Trim Rings on 2006

The "trim rings' are there to assist the flow of air around and past the wheel well.

 

Tom (isn't it?), did you learn this somewhere via Toyota information, or do you just surmise it? I've seen it posted before, but with no backup.

I also have a hard time believing it. :huh:

 

In any case, Walker, yes, hundreds of thousands of ill-conceived trim rings should now be collected and melted down to make, uh---what COULD we make, other then a giant gray plastic blob?

 

we could make sharon valerii cylons

 

Yes, but I don't remember where it was. I know that there is a lot about airflow on the Prius that isn't really obvious. I was driving through some farming country in the evening and when I got home there were all these little black spots from about 6" ahead of the antenna down to the top of the hatch window. (My Prius is white so they were pretty obvious.) They wipped right off and when I looked closely they were small flies. It kind of woke me up to one of the reasons for the shape of the Prius.

It just makes sense if you look at the front of the car. Air will be compressed as it flows around the bumper and then it would get sucked into the front wheelwell and cause drag because it couldn't flow out the back of the wheelwell and would need to be compressed under the car. I think the issue with the rear wheelwell is more of a flow of air compressed under the car and up along the side panels. Once the air is moving towards the rear you want to minimize the disturbance of that laminar air flow. Removing the trim rings would encourage the air to suck into the wheelwell and cause additional drag.

 

Than should I remove the mud flaps that I recently installed?
Kathleen

 

Ah yes. Asuming they are "ill-conceived".

However, in some cases the trim rings serve an important purpose. Some cars use the design of the wheel rings to pull heat away from the disk brakes. I read on another forum where a guy was rotating his tires and got the trim rings on the wrong sides which resulted in the rotors warping. He thought they were suppose to scoop air into the brakes while they were really designed to create a small vacum to suck the hot air out of the brake area. BTW, this was a production car and not something designed just for competition.

IMO, Toyota uses the trim rings to reduce the drag of the wheelwells.

 

I don't have the mud flaps. I just wash my car one a week so they're not an issue for me.

 

Hmmm... I took mine off because I like the way the wheels look without them, but if they help keep the drag down, maybe I'll put them back on.

I knew I should have bought those racing disk moon covers... :lol:

 

Found this out in Google land.

"I noticed that the alloy wheels have a suspicious looking plastic wheel cover on the outer rim. This easily pops off using the provided tire tool to reveal a nice sporty 6 spoke rim, similar to that of the RAV4. After about a week without the covers, I noticed a drop of 3-4 MPG, which I can only assume is related to the poor aerodynamics of the alloy wheel. Seems the folks at Toyota bought a few more MPGs by adding the plastic covers after a few wind tunnel tests found disturbance around the alloys. (Stick with the wheel covers)"

Nothing definitive but....

Here's the link:

http://greendeed.com/

 

Took mine off sometime ago and have not seen any noticeable drop in mileage. Really like the look better.

It is a beautiful day in SD!!! Time to get the dog in the car and go someplace!

 

I do understand what you're saying here. And let me add that there is NOTHING even approaching "laminar" flow in and around those wheel wells. Well... nothing on the whole car, but ESPECAILLY around the wheel wells. With the spinning tire/wheel, and the gaping hole of the well itself, the air is so mixed up in there that I'd have great difficulty in believing that something like the wheel trim ring could change the drag of the entire vehilce system in any meaningful way. A case could almost be made for smooth hub caps, or even skirts. But without full wind-tunnel testing, all we can do is guess. I have yet to hear of any wheel treatment short of a skirt that can significantly change the cd of a full-size vehicle.

** But I've been wrong before!

 

This subject has been debated since the beginning of Pruischat and it boils down to a matter of personal preference. There is no evidence that the trim rings were provided for anything but looks. I think the wheels look better without them.

 

Well, based on this thread, I just popped mine back on for a while. I am driving up to New Hampshire for a few weeks for business. Hopefully, I will be able to determine whether or not they make any difference.

Visually, I prefer the wheels without the rings, but if they get me a few miles more from each gallon, I'll go with form over function anytime. [edit] Make that function over form! [/edit]

 

about 7,000 km's with them on and 15,000 with them off and looking at the mileage spreadsheet guess what............ no difference. Now on the HCH '06 maybe those wheels make a difference but the mag on a Prius. spare me. I pulled the rings off one side of her car and called her out to have a look at both sides. Her comment was throw them away. They're in the basement. The Toyota Division rep that looked at her car said they are on it for airflow. I want to see the film from the wind tunnel to support the claim.

 

Nope. You'd be going with function over form.

 

Anyone who thinks the trim rings give you better mileage can buy my set and run two sets at the same time for really good mileage.
Or better yet I have some magnets that you cap put on your carbuator and get 100 MPG

 

Doh! Beaten to the punch. My trim rings are shown to improve mileage by 10%* (one test vehicle, for one mile, no season testing complete). I am willing to sell them for just $59.99 plus shipping.


*no guarantees of anything I say, beyond the fact that I'll sell mine to you.