My tires are too big!!!

[Greg_B]

I have a set of older Centerline HT II wheels. I have been running these for over 12 years... I cant remember for sure... maybe 15 years...

Anyway... I started out like everyone else with a smaller set of tires... BFG ATs in 11.5 x 32... then I moved up to a 12.50 x 33 tire... about 5 years ago I mounted a set of 12.5 x 35 tires on them.

Not sure why but I got to wondering what the largest tire Centerline recommended for those wheels back in the day... I called them to find out and they said 33" was the largest tire for that wheel.

The question now running through my mind is... is this safe? Do I need to be shopping for new wheels? I have no plans on going smaller with the tires.

Does anyone know of a wheel that looks similar to the HT II? I really like the look of that wheel.... even though it is fairly soft.

On a similar topic... should I stick with 15" wheels if I do buy new? Or would a larger wheel open up more tire choices?

Greg

http://classicbroncos.com/photos/showphoto.php/photo/23330/ppuser/28000

 

[JWMcCrary]

I think running a 35" tire for the last 5 years on them should answer the question about safe..???

Looking at the pic in your link I don't see anything wrong with those wheels and a 35" tire.

 

[Greg_B]

Well thats what I thought but I am not a chemist or enginneer... I didnt know if the metal would fatige over time due to some strange aluminum / rubber / O2 compound created when a tire stays on a rim for years...

J/K... but seriously... I didnt want to think I have been living on the edge for years with that setup and today is the day they let go.

I wonder why tire diameter has a bearing on it? Smaller tires run higher pressure in them plus the taller sidewall should add more impact resistance I would think.

Greg

 

[gearida]

Well i went to a larger diameter wheel because when I was in high school one of the older guys who had money that we ran with bought a new Chebby 4 X 4 and ran 44s on it, lifted sky high. One morning he had a flat on the front. That truck fell so far down, rim in the road that he lost control and into the medium and almost rolled. Since then I thought that his 15" wheel had it been larger he may not have dropped that corner of the truck so far down. With that thought, maybe that is why Centerline said they only recommended a 33" tire.

 

[DirtDonk]

But with a tire that's 44 inches tall, just think how large the wheel would have to be to not drop that far down. Even with 22's you're still running on some serious sidewall height. There's just no getting around it. At that height, something's gonna fall.
With heavy-equipment and tractor-stiff sidewalls on the tires, even Bigfoot and Grave Digger still fall over when they lose a tire. And those wheels are huge!

The question with yours Greg, I think falls into one category with two headings:
Warranty and Lawyers
Pretty simple. Centerline just had to choose a size they felt was sensible and, back then, 35's were considered to be pretty big tires. Only a very few specialty companies made anything larger. And most mainstream companies were just dabbling with things over 33 inches anyway. So probably not as much safety testing was done with those sizes as they do nowadays.
Up until just a few years ago in fact, I think the only wheels you could find that did cover anything over 33 were Weld (but only a few of the forged ones if I remember) and Alcoa/Micky Thompson.
Even then though (again, if I'm remembering correctly) at first only the M/T's were warranteed for 35's, not the Alcoas. Even though they were both made in the same factory.

Yes, a larger diameter tire does put more stresses on a wheel. Mainly at the hub/mount/flange area I'd guess. So Centerline might have been concerned about that, but those HTII's are pretty robust wheels if I remember. So I wouldn't worry about them any more than I would about anything else in that category. Might depend more on how you drive it than the actual product.

Are those HTII's the cast aluminum ones wth the 5-pointed star centers? OR are they the thinner spun-aluminum ones that Centerline made? Seems to me the "II" series was the heavier cast variety. And if so, I'd say you're fine unless things get abusive or you have an accident.
Or hit a curb REAL hard. But then, I've seen 'em break with smaller tires than that under those circumstances.

Paul

 

[Bronco69Sport]

I run 37" boggers on 15s there is no safe rim for them. Only minimally safer... I mean MINIMALLY.

 

[jim3326]

You didn't mention the width of the wheel. With the wider tire you have to have a wider wheel, an 8" wheel will handle a 11.5 tire barely and scary and not recommended, with the 12.5 you will need a 10" wide wheel, that is probably what they were talking about.

Jim W.

 

[Greg_B]

Sorry... they are 15 x 10s...

They told me they never made a two piece welded wheel for a tire larger than a 33.

The HTIIs are the 5 spoke flutes rim model and are pretty heavy duty... they are cast... the flange area is about 3/4" thick if not more.

These wheels have been my favorite since way before I bought them.

Seems like the newer tires are not made for 15" rims anymore. I have a set of MT ATZs on my Tacoma DD and I wouldnt mind a set on my EB but they dont make a 15 x 35... I am considering the MTZ tire but I would like to hear how loud they are... My Procomp MTs are screaming loud.

Greg

 

[DirtDonk]

...an 8" wheel will handle a 11.5 tire barely and scary and not recommended, with the 12.5 you will need a 10" wide wheel, that is probably what they were talking about...

I partly disagree with you here Jim. Not that a 10" wide wheel might not be better than an 8", under some circumstances, but scary is not a term I'd use. Done the narrow-rim thing many times myself, on different vehicles, and had nothing but good results. Until I bought my Thornbirds that is. But I can't lay blame on the wheels specifically because I haven't used the same tire on another rim width. So I've got nothing to compare to there. I just think Thornbirds suck on wet pavement!

