Steel vs Alloy rims

[amanda]

I plan to buy 4 dedicated Blizzaks with rims for 2001 Forester S---I
have been told that the only reason to use alloy is for appearance .
Are there other reasons to justify the added cost of alloy over steel ?

Thanks
Amanda

 

[Mark T.B. Carroll]

I plan to buy 4 dedicated Blizzaks with rims for 2001 Forester S---I
have been told that the only reason to use alloy is for appearance .
Are there other reasons to justify the added cost of alloy over steel ?

Alloys are certainly usually lighter. I don't know if it makes for a
smoother ride seeing as there's then less impulse for the suspension to
absorb when your wheels hit bumps, but I figure that at least it's
better to be lugging less weight around - presumably that pays for
itself in gas at some point. I've heard some people say that alloys are
less likely to crack, too, but I don't have experience of enough wheels
to really say.

-- Mark

 

[David Coggins]

I plan to buy 4 dedicated Blizzaks with rims for 2001 Forester S---I
have been told that the only reason to use alloy is for appearance .
Are there other reasons to justify the added cost of alloy over steel ?

Thanks
Amanda

Alloy wheels are lighter, giving the wheel assembly a lower "unsprung
weight". As the suspension system of a vehicle would be designed for the
unsprung weight of alloy wheels, changing to heavier steel wheels may effect
the ride and handling.

 

[Body Roll]

I plan to buy 4 dedicated Blizzaks with rims for 2001 Forester S---I
have been told that the only reason to use alloy is for appearance .

By the same man who drives a Prius?

Are there other reasons to justify the added cost of alloy over steel ?

On Forester with Blizzaks: I doubt it.

 

[Kevin Hall]

We use alloys for the summer rims, and cheap steel for the snows. Alloys
react pretty swiftly to salt contamination once the paint/powdercoat or what
ever chips and wears. Corrosion from winter road salt will be much faster
and damaging to the alloys than to pressed steel.

Got our steel rims from the Suby dealership. Apparently they are
'take-offs' that come on some of the more elevated Forester models, and
which are then swapped in the dealership for the more costly alloy rims
before the sale. Those 'take offs' are often available at about the same
price as cheaper, plainer generic rims from discount parts joints, but
they are orig. Suby parts so they look right.

Alloys are lighter, reducing unsprung weight as mentioned by prev. posters.
Because of the weight differential they may also 'spin up' faster but the
difference on something like a Forester would be virtually undetectable.

One possible downside is that alloys have been known to let the air out of
tires when it gets very cold out. By 'very cold' I'm talking about -30C or
so. Nothing like coming out on a morning like that and finding 2 or 3
flats in your driveway.

KH

 

[amanda]

Thank you very much for all the replies and information.

Amanda

 

[KLS]

One possible downside is that alloys have been known to let the air out of
tires when it gets very cold out. By 'very cold' I'm talking about -30C or
so. Nothing like coming out on a morning like that and finding 2 or 3
flats in your driveway.

Well, I live in a climate with such cold temps, and I've never
experienced such drastic air loss in my snow tires mounted on the
1998-vintage OEM alloys of my Audi.

I leave these tires on the car for 5 months a year, and that's a long
time to be looking at the same wheels, hence my preference for the
alloys over the ugly steelies.

 

[Kevin Hall]

I've had alloys on vehicles which had no problems in cold weather, but have
personally had alloys allow tires to go flat in winter on a full sized Chevy
Blazer, a Ford Exploder
and a Chrysler minivan. Lots of other folks in this area have had similar
experiences, so I don't tempt the fates.

I'm also not willing to feed $1,000 worth of fancy rims to the salt fairy
every year.

KH

 

[news]

One possible downside is that alloys have been known to let the air out of
tires when it gets very cold out. By 'very cold' I'm talking about -30C or
so. Nothing like coming out on a morning like that and finding 2 or 3
flats in your driveway.

my wife's Beretta has alloys for the last 17 years. We live in Winnipeg
(-40 in the winter) and they lose air over time in the winter, but never
quite that dramatically.

I'd say 2-3 psi per week would be "normal" for the cars I've owned with
alloys in the winter. Just enough to be annoying.

If I was putting snow tires on a car, I'd go with steels, or if I had
nice wheels and didn't want them to look like crap in 3-4 years, I'd go
with steels in the winter.

My Legacy has stock steels and hubcaps...

Ray

 

[Jirí Lejsek]

"Alloys are certainly usually lighter."
This is common myth. Did you ever weigh them? Alloys are almost always
heavier. At least here, in Europe.

 

[Mark T.B. Carroll]

"Alloys are certainly usually lighter."
This is common myth. Did you ever weigh them? Alloys are almost always
heavier. At least here, in Europe.

That's curious. I'd thought that my WRX STi has aluminium alloy control
arms, pistons, etc. instead of steel so they could get good enough
strength while making the car lighter. Similarly IIRC the Ford Prodigy
was full of aluminium alloy in a rather non-cosmetic role, I thought,
and consequently lighter? In Europe, I thought that some recent Audis
had much more aluminium alloy in them, including in structural parts as
well as just body panels, etc., to save weight? Am I mistaken?

So, no, I hadn't actually tried weighing the wheels, but I seem to see
plenty of use of aluminium alloys to replace steel in other engineering
applications, to reduce weight, where the parts will be under some
stress and their strength is important - is there something odd about
wheels that makes them an exception?

-- Mark

 

[Paul Pluzhnikov]

That's curious.

And probably wrong ...

A quick google search finds:
http://www.tirerack.com/wheels-techpage-1/108.shtml
http://www.edmunds.com/ownership/tires/articles/43860/article.html
both of which imply that alloy wheels are lighter.

is there something odd about wheels that makes them an exception?

