Tire stability on narrow tires

[Zen89]

That's a stick bud lol


Would you say like you're floating?
That's more of a symptom of over filled not under filled tires, since when you drive the faster you drive the more narrow your tires get ergo less traction. This is why you see wider tires for drag/race cars.

Not doubting you, but my tires are sitting at 36psi and I have a BD also, are you sure 39psi what they should be set at? I'll look at mine in the morning to verify I'm not running low. And the AT3's are a great tire, I have them on my truck with no issues. From time to time I feel the floating sensation from the back tires but I keep them 5psi over for when the trailer is on.

I went and checked and the door says 39psi. Yes you could say it feels like floating and yes it’s the rear tires. Is this normal with these Toyo at3’s?

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[mybikeisred]

Could it maybe be that you’re getting more lateral flex in the sidewalls because the rim is kind of wide for that tire width? Your tire is only 1.5” wider than the rim. I’ve never run a large diameter tire on wheels that were less than 2.5” under the tire width. Right now, I’m running the same size rim as you with a 35x12.50 and don’t have any of that feeling even at 35lbs with mud tires that have large tread blocks. The stock Sasquatch wheels are a half inch narrower for a tire almost two inches wider. I’m no physics professor and probably can’t explain it correctly, especially without drawing pictures, but it makes sense in my little brain that you would get more side to side flex the more vertical the sidewalls are. It’s also quite possible that I’m full of shit and don’t know wtf I’m talking about.

 

[Havoc1]

My guesses

1. Alignment
2. Taller tread blocks
3. Wheel balance (lateral runout issue)

Edit: if the alignment doesn't work, I would ask if they can road force your tires.

 

[mybikeisred]

Could it maybe be that you’re getting more lateral flex in the sidewalls because the rim is kind of wide for that tire width? Your tire is only 1.5” wider than the rim. I’ve never run a large diameter tire on wheels that were less than 2.5” under the tire width. Right now, I’m running the same size rim as you with a 35x12.50 and don’t have any of that feeling even at 35lbs with mud tires that have large tread blocks. The stock Sasquatch wheels are a half inch narrower for a tire almost two inches wider. I’m no physics professor and probably can’t explain it correctly, especially without drawing pictures, but it makes sense in my little brain that you would get more side to side flex the more vertical the sidewalls are. It’s also quite possible that I’m full of shit and don’t know wtf I’m talking about.

It does list the 17x9 as the maximum approved rim width for that tire on the Toyo website, but I think if you went to a narrower wheel, it might take out some of the lateral flex in the sidewall.

 

[Copperhorse73]

I’d lower them to 35 psi , at least in the rear, and give it a test.

 

[Jhuff]

I went with 35x10.5 Kenda RTs and have no issues at 40psi.

As far as tire pressure, anytime I change wheels, tires, or normal payload; I will ignore the factory suggestions.

I like to do the chalk test, where you use sidewalk chalk and clean concrete to get a clear indication of how the tread is contacting the pavement. If the tread pattern on the concrete is lighter on the outside than the center of the tread, you're overinflated.

 

[LockedBronco]

I went with 35x10.5 Kenda RTs and have no issues at 40psi.

As far as tire pressure, anytime I change wheels, tires, or normal payload; I will ignore the factory suggestions.

I like to do the chalk test, where you use sidewalk chalk and clean concrete to get a clear indication of how the tread is contacting the pavement. If the tread pattern on the concrete is lighter on the outside than the center of the tread, you're overinflated.

Yes that's exactly it

Also short wheel base at high speed on bad roads doesn't help

 

[swami37]

blow up the tires...40 is too low

 

[Phil]

Hey everyone,

I just recently installed my new wheels and tires. I chose to go with 17x9 and 34"x10.5" Toyo AT3 D Load tires. I noticed today on the freeway around 70mph that it feels (for lack of a better term) kind of "squirrelly". This is on a Black Diamond with 1" leveling kit. It felt much more grounded with the stock tires.

