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-   -   Wheel arches - shape (https://ecomodder.com/forum/showthread.php/wheel-arches-shape-6907.html)

MaxMatt 01-27-2009 12:37 PM

Wheel arches - shape
 
I noticed that most modern cars have similarly shaped wheel arches these days. Examples:

http://paultan.org/gallery/d/6134-3/...atria_neo5.jpg

http://lh4.ggpht.com/_QZCEofQMIcw/R5...MAM7-GOLF5.JPG

http://image.trucktrend.com/f/auto-s...ult-kangoo.jpg

In opposition to the old style:

http://upload.wikimedia.org/wikipedi..._Omega_A_L.jpg

The difference?

Nearly all new cars have wheel arches finished with vertical surface which is cut from the rest by a sharp edge. I wonder if it's just some concept of styling or is it somehow related to aerodynamics and fuel economy?

If it had sth to do with FE, I think I could try to adopt it in my Benz...

I hope You will understand sth from the pics. If not, I'll try to draw a scheme and drop it here.

lunarhighway 01-27-2009 04:22 PM

good question.

one thing to note is that car have an increasing wide track, this might be to improve handling,and since i have the impression most cars are a bit taller as well their center of gravity might be a bit higher as wel than the average car lets say 10 years ago.

styling wise these bold arches probably give the car a bit more muscular apperance... wich is a nice trick to give a small car or a potentially "boring" family car like the cangoo a bit more muscular appearance.

on the other hand i noticed you'r example of an "old" car is one of my favorites... and probably the one with the lowest drag of them all with and 0.28 Cd... so i'm not sure if these new arches are that much better than the old ones.

something else i've noticed is that on older cars there much more space between the wheen arch and the tire... probably because they had a little more suspention travle.

MetroMPG 01-27-2009 04:28 PM

Tightening the tire/wheel arch gap improves aerodynamics as well.

MaxMatt: the first two links you provided didn't work for me, so I don't really know what the examples were meant to show.

As for wheel arch design for best aero - a minimal tire gap, is best, plus adding a radius to the aft edge to permit air exiting the arch to make a clean transition to the vehicle side.

EG see: 60+ Vehicle modifications for better fuel economy - EcoModder.com

Low Cd production vehicles that took pains specifically to shape the wheel arches include GM's EV1, Solectria Sunrise (pictured), Honda Insight (gen 1)...

http://ecomodder.com/imgs/mods-list/38.jpg

Toyota mentioned tweaking the wheel arch liner on the new gen 3 Prius, but I'm not sure if it's to address the same thing.

MaxMatt 01-27-2009 04:52 PM

After I noticed that straight vertical surface on few cars I started real-life observation and these style of wheel arches is actually on nearly every modern car:

http://www.ford.pl/spg/getImage.asp?...l_LC_13860.jpg

And that's on a pick-up!

And here - an older vehicle - curvy all the way:

http://www.mycompactpickup.com/inclu...ckup/truck.jpg

And an image of my production - it's awful, but I hope it explains something:

http://img216.imageshack.us/img216/1408/archestb1.jpg

After looking at my own picture I think there is sth to do with wide tires better fitting in the new design, but it also reduces the space between the wheel and the fender.

Bicycle Bob 01-27-2009 06:48 PM

I'd vote for that being a styling item, but it lets you continue the curve into a wheel skirt with a simple transition.

Christ 01-27-2009 09:20 PM

I can see a benefit for wider tires, but I can't really see an aero benefit... in fact, I see an aero penalty in the form of increased A.

lunarhighway 01-28-2009 03:12 AM

i assume they might be the "best looking" low drag approach to tires that sit outside the general bodywork, however i don't think they reduce drag...

the problem is what's the alternative? a wider body or a smaller track width, an overall wider body would give you more weight, canceling out the gains perhaps

imo lowering a cars roofline again would be a nice way to start... as this would lower the center of gravity

MaxMatt 01-28-2009 07:49 AM

I read a thread recently: Does lowering the car really help FE? or sth like that and I am quite puzzled. My car has quite smooth underbelly with smooth covers provided by factory. However, a friend after lowering his W124 says it feels more aerodynamic - he doesn't feel that much drag when pushing accelerator. Unfortunatelly no mpg stats from that source...

Here is how my wheel arches look now (not my car though):
http://www.w124performance.com/image...side_front.jpg

You can notice that the metal folds inwards. I thought that by unrolling it to reach vertical surface on the side would decrease the wheel-fender space.

