Tire Questions

[Pullin' Chocks]

We copied the info on our tires and insert below:
Goodyear
ST235/80R16
Load Range E
Tread 5 Plys, 2 polyester + 2 steel + 1 nylon
Sidewall 2 Plys, polyester cord
Do Not Mount on 16.5" Rims
Max Load Single 1550 kg, 3420 lbs @ 550 kPa, 80 psi cold
Max Load Dual 1360 kg, 3000 lbs @ 550 kPa, 80 psi cold
Made in China
2212

We think this tire was manufactured the 22nd week in 2012. Does that seem correct given the 2212 code?

Are these tires the "China Bombs" we read the horror stories about?

Does the Max load single 3420 lbs spec mean 2 tires per axle? And the Max load dual 3000 lbs spec mean 4 tires per axle? Why is the single spec rated to carry more weight than the dual spec? (3420 vs 3000)

Our weight rating sticker indicates three 7000 lb axles. Each axle has two tires. Does this mean one of our axles has a GAWR of 7000 lbs? How do we reconcile two tires rated at 3420 or 6840 lbs total to be rated at 7000 lbs? Is it because the axle does not carry the weight of the wheels? (Tire and rim)

We think we are loaded to ~22,500 lbs and will check next time we roll. Do we have a serious problem with three (7000 lb) axles and the above specified tires?

Thank you for your knowledge and experience, we are not completely clear on all theses weights, parts and ratings yet.

[wingnut60]

Pullin,

The load rating for dual applications is less than for single aps because of the bulge at the bottom of the tires--if you load them to single weight ratings, the bulges could possibly rub on dual aps.
Max load is PER TIRE--2 tires per axle, = 2x one tire load capability per AXLE.
Yes, each axle is 7000k axle rating.
Axles only come in 3500/5000/6000/7000/8000 ratings (there are other ratings also, but these are some of the more common). 3 x 7000lbs/alxe = 21000lbs total axle load rating. The tires/axles never see the total weight--about 20% or it is on the kingpin (truck axle) or on the front legs when parked.
Tires: 6x3420lbs=20520lbs carrying capacity.

You think your weight is 22500. 20% of that (4500lbs) is on the pin when towing, leaving 18000 on the tires/wheels/axles. You have about a 400lb cushion on each tire.

You are ok from these figures, but if I had a 22500lb trailer, it would have 8k axles on it and 17.5" wheels/tires that carry 4800lbs each. This revelation did not come to me until I had a 17000lb trailer on 16" wheels/tires, so you are not alone.

Everything is ok, but over the long term, I would look for LT tires to replace the ST tires (my opinion) and eventually consider a changover to 17.5" wheels/tires. It is a simple, but not cheap, changeover.

Joe

Joe

[Pullin' Chocks]

Thank you Joe, your thoughts make sense to me. I was having some regret previously for not having selected the 17.5" tires, now I understand more clearly why I had that gut feeling. In fact I have thought about what it would take to up size to 17.5" tires at this point. In looking at the tire spacing, I wasn't sure there was 1.5" to spare between the existing 16" tires. If there isn't room, I guess that would require moving two of three axles.... That seems like more than I would want to get into... but I sure do like the idea of the extra capacity or safety factor on the larger tires. Thanks again for bringing us up to speed on our setup, I do have more confidence with an improved understanding.

[RustyJC]

The 215/75R-17.5 tires are 1/2" smaller in diameter than the Goodyear G614 which comes in an LT235/85R-16 size. They will fit anywhere the G614s fit. It's an easy (but not cheap) swap, but after failing two (2) G614s, the peace of mind is worth it, IMHO. I've been running the 17.5" Michelin XTAs since June 2010 without any problems whatsoever.

Rusty

[wingnut60]

Ditto on what Rusty said--the 17.5" tires I put on were about 1/2" smaller in diameter than the 16s.
If you have any interest in pricing complete sets of wheels and tires, mounted and balanced and shipped to you:

www.trailertiresandwheels.com

talk to Scott, he knows a LOT about RV and trailer tires.

