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Alcoa Wheel info and questions (offset, valve stems, etc.)

Posted: March 26th, 2021, 12:22 pm
by Blue~Go
Hi folks,

It's time for new tires on my Chinook and I'm considering moving to Alcoa aluminum rims.

The Alcoa rims that matched our original Ford wheels are no longer made (they stopped around 2016 or so), and the newer Alcoa rims that are available have a larger offset than the matching ones did. I run stock on everything (wheel and tire wise anyway). 2WD, 16" stock sized tires, etc. [Edited to add: But I do have a complete 2014 front end with the bigger brakes and improved suspension components]

I understand offset by the book, but it seems like with vehicles there can be things that show up when actually installing that aren't obvious just by book numbers. Since I will need to have the valve stem holes drilled out to fit my extended stems, there won't be any "returning" them once I try them out. So...

The stock offset (which was the same on the discontinued Alcoa rims) was 5.15"
The offset on the currently available Alcoa rims is 5.40"

If I'm envisioning this correctly, the front wheel/tire would thus sit about 1/4" inward of where they are now, and the rear (outer) ones would sit about 1/4" outward of where they are now (inner rim stays steelie).

A note: I have the 2014 front end with the bigger brakes and other larger components. I'm not sure if that means that a front wheel with more offset could be more problematic than with the earlier front end?

More offset wouldn't be my choice on the rear as the stock offset is already kind of "sticky outy" as compared to the fiberglass body, but what can you do.

Has anyone installed these? Any issues? Anyone with the 2009-up front end?

Also, for anyone who had the rims drilled out to fit the Tireman/Borg extended valve stems, where did you have that done. Machine shop? Tips?


PS: For reference.
Original size Alcoa rims for our E-350 21-ers were part numbers 160241 (front) and 160242 (rear) These were 5.15" offset.

Currently available Alcoa rims for our E-350 are part numbers 160281 (front) and 160282 (rear). These have 5.40" offset.

Re: Alcoa Wheel Offset change ok?

Posted: March 29th, 2021, 11:38 am
by Blue~Go
So this is getting a bit more complicated than just offset, and I thought I would write down what I know at this point. I got this info by calling an Alcoa dealer, plus talking to the parts guru at Borg (who make the extended stems).

So first of all, the Ford steel 8-hand-hole 16" wheels have a .453" hole where you mount the valve stem. Tireman's stems (apparently no longer available) and the (original) Borg stems were made to this diameter. Alcoa wheels though, have a 9.7mm valve stem hole, which is ~.381" So this is why a person would have to drill out the valve stem holes in the Alcoa wheels to fit the Tireman or (original) Borg extended stems.

This is actually partially what discouraged me from getting Alcoa wheels sooner. I like my extended valve stems (mine happen to be Tireman), but I wasn't super fond of the idea of having my new Alcoa wheels drilled out (especially if I got the Dura Bright ones). So I kept running with the steel wheels which I think may be at least part of my "unbalanced" problem.

But now Borg has started making extended stems that are 9.7mm and fit the Alcoa wheels as built. Yippee!

So next I was trying to figure out which stems (or kit of stems) would make it so they stuck out at all the correct angles like my Tireman stems. However, I found out it's not that simple, because the valve hole in the Alcoa wheels is in a different place than the one on the Ford steel wheels. This actually means one may not need the dramatic U-shaped rear/outer stems.

The parts person at Borg actually recommended I get the Alcoa wheels and then set them up on my bench and see what I'd need. The wheels do come with some solid metal stems which might already work. I wondered why I'd be having to "invent the wheel" here, which is when she said they only recently started making the slimmer stems for the Alcoa wheel native stem size.

Or at least that is what I could glean so far.

Borg original extended stems (the .543" ones, were 515 series (?) and used a "grommet" style seal (this is a hat shaped rubber thing that seals the stem to the wheel and that's also what my Tireman stems used. Never a problem.

I will add to this as/if I find out more. Anyone else of course feel free to chime in. I still am pretty sure the additional offset on the Alcoa wheels will be fine, but if anyone has used them that would be nice to know.

Additional notes:

Borg 540 series uses an o-ring (not as good)
Borg 550 series uses a grommet (the better hat-shaped rubber type) (this stye was used on my Tireman stems)
Buytruckwheels includes 553-C stems on both front and rear which may work as-is (?)

Re: Alcoa Wheel info and questions (offset, valve stems, etc.)

Posted: May 5th, 2021, 5:38 pm
by JabberBox
When people install Alcoa's they generally only purchase four wheels, two front and two rear. The rear inner wheels remain stock steel wheels.
Im thinking the reason is that the lug studs may not be long enough for two thick aluminum wheels? That said i dont follow your valve stem concerns considering your inner rear wheels which will be steel can use an off the shelf extended stem not an Alcoa stem. Also the wheels on the E series are hub-centric. Im not certain you can sandwich two Alcoa's on the rear axle hub and still have the outer wheel making contact with the hub-centric shoulder on the hub?

Disregard, i see now that you recognize the need for retaining the rear inner steal wheel. I overlooked it the first time i read your post.

Re: Alcoa Wheel info and questions (offset, valve stems, etc.)

Posted: May 6th, 2021, 3:37 pm
by JabberBox
This is the hub-centric shoulder im talking about..
I feel i should also mention that if you manage to sandwich two aluminum Alcoa's on the the rear hub, make certain you do routine maintenance by removing the wheels periodically and smearing some anti-seize or similar product on that shoulder or you may never get the inside wheel off again due galvanic corrosion.

Re: Alcoa Wheel info and questions (offset, valve stems, etc.)

Posted: May 18th, 2021, 7:33 am
by markatherton
I drilled out my valve stem holes with a common drill and drill bit; Took all of 30 seconds per wheel. You might be making a bigger issue of it than it is...