Yes, enquiring minds want to know.

Cheers,

 

[Jiøí Lejsek]

You are right, commonly using aluminium alloys brings less weight.
But I know that usual alloy wheels are heavier than steel (I don't know
about alloy wheel that is lighter than steel - maybe some racing or very
expensive are.)
I think reason is that steel is more elastic, so must not be so tough as
alloy. Steel bends and returns back, but alloy stays bended (which have to
be avoided).
Some of reasons for using alloys is better heat distribution (from breaks) -
but it is important only for sport or racing cars.

 

[Howard Nelson]

"Alloys are certainly usually lighter."
I think volume for volume alloys are probably lighter. However on a couple
of cars I have owned the steel wheels seem to be thinner metal ( I haven/t
measured). alloys probably have to thicker in stress parts because of the
strength and elasticity issues raised in early post.
Just MO
Howard

 

[y_p_w]

I think volume for volume alloys are probably lighter. However on a couple
of cars I have owned the steel wheels seem to be thinner metal ( I haven/t
measured). alloys probably have to thicker in stress parts because of the
strength and elasticity issues raised in early post.

Iron is about 2.9 times as dense as aluminum. However - one of the
features of aluminum I learned in basic metallurgy is that one can
make it aluminum stiffer by using greater volume, and stronger with
certain alloys. It might not actually be stronger than an equivalent
steel wheel though.

I had a complete blowout on a steel wheel once. I just happened to be
close to a tire dealer and got a replacement. The installer (the
manager) noted that steel wheels are tough. I guess it probably flexed
a bit, but didn't permanently deform. I don't think an aluminum alloy
rim would have survived the same incident.

 

[Mark T.B. Carroll]

You are right, commonly using aluminium alloys brings less weight.
But I know that usual alloy wheels are heavier than steel (I don't know
about alloy wheel that is lighter than steel - maybe some racing or very
expensive are.)

I think there are some magnesium alloy wheels that are very light and
expensive and used in racing; IIRC they're not really very durable. Not
something I know about. I don't think anyone uses titanium alloy wheels
- they'd be light and strong, but very expensive indeed. (-:

I think reason is that steel is more elastic, so must not be so tough as
alloy. Steel bends and returns back, but alloy stays bended (which have to
be avoided).

(snip)

Ah, I don't know enough to know how the elasticity trades off against
being able to make the piece a bit thicker for the same weight - if they
just balance linearly or what.

-- Mark

 

[DK]

I had a complete blowout on a steel wheel once. I just happened to be
close to a tire dealer and got a replacement. The installer (the
manager) noted that steel wheels are tough. I guess it probably flexed
a bit, but didn't permanently deform. I don't think an aluminum alloy
rim would have survived the same incident.

This thread leaves me wondering - what exactly *are* advantages
of alloy wheels if any? There are a lot more expensive then steel,
so there has to be something that justifies spending that much
extra money? My list of what I can think of:

- Lighter. Are they really? How much of a factor is this driving
a normal car?

- Don't rust. Are there really 10-15 years old cars where wheels
are compromized from rust?

- "Better looking".

- Heat dissipation. Again, how much of a factor is this driving
a normal car?

- More uniform to begin with and better keeping their shape.
Perhaps that makes alignment easier or suspension lasting
longer?

DK

 

[Jiøí Lejsek]

This thread leaves me wondering - what exactly *are* advantages
of alloy wheels if any? There are a lot more expensive then steel,
so there has to be something that justifies spending that much
extra money? My list of what I can think of:

Extra money?
In last year I saw cheapest alloys have almost the same prize as steel rims.

- Lighter. Are they really? How much of a factor is this driving
a normal car?

No, they are heavier. For a normal car probably no difference.

- Don't rust. Are there really 10-15 years old cars where wheels
are compromized from rust?

Alloy wheels also rusts, especially cheaper ones - from salt in winter -
they have internal corrosion, not visible, after few years they can break
down suddenly. (Some are "certified" for winter use.)

- "Better looking".

Definitely yes.

- Heat dissipation. Again, how much of a factor is this driving
a normal car?

For a normal car zero. For sporty maybe some.

- More uniform to begin with and better keeping their shape.
Perhaps that makes alignment easier or suspension lasting
longer?

Alignment (balancing) easier?
No, more difficult and more expensive.

Suspension lasting longer?
No, they are harder so suspension suffers from that, especially if you use
bigger rims and lower profile tyres (So they are also less comfortable). For
profile /60 and higher will be no difference.

Handling better?
Yes (especially with bigger rims and lower profile tyres). For profile....
(see above)

It is also more probable that you deform (permanently) alloy wheel so add
further $s for aligning.

I think steel rims are not usable for extra low profile tyres - must be used
extra hard (and expensive) alloy wheels.

Did I forget something?

Conclusion: for normal car and driver it is only a fashion, for more
demanding driver it has a sense, but only with low profile tyres.

 

[Mike]

I read a little thing about this on a tire shop website while I have been
shopping for new tires. They say alloys are lighter and stronger. Alloys
wheels have a positive affect on tire wear, steering is more responsive ,
brakeing and performance is better compared to steel wheels.

 

[Paul Pluzhnikov]

No, they are heavier.

You've made this statement twice now without *any* substantiation.

Would you care to tell us *where* you got that info from?

Are you an expert on wheel design? Did you personally weigh 100s
of steel and alloy wheel pairs for the same car? Did you find a web
site that carries both steel and alloy wheels for the same car and
shows their weight?

Or are you just repeating your unsubstatiated *opinion* ?

For a normal car zero. For sporty maybe some.

How do you *know* that?

Cheers,