By the way - here is a bodykit mounted on a coupe which helps aerodynamics, but I don't know if it's just about downforce or also reducing drag. Especially the front bumper looks similar to what we can see in Calibra.

http://img218.imageshack.us/img218/9...mmeramgcd3.jpg
http://i14.photobucket.com/albums/a3...24/W124_57.jpg

lunarhighway 01-28-2009 08:23 AM

lowering a car might help in two ways by lowering the car you expose less of the tire so you effectively decrease frontal area, although only just a little... you also cover more of the tire... you may have noticed a lot of cars have airdams that are lower in front of the tire than in the middle, the calibra is on of the earliest cars where this design was mentioned but a lot of modern cars more or less have this design some even have small plastic dams in front of the wheels. it's not entirely clear to my what the effect of shielding the front of the tire actually is, but if factory cars have this, i'm sure it does something.

lowering the car also reduces the ammount of air under the car... this might help to stabilise the air and it also creates a little downforce...

recently a lot of carmakers have introduced "eco" versions of their vehicles... i think VW more or less started the trent with their bluemotion lineup.

one of the things mentioned with most of these cars is that they sit a little lower than the standard model.

donee 01-28-2009 09:35 PM

Hi All,

The vertical section of the new fender style allows the fender to be narrower, for a given amount of tire vertical travel. I think it also stiffens the stamping, resulting in less noise. So, they may have noticed the aero effects - reduction in car cross section area, but probably did it to make the car fit narrower areas, and avoid fender drag scrapings, besides stiffening the fender.

Taylor95 02-01-2019 10:30 PM

2 Attachment(s)
Sorry to bring this back from the dead, but I figured that doing this is better than making a new thread. I agree with the posters that have said that most of the wheels shown are designed with style in mind rather than FE. However, does wheel design affect the overall aerodynamics much? Ten years after the OP I still see cars with similar wheel designs that probably aren't that good as far as aerodynamics are concerned. That being said, I am looking at alloy wheels for my Jeep. Most of the designs are similar to the ones pictured. Is one more aerodynamic than the other? Or would it be better to go with one that is styled more like today's modern cars?

freebeard 02-01-2019 10:57 PM

Of the two you show, the one with the flatter face and less dish would be better. What is the use case for the Jeep? What tires?

The simplest effective treatment would be Moon disks, but they're hard to attach to alloys.

https://i.imgur.com/6lcmS.jpg

You'd need threaded inserts.

https://ecomodder.com/forum/member-f...8-10-25-04.png

Beyond that you're into fancy turbine wheels.

https://i.imgur.com/EpbbL.jpg

redpoint5 02-01-2019 11:08 PM

I had a problem where a power strip wouldn't stick to the bottom of my height adjustable desk using various double sided tape.

I ended up JB Welding a hard drive magnet to the underside of the desk, and one to the power strip. It holds very well now, yet I can remove the power strip if I want.

I'm thinking a hard drive magnet epoxied to the hub of a wheel, and one to the moon disc, would be a very good solution.

Bicycle Bob 02-01-2019 11:36 PM

Quote:

Originally Posted by redpoint5 (Post 590150)
I had a problem where a power strip wouldn't stick to the bottom of my height adjustable desk using various double sided tape.

I ended up JB Welding a hard drive magnet to the underside of the desk, and one to the power strip. It holds very well now, yet I can remove the power strip if I want.

I'm thinking a hard drive magnet epoxied to the hub of a wheel, and one to the moon disc, would be a very good solution.

If I tried that, I'd also have a mechanical interlock so that the disk could not slide off in plane when the wheel hits a pothole.
I don't understand the need for threaded inserts, unless you've stripped out your first set of threads for the traditional installation.

freebeard 02-02-2019 12:07 AM

Quote:

That being said, I am looking at alloy wheels for my Jeep.
I was suggesting why alloys may not be needed. How about these?

http://www.carhubsales.com.au/oc-con...ads/8/1576.jpg
HDT VK SS AERO GENUINE x1 HDT - HSV

Bicycle Bob 02-02-2019 12:19 AM

Quote:

Originally Posted by freebeard (Post 590156)
I was suggesting why alloys may not be needed. How about these?

http://www.carhubsales.com.au/oc-con...ads/8/1576.jpg
HDT VK SS AERO GENUINE x1 HDT - HSV

Those little slots are a turbine to cool brakes, so you'd want to cover them, but it could be permanent.

redpoint5 02-02-2019 12:23 AM

Let's be honest, I appreciate experimenting and improving the efficiency of things.

The problem with the Jeep isn't that it has unaerodynamic wheels, it's that it's a Jeep. I owned a Jeep Liberty for a few years and applied many of the ecodriving techniques, and I averaged something like 18 MPG. The thing is a brick.

I'd drive the Jeep when I need something that behaves like a Jeep, and I'd drive something else when I need to slice through the air and chew up the miles comfortably and efficiently.

Taylor95 02-02-2019 12:57 AM

Right now the Jeep is my daily. Eventually I want to make it into a crawler while still being able to drive it on the street. The biggest tire size I would want to go is 33". I would keep them skinny too--I think 10.50" is the skinniest you can get at 33". 17" wheels and 33" tires I think are a good combo for rock crawling.
I want alloys because they are stronger and because it will reduce rotating mass somewhat.
My Jeep has a lot of sentimental value to me so I really don't want to get a different car. It was my first car. It is a brick but I think I can have the best of both worlds. On another forum, a respected member was able to get almost 25 mpg out of his XJ. I've done my research, and I think I can do even better while still making it more off road capable. It will just be very expensive (like in the thousands). I know I can just get better mpg by buying another car, but there's no challenge to that. I want to challenge the idea that Jeeps can't be fuel efficient. I do want to buy something more efficient though--don't get me wrong. I currently live in an apartment and I can't really have a lot of vehicles.
As far as wheels go, I'll go for the ones that don't have a deep dish then. I assume that having less open space is better?
Using a magnet to attach moonhubs is a very ingenious idea. Do you think it will be safe at highway speeds?

