fall) will cure the balancing issue. Or will I always have a problem because these rims are not hubcentric? Should I try and find some of those special rings they make which convert rims over to hubcentric? (if so, who would sell them for my 98 Corvette?)

Out of curiosity, are most aftermarket rims non hubcentric? I'm assuming they must be, in order to fit multiple applications.

 

[MGregoir]

Most are not hub centric but you can find rings to make them do so, I am just not sure where.

 

[mechtech2]

Slightly out of round?
Well, that sure seems like a huge problem to me concerning balancing!
Jack each corner of the car up and spin the wheel . Use a reference pointer, like a WD 40 can with the plastic hose attached. You will see if the rim spins true, and can also check the tire.

 

[Russell]

I have seen several sources of hubcentric rings on ebay. Some rings are plastic and others are metal. Also TireRack sells them for some cars. I know they do for mounting e39 bmw wheels on e34 bmws.

 

[Quattro Pete]

Definitely get the hub rings. They're a must! You shouldn't even be driving without them.

You should be able to find the rings at places that sell rims. I know you don't like buying from TireRack due to cross-border customs issues, but I'm sure they'd have them, if you provide them with the specs of your rims. Each set of aftermarket rims they sell, they provide you with a set of rings to make a perfect fit for the car. Any other larger rim store should sell rings as well.

However, having the rings is not a guarantee of solving your issues. Some cars have very sensitive steering, so only OEM rims with a perfect factory hub fit will eliminate vibrations. Of course, out-of-round tires must also be eliminated.

 

[CapriRacer]

Based on my experience, if you have had more than one set of tires on the rims and the Hunter machine indicates they are out of round - then it is more likely the rims are out of round - and that's what's causing the Hunter machine's reading.

BTW, I have not seen very many techs who really know how to diagnose a rim out of round. So the next time you go to get tires - get the hub rings for sure - and insist the shop measure the bare rim. If they don't know how, you can either show them how or find some place you does know how. (You have to use the other side of the mandrel on the arm on the bead seat area of the rim. There a special setting of the machine marked "Measure Bare Rim")

 

[Quattro Pete]

Good point Capri. It's amazing how many shops spend the money on a Hunter machine, but don't bother ensuring that their techs know how to use it.

 

[alreadygone]

when tire/rim assembly is mounted on balancer, it will be balanced to center of hole in wheel. When mounted on car and 5 or more lug nuts are torqued to 90+ ft/lbs, any centering ring is going to be deflected unless center hole and boring of lug nut holes are in perfectly aligned circles. You might try finding a balancer that mounts to bolt pattern instead of center hole. I know they are out there, just don't know a brand or model.

While I bow to Capri's training and experience, I will respectfully disagree that center hole isn't the beginning and end of wheel concentricty.

Bob

 

[kartracer55]

Wait, so your a vette enthusiast and put chrome aftermarket rims on your car, but you are putting 95$ "performance" tires on the front? I chuckled a little bit when I read that.

If these are cheap rims, I would not be surprised to hear they are out of round. We get a lot of "tuners" who bring in cheap rims they got online somewhere and have us balance them, and are surprised when the "best" wheel took 3 ounces of weight. Dont be afraid to send them back for another set if they are out of round, harass the company because there is a substantial markup on low end aftermarket rims

Jim

 

[Dominic]

We never had a balance issue on our 99 Vette... but we used OEM wheels. I have only ever heard of this hub-centric problem on foreign cars (Honda/Toyota) so I think it's more likely the tire or wheel being out of round. Make sure when they rebalance the tire they remove ALL weights before balancing, and if they have the technology you should insist on a road force balance (thrust balance).

I've found that road force balancing is critical for tires beyond 245mm width.

Goodluck patman!

 

[Patman]

Originally Posted By: kartracer55
Wait, so your a vette enthusiast and put chrome aftermarket rims on your car, but you are putting 95$ "performance" tires on the front? I chuckled a little bit when I read that.

