Question about wheels

Status
Not open for further replies.
B

Brogy

Joined
Dec 14, 2006
Messages
595
Location
NJ
I read on tirerack the benefits of having alloy wheels over steel wheels. I know it's marketing to sell more things, but how much of it is true?

Reduced Unsprung Weight Compared to Steel Wheels
This is one of the most critical factors affecting a vehicle's road holding ability. Unsprung weight is that portion of a vehicle that is not supported by the suspension (i.e. wheels, tires and brakes) and therefore most susceptible to road shock and cornering forces. By reducing unsprung weight, alloy wheels provide more precise steering input and improved "turning in" characteristics.

Improved Acceleration and Braking
By reducing the weight of the vehicle's rotational mass, alloy wheels provide more responsive acceleration and braking.

And the other ones are added rigidity, and increased brake cooling, which im sure are true. There any disadvantages?

Im not looking to get new wheels or anything, not at $80 a pop, but im curious if there's any truth to these statements. Cant hurt to know... or in my case sometimes if I know too much I hurt things, but thats a different story...



crushedcar.gif
 
It's generally true. What's questionable is whether the difference will be large enough for you to actually notice.

Keep in mind, not all alloy rims are created equal. Some of the cheaper and OEM ones can be as heavy as their steel counterparts. And if it's light and cheap, it is also generally weak, so it can easily bend on potholes. If you want light AND strong alloys, it's gonna cost you big bucks.

As for disadvantages, repairing a bent alloy can be more expensive. Also, it requires more care to look good. If you don't clean it regularly, brake dust will get baked on its surface. Other contaminants can also stain the surface if left for too long.

Sometimes getting a different tire can help you shave a few pounds, too.
 
Ah thanks quattro pete. So if one of my wheels becomes damaged, it's probally in my best interest to visit a junk yard rather than a pepboys
wink.gif
 
If the alloy wheels are significantly lighter, you may be able to feel it in your steering and suspension. The improved acceleration and braking of lighter wheels probably wouldn't be noticeable, but there is some benefit. If you dropped 20 lb off your 4 wheels, with the same tires, it would probably have an effect similar to dropping 25 to 35 pounds from the car, depending on the diameter of the wheel and tire.
 
Those benefits of reduced unsprung mass are definitely real. It's particularly true when it is unsprung rotating mass like the wheel or tire. The only disadvantage (besides $$$) would be if the wheel is less strong in order to get the reduced weight you are more vulnerable to a bent or broken rim.

Somewhat ironic that ricers are always looking for the largest wheels and tires possible and are in fact ruining their handling.
 
I agree with Lorenzo. The big downside is cost.

Also, there are instances where aluminum wheels can be stronger than the steel ones it replaces. At our lab we do Kerb crash tests on our wheel hub product mounted to rims with tires. We've gone to aluminum rims for the test because they last longer. I don't know if they are necessarily lighter though.

It's true what Lorenzo says about ricers ruining their cars with style. Rubber is lighter than alloy rim. Though larger rims give better cornering, the heavier combination has higher rotational kinetic energy and reduces the car's performance when it comes to acceleration and braking... so much that it can take the car a dangerously long time to stop.
 
I needed some wheels for snow tires and ended up with some alloy wheels, ones that I've since moved my 3 season tires to. One had a slow leak, and we finally found it after about three different people looking for it when dunking the tire; it was a small leak around the casting sprue (where the metal gets injected into the mold). This obviously suggests some porosity around the sprue. In the meantime I lightly sanded and cleaned the area on the inside of the wheel after having the tire removed, using dilute alcohol and then applying a thin layer of polyurethane glue (gorilla glue). The stuff needs water to cure, and for me has worked well fixing leaks around seams in the trunk of am older car. The glue seems to be holding ok so far, which is impressive as that wheel usually runs at 65 psi.

Anyway, porosity is a potential problem on alloy wheels.
 
alloys are better for things like a quiet ride, they are easier to balance and hold the balance longer than steelies, they can make the car handle a little better all of this is true. but the tire rack is interested in making profits and so they present their info in an alarmist nature so almost SCARE people into buying aluminum wheels.
sure aluminum wheels will reduce a bit of weight and help the suspension work better, but not by much.

quote:
Reduced Unsprung Weight Compared to Steel Wheels
This is one of the most critical factors affecting a vehicle's road holding ability.

if that isnt alarmist i dont know what is. why they make it sound like just using steelies will result in an uncontrollable car! fact is nascar doesnt use aluminum wheels, and they seem to handle OK.

i can think of a hundred other things that are more critical than what mattereal youre wheels are made out of that will effect a vehicles road handling ability. how about tread depth, tire pressure, worn out brakes to name a few. these are all VASTLY more important than what matereal youre wheels are made out of.

haha i have to laugh at that.

so take what tyre rack says and anyone else who is trying to sell you things says with a big old grain of salt. remember its in THEIR best interest to get you to buy things.
having aluminum wheels isnt going to make you stop quicker, it isnt going to help you avoid accidents, and it isnt going to lower youre insurance rate for having wheels that make youre car safer. go ahead and ask any insurance company if you get a discount for having safe wheels. (like the discount they give for having abs brakes) and all will say no.

with that said, steel wheels are aincent tech. they are right above iron wheels which are probably right above wood wheels. heck aluminum wheels are old tech.

i wouldnt own a daily driver that had steel wheels. aluminum wheels just flat out ride better. even boat trailers and lawnmowers come with aluminum wheels now a days.

my advice is to look in the for sale section of youre newspaper, hit up ebay, try a few junkyards and see if you can score a set of clean original equipment aluminum wheels for under $25 each.
 
on my mustang i got lighter weight and slightly wider wheels and the handling was noticable better. ride was slightly more rough, but a different sidewall might have been the reason. the wheels i have are 17x9 and weigh 21lbs. they are pretty common on a lot of American Iron cars (Konig Villian). i have been pondering getting a different set of street wheels just to look cool. that would let me have dedicated track rubber.
 
