[sAP]

Perhaps this information might help someone out there experiencing a vibration issue at speed after installing aftermarket alloy wheels.

Day One:
Installed a set of 13" K-speed KS315 alloys on stock tires (175/70R13 Bridgestone S322). All wheels were dynamically balanced before mounting on the car.

Evening One:
Wheels & steering vibrate between 100kmph to 120kmph. (My stock rims never did that)

Day two:
Researched Internet & other sources. Found out that re-balancing the wheels would not solve the problem. Wheel centering was the problem.

Opel Corsa hub diameter (center bore): 56.5 mm
K-speed alloy wheel hub diameter (center bore): 73.1 mm

Alloy wheels were centered on lug-nuts/ bolts instead of being centered on the hub!! (Note that a wheel that is only 0.006 in. off-center can cause an imbalance equivalent to 0.5 oz.)

Solution:
Install hub-centric rings (also known as hub centering rings, hub rings or simply, centering rings). They are available with international tire installers, available in plastic or metal http://www.1010tires.com/hubrings.asp Your wheel installer should also be able to get you a set that matches your alloy wheel & car.



Q. What are hub-centric rings; do I need them?
A. Most aftermarket wheels are manufactured with a center hole that will fit a wide range of vehicles. The hub-centric ring is used to fill any gap that may exist between this hole and the vehicle's hub, thus centering the wheel on the axle. If you have vibrations after installing new wheels, chances are hub-centric rings were not used.

Day seven:
Installed metal hub-centric rings on all four wheels (rings with inner diameter of 56.5mm and outer diameter of 73.1mm... some lathe modification was required for exact fit).

Result:
The vibration between 100kmph and 120kmph dissappeared!!!

Hope this post helps you...
sAP

Custom wheel centering rings http://www.autospeed.com/cms/A_2242/article.html
wheel FAQ: http://www.therimsite.com/wheelfaq.html

[Ajay]

Did the top end speed reduce or my guess you would have felt a drop in pick up?Faced the same issue recently when I upgraded the tires on our lancer. stock rims 175/80/R13. Upgraded to lenso wheels & Dunlop SP Sport DSST -205/50/R15 with matching PCD to stock arrangement. After the upgrade ,wheel balancing and rotation done, went on a trip to T.Nadu. Experienced lot of body roll, drop in pick up and top end. It was only when I opened one wheel to check and guess what I find, Glaring gap between the wheel and the hub centre.The problem areas seem to have reduced after installing the aluminium spacers / hub centric rings.The body roll still exists albeit lesser than what it was before installing the rings. Think the safest tire upgrade on a lancer would be 195 width!My thoughts.

Cheers

[sAP]

Ajay, your overall tire diameter has reduced from 24.02" to 23.07". Thats almost an inch less than stock. Your tires now need to revolve longer to cover the same distance... and need to rotate faster to reach the same speed.

sAP

[santosh.s]

Thanks SAP, that was quite useful piece of information which I was looking for!

After understanding PCD, offset, OD etc, I was still wondering about the centering of alloys while mounting them on car or even on the balancer machine for that matter. Common sense would make me think that there are so many cars around riding on alloys, so after-market guys must be well versed with this problem. However, it is desirable to learn more and take no chances!

The car (to be bought) is baleno-lxi and the alloys most likely will be one of the shortlisted LEAGUE designs. I would appreciate if somebody comments on compatibility issues or any extra care required...

[sAP]

Santosh:

Exercise some caution if you trust that your installer knows all about alloy fitment. 3 out of 4 alloy installers I contacted did not know how to tackle vibration issues.

Most of them just balance the wheels again. When customers still complain, they re-balance both sides of each wheel.... can't quite say that the customer is benefitted... especially when he has to pay over and over again. At the end of it all, the vibration is still there.

In my case, only Aura (www.auraalloywheels.com) had a fit that exactly matches my car's center-bore (56.5mm)... but personally I found their limited model range a wee bit boring...

Installing the rings solved my vibration problem once and for all. You may need to demand for a set (or demand to get them made)... that exactly matches your car and wheel.

sAP

[Ajay]

[SIZE=2]Thanks SAP! So do you think upgrading to either 16" wheels or upgrading the tyre profile to 55 instead of 50 would help in negating this effect?[/SIZE]
[SIZE=2][/SIZE]

[GTO]

Hey SAP, Thanks a ton for sharing this information. With the number of alloy wheels on Team-BHP, I am sure that several will find this resourceful.

GTO

[nitrous]

Sap, i got a question here.

Does hub centric rings and spacers mean the same thing???

[Rtech]

Good info.

I had this problem with my Astra wheels. Finally fabricated a set of rings for the hubs similar to what is given here.

[santosh.s]

here is some more information on wheel centering mechanism...

http://www.miata.net/garage/hubcentric.html
http://www.leadfreewheels.org/101.shtml

there are two types- hub-centric and lug-centric and hub-centric seems to be more common. In hub-centric cars, I would expect hub (protruding center portion) and the center bore on the wheel to be precisely machined. but bolts and their respective holes in the wheel need not be as precise. On the other hand if its lug-centric, then all bolts/holes must be precisely located. here center bore/hub may not be accurate enough!

