very dangerous tire bounce

Status
Not open for further replies.
Thanks. I plan on taking it to the shop as soon as I can. The curiosity is killing me. I get the info on the tires either tonight or tomorrow. just got home and the power has just come back on. Even mention the word snow or ice and the power goes out. But that is for another forum. Sorry to get off topic so many times. i will also replace the stabilyzer shock soon, it can't hurt.
 
tires on the truck Toyo Open Country A/T P265/75R16 114S M+S DSOC II Max load 2601 pounds Standard load at 240 kp 35 psi max

placard- GAWR Front 3806 ponds with P225/75R16xl rims at 16x7 41 psi rear reads the same.
 
What is the weight of a standard P225/75R16 tyre versus a P265/75R16? If there's a significant difference (say >15%), then it will change the unsprung weight of each axle corner.

Could it simply be, the unsprung weight contributes to a natural frequency of the suspension which isn't sufficiently damped by the shocks, even if the shocks are new?
 
I would replace the steering damper last. The damper can mask the real problem, which I suspect is something worn out in the front end.
 
May or may not be related.

There have been vehicles with (failed) dual mass flywheels nearly shake themselves off the road at highways speeds.
 
Originally Posted By: OVERK1LL
Yup, you have car tires. They would say LT265/75R16 on them if they were truck tires.


My former Ram 1500 (2001 2WD) came with P-225-75R-16 Goodyear Wrangler tires on it from Chrysler, so they are car tires too, I suppose. Also, my 2008 Chevy Colorado has General P-225-75R-15 tires, but is a lighter weight truck. I think the tires he has are OK and not any danger to anyone. The door jamb on my 2001 Ram-1500 said 35 psi, with 41 if the truck was loaded to the GVWR. Personally, my guess is that there is something loose or worn out in the front end causing the problem.
 
I went to the toyo website and put my vehicle make and model in and there were three recomended sized tires for my vehicle, one is the one on the placard and one of the others is the one on the truck now. The website states in its description of this very tire that is on the truck now it is for light trucks and suv. I guess you could put it on a car but it sure would look strange and you might have to make some modification to the wheel wells. Apparently these tires, the ones on the truck now are max psi 35 but the load limit is higher than the ones that are on the placard. If these are not the right tires for the truck and they are not for truck and suvs then the Toyo website and the tire rack website are wrong. Something tells me they are not. It is obvious, unless I am completly misunderstanding things, that these tires are P metric tires with a load rating higher than the tires that the truck came with from the factory. It is my understanding that that would make these tires better than the ones that came from the factory. I could be wrong. Both the tires on the placard and the ones on the truck now have P in front of the size, if that makes any differance. All I know is these are the tires recomended by Toyo and the tirerack and it has a higher load rating than the ones that came on the truck. Therefore, I feel safe to conclude, especially after all the advice here, that these are the right tires for the truck, they are better than the ones that came on it from the factory, and the tires in no way endanger me or anyone else and are not the cause of my problem. To be honest, I have learned more about tires from this post than I ever wanted to know and I am sick and tired about talking about them. Still love to hear everybodies opinion on what going wrong with the front end. I will take it to the shop soon to find out. When I do I will let everybody know what it was. One last thing, thanks again for all the advice and I would like to wish everybody a Merry Christmas and Happy New Year, even Calvin1 and Eljefino.
 
Originally Posted By: OVERK1LL
Yup, you have car tires. They would say LT265/75R16 on them if they were truck tires.

Many half ton trucks come from the factory with "P" tires.
His tires are fine for his application.


Originally Posted By: chrome
What is the weight of a standard P225/75R16 tyre versus a P265/75R16? If there's a significant difference (say >15%), then it will change the unsprung weight of each axle corner.

Could it simply be, the unsprung weight contributes to a natural frequency of the suspension which isn't sufficiently damped by the shocks, even if the shocks are new?


If anything, a 225 will be lighter than a 265, so that would help the shock dampen the spring oscillation. Many people run much larger tires under their Rams than a tiny 225 or 265 without issue.
The 38's on my Jeep weigh 140 lbs each (including the wheel) and they run nice and smooth. They're not even balanced either.
 
Originally Posted By: vance1
I went to the toyo website and put my vehicle make and model in and there were three recomended sized tires for my vehicle, one is the one on the placard and one of the others is the one on the truck now. The website states in its description of this very tire that is on the truck now it is for light trucks and suv. I guess you could put it on a car but it sure would look strange and you might have to make some modification to the wheel wells. Apparently these tires, the ones on the truck now are max psi 35 but the load limit is higher than the ones that are on the placard.