Do you think it would be better with a slightly wider 285/75/17 or 285/70/17 which are about .7" wider? I drove a 3" lifted 4runner on 297/70/17 before this bronco, and it didn't feel loose like this. The bronco actually felt great on the stock tires, so I'm wondering if it's the narrower tires with increased height. Any insight is appreciated, thanks!

pic is for reference

That is something on the ground under the truck

 

[GToddC5]

I’d lower them to 35 psi , at least in the rear, and give it a test.

I came here to say the same. Sounds like the pressures are too high. Larger volume tires does not mean higher pressures. The opposite actually. Ever notice on tiny road bike tires, the pressures are crazy high, but balloon tires are low?

 

[kodiakisland]

Unless you are hauling some serious weight, you do not need more PSI.

PSI is a function of weight rating for the specific size tire you have. It does not matter what the door sticker says if you are not running the exact tire size on the sticker, as each size tire has a different rating at a particular PSI. Also, the door sticker PSI is based on GVWR. If you are never at that weight, you don't need that PSI.

Start at the beginning and get an alignment. Then go from there. You changed the suspension so that should be your first priority. After an alignment, look for other issues. Toyo ATIIIs are good tires, but you could have some balance issues in either the new tires or wheels. Adjust air pressure down as well. Could also be partly the really wide wheel and narrow tire.

 

[SuperDave150]

I read the Toyo AT3 was a pretty good tire. I use to run Nitto Ridgegrapplers. Should i have went KO2 instead?

What I’m about to say is sacrilege:
KO2‘s on my Tacoma were the worst. No kidding.

 

[ctandc]

Unless you are hauling some serious weight, you do not need more PSI.

PSI is a function of weight rating for the specific size tire you have. It does not matter what the door sticker says if you are not running the exact tire size on the sticker, as each size tire has a different rating at a particular PSI. Also, the door sticker PSI is based on GVWR. If you are never at that weight, you don't need that PSI.

Start at the beginning and get an alignment. Then go from there. You changed the suspension so that should be your first priority. After an alignment, look for other issues. Toyo ATIIIs are good tires, but you could have some balance issues in either the new tires or wheels. Adjust air pressure down as well. Could also be partly the really wide wheel and narrow tire.

What he said.

1. Alignment. Doesn't matter if it tracks straight or not.
2. Lower your air pressure. Higher load rating tires (like D / E) are rated at certain LBS of weight for each tire based on a certain PSI

Find a Load D tire PSI chart and go from there. I can tell you there is NO WAY you need 40psi in those tires.

Our '22 dr BB got 17x8.5" (0 Offset) wheels and 315/70/17 Load E tires the day we picked it up from the dealer. (Zero lift / spacers BTW - removed crash bars. No run / scrub lock to lock even under flex).

I did the math (Load E tires / actual weight of the Bronco etc) and got a starting point. I run 'em at 32 psi and it's rock solid stable to 80mph.

You want to know why so many people add bigger LT tires to trucks / SUVs and then gripe about how "harsh" the ride it? Because they have way too much air in them.

Recommended PSI for your tires is based on the LOAD Range / Size of the tire and Gross Vehicle Weight.

I can almost GUARANTEE you that if you lowered your air pressure to 34-35psi it would ride / handle better.

I remember buying an older Miata for almost NOTHING. Kid says his Dad said the suspension was totally worn out and needed replacing and it had a blown head gasket. Got it for $150 ($50 more than the junk car guy was offering him). It was a cut radiator hose. (yes I'm serious) and it had BRAND NEW Michelin tires on it that were aired up to 40psi. That thing jumped around on the road like it was trying to wreck.

Recommend tire psi for that car (remember it's based on WEIGHT) was 26psi. Aired 'em down, replaced the radiator hose and ran the hell out of that car (like a go cart) and sold it for a nice profit a month later.

I don't even run 40PSI in my F150 with Load E when towing my tractor / equipment trailer.

 

[Deleted member 3063]

toe needs corrected

 

[GToddC5]

What I’m about to say is sacrilege:
KO2‘s on my Tacoma were the worst. No kidding.

Truth! And on my 1989 Toyota Pickup, they were like plastic death rollers in Winter. Had to air 'em down to like 18 or some shit.

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