M35A3 Tires , Something to keep a eye on .

[SEAFIRE]

Do the rear 15.5R20's rub at all? how about going over bumps and such?

We had a chance to get some brand new 15.5R20's on rims for $125 each, but passed it up as we didn't think they would fit, the rims weren't deuce rims, maybe 5-ton.

 

[R Racing]

So far no hitting issues on my A3 what so ever but I haven't went extream offroading yet either, lol . Were did you find the 15.5 x 20s at ?

 

[mktopside]

So far no hitting issues on my A3 what so ever but I haven't went extream offroading yet either, lol . Were did you find the 15.5 x 20s at ?

Yea really, are they still for sale? I'll buy them today! Lol

 

[SEAFIRE]

These are/were at the DRMO yard in San Antonio.

They never have the size or quantity of tires/rims we need. Always some kind of oddball stuff that won't fit our deuces. We did get three brand new 12.5R20's there for $125 each, wish they had more....

I've never seen 14.5R20's there. They also had/have 14.0R20's and 16.0R20's brand new on pallets without rims.

I had never seen the 15.5R20 tire size before, I guess they are for 5 ton trucks?

 

[gringeltaube]

.......I had never seen the 15.5R20 tire size before, I guess they are for 5 ton trucks?

Yes, 5ton and up.... It's a heavy, extra- high load capacity tire. Six of them, put on a M54 W/W could still carry more than twice the max. highway cargo load, at 50mph...... if the wheels (plus everything else) were strong enough!

Actual tire data, below...

G.

 

[Rustygears]

The biggest problem I have seen on the A3 tires losing air has been the grommets. I have never had a CTIS wheel cylinder leak, not the tubing. The large wheel o-ring hasn't leaked either. Like previously, the grommets are dry rotted and/or loose due to a loose nut. I happen to like the CTIS system. Perhaps if mine didn't work well, I would have a different opinion. The only thing I don't like about the CTIS system is that you have to screw with it when you remove a wheel.

I have a few gross leakers on my A3. Can you please describe where these grommets are located? I don't think the actual tire has a hole and the CTIS lines aren't letting any air out so it must be something else. I'd love to avoid destroying a tire sidewalk and fix the problem so the air stays up for over a week in those tires

Thanks!

 

[glcaines]

If you look at the brass tube that feeds air to the tire from the CTIS, it terminates through a hole in the wheel. You can see the grommet in the photo between the brass nut and the valve stem. They are supposed to be torqued at 45 - 60 Lb- Ft, but are commonly found finger tight with dry-rotted grommets. Erik's sells them new. To replace the grommet, the wheel has to be completely dismounted which calls for a new o-ring, also available at Erik's.

It is very important that minimal disturbance occurs with the valve stem. When disconnecting the CTIS plumbing, it is very easy to move the valve stem, which disturbs the seal with the wheel. If it is moved, you will likely have a leak. Don't be afraid to torque them to the proper specification, although it sounds high. The TM covers this fairly well.

 

[Rustygears]

Thanks much for the detailed info and pix! This gives me a good starting point to figure out those leaky wheels. Thankfully that setup is only used on the super singles. I can't imagine having to maintain O rings, grommets, wheel valves for 10 wheels!