Ive gone through two sets of rear tires this month (they were used, so I just paid for mounting and balancing).

The tires end up bubbling/lumping every other week or so.

Is this related to tire pressure, or could it be related to the previous way the tire rotated when it was on another vehicle?

if this is a tire pressure problem, I have been inflating to the "Max Pressure" listed on the side wall, should I be doing this?

left side tire run on the right.. belts don't like switching direction..

No, you shouldn't be inflating to the sidewall pressure. Inflate it to the pressure that the car owners manual, or info plate attached to the car somewhere, states.

It's belts shifting that causes the bulges and I've usually found that happens in the cheaper tires.

Rick

quote Originally posted by AL87: Is this related to tire pressure ... ?

Probably. It most often results from tires being run for some period of time near-flat or with too-low pressure. I would be very cautious about inflating ANY used tire to its "max inflation pressure." For that matter, I wouldn't buy ANY used tire that I didn't know the history of. Ask yourself: Are you saving any money by buying used tires that only last a week or two?

quote if this is a tire pressure problem, I have been inflating to the "Max Pressure" listed on the side wall, should I be doing this?

Why? The proper inflation pressure to use is stated on the door sticker of the car. (It's ~32 psi for most Fieros) The "max inflation pressure" printed on the tire sidewall is only appropriate when the tire is used at its "maximum load" rating; the Fiero tire loading is only about 50% of that.

[This message has been edited by Marvin McInnis (edited 09-29-2012).]

quote Originally posted by E.Furgal: left side tire run on the right.. belts don't like switching direction..

Only tires that use unidirectional belting and Tires with that will say rotation arrow on sidewall.

standard radials setup won't care.

------------------
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let me restate, ony one tire in each set ive put on has bubbled/lumped.

im just going to go get some new tires, recomendations?
whats the cheapest new tire?
and whats the most expensive?
and what about a good in the middle one?

its more about price for me, I can afford tires, just not if they bubble up like they have been.

I inflate to max pressure for fuel economy mostly, is it wrong to run the car like that?
most of my driving is in town. am I losing grip or wearing the tread wierd if I inflate to max pressure?

quote Originally posted by AL87: I inflate to max pressure for fuel economy mostly, is it wrong to run the car like that?

The short answer is yes.

quote Originally posted by AL87: ...am I losing grip or wearing the tread wierd if I inflate to max pressure?

Yes on both accounts. Inflating to max pressure without having the max permissible weight (load) on the tire will cause the tread patch to bulge outward in the center giving you less contact with the road causing a loss of traction and uneven tire wear. You can expect tread life to be reduced by as much as half. So while you may save in fuel costs, you are losing in tread life economy and traction (both accel and decel).

quote Originally posted by AL87: could age have affected them? they had been sitting around off the rim or just not inflated all the way.

That could be it. Sidewall bubbles are a result of the belts separating. This can be caused by trauma (big potholes), or driving around on a severely underinflated tire.



Here is a tire that was driven on while flat, then pumped back up. Sidewall bubbles cannot be repaired, and the tire must be replaced before it bursts.

omfg! that poor tire!

lmao! XD

quote Originally posted by raccoons: Sidewall bubbles are a result of the belts separating.

Umm no. That could be true, IF there were "belts" in the sidewall. Sidewall "bubbles" could come from many types of damage, but belt damage is not one. Bulges in the tread are are from belt separation which can be caused by many factors also.

As for the over inflating, you might not go to the max pressure listed on the side of the tire but inflating higher then on the placard is fine to obtain lower rolling resistance to some degree.
http://www.mpgenhance.com/tire_pressure.html

Switching tires from side to side has no effect on modern radial tires. Was the case in say the 70's maybe 80's, but not for some time. As a matter of fact, the owners manual of the cars will show the correct pattern for rotation, which usually involves crossing a pair in each rotation.

You will run into the tread not being in proper contact with the road more so with an improper sized wheel/tire combo then over/underinflated inlfated tire.

Kevin

quote Originally posted by theogre: Only tires that use unidirectional belting and Tires with that will say rotation arrow on sidewall. standard radials setup won't care.

I know thats what should happen.. but way to many do this after rotation to the other side of the car.. and are back replacing tires we just rotated for them weeks before.. the "road hazzard" dept. is looking into this ,as they are replacing more tires from belt squrm after rotation than they like..

This happened to me on a new tire. I was told it was the result of hitting a pothole, actually a manhole on a street that was being repaved. How old are these used tires? If they're four years or older you probably shouldn't be using them. That may be why you get them for free - because it would be illegal to sell them. Besides all that mounting and balancing could buy decent tires. The reason you're not supposed to be using old tires is they come apart.

Ive usually seen them on tires run under inflated, damaged or cars stored for months. Best middle class tires I like are Dunlop and Bridgestone. Ive never had any problems with a single one. I run 40-45 pnds in ALL my cars. I tend to believe the manufacturer sticker pressures are so you get a cushy ride. I almost always get better than 100,000 miles on a set of new tires. My Astro has the original 1995 tires with 130,000 miles and my Sebring (bought new) has 95,000 on its original Continentals with still over 75% of the tread left. They all handle better and get better gas mileage with the 40+ air pressure.

[This message has been edited by rogergarrison (edited 09-30-2012).]

I just bought 2 sets 215 60/15, 215 55/16 from a "small garage"(NOT a big chain) the set was $380 mounted/balanced taxed, "out the door". Places like tire kingdom, pepboy,s etc were almost $200 MORE ! don't fall for their by 2 , get 2 ! ya gotta "Shop around"