(snip)

One last thing, thanks again for all the advice and I would like to wish everybody a Merry Christmas and Happy New Year, even Calvin1 and Eljefino.
56.gif


Just keep one thing in mind: there is more to the P vs. LT issue than just load rating and size options. P and LT tires are built differently. LT tires are generally stiffer in the sidewalls and more rugged in the treads. That is also why LT tires need more air - to keep them inflated so the sidewall doesn't flex causing it to overheat. Size and load rating aren't the only factors to consider, that first letter(s) had a meaning as well.

calvin
 
Originally Posted By: Zaedock
Originally Posted By: OVERK1LL
Yup, you have car tires. They would say LT265/75R16 on them if they were truck tires.

Many half ton trucks come from the factory with "P" tires.
His tires are fine for his application.


Originally Posted By: chrome
What is the weight of a standard P225/75R16 tyre versus a P265/75R16? If there's a significant difference (say >15%), then it will change the unsprung weight of each axle corner.

Could it simply be, the unsprung weight contributes to a natural frequency of the suspension which isn't sufficiently damped by the shocks, even if the shocks are new?


If anything, a 225 will be lighter than a 265, so that would help the shock dampen the spring oscillation. Many people run much larger tires under their Rams than a tiny 225 or 265 without issue.
The 38's on my Jeep weigh 140 lbs each (including the wheel) and they run nice and smooth. They're not even balanced either.


But the OP's truck specifies LT tires by the sounds of the door jam pressure range.

Similar to how my F-250 spec'd 80psi for the rear tires and 65 for the front.......
 
Did you read the OP's post of the placcard? The OEM tire was a P series tire with an XL Load Rating instead of a standard load P series tire. Not an "LT" series tire... Very, very few half ton trucks come stock with LT tires anymore...
 
Originally Posted By: MNgopher
Did you read the OP's post of the placcard? The OEM tire was a P series tire with an XL Load Rating instead of a standard load P series tire. Not an "LT" series tire... Very, very few half ton trucks come stock with LT tires anymore...


Nope, missed that. That's interesting.
 
Originally Posted By: MNgopher
Did you read the OP's post of the placcard? The OEM tire was a P series tire with an XL Load Rating instead of a standard load P series tire. Not an "LT" series tire... Very, very few half ton trucks come stock with LT tires anymore...


Agreed. My Silverado Z71 came with P265/75R16. However, my F150 FX4 came with LT265/70R17.
 
I agree with the harmonic theory. Maybe something is upsetting your wheel rim/axle/steering linkage and it's shaking like crazy and you feel it in the wheel. A firmer tire would push that load into the road and tell the harmonics to knock it off, while a squishy one would let them persist.
 
The truck does not shake at all. It was the one time on the interstate that I hit a bump and it did it. It has not done it like that since then. When I changed the shocks you could really tell a differance in the handeling and bounciness, if that is a word. When it did happen it was a literal bouncing like a basketball, absolutly no shaking. Nothing transfered through the steering wheel. When I take it to the shop maybe i will go via the interstate and hit the same bump and see if it does it again. Then again, maybe not. It does have a very slight shimmy at 60 mph but when you speed up it goes away.
 
If his current tires are *under-rated* for his truck, of which they are not, then that means the truck came from the factory with under-rated tires.

OP, the tires you have now, are far superior in size/weight load then what you had before, there is nothing wrong with them.

I have a Dodge truck too, check out your track bar, ball-joints, wheel bearings, but most likely a bad ball-joint or two.

It's VERY uncommon to purchase an suv or 1/2 ton truck with anything other then a P rated tire.

In fact, my diesel DID come with LT's but that's because it's a 3/4 ton truck.

Now you could have a bad tire though....that's been known to happen.
 
Originally Posted By: OVERK1LL
Originally Posted By: vance1
Strange you should mention tire pressure. I just got this truck to use around the house. Not a dailey driver and will not be used for long trips. After the incident happened I checked the tire pressure. It was 28. I inflated to 32. The doorjamb of the truck says 41 or 42. The tires says max Psi 35. What should it be?


It means you probably have the wrong tires on the truck
wink.gif




this is not necessarily the case without knowing the specs (size, speed, load ratings).

maximum air pressure for tire is not always indicative of improper tires ([censored], i bet a lot of the lifted jeep guys can tell you they have tires that are rated for max PSI well below what the door placard says, and yet they are still perfectly safe)
 
I have to laugh, "lifted Jeep" and "Perfectly Safe" occurring in the same sentence
wink.gif
(just buggin' ya).

I was thinking more like P rated tires on a 3/4 ton truck. Figured myself out later in the thread
wink.gif
 
Originally Posted By: OVERK1LL
I have to laugh, "lifted Jeep" and "Perfectly Safe" occurring in the same sentence
wink.gif
(just buggin' ya).



LOL.gif


My Jeep is perfectly safe on 38x15.5's. The 12 psi street pressure really hugs the road.
19.gif
 
Status
Not open for further replies.
Back
Top Bottom