If there are good and bad here then, it might depend on the particular model of tire more than anything else. Some of the tire manufacturers even use 8 or 8.5 inch wide wheels in their "range" of recommendations for both the 33 x 12.50 and 35 x 12.50 tires. BFG lists 8.5 to 10 as their range for the 12.50 x 15 tires if I remember.
I figure not much difference between an 8 and an 8 1/2 inch wide wheel in most cases, so probably not not so much a dangerous thing, as perhaps not optimum.
The air pressure needs will certainly change, but narrower wheels can work better at bead-retention and protecting the rim edges.
I got 67,000 miles out of a set of General Grabber M/T's with 15x8 wheels on my IFS Chevy with 6" lift. Then another 30,000 on a set of BFG muds and they still looked practically brand new when I sold it.
The truck handled the roads great on both as well, in good weather and bad.

Not trying to gainsay your own personal experience, just adding mine and others. If you had a bad experience with that setup, it's certainly legit. Just not universal.

Paul

 

[jim3326]

I suppose "scary" wasn't quite the right term. I have just seen a few blow the bead under low pressure and extreme conditions. Mudders might not have the same issues, I just don't think a tire should look like a donut, but that's just my $.02.

Jim W.

 

[broncnaz]

The main reason they probably only recommeded a 33in tire on those rims is Rim strenght or load rating. Cast rims are thick because they have to be to gain strenght. Even then they are still fairly weak compared to steel or forged wheels. Thickness doesnt mean they are all that strong. they are probably about as thick as they can be for all intesive purposes. But 33x12.50 tires and 10in rims is fine and with the lighter weight of a bronco it should be no problem at all.

 

[stock1970]

33s are safe, 35s are dangerous, 37 are safe again.. go with some 37s or larger.. lol

 

[Greg_B]

The main reason they probably only recommeded a 33in tire on those rims is Rim strenght or load rating. Cast rims are thick because they have to be to gain strenght. Even then they are still fairly weak compared to steel or forged wheels. Thickness doesnt mean they are all that strong. they are probably about as thick as they can be for all intesive purposes. But 33x12.50 tires and 10in rims is fine and with the lighter weight of a bronco it should be no problem at all.

I appreciate the fact that 33 are safe... that is what Centerline says as well. Unfortunatly I am running 35's. I have been for years with no problem. I posted this to see if anyone had ever heard of a problem with this setup. I certianly do not want to be driving around with a potentially dangerous combination of tires and wheels.

As far as the lighter weight of a Bronco... I thought these things were pretty heavey for their size. If I remember right a few years ago everyone was weighing thier Broncos and they ranged from 3800 to 4800 lbs according to how they are built. Thats pretty heavy... I think that is almost as much as a new F150 4x4.

I "believe" they will be safe I just wanted to make sure there were no horror stories out there I guess.

Greg

 

[broncnaz]

While broncos are heavy you cant load them up as you can a pickup so basically you'll never have much more than vehicle weight so that would be the differance and at which point i would guess that 35's would be ok although I'm really not quite sure of why they have a tire height limit Might just be leverage factors on the rims are more with bigger tires.

 

[needabronco]

It's all legal CYA!

Several Bronco owners have been running 35's on 7.5-8" wide rims for years, I have 35's on an 8" wide rim myself. The bigger challenge is finding a tire shop that will mount them, again legal CYA! The biggest problem is that the tread pattern won't be 'square' like it would be with a wider wheel. My opinion is your fine! If you were running the same combo on an F350 that see's serious towing/hualing duty then you would likely not be safe...

 

[DirtDonk]

..I have just seen a few blow the bead under low pressure and extreme conditions...

And my personal experience has been the opposite. I've seen it happen more often when the rim was too wide for the tire size. Such as having a 10.50 tire mounted to a 10" wide rim. Watched one peel right off the wheel when she made a turn into the kid's school and through a tiny bit of water in the gutter. I was about to tell her that she was running low on one tire. Too late.
Just peeled that sucker off slicker'n a tire machine at 5pm on a Friday. An extreme case of course, and most likely out of the normal recommendation of the tire manufacturer, but it was a wide wheel/narrow tire thing nonetheless.
With the narrower tire scenario, you should have better bead retention at lower pressures than the wider wheel would, due to the inherent pressure of the tire bead at it's neutral size trying to push out on the bead. With a wider wheel, you need more pressure to retain the bead. Look at an unmounted tire sometime and I bet you find a bead-to-bead measurement of roughly 7" on a 12.50" wide tire. Takes a lot of pressure to keep that tire bead pulled way out on a 10" wide rim compared to say a 7" wide one.
Desert racers in the '60's and '70's often ran their 12.50" wide tires on as narrow as 7" wide wheels on Class 8 full size trucks. Not because they couldn't get wider ones, but because of better bead retention, more protection of the rim bead area from rocks and other impacts, and probably too, because it was easier to find an off-the-shelf wheel with an offset more appropriate to their race chassis setup. Obviously, tire wear over many thousands of miles was not their concern. Keeping the tire on the wheel with potentially lower tire pressures probably was though.

Learning from the motorcycle crowd no doubt, as needs and technology changed, we ended up with bead lock wheels so that they could have their cake and eat it too.

...Mudders might not have the same issues, I just don't think a tire should look like a donut, but that's just my $.02...

Maybe, but within the same manufacturer, probably not. I can't say for all, but I bet a lot of M/T's and A/T's, within a manufacturer, run the same basic carcass design.
And as you probably guessed, I actually like the look of a narrower wheel combination and don't think it looks like a donut until you get to the extremes. I think an 8 inch wheel with an 11.50 or 12.50 inch tire looks good. I've always run my 11.50's on 7's, so going up one size each would fit just right in with my personal tastes.

Paul