Aluminium Wheels vs Areodynamic Hubcaps

[hootis]

Hi Guys,
Currently have 16" x 6.5" wheels and they're steel. I was thinking about buying aerodynamic moon caps that seem pretty popular here. There is probably also a significant benefit by getting aluminum wheels. Has anyone tested this which is the better option?

There will probably be a weight difference of about 50-100lbs. Which is always nice but I haven't seen any aluminum wheels that have hubcaps. Unless anyone has any ideas there are the choices I see.

Aluminum 16" wheels - Save weight

Aluminum 18" wheels - Lower the RPM of engine at highway speed
Save weight

Aerodynamic hubcaps - Est 5% based on other people guesses on this forum.


Any ideas?

[gone-ot]

Less weight will enhance in-city mileage slightly where mass dominates.

Wheel covers will enhance highway mileage where aero-drag dominates.

[hootis]

Just wondering if anyone has run into this problem before. Seems like everyone goes with The covers. That is also the cheapest option.

[BrandonMods]

Originally Posted by Old Tele man

Less weight will enhance in-city mileage slightly where mass dominates.

Wheel covers will enhance highway mileage where aero-drag dominates.

As suggested depending on your route parameters. I have aluminum rims and they're just as easy to place wheel covers on as steel rims with covers.

[oil pan 4]

Lighter wheels will only make a noticeable difference if you drive 30 feet, stop drive 30 feet, stop and do that all day. Like a mail truck.
If you drive at speed like a normal person, moon caps or aero OEM hub caps are the way to go. Plus they will only be a fraction of the price of a new set of aluminum wheels and a fraction of the price of a used set too.

[oldtamiyaphile]

Originally Posted by hootis

Currently have 16" x 6.5" wheels and they're steel.

Aluminum 16" wheels - Save weight

Aluminum 18" wheels - Lower the RPM of engine at highway speed
Save weight

Aerodynamic hubcaps - Est 5% based on other people guesses on this forum.

Unless you're talking about buying very expensive forged wheels, the assumption that alloy wheels will save weight is often faulty.

OEM alloy wheels are much thicker than steel (because of the fatigue characteristics of alluminium), and will often end up heavier.

I swapped my factory 16" alloys to OE 14" steelies and saved 1.5kg per corner.

It's not helped by the fact that while your steel wheels are 6.5" wide, you'll probably struggle to find much in the aftermarket that isn't at least 7-8" wide.

[vskid3]

Originally Posted by hootis

Aluminum 18" wheels - Lower the RPM of engine at highway speed
Save weight

Wheel size doesn't dictate tire size, it only changes your options. You could stick with your existing wheels and get taller tires if you wanted.

Plenty of people cut circles out of coroplast and zip tie them to their wheels, so you're not really limited by the wheel design.

What kind of car do you have?

[ConnClark]

Something that nobody has mentioned to take into consideration, Reduction of unsprung weight will reduce rolling resistance

[BabyDiesel]

Originally Posted by ConnClark

Something that nobody has mentioned to take into consideration, Reduction of unsprung weight will reduce rolling resistance

This. Reduction in RR is good for mpg gains across the board, irregardless of driving.

I'll add my own $0.02. One of the mods I have done to my car is lighter wheels. My stock ZX2 steelies were heavy, I'd have to say upper teens since the 14x4 spare wheel by itself was 16-17 pounds. I replaced the stocks with Mazda MX-3 alloy wheels I got for cheap ($110 with low tread tires!) They weigh 12.5-13 pounds, and have been covered in coroplast covers for over a year. They have provided gains in FE, aero and RR, though all I have is anecdotal evidence and your trust of my word. I have a thread somewhere where I tested the MX3s against the spares in real world driving... let me try to dig it up.

I looked at getting lighter wheels like this - they would help constantly. They would give lower RR during acceleration, cruising and coasting. Every stop sign and traffic light I get caught at and have to accelerate from, the lighter wheels are requiring less fuel to get back up to speed. The only downside is cost. But there are deals out there such as my MX3 wheels for $27.50 a piece, and then selling the steelies for $65 for a grand total of $45

I say go for both if you can!

Tell us what you're driving and we can make better recommendations for you

[Ryland]

There are a lot of options for efficient alloy wheels, depending of course on your vehicle.
Switching from summer alloy wheels to winter steel wheels I notice my car feeling sluggish in town, my winter tires are lrr snow tires so I don't see a mileage drop on the highway, just on town.

Look for wheels from a hybrid, not aftermarket egg beaterwheels.