Joe

[Franka548]

I agree with Rusty and Joe, Going with the 17.5" is the way to go. I only have about 4000 miles on mine but they run about 10* cooler than the G614,s which translates to less problems and longer life. I went with the Cooper enginered Roadmaster tires rather than the Michelin. I have delt with the dealer for many years and ran this brand on my 10 wheelers for many years, also a little over 1/2 the cost of the Michelins. Whatever tire brand you go with, they are better than what you have on now.
Frank

[wandering1]

If you really want to know why don't you contact the tire dealer or tire manufacturer and ask and get the facts?

[mhs4771]

Not to disagree with an earlier post, but with 7K axles LT tires are out as the load range in that size would only be just a tad over 3K per tire, thus good for 6K axles. I will fully agree on the comments about the 17.5 tires and wheels. Because we run heavy we upgraded from the 16" Gs to 17.5" Hs at the beginning of the year.

[Ray,IN]

Originally Posted by Pullin' Chocks

We copied the info on our tires and insert below:
Goodyear
ST235/80R16
Load Range E
Tread 5 Plys, 2 polyester + 2 steel + 1 nylon
Sidewall 2 Plys, polyester cord
Do Not Mount on 16.5" Rims
Max Load Single 1550 kg, 3420 lbs @ 550 kPa, 80 psi cold
Max Load Dual 1360 kg, 3000 lbs @ 550 kPa, 80 psi cold
Made in China
2212

We think this tire was manufactured the 22nd week in 2012. Does that seem correct given the 2212 code?

Are these tires the "China Bombs" we read the horror stories about?In my opinion most tire problems are "operator error", ST tires are speed rated for 65 MPH maximum, and should be inflated to sidewall maximum. Carlisle Tire even states that in their warranty.

Does the Max load single 3420 lbs spec mean 2 tires per axle? And the Max load dual 3000 lbs spec mean 4 tires per axle? Why is the single spec rated to carry more weight than the dual spec? (3420 vs 3000) Because of variations in driving surfaces, at any given time one dual tire may be supporting the majority of the load, thus the reduced rating

Our weight rating sticker indicates three 7000 lb axles. Each axle has two tires. Does this mean one of our axles has a GAWR of 7000 lbs? How do we reconcile two tires rated at 3420 or 6840 lbs total to be rated at 7000 lbs? Is it because the axle does not carry the weight of the wheels? (Tire and rim)Yes.

We think we are loaded to ~22,500 lbs and will check next time we roll. Do we have a serious problem with three (7000 lb) axles and the above specified tires?Trailer mfgrs. calculate that way because between 15-25% of total weight is hitch/pin weight.

Thank you for your knowledge and experience, we are not completely clear on all theses weights, parts and ratings yet.

This calculator will be helpful properly and safely matching a tow vehicle and trailer.
Those are my opinions and experience.

[Pullin' Chocks]

Thank you everyone for the outstanding information and advice. We have decided to act on your collective advice and will start working on a tire swap project. We have learned so much from the good folks on this forum. We are very grateful that we found our way here and to be a part. Blessings to All.

[Pullin' Chocks]

We started a preliminary search for 17.5" load range H tires, and it is looking like they no longer exist or are available. we tried the links provided above, and others we found on other threads, did Google searches and we didn't find much of anything in that niche. I thought I had heard or read that in the last 6-10 months that 17.5's were phasing out. Could that be? I also notice that New Horizons, the mfg of our 5er no longer offers the 17.5" wheel option. mmmmm... have 'they' moved my cheese again...?

[JPFretired]

Pullin Chocks,

I just checked the sight listed above and the 17.5 tires are still available. NH still offers them as an option it's just not listed on the web site page. I had them put on my rig. After hearing all the stories with the 16" tires and the weight of these rigs I'm glad I did.

[RustyJC]

Did you see the note at the top of this page? It says:

Please Contact Us if you have any questions. We do have (17.5") tire and wheel assemblies available.

Give Scott a call and see what he says.

Rusty

[Franka548]

Pullin' Chocks,
I just looked up on the Michelin tire site and the XTA tires are still readily available. Rember that these tires are listed under the commercial tire section, not the RV section. I don't believe that the 17.5" tires will be discontinued any time soon because there are a lot of commercial flatbed trailers that use this size.
Frank