Can any of many baleno owners out there tell me what type of mechanism is used for baleno stock wheels?? and what is the hub size?
(hub-centric should be safer, provided proper centering rings are used)

If I remember correctly, Neo wheels claim them to be lug-centric (on bolt fitting or something) and put it as a plus point (relief from spacers etc.). But if original wheels are hub-centric and if bolts are not precisely positioned on the hub assembly then it doesn't make sense. also in this case bolts will have to bear all the weight and extra stress due to bumps/pot holes which is not a good idea...balancer machine mounting is another story...any expert comments?

[sAP]

Originally Posted by nitrous

Sap, i got a question here.

Does hub centric rings and spacers mean the same thing???

Nitrous:

They are not the same; they serve 2 different purposes. See spacers and what they do here: http://www.off-road.com/atv/pilot/ct.htm

What spacers look like:


sAP
*Glad to share research information*

[sAP]

Originally Posted by santosh.s

here is some more information on wheel centering mechanism... .....balancer machine mounting is another story...any expert comments?

Santosh: I see that you have done your research. I can appreciate that. You are right about the 2 types of wheel centricity.

What I have come to understand is that it is a car manufacturer's design that determines the type of centricity it needs, and not the aftermarket wheel manufacturer. For instance, if a wheel manufacturer claims that all his wheels are made lug-centric, it may not be a good idea to install them on hub-centric cars. [I am not necessarily saying that you disagree with this... but have merely stated it so that buyers don't get confused]

Most modern cars are hub-centric designs, I am told. But I am not an expert and do not know what type the Baleno is.

Addressing your last question, "how to balance lug-centric wheels", the wheels need to be mounted on the balancing machine using the lugholes, versus using the centerhole. This can be done using a flange-plate adaptor seen here: http://www.hawekana.com/Pages/Haweka_FlangePlate.html

sAP

[Samurai]

Originally Posted by santosh.s

Can any of many baleno owners out there tell me what type of mechanism is used for baleno stock wheels?? and what is the hub size?
(hub-centric should be safer, provided proper centering rings are used)

This was one thing I was worried about while deciding on the alloys. In fact I was worried about pcd, offset, rimwidth and centre bore.

Baleno pcd is 100, the alloys has to match this.
Baleno offset should between 35-40, mine was 38.
Rimwidth depends on your choice of tyre width, I took 6 inch.
Center bore was one thing I couldn't match. The wheel center bore is much bigger than baleno's wheel mount. I was quite worried about that, but iceman said it was not a problem. And I have not had any problems until now.

BTW, my alloys dealer didn't know anything about offset. He only knew tyre company and models names and what sells.

[sAP]

Originally Posted by Ajay

Thanks SAP! So do you think upgrading to either 16" wheels or upgrading the tyre profile to 55 instead of 50 would help in negating this effect?

You guessed right. Either of the steps should help.

(i) replacing to 55 profile sounds good enough -- considering you don't need to change the wheel -- results in less than 1% overall diameter reduction

Dia: 23.88" (stock 24.02")
Sidewall height: 4.44 (stock 5.51")

(ii) 16" requires both tire and wheel change, results in less than 1% overall diameter enlargement

Dia: 24.07" (stock 24.02")
Sidewall height: 4.04 (stock 5.51")

I am assuming you have already taken care of lateral clearance issues with the 205mm width. Personally, my choice would probably have been 195/60R15 (dia 24.21" and sidewall 4.61") if that meant not having to use spacers.

sAP

[santosh.s]

Originally Posted by Samurai

Baleno pcd is 100, the alloys has to match this.
Baleno offset should between 35-40, mine was 38.

will ensure this.
one question- league brochure mentions PCD like 100~114.3, does this mean dual pcd 100 and 114.3 or anything in between also??

Center bore was one thing I couldn't match. The wheel center bore is much bigger than baleno's wheel mount.

This is probably done by wheel makers so as to fit it on as many cars as possible... and so may be the case with bolt bores as well (bigger holes than required)

I was quite worried about that, but iceman said it was not a problem. And I have not had any problems until now.

What this means is bolt positions are also accurate enough. Additionally, there may be tapered (cone like) edge on nuts/bolts to compensate for bigger bores and achieve lug-centering. If it is so then centering shouldn't be something to be worried about much! may be thats how it happens for most of the cars... but after all perfect hub fitting should be preferrable

BTW, my alloys dealer didn't know anything about offset. He only knew tyre company and models names and what sells.

Though they may not be aware of specification details, they must be having an idea as to which models/sizes fit a particular car without troubles

Rimwidth depends on your choice of tyre width, I took 6 inch.

Searched related threads and zeroed in on either 14"x5-5" or 14"x6" alloys with either 185/65R14 or 195/60R14 tyres... conclusion was that any combination should be good enough(?). Still have no idea as to which one to pick and which tyre brand/model... probably I will arbitrarily choose something within above size limits!