View Full Version : Email from Keystone Regarding "E"Rated tires!

Artemus Gordon
04-01-2015, 10:29 AM
Note: These were Emails from 2012! Between me and Keystone!
I never had a blow out, but believe me had I personally experience one, this would have been an issue !

From: Michelle Diaz
Date: May 18, 2012 at 9:27:27 AM PDT
Subject: C4701613
Dear Ms. Arnold:

Thank you for contacting Keystone RV. The appropriate tire size for your Montana is ST235/80R16E. Keystone will not participate in upgrading to G rated tires, nor do they recommend changing the rating. The E rating is what the Montana 3750FL's are tested & equipped with. Some of Keystone's productions have the option for a G rated tire. Your particular Montana does not.

Thank you,

Michelle Diaz
Owner Relations

-----Original Message-----
From: marnold7575@gmail.com[mailto:marnold7575@gmail.com]
Sent: Wednesday, May 16, 2012 7:12 PM
To: CS Service/Parts/Warranty
Subject: Service/Parts/Warranty - Keystone RV

request_type: warranty
division: MO
email: marnold7575@gmail.com
realname: Suzanne M. Arnold
Address: 813 Metro Way
City: Redding
State: Ca
ZipCode: 96003
PhoneNumber: 530-524-4015
SerialNumber: 4YDF3752XC4701613
VINNumber: 4YDF3752XC4701613
Comments: I am concerned about the E Rated tires that came on my New Montana 3750. From both the Montana Owners Forums and RV Net it appears to have become an issue as to the proper Rating for My fifth wheel purchased just last month. The reports of failure appear to be numerous. I would like your opinion on this issue and or any assistance Keystone can provide in updating my tires to G rating. Some members have made claims Keystone has participated/ initiated in the exchange of E for G rated tires. Since my RV is less than a month old, I feel time is of the essence in this matter. I as you might well imagine am fearful for myself and family, that we are in danger of experiencing a \"castistropic tire failure\" resulting in property damage or injury! Your prompt response is awaited! Thank you!
B1: Submit Request

04-01-2015, 10:50 AM
Obviously there is something special about the 2012 3750fl that makes it substancially lighter than other models or their "testing" showed that g rated tires were a danger if put on this model. Does towing it out of the door at the assembly plant constitute testing? This reply is an reflection upon the company in my opinion. Count me in as someone that will not be buying another keystone product when I trade this one in two years from now. John

04-01-2015, 11:08 AM
Helium Technology.

04-01-2015, 11:33 AM
I had one blow on my 3750 2 weeks after warranty expired. I replaced all 5 with G rated tires

04-01-2015, 11:50 AM
Not just montana. Noticed at the Tampa RV show this year that many other bigger fivers come with E load trailer king or marathons to include Jayco, coachman, cedar creek, sanibel, Dutchman, to name a few.

Artemus Gordon
04-01-2015, 12:17 PM
I have been holding on to email for sometime. Have been reluctant to share it publicly. In spite of evidence to the contrary, this "Company Representive" put in writing, unwavering support of the decision to use and recommend these tires. I think it's a real smoking gun so to speak!

04-01-2015, 01:02 PM
Thanx for Sharing Artemus predictable response not just from Keystone but I bet you would get the same exact response from ANY other Company that uses ST E rated tires on the Big rigs and Sadly there are Many SOB's in Montana's price range and Too many to list here,if people want the G rated tires standard I guess you gotta pony up the cash for a Big Sky,Redwood,DRV etc...Myself personally I will save the cash from buying those rigs and just upgrade myself

04-01-2015, 03:02 PM
Frankly Keystone does have a test crew that abuses those tires putting them to the test and that testing leaves Keystone feeling comfