Airing-down 265/75R16 BFG AT T/A KO on 8.5" MB V-Drive wheels?

**ocr14a** · 04-30-2008, 07:34 PM

Hi All.
I just got a set of BFG AT T/A KO tires (265/75R16) on a set of 16" zero-offset MB V-Drive wheels.

We went on a trail run this past Sunday on Metberry Gulch near Woodland Park, CO with some of the Colorado FJs, and everything seemed just fine.

However, at one point, a fellow FJer commented on how the tires seemed to be bulging out a bit.

The thing is, this was said at the main trailhead where some of the group were airing down, but I did not (and was not planning to) air down yet.

He pointed to another rig next to mine and noted how the sidewalls of my tires looked like they were bulging out a bit while the other ones on the other rig were pretty much flush with the rims. He wanted to know what size my rims are (they are 8.5).

As I thought about it more today, I realized that I might have a problem (ok, yep, I'm a bit slow) and want to make sure that I get them swapped out before the one week trial on the wheels is over (at the end of the day this Friday) if need be.

So, do I?

i.e. Given the dimensions stated above, and given where people usually want to air down to for moderate, Colorado off-roading, if I air down on a trail run, will I be in danger of losing a bead or anything with this particular configuration?

I kinda don't think so, but I just figured I better put it out there to you guys and listen to your advice.

steven

UPDATES:
See post #23 about the bulge

**VooDude** · 04-30-2008, 08:36 PM

I am not an expert, but one of the guys at a local tire shop filled me in on this:
A shop is more worried about the tire when they're airing it up for the first time and thus would be more unwilling to mount the tire at a width lower than recommended (my specific example was for BFG AT 285/70/17 on the factory wheels which are at the "minimum wheel width" recommended by BFG). I have no idea if that is the case, but if they were worried about throwing a bead, it would be when they were airing them up. Most Tire manufacturers list the specs on wheel width on their webpages. just my $.02

**ocr14a** · 05-07-2008, 06:06 AM

Thanks for your reply, VooDude.
Sorry for waiting so long to get back to this one....it's just that, I was hoping to get lots of comments, and then the time expired and I think I just forgot about it.

I think I'll be fine.....we'll see, the first time I go aired down out there on the rocks.

steven

Z'sFJ · 05-08-2008, 12:53 AM

Hey Steven. I wouldn't worry about losing a bead. You most likely won't air down enough to have to worry about that. The sidewall will be more prone to trail damage sticking out versus being flush. Not saying that it will happen just more likely. As long as you are careful and pick your lines I would say that you have nothing to worry about. If you put them on some 285's it wouldn't be an issue. Hopefully you kept them. I liked that look on your Sandstorm!

Zane

Fjamming · 05-08-2008, 12:56 AM

I'm curious as to why it would be bulging out when the wheels are wider then they need to be. Usually you get more "bulging out" when you mount a tire on a narrow rim.

layonnn · 05-08-2008, 12:56 AM

i am assuming your wheels are about 8inches wide. That is the correct wheel size for that tire. What PSI do you have them at?

Fjamming · 05-08-2008, 01:02 AM

Quote:

layonnn previously said:

i am assuming your wheels are about 8inches wide. That is the correct wheel size for that tire. What PSI do you have them at?

He's running 8.5" wide wheels.

layonnn · 05-08-2008, 01:21 AM

Man, i always miss information in the title. I never even look there when i am looking for information, dang son.

FJ-Piper · 05-08-2008, 01:25 AM

Could be the difference between Radial tires and Bias Ply. Radials have a tendancy to buldge sometimes making them look low on air.

**ocr14a** · 05-08-2008, 05:51 AM

Quote:

FJ-Piper previously said:

Could be the difference between Radial tires and Bias Ply. Radials have a tendancy to buldge sometimes making them look low on air.

Finally! Man, I've noticed this about a thousand times over the years when running this tire on other vehicles....so is that all it is?

The other day when I was getting gas, I noticed it again on Sandi. So, I got out the presure gauge....... they're all fine (as long as 35 is fine - that's what Discount set them at and I've just left them there).

...and I forgot if I mentioned this yet, but I'm thinking of airing down to 20 for trail runs to see how it goes (not this one on this coming Sunday, because I don't have an air-up system in place yet). Is that too far down with this setup?

steven