Alcoa wheels

[martin300662]

I have just picked up a set of four 16" Alcoa wheels (and two steel inner rear wheels, and a couple of matching spares) for my 20' Argosy.

I saw them on the previous owners Chevy truck; they are hub piloted/stud stand-outs, but rather than the lugs tighten flat on the wheel face, he had what looked like a spacer/load distribution ring between the wheel and the lug nut. This was a complete metal ring, approx 3/8" thick, with the same 8 bolt pattern against which the lug nuts were tightened.

I can't find anything about this ring on the Alcoa website and not sure if I need to still use it - any suggestions?

[martin300662]

Well it turns out this spacer ring hid a multitude of sins....the biggest of which was only one of the wheels was an Alcoa, the others were copies, and all had a different lug type. Needless to say the seller had only 'demonstrated' the one Alcoa.

So now I am looking for a Plan B, and it got me thinking, why keep the smaller 16" wheel? I am going to test fit the larger 19.5" wheels and tires from our 28ft donor, but has anyone else fitted larger wheels and tires on a 20ft.....and I don't mean like these (slightly) crazy Germans?

[mayco]

Not sure if they will work Martin but the 19.5 8r are getting harder to find these days. Just my experience and research. You can still get them but I am concerned about my next tire replacement. May have to replace wheels as well. Make sure you research a bit.

[Smartstream]

Martin I'm not sure about your donor 28' but most have 10 lug 9.5's and only use 5 lugs on the front wheels. My coach with steel wheels the wheels are hub centered and use a "ring" that has countersink drilled holes to use the tapered lug nuts used on lug located wheels. I also have a GM truck that uses the same 10 lug rear 5 lug front hub centered wheel with the flat washer type lug nuts. I talked to a technician at Alcoa and he recommended not to use Alcoa wheels on the 5 lug P-30 front hubs. That being said Airstream and others sold coaches with Alcoa wheels on P-30 chassis. I bought a used set that was from Winnebago. They all seem to use that spacer ring.

If you want 19.5 wheels on your 20 you could switch the rear axles however I don't know if the 5 lug hubs would fit on your 8 lug spindles. You may be able to fit the spindles to the 20' ball joints or even swap the entire "A" frame spindle assembly. GM used a lot of interchangeable parts but not many people are modifying old motorhomes so there isn't much written on the subject. Who knows you may start a new trend.

I'm not sure about Mayco's experience because I find lots of 8x19.5 tires from both major and smaller less known tire brands. My local Les Schwab store carries 3 different brands in stock.

[martin300662]

I hadn't even consider that Dan, I will have to check. Since writing and based on Mayco's advice to research a bit. I now believe the 8 x 6.5 lug pattern was used by Ford up to '03 but on all GMC 8 lug dually wheels. For GMC it seems the last 15 plus years has been a 17" rim - so it would look like that is the way to go.
I have 225/75/16 which work out to 29.3" high (a little more than the original 8.75x16.5), but a lot smaller than the 33.6" of the 8x19.5 used on the bigger motorhomes. Currently GMC use a 235/80/17 which works out to 31.8", which at least on paper is +8% over what I have but 6% under the 19.5. A 225/70/17 would be the same but there aren't many tires available in that size, so it looks like 235/80/17 on a 17" is the best compromise.
I am assuming (simply based on the number of Chevy duallies sold) that a set of 17" GMC wheels will be easier to get.

[Smartstream]

It is indeed a fun game playing with the wheels on these coaches. I hope you find something that makes you happy.

[mayco]

Might have been a local thing but when i bought my tires a couple months ago, i checked with a half dozen or so shops here in Champaign and only found two that dealt the 8r 19.5s. One of which couldnt guarantee a DOT date stamp of less than a year. Um no way. Sooooo, i started reading and it looked like there are still off brands available but personally had trouble finding major brands of that size. I never did research the possibility of buying online and then having a local shop install. Im kinda reluctant to do that but i know some have had good luck with it. Anyway, i was hoping to buy bridgestone, thats the one who couldnt guarantee a recent date stamp but ended up buying hankook....i just wonder whats gonna be available next time around.

[Isuzusweet]

Originally Posted by mayco

Anyway, i was hoping to buy bridgestone, thats the one who couldnt guarantee a recent date stamp but ended up buying hankook....i just wonder whats gonna be available next time around.

Mike

Hankooks AH-11 are the way I'm going too. I do have in storage (dark storage) a couple Michelins XRV's which were on my coach when I bought it but got a deal on a set of 6 almost new Mastercraft 8R's for $450.00 in Ohio when I had bought my rig.
Switching to metric to accomodate my rim width will only happen if I come across an Allison wide ratio 5 sp with a .67% OD to offset the 500+ rpms that will be added by the smaller diameter tire. Even with the same 4 sp Allison you have Mike, John (Shepherd57) is still wanting a higher OD for his TD 325. John has found a 5sp Allison but needs to find out if it is close or wide ratio, before he does the switch.

The tire selection is getting smaller.

Cheers
Tony

PS Someone had fun getting an Airstream body on an Unimog Chassis.

[Smartstream]

I've been running Goodyear's because the 647 is actually mud and snow rated. It's nice when the weather turns nasty. The last ones I bought were at Camping World. They had an unadvertised sale and there was a pallet full of them by the door. I went through the stack and found two that were less than 3 months old. I loaded them up and mounted them at home. They really are pretty easy to mount by hand.

[martin300662]

Originally Posted by Smartstream

Martin I'm not sure about your donor 28' but most have 10 lug 9.5's and only use 5 lugs on the front wheels.

Hi Dan, I have been over the Airstream shop today and think I may have struck lucky. Our donor has 19.5" rims but has 6.5x8 lug wheels all around, so I am going to ask the guys to try fitting those first and see how we go.

They are a full 4 inch greater diameter (so something like 12" longer diameter). I guess that means the speedo will read somewhere around 11-12% under actual, but I think it means we would decrease the cruising revs by the same?

[DA TAZ]

If both units have trubo 400 trans check for the spedo reduction box on the donor's trans you may get lucky