Taylor95 02-02-2019 01:00 AM

Quote:

Originally Posted by freebeard (Post 590156)
I was suggesting why alloys may not be needed. How about these?

http://www.carhubsales.com.au/oc-con...ads/8/1576.jpg
HDT VK SS AERO GENUINE x1 HDT - HSV

Those look pretty cool. It would be something I would consider if I found the right size. Those are probably metric so I don't think it would be an exact fit.
Edit: I'll do some looking around for them. Even I don't want them they would look nice on my wife's car.

freebeard 02-02-2019 02:26 AM

I found them using this search: https://duckduckgo.com/?q=aero+jeep+wheel&ia=images

If your headed toward a rock crawler here are beadlock wheels:

https://static.summitracing.com/glob...184740_w_w.jpg
https://www.jeepforum.com/forum/f12/...meone-1523604/

Quote:

Wheel Circle Track, Series 53, Steel, Black, 15 in. x 8 in., 5 x 4.5 in. Bolt Circle, 4 in. Backspace
These should take Moon disks Okay. :)

Piotrsko 02-02-2019 11:21 AM

I think CHEVY uses a dual nut for hubcaps that is 1/2-20 lh internal thread. Use those with whatever chevy uses for retention. Or use really long lugnuts with the closed ends tapped & threaded.

oldtamiyaphile 02-10-2019 10:50 PM

Quote:

Originally Posted by Taylor95 (Post 590161)
Using a magnet to attach moonhubs is a very ingenious idea. Do you think it will be safe at highway speeds?

It's been done on this forum and failed - but enough magnets should eventually do the trick. You can buy magnets that will hold 100's of pounds of weight, but they cost 100's of dollars.

Gluing magnets means two potential points of failure, the magnet to magnet interface, and the glue itself. The coatings on cheap rare earth magnets fail, and then the magnets crumble. Quality magnets are expensive.

A flying disc can do a lot of damage, and in the era of dash cams you'd want to be certain of your install.

freebeard 02-10-2019 11:50 PM

Use sufficient magnets and you'd bend a Moon disk trying to get it off. They're not that thick.

Taylor95 02-15-2019 05:02 PM

Quote:

Originally Posted by freebeard (Post 590938)
Use sufficient magnets and you'd bend a Moon disk trying to get it off. They're not that thick.

Has anyone actually tried attaching moon disks with magnets?

freebeard 02-15-2019 09:27 PM

I haven't but I have a candidate set of disks. The original three holes were worn out, so I got them for $5 for the set of four at a swap meet.

https://ecomodder.com/forum/member-f...1-100-0960.jpg

If I were to implement this, I'd try pulling on the magnet with a 2nd, more powerful magnet and then ring it off.

Taylor95 02-15-2019 10:55 PM

Those look good. Be sure to let us know how they end up working out!

freebeard 02-15-2019 11:11 PM

Swap meet material.

They could stand planishing and buffing. My intention is to sell the Superbeetle as is and put these Marathon/Jubilee OEM wheels on my last remaining Beetle.

https://ecomodder.com/forum/member-f...7-100-0920.jpg

Maybe they will wind up on those. I wouldn't want to drill holes in them. My son buys magnets for gaming miniatures in bulk.

https://duckduckgo.com/?q=magnets+for+gaming+miniatures

Piotrsko 02-16-2019 11:51 AM

Planishing? There are welds that need to be flattened by force?

freebeard 02-16-2019 01:01 PM

Wouldn't that be hammer welding?

Quote:

Planishing is a metalworking technique that involves finishing the surface by finely shaping and smoothing sheet metal.
https://en.wikipedia.org/wiki/Planishing

I hadn't thought about welding patches in the notches. Instead I was going to fold aluminum disks like a taco and crimp them over the (12) notches and drill holes in them.

Piotrsko 02-17-2019 04:51 PM

I stand by my definition.
I was wondering what you were beating on.

Bicycle Bob 02-17-2019 05:43 PM

Quote:

Originally Posted by Piotrsko (Post 591391)
I stand by my definition.
I was wondering what you were beating on.

It sure looked like a typo to me. A silversmith will shape a piece with hammers not unlike those in a body and fender shop, and then switch to a set of planishing hammers and bucks. They may refine the shape slightly, but their job is to flatten all the tiny imperfections to match the polished hammer face. This is the impact version of burnishing, and both are alternatives to polishing, an abrasive process.

freebeard 02-17-2019 06:21 PM

Quote:

Originally Posted by Taylor95
Those look good.

Quote:

Originally Posted by Piotrsko
I stand by my definition.
I was wondering what you were beating on.

A closeup of on of those disks would make everything clear. They're not show quality at present but they have a lot of potential. Even for some welding. :)

Better to be beat on than beat... [mumble mumble] Hey! How about those wheel wells?


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