If these are cheap rims, I would not be surprised to hear they are out of round. We get a lot of "tuners" who bring in cheap rims they got online somewhere and have us balance them, and are surprised when the "best" wheel took 3 ounces of weight. Dont be afraid to send them back for another set if they are out of round, harass the company because there is a substantial markup on low end aftermarket rims







I have nowhere to send these rims back to, I did not purchase them, they came with the car when I got it in 2004. They appear to be very good quality chrome aftermarket wheels, they aren't low quality at all. If they were, the chrome would be peeling off by now, especially after going through 3 Toronto winters with all the salt they dump down.

As far as your $95 performance tire comment, I take a bit of offense to that statement. I need to run an all season tire on this car since it does get driven in light snow, and the Kumho ASX is one of the top rated all season tires you can buy. It's very close in performance to the Pirelli P Zero Nero but at a lower price. Just because I own a Vette doesn't mean I waste money by just getting the most expensive tires, especially when there are plenty of real good tires out there that don't cost a bundle. I'm sure a lot of guys in this forum will agree with me that Kumho makes an awesome tire that equals or outperforms tires that cost way more.

 

[Buffman]

I agree Patman. I was very impressed with the Supra 712s I had on my Roadmaster. Now that they've been discotinued and I need new tires, I'll probably looking to Kumho again for my tire purchase.

 

[Squishy]

When the machine spits out an out-of-round reading, have the techs ever tried spinning the tire 90 or 180 degrees about the rim? Most wheels have a dimple in them that you are supposed to match the red dot on a new tire to, but the dot would have washed off of old tires by now. The red dot marks the high or low spot on the tire (can't remember) and the dimple on the wheel marks the opposite.

I've never had a problem with non-hub-centric wheels, and we run five sets of them every winter. Just make sure to torque the lug nuts on an unloaded wheel.

 

[CapriRacer]

Originally Posted By: Squishy
When the machine spits out an out-of-round reading, have the techs ever tried spinning the tire 90 or 180 degrees about the rim? Most wheels have a dimple in them that you are supposed to match the red dot on a new tire to, but the dot would have washed off of old tires by now. The red dot marks the high or low spot on the tire (can't remember) and the dimple on the wheel marks the opposite.

I've never had a problem with non-hub-centric wheels, and we run five sets of them every winter. Just make sure to torque the lug nuts on an unloaded wheel.


Squishy,

You need to read this thread concerning the red dot on the tire:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1080846#Post1080846

 

[Squishy]

Argh, misinformation strikes again!

Almost every "reliable" source I've read or talked to has agreed that red dot = high (or low?) point, and yellow dot = lightweight point. But, knowing what little I know about your background, I have to say I respect your insight a lot more than those other sources.

My advice on spinning the tires about the rim still stands, though. I've personally done it with good results when the balancer spits out a ridiculously high amount of weight or when a customer comes back with a vibration in a "perfectly balanced" tire.

 

[Patman]

Originally Posted By: Squishy
When the machine spits out an out-of-round reading, have the techs ever tried spinning the tire 90 or 180 degrees about the rim?


Yep, that's one of the things they tried the last time I saw them for balancing. These guys are probably the best in the city, they have been in business since 1945, and all the hardcore autocrossers and road racers recommend them.

I will admit, I'm being super picky about the balancing on this car, most people who drive it probably wouldn't even notice it. And this tire shop has gotten it closer to perfect than any other shop (I tried two others before going to them) Hopefully when I switch from the Pirellis it'll be even closer so that I don't need to mess around with those rings on the rims. When I started this topic I just wanted to know if anyone that is super picky about balancing has been happy with the balance they've gotten on rims that are not hubcentric.

 

[Quattro Pete]

Heh... like you, I'm super picky about these things. And even though my rims are hubcentric, I still can't get a perfect balance. Like your Pirellis, my Dunlops are very slightly out of round, but not enough to call it a manufacturing defect, so i'm putting up with them until they wear out.

 

[Squishy]

You could try using weights along with a balancing compound.

 

[Papa Bear]

Patman, you should take a short jaunt up the 400 and let Squishy have a go at those tires...

 

[Squishy]

If you buy me a shop first

I haven't worked in a shop for three years now, and all I have at home is a manual tire changer (and no balancer, because I'm going to try to get away with just using balancing compound).