tires and wheels RE: Octavo 100+ bummer... lotsa pics here

[john_a]

Hijacked this thread from the next older page.

I was informed my Octavo 100+ wheels are toast. After media blasting, they found most of the steel lug inserts to be cracked...

Delia

Is this a common problem for 100+ wheels?

Last set I got, I had to throw in the trash. The aluminum around all the steel lug inserts was shot -- soft & cracked. These were Alfa fitment for my Mustang (4x108), but the larger bolt circle also had a bigger centerbore than BMW, so there was too little material between the lug hole & c-bore. I'm sure most 100+ wheels are in far better shape than these pictured here, but I was shocked to see how marginal the design was (at least for this Alfa application.)

For just being old and worn out (not bent on rim flange or curbed), these were the worst condition alloy wheels I had seen in quite a while.

Delia, if the steel inserts did not stay fixed in place (or cracked), the hole they are pressed in is probably too far gone to save.

more pics

This centerbore is not even round ! I think the center cap is keeping it from total collapse.

Wheels take a lot of stress, don't take a risk (see these street Revolutions, they could not hold up on an IT racecar!)

[Delia]

Jeez-Lou-eez!

That's not a pretty sight.

My Octavo 100+ wheels aren't quite that bad, but the disasterous racing picture is good incentive to think twice about wheels, old or new.

I was extra careful re-doing my Minilite "Doublefin" Sport Wheels with custom made copies of the original steel lug inserts and shank-type lugnuts. Fortunately, they were nice enough to use without refinishing.

Many, many thanks, John for the heads-up!

Let's be careful out there!

Delia

[f1reverb]

my parts-car 100+. I'm curious what other wheels use this type of design, aside from Delia's Minilites. Could the steel and the aluminum, or some coating/alloy on either have caused extreme corrosion of the alum? I'm gonna check my bottlecaps and e30 BBS too since I don't remember whether they have inserts or not. Thanks for the post from me too.

[MichaelP]

Using steel inserts for aluminum wheels is a recipe for disaster - or more specifically, galvanic corrosion. Both steel and aluminum are anodic metals (as opposed to noble -- or how corrosive they are in seawater) and are best isolated by plastic or brass (something, anything) whether your building buildings, boats or cars, especially in exterior applications. Over time, the alloys in the metals react to one another (spurred on by salts), ionizing the aluminum and creating a corrosion layer. I'm guessing the aluminum failure in the Octavos is the galvanic stress of the new corrosion layer having nowhere to go but outward.

Short story: don't use steel (or some kinds of stainless) and aluminum together without something in between. Here's a handy chart:

Galvanic Corrosion Information

* The Galvanic Corrosion table is a measure of how dissimilar metals will react in sea water.

* Generally, the further apart items are on the table the greater the galvanic corrosion that will result.

* The material closest to the anodic end will corrode more rapidly.

Noble (Least Corrosive)

Platinum

Gold

Graphite

Silver

Stainless steel, type 316 (passive)

Stainless steel, type 304 (passive)

Titanium

Stainless steel, type 410 (passive)

7Ni-33Cu alloy

75Ni-16Cr-7Fe alloy (passive)

Nickel (passive)

Silver solder

M-Bronze

G-Bronze

70-30 cupro-nickel

Silicon bronze

Copper

Red brass

Aluminum bronze

Admiralty brass

Yellow brass

76Ni-16Cr-7Fe alloy (active)

Nickel (active)

Naval brass

Manganese bronze

Muntz metal

Tin

Lead

Stainless steel, type 316 (active)

Stainless steel, type 304 (active)

Stainless steel, type 410 (active)

Cast iron

Mild steel

Aluminum 2017, 2024, 2117

Cadmium

Alclad

Aluminum 1100, 3003, 3004, 5052, 6063

Galvanized steel

Zinc

Magnesium alloys

Magnesium

Anodic (Most Corrosive)

[Delia]

My new Minilite lugnut inserts are machined from stainless, so based on your chart, I feel a little better.

My sunroof tii (from the South and Southwest) is a "fair weather" driver and stays out of the rain/wet. I've washed it once in the five years I've owned it.

Thanks,

Delia