Quote:

quote:
Reduced Unsprung Weight Compared to Steel Wheels
This is one of the most critical factors affecting a vehicle's road holding ability.

if that isnt alarmist i dont know what is. why they make it sound like just using steelies will result in an uncontrollable car! fact is nascar doesnt use aluminum wheels, and they seem to handle OK.

i can think of a hundred other things that are more critical than what mattereal youre wheels are made out of that will effect a vehicles road handling ability. how about tread depth, tire pressure, worn out brakes to name a few. these are all VASTLY more important than what matereal youre wheels are made out of.

Click to expand...


Very good point. I didn't really notice how absurd that statement is until you pointed it out!

Quote:

It's true what Lorenzo says about ricers ruining their cars with style. Rubber is lighter than alloy rim. Though larger rims give better cornering, the heavier combination has higher rotational kinetic energy and reduces the car's performance when it comes to acceleration and braking... so much that it can take the car a dangerously long time to stop.

Click to expand...


Ridiculous? Absolutely! But unless it's a Donk/Bubble car, I wouldn't call it dangerous. Adding the equivalent of a few percent of the vehicles mass as extra rotating mass can't possibly increase stopping distances by more than an equal number of percentage points.
 
If you are on the track or looking for high performance the difference is real. And there is also improved comfort by allowing the suspension to work better as Master Acid pointed out.

But to keep things in perspective, most drivers won't notice the difference when commuting to work or driving to the supermarket. If you're just a regular guy shopping for wheels that look good, then just go with something reasonably close to the weight of the stock wheels or maybe a little lighter.

What you want to avoid is choosing a wheel that looks good but is grossly overweight, or a wheel that is very light but weak and vulnerable to damage.

Finally, the most important factor is to keep the overall diameter the same as stock, and to keep the offset close to stock to avoid steering geometry changes. Another ricer mistake is to go for lowest offset possible which pushes the wheels out wide for looks, which screws up steering response and stresses the wheel bearings.
 
There are expensive light weight alloy wheels out there. Most good looking OEM alloy wheels have little weight advantage over steel.

Richard.
 
Quote:

Though larger rims give better cornering

Click to expand...


Not always, and there ARE upper limits on useful diameter/uber low sidewalls. Large diameter racing wheels were brought about mainly to allow the use of giganormus brake rotor diameters/multiple piston calipers, where permitted by the rules.
But larger profile sidewalls can be made sufficiently stiff enough for great handling (combined with a superior suspension setup, and/or positive aero downforce).
Case in point; F1 cars. Yes I know it's an extreme example, and it is dictated by the rules, but they seem to do just fine on 15" diameter wheels.
 
Quote:

... Case in point; F1 cars. Yes I know it's an extreme example, and it is dictated by the rules, but they seem to do just fine on 15" diameter wheels.

Click to expand...


Actually, according to the (2007) technical regulations they're limited to 13". Now depending on the track and if the regulations allowed larger diameter wheels and tires, you bet the teams would take advantage of them.

Quote:

ARTICLE 12: WHEELS AND TYRES
12.1 Location:
Wheels must be external to the bodywork in plan view, with the rear aerodynamic device removed.
12.2 Number of wheels:
The number of wheels is fixed at four.
12.3 Wheel material:
All wheels must be made from an homogeneous metallic material.
12.4 Wheel dimensions:
12.4.1 Complete wheel width must lie between 305 and 355mm when fitted to the front of the car and between 365 and 380mm when fitted to the rear.
12.4.2 Complete wheel diameter must not exceed 660mm when fitted with dry-weather tyres or 670mm when fitted with wet-weather tyres.
12.4.3 Complete wheel width and diameter will be measured horizontally at axle height, with the wheel held in a vertical position and when fitted with new tyres inflated to 1.4 bar.
12.4.4 Wheel bead diameter must lie between 328 and 332mm.

Click to expand...
 
although the cars seem to stop really well the the carbon rotors/pads. if they went any bigger i could see issues with head trauma. i know on the top fuel cars when they pull the chutes you have to keep the foot in the gas to keep the front to rear g-forces in check.
 
I'm still skeptical of that being the reason for the relatively small wheels, even though I hear it tossed about often. If the FIA wants to limit brake rotor size, why not do so directly?

I just looked it up online, and it turns out that they do just that. 2007 Formula One Technical Regulations (warning - PDF), article 11.3:

11.3 Brake discs:
11.3.1 No more than one brake disc is permitted at each wheel.
11.3.2 All discs must have a maximum thickness of 28mm and a maximum outside diameter of 278mm.
11.3.3 No more than two brake pads are permitted on each wheel.

Bolding mine.
 
Status
Not open for further replies.

Similar threads

M
brake dust sticking to wheels
Replies
12
Views
787
nthach
N
Falken SN250 A/S louder on freeway than cheap tires - need quieter tires
2 3
Replies
45
Views
2K
Nukeman7
supton
Additional wheel/tire weight
Replies
2
Views
3K
Jetronic
Number_35
Audi S5 - Winter Tire/Rim Recommendation From Dealer - Opinions/Advice?
2
Replies
20
Views
5K
edyvw
L
Do bigger (=taller, more rolling diameter, not necessarily wider) tires promote a 'better' ride over road imperfection (potholes, dips, etc.)
Replies
14
Views
7K
userfriendly
Back
Top Bottom