Tire weight and scraping sound

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I have 2 new trailer tires. One will only be used as spare and I'm not mixing tires.

Tire #1:
  • ST205/75R15D
  • Load Range: D 108/103M
  • Radial
  • Max load: 2200 lbs/Single
  • 15x5J Steel rim. 5 x4.5" Directional. Rated 2150 lbs
  • Tire weight : 46 lbs
Tire #2:
  • ST205/75D15
  • Load range: C 101/97L
  • Steel belted
  • Max load: 1820 lbs/Single
  • 15x5J Steel rim. 5x4.5" MOD. Rated 2160 lbs
  • Tire weight 38 lbs

Both tires and rims are reputable but different companies with good reviews ...

I was moving them in the garage and felt like one was heavier. That's why i decided to weigh them.

The radial tire weighs 8 lbs more (46 vs. 38 lbs). Rims have different kind of holes (Directional vs. MOD/ Round). I am assuming the rims can't be that much different since they have almost the same rating (2150 vs. 2160 lbs) or are the radial tire in general that much heavier than steel belted tires? The radial tire/rim weighs %21 more.

Q1:
Extra 8 lbs!
Kind of curious since this is %21 more. if it was %5-10 more, I would not be asking this question.

Q2:
This is a bigger concern.
When I had the empty trailer on jack and spinning the lighter tire (Steel belted) by hand, I didn't hear any noise. However when I had the radial tire and spinning, I could hear a short scraping sound at every turn but it turned smoothly and didn't seem to be slowing down at the turn. Also the Tire is exact same size as steel belted tire and was not catching anything.

The trailer is practically new and in great condition. It doesn't have brakes.

do you think the additional 8 lbs is causing extra load on the bearings since the tires are off the ground? Not sure how else to explain this.

I swapped tires on both sides and same result as far the scraping sound. no sound with the lighter tires!
 

OilUzer

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No the tires and rims are new but are different brand rims and tires The radial tire has a Dexstar rim and the Steel belted tire has a SRW rim. I checked the reviews on different sites and both are considered good rims and tires.

I could take the tires off the rim and weigh the rim and tire separately to see what's contributing to the 8 lbs weight difference ... but I think that's going too far :)

did some search but couldn't find any info on the weight difference between a radial and steel belted tire. The radial tire is a more of a heavy-duty tire based on the specified load range.
 
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I would be looking at the rim rubbing on something. Tire weight should make no difference, unless they rub on a part.
 
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Steel belted and radial are the same.

With that said there's definitely different offfsets on trailer wheels. I rotate in my spare, which is the same tire on a fifth , unmatched wheel, and it doesn't stick out as far as the other 4 do. If I had clearance issues with the springs, etc, I could see it rubbing.
 

OilUzer

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Steel belted and radial are the same.

With that said there's definitely different offfsets on trailer wheels. I rotate in my spare, which is the same tire on a fifth , unmatched wheel, and it doesn't stick out as far as the other 4 do. If I had clearance issues with the springs, etc, I could see it rubbing.

I was about to make a correction and saw your post. Thanks

Tire #2 is Bias Ply D15 (I said steel belted) and tire #1 is Radial R15.

is there a huge weight diff between radial and bias ply?

also I checked and nothing is rubbing. pretty sure about that but will check again!
Tires are pretty much the same size. I even measured that. If any, the radial tire is a tiny amount narrower! There is tons of space around tires. It's just a basic trailer with no brakes.
 
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First, those steel belts weigh a couple of pounds.

Second you didn't say how much tread was left on those tires. Rubber is heavy! I'm guessing that tread rubber is about 1/3 the weight of a tire.

Third, Steel Belted Radial tires tend to have wider footprints = more rubber!

Rubbing? No witness marks on the tires or the wheels? Maybe brakes? Things in the real world aren't perfectly round nor perfectly flat.
 

OilUzer

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First, those steel belts weigh a couple of pounds.

Second you didn't say how much tread was left on those tires. Rubber is heavy! I'm guessing that tread rubber is about 1/3 the weight of a tire.

Third, Steel Belted Radial tires tend to have wider footprints = more rubber!

Rubbing? No witness marks on the tires or the wheels? Maybe brakes? Things in the real world aren't perfectly round nor perfectly flat.

Tires and rims are factory new except one tire has 23 miles on it.

It's a utility trailer with no brakes.

I crawled under the trailer and checked everything again and there is at least 1.5" spacing all around the Tire and the rim to as high as 3.5+ inches on top. also when it was on the jack, I checked and saw no rubbing.

I can see the radial tire being heavier and maybe the combination of that and the rim (both rims are steel but different manufacturer) adds up to 8 lbs! However, it was somewhat more than I expected being %21 heavier.

the scraping sound still a mystery when the trailer is on jack. That's why I thought maybe the additional 8 lbs is adding more pressure/stress on the bearings since it's up in the air ... I can't think of how else to explain it.

after confirming for the 3rd time that nothing is rubbing, It's now more of a puzzle and curiosity.
I'll have to jack it up and test it again.

I know trailer axles are designed to have a bow and flatten when loaded. I thought maybe the combination of that and the extra weight of the tire is causing the bearing noise given the fact that being on jack and unloaded is not the intended design and normal operating conditions.
 

OilUzer

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Update:

Mystery solved.

I had purchased a pair of R15 wheels. one for me and one for a friend ... The thought crossed my mind that it could be the tires but since both tires were making the same scraping sound, I kind of dismissed it.

Anyways, jacked up the trailer and did more testing ... there seems to be something inside both tires (both new from factory/dealer) that is rolling.
If I spin the tires and quickly stop the rotation, I can hear the "sound" (scraping sound) for a split second even when nothing else is moving. So it's neither the bearings nor the tires catching ...

Is it common to have debris inside tires and wheels?

Tires have different DOT number and date (several months apart) and are not of the same batch as far as I can tell. So if it is a quality issue, it's happening with different series.
Not a big deal just curious!

Maybe the car tires do this also and we never know. I could hear the sound inside the quiet garage (turned off the radio) but it's not a loud sound.
also these were relatively the most expensive tires & rims with very good reviews ... Not that the price matters but I could have spent half the price for some other inexpensive and less known brands.
 
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First, you should not hear any sounds from inside the tire - and if you do, it's a problem caused by whoever mounted the tire. There is something in the tire that they forgot to remove.

In other words, there is nothing inside a tire that can break loose. There is nothing in that part of the wheel that can break loose. If there is something there it was there when the tire was mounted and depending on what it is, it could damage the inside of the tire enough to cause failure.

So check again. Are you sure the noise is coming from inside the tire? If so, you need to have it removed, which means dismounting the tire and cleaning it out.

But I am puzzled by the noise being described as a scraping noise. I would think any loose object would cause a booming kind of noise as it tumbles around.
 

OilUzer

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I can't spin the tires fast enough with hands. definitely doesn't tumble in there but sounds like a catching or scraping sound. maybe something (flat piece of rubber?) inside goes up partially and slides down? Just guessing and have no idea.

I can hear it for a second after I fully stop the spin. I'm assuming nothing else should be spinning (bearings, etc.) free after I stop the spin. No?

Good suggestion @CapriRacer, i may dismount one tire and get to the bottom of this.
 
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Probably the original valve stem was rotted and someone cut the original off to replace it. The bottom fell inside the tire and they slid a new one in.
 
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