Speed Rating on ST tires.

[CWSWine]

Originally Posted by Jim34RL

Are you looking at the LT235/85R16 tires by Goodyear? if so per their load inflation table (chart) these are only good for a load of 3750 LBS @ 110 PSI in a single wheel application at this site: The Inflation Loading - Goodyear RV
So they will not support your Cedar Creek trailer adequately.

Jim
Now that's different from what I have told. I believe that Cedar Creek has 7000 lbs axles so two 3750 tires would be 7500 lbs. The Gross weight is 16407 but about 20% of that is supported by the TV. Then you should use the inflation chart to inflate to the correct scale weight on the 5er axles which should be less than 7000lbs per axles.

[Airdale]

Originally Posted by BandJCarm

A question........the G614 is touted as the 'best' alternative to the original tires on 5er's, because they are LT and have higher weight rating, but also have higher speed rating.

Yet, several online sources I find show the G614 to be rated at 62mph. That's LESS than an ST tire.

Which is correct? I find a lot of info online, most contradictory or confusing. Is there a link to show the true speed rating of these?

Also, the G114's appear to have a high speed rating, but are on larger rims. Don't know how to find out if they are simply "Replace as is" or "Plug and Play" with the bigger rim, or not........ How does one figure that out before buying?

Thanks.

What size and load capacity are your Original Equipment tires?

The best place to look for a tire's speed rating is on it's sidewall. If you're shopping, the best place to look is on the tire manufacturer's web site. Retailers often build web pages with in-house experience and are often wrong.

Look on page #16.
http://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf

On Edit: http://www.nhtsa.gov/cars/problems/e...ire_safety.htm

[CWSWine]

Now another dumb question. Not everyone going to the scales to determined what pressure they should run in their tires. I have 7000lbs axles and the last weight was 14,100 and 10980 on the rear axles of the 5er. So if just divided 10980 by 4 you get 2745 lbs. So if I inflate the tires to sidewall pressure like I have be told before and used 110 psi with 3750 load rating what negative impact would that have on the tires/5er.

[Airdale]

Originally Posted by CWSWine

Now another dumb question. Not everyone going to the scales to determined what pressure they should run in their tires. I have 7000lbs axles and the last weight was 14,100 and 10980 on the rear axles of the 5er. So if just divided 10980 by 4 you get 2745 lbs. So if I inflate the tires to sidewall pressure like I have be told before and used 110 psi with 3750 load rating what negative impact would that have on the tires/5er.

Does your tire placard list 110 PSI as the recommended tire inflation pressure?

The tire placard has listed the correct pressure for the Original Equipment tires. Anything below that recommendation is considered under-inflation.

The RMA recommends weighing your RV, remove items if overloaded and balance the load.

If you inflate your trailer tires to support less than 3500# you would be under the minimum requirement for your axle system.

[mnoland30]

After 4 trips in my 2009 21ss Roo, with two blowouts, I decided I needed new tires. I finally found a video at eTrailer that said their tires had M speed rating (81 mph). When they came, sure enough there was an M on the side of the tire. I also upgraded from load range C to load range D. The tires were 1" taller, but fit fine. Trailer manufacturers use the cheapest components they can get away with. That doesn't mean we should.

[mnoland30]

I just checked eTrailers website, and they still show 65 mph rating on the M rated Load range D ST215/75/R14 tires I purchased. They aren't too bright, but they sell good tires.

[ferguson65]

Originally Posted by Jim34RL

I will send you a PM (private message).

I'm curious as to why you feel you need to PM info rather than post it here for all to see.

Assuming the Cedar Creek in question has 7K axles, the GYG614 will work as already pointed out. The two tires combined will be good to 7500 at 110 PSI each. If you're looking for tires that will support the entire GVWR of the trailer you're barking up the wrong tree, and you're not going to find it.

BandJCarm, what tires are coming installed from the factory on the trailer?

I only ask because the last show we were at, the higher end 5ver's had either Sailun S637's or GY614"s from the factory. The Sailun from my research is a good tire and slightly less expensive then the GYG614.

[BandJCarm]

Originally Posted by ferguson65

BandJCarm, what tires are coming installed from the factory on the trailer?

I only ask because the last show we were at, the higher end 5ver's had either Sailun S637's or GY614"s from the factory. The Sailun from my research is a good tire and slightly less expensive then the GYG614.

Westlake 16" G rated. Goodyears not available from Cedar Creek anymore.

[emm-dee]

Originally Posted by Jim34RL

Are you looking at the LT235/85R16 tires by Goodyear? if so per their load inflation table (chart) these are only good for a load of 3750 LBS @ 110 PSI in a single wheel application at this site: The Inflation Loading - Goodyear RV
So they will not support your Cedar Creek trailer adequately.

The CC model referenced has a GW of 16,407 and pin weight of 2,407, so wouldn't the total load on the tires be 14,000? 3,750 * 4 tires would be 15,000 so it appears the 614 would meet requirements.

[BandJCarm]

That's the way I looked at it, but I admit much of this has kept me confused. I just want a completely safe setup........and tires seem to be a major concern.

[rockfordroo]

mnoland30: In post #25 you said M rating, 81mph. In the next post you say M rating 65mph. Which is it?

