Thump-Thump-Thump Front Suspension?

[Bottomlesspit]

I have delayed posting about this, but can't stand it anymore. I hope some of you might have some ideas/things to check.
My 99 X has 34,000 total miles 2WD and was taken very good care of by the first owner. Ever since I got it the front end has had a thump, thump, thump sound when driving. I REALLY notice it around 20-40 MPH. It feels like the front tires have a ridge on one side of each tire....or like driving over continuous mini speed bumps. I can hear the sound, as well as feel it in the floorboard.
I figure it might be the tires (unknown brand with Tacoma Trail GT on the sidewalls...fairly new).
I tried 32psi, 28psi, AND 26psi and think the sound might have diminished slightly with lower pressure??? Hard to tell though.
I am concerned about how much I can feel it through the floor. Are there other suspension or drivline components that I should look at under the front end? Everything appears proper and in good working order.
Other than changing tire pressure, the only other thing I have done is put the transmission in N and tried coasting...with no change. I tried speeding up and slowing down. I can't tell if the sound/feel changes all that much. Once over 40 it gets hard to hear it.
It is really annoying and does it all the time. Any help here is appreciated. I'd hate for the front end to fall out or something!!!!!
Ken

 

[BAYDOG]

My guess would be a broken belt in one of th tires. I ahd this happen to my wifes Tempo, and it did the same thing. You can't see it in the tire till it gets really worn. I would have them looked at, and maybe , if you can find the previous owner, there is a road hazzard warrenty on them?

 

[TPLYNCH]

Did anyone use Fix-a-flat or similar product on one of the tires?? Try rotating the tires and see if there is any change....

 

[Bottomlesspit]

Thanks for the replies!
Either idea is worth merit in this case. What confuses me the most is that it "feels" like both sides are doing it, although that could be deceiving. It just feels like the thumping is the whole front, at an even pace as the tires turn. The truck goes straight as an arrow, no pulling...just thump-thump-thump as I go along. I'll try rotating the tires and see what happens.
I have just been concerned that there might be something under the front end that could be involved besides the tires...definitely something that rotates!!!I was not sure whether a tire problem would be felt that much in the floorboards. I do not know the previous history on the tires. The dealer is now out of business here in town, but was very reputable. I'll let you know. Thanks again,
Ken

 

[Mike]

ya i would rotate the tires.. see is it changes..

 

[TPLYNCH]

Did the truck sit in one place for an extended period of time?? Could also be a flat spot in the tires. When you rotate, see if you can make sure they are still "round".

 

[Bottomlesspit]

Thanks for all the replies...again!
Tom- Now that you mention it, the Explorer did sit for some time. I don't know all the specifics, but what I do know is: It is a 99 XLS that I bought from a local used dealer. This dealer specialized in obtaining program vehicles. I bought the 99 X in October with 27,000 total miles on it. I had seen it at the dealers lot for at least 4 months before I bought it. I assume, with the relatively low mileage, that the truck was either: not driven very much for 3 years, or was driven early on and then sat waiting to be dealt off to a dealer. Maybe that is the deal? I can't find anyone who can identify the make of tires on it. I'm thinking they are cheap, rock hard, off brand tires (Tacoma....Trail GT)
Flat spot? Belt seperation? I don't know, but it sure sounds and feels terrible to drive. Worst part is, money is tight for replacement and/or the darn things look almost new...plenty of tread. It really makes the drive bad though.
BTW, I payed careful attention today and DID notice the clunking vibration in the floorboard and steering wheel while at 60 mph...so I guess it does it at all speeds.
I am starting to believe it is the tires...just want to make sure it is not something else more suspension oriented.
Thanks for all your help...everyone!
Ken

 

[Robert]

Tacoma tires are sold through Parrish Tire Company.

 

[Blee1099]

Sounds like possibly the tires are out of balance and probably need rotation badly. I had a set of Bridgestone Dueler APT that had the same problem. I'm thinking the cause of my problem was because the tires were never rotated and balanced and the high speeds I placed on the tires. Doing over 95+ in an SUV is not good.

 

[Bottomlesspit]

OK, thanks for all the info.
Parrish tires huh? I can't say I've ever heard of them.
I just got back from a weekend trip. I experimented a bit and put the pressure at 35 in all tires. The sound and feel was WAY louder and harsh. I could easily feel the thump, thump at all speeds.
On the return trip I lowered the pressure to 26 and it all reduced...but never will go away.
I will try the balance and rotation and let you know what I get. I can't believe the tires could get that out of whack so quick though. I don't have a lot of free cash floating around right now, so I wanted to be reasonable sure of something before I changed something. Thanks again.
Ken

 

[TPLYNCH]

You may be able to get $ back on the tires if you go to Sears, especially if they are nearly new. Before the Firestone recall fiasco started (like 2 weeks), I brought my Ex to Sears and they gave me a prorated amount on the Firestones based on the tread depth that was left after ~25K of use. Actually got a good amount of $ for them even tho they were crap tires. Got the Michelins I have now, and with nearly 70K, they still ride and grip like they were new in snow, ice and rain.

 

[Muskrat]

check the lugs, happened in my momn's B2, and the tire fell off, sheared the sttuds, not cool

 

[Bottomlesspit]

Tom,
Thanks for the idea. Prorated might be worth something? I'll check around and see what a few places are willing to do. These tires are just terrible. I just noticed we have the same Explorers. I like my XLS, it has the sport fender stuff and foglights. I just don't care for the front seats...2 square looking boxes. Also, without cruise control, I miss having the leather steering wheel. I put one of those leather slip on covers over the wheel, but it's not the same.
Muskrat,
You are just plain scaring me now!!! I definitely don't want a tire falling off. I used to get my stang over 100 on the drag strip...and I found some lugnuts loose once. Very scary. I check them often!!! I think I'm more afraid now that there might be a tire defect causing this thumping feeling and sound, and I'd hate for one to blowout on me.
Thanks again for all the help.
Ken