DamonB

We all know the early FD wheel design was changed because they were prone to cracking. The pics below show one of my "improved" design wheels which has cracked. Since in my possession (approx 7 years) this wheel has seen mostly street use but has had sticky track tires mounted to it on a few occasions. I can't say what it's life was like before I got it, but apparently the improved wheels are not impervious to failure after all these years.

The failure ocurred while on the right front of the car with stock sized street tires. I happened to notice it while washing the car; the crack wasn't there two weeks earlier when I had washed it last. I don't recall striking any curbs, potholes etc and the wheel seems to have failed from fatigue as the crack began behind the spoke.

I had the tire remounted onto one of my spare wheels and then broke the failed wheel in my hydraulic press to ensure it may never be used on another vehicle. Maybe it will make a nice hose reel

I will certainly keep a closer eye on all my stock wheels as they are all about 15 years old now. Check your on occasion too.

JTurtonRX_7

Get a piece of glass from pier 1 and make a table out of it like i did with my broken wheel

dubulup

show the WAR ROOM PICTURE!!!

JTurtonRX_7

Ultimate coffee table

do it

theorie

iTrader: (31)

i did the same thing with two extra rims i had!!!

here's mine

Mahjik

iTrader: (1)

TBH, I've seen more reinforced rims crack than the non-reinforced rims. That might be because people are just reporting the failures more that the others, but just my observation over the years.

sevensix

iTrader: (1)

^^^ thats my experience as well. more reinforced ones are cracking, looked JUST like that

mono4lamar

iTrader: (32)

Wow, I've never seen a crack on the spoke like that! I've had a bunch crack at the beat seat...

dgeesaman

iTrader: (7)

Damon, were you able to look at the crack surface and find fatigue marks or the initiation site?

Dave

Sr20fd3st

that really looks like torsional damage. just the way it goes straigh across the top and then the split goes off left and right. maybe cracked during some front wheel hop during a sudden hard turn

adam c

iTrader: (2)

Yikes!!! Its a good thing you noticed it. I guess I better start washing my car more often

Wargasm

Aren't those the non-reinforced ones?

http://www.fd3s.net/wheel_cracking.jpg

scotty305

iTrader: (2)

Good catch, Wargasm. According to that article,it looks like Damon had non-reinforced wheels.

-s-

Larz

This is why I race on SSR's. Forged for strength and light weight.

sevensix

iTrader: (1)

damon never said he had the reinforced

kuroi FD

The pics below show one of my "improved" design wheels which has cracked.

yes he did.

DamonB

I haven't bothered to study it that hard. From the shape of the crack it had to have started behind the spoke as a result of bending or possibly from the edge of the spoke as a result of torque. If from the edge I find it hard to believe that two seperate cracks from each side of the spoke were started when this wheel was mounted on the front, so it only sees torque in one direction.

The crack doesn't go all the way across the front of the spoke, there is some material on the face that is still solid; you have to look cery closely. The back however is cracked all the way across and is actually two seperate cracks that start from the spoke edges. This leads me to believe it failed at the back of the spoke from bending.

I could be mistaken. From memory I thought these were the improved ones. The wheel in my pics would be the one on the left in your link.

What surprises me most is that this wheel was daily driven on street tires when it failed and two weeks ago it was fine. The cracks formed and propagated in that small amount of time just driving to work and back.

DamonB

Don't have one. I didn't completely smash it, I just put enough pressure on it to make it very obvious as the crack goes all the way through now. I then hit that damaged area with some yellow paint for good measure I think I'll hang it and coil my airhoses around it.

You coffee table guys apparently don't have female co-habitators

DaveW

IMO (I am a mechanical/structural engineer) you are correct.

It could also have had hidden defects (porosity, etc.) that may have caused the crack to start. However, looking at the wheel structure, that area (the inside edge of the spoke - high bending stress, and cross-section becomes smaller) is most likely the highest-stressed area in bending in the wheel, and would be the logical place for fatigue cracks to form.

Dave

dradon03

iTrader: (2)

Eugh SSR's which model aren't they semi-forged process?

Also he said it was the reuslt of street driving.

saxyman990

Yep! This is the exact spot that fatigue cracks typically form on the non-reinforced wheels. When Mazda had them redesigned, they added material to this area to help reduce the propagation of cracks.

NOTE: since aluminum has no endurance limit, even the newer reinforced wheels WILL crack over time. Generally, the cracks that I see on the reinforced versions occur on the spokes, but closer to the rim.

-Rob

3GRX7

iTrader: (1)

Exactly what I was thinking

DriftTrix

My proibibly none reinforced wheel had a crack in it I noticed a couple months ago. My co-habitor wouldnt let me hang it up in the living room =D

TitaniumTT

That's a frightening thought. Didn't Mazda squeeze cast these wheels to minimize the porosity?

I was lucky - I powdercoated a rotor and got it ontop of the entertainment center. Although, occasionally the flowers I bring home end up blocking my view of my handywork

wanklin

iTrader: (2)

We're glad you caught it "early" Damon. feeuwww