[ferguson65]

Originally Posted by emm-dee

The CC model referenced has a GW of 16,407 and pin weight of 2,407, so wouldn't the total load on the tires be 14,000? 3,750 * 4 tires would be 15,000 so it appears the 614 would meet requirements.

That's correct. And the axles are only good to 14k. So there's no reason it won't be ok.

Not sure what Jim is trying to prove, that's why I asked why he was PM'ing rather than posting.

On another note we all know posted "empty" pin weights are light to begin with and will increase as the trailer gets loaded. I doubt the axles (and tires) will ever actually see 14K.

[CWSWine]

Originally Posted by mnoland30

I just checked eTrailers website, and they still show 65 mph rating on the M rated Load range D ST215/75/R14 tires I purchased. They aren't too bright, but they sell good tires.

You have to check your tires for the speed ratings. If your tires has the "M" it is speed rated to 81 MPH if the "M" isn't there they are rated to 65 mph. So they could either 81 mph or 65 mph tires and have the same part number. This is a recent change to the importing rules.

Here is what the markings look like, you should have a "M" where the "L" is on this tire.

[Tireman9]

Originally Posted by CWSWine

I notice at the dealer most of the 2016 TT and 5er are coming with ST tires that are speed rated "L". The tech said that most of the inventory after 1 Dec are coming with the "L" rated tires. The tech also said there has been a "recent change" in NHTSA requirements to include speed ratings of "L" (75MPH) on all "new ST tires". That rating is not retroactive and doesn't apply to tires produced before the NHTSA changes. When the current stock is used up the unmarked "ST" tires will be history.

Can anyone in the tire business or with better connections confirm this?

Are these really upgrade construction or just "L" put on the same tires?

I have seen on Amazon ST tires rated "R" to 106 mph.

I still tow at 63 mph with my 5er with "L" rated tires because "I" feel any faster is not safe.

Changes in tire construction are most likely required to allow a tire to meet the speed ratings higher than 65 MAX. No "Speed Symbol" = 65 MAX which is like the red line on your tach. It is possible to rev your engine faster but you are consuming tire life. When you do damage to a tire with excess load, excess speed, excess heat or low pressure the damage does not repair itself it just gets worse.

No matter what speed symbol is on a tire it is recommended that you never tow faster than 75 with lower speeds being safer.

[Big Red and 30WR]

All these ratings are to protect the manufactures . There is always some wiggle room. Doesn`t matter weather its tires, tow rating , hitch capacities , axle ratings and the list can go on and on.

[Tireman9]

Originally Posted by Airdale

The new ST tires with speed letters are a result of a tariff increase for imported tires. To avoid the increased tax assessment, tires previously manufacturer without speed restrictions displayed on their sidewalls had to start identifying the speed restrictions. The most acceptable way to do that is to manufacturer tires capable of attaining the speed restriction displayed on their sidewalls.

Because there is no speed letter for 65 MPH the ST tire manufacturers had to raise the bar. The TRA previously approved all ST tires to 65 MPH. They have now got onboard with the ST tire manufacturers and increased their approval to 81 MPH. That does not limit any individual ST tire manufacturer to that limit, it’s just the bar set by the TRA.

NHTSA certifies tires with their DOT seal of approval. Tires are independently tested, normally by a third party after initial manufacturer testing. NHTSA only steps in when serious problems occur.

J = 62
K = 68
L = 75
M = 81
N = 87

Sorry info not quite accurate.
NHTSA does not certify tires for performance. The "DOT" symbol on a tire sidewall is used by the tire company to indicate that the tire company certifies that the tire will meet all NHTSA regulations. "DOT" is not a "seal of approval"

Tires MAY be tested by independent 3rd party companies but only when someone pays for such a test. I know of no ongoing program to do such testing as it is expensive.

Also TRA does not "approve" tires. They only publish industry standards. NHTSA in their regulations use the TRA standards when specifying the dimensions, loads and inflations a tire company is to use when certifying a tire's performance.

[Airdale]

Originally Posted by Tireman9

Sorry info not quite accurate.
NHTSA does not certify tires for performance. The "DOT" symbol on a tire sidewall is used by the tire company to indicate that the tire company certifies that the tire will meet all NHTSA regulations. "DOT" is not a "seal of approval"

How about I word it like this?::: The "DOT" symbol certifies the tire manufacturer's compliance with the U.S. Department of Transportation tire safety standards.

[emm-dee]

So exactly who is this TRA guy y'all keep mentioning?

[Tireman9]

Originally Posted by Airdale

How about I word it like this?::: The "DOT" symbol certifies the tire manufacturer's compliance with the U.S. Department of Transportation tire safety standards.

I guess that's OK as long as people realize that only the tire manufacture is "certifying". Others just publish standards and regulations.

[Tireman9]

Originally Posted by emm-dee

So exactly who is this TRA guy y'all keep mentioning?

US Tire & Rim Association. publishes the standards book with fitment dimensions for tires, wheels and valve components.
This is to ensure that a 15" tire will fit a 15" wheel and the hole in the wheel is correct for the valves that are to be used. Also to provide some standardization in dimensions of tires.

Time was when each tire company followed their own guides so if you had a 7.50-15 from one company t might or might not be the same size and load capacity as a 7.50-15 from another company.

Note the "fitment" is not a list of what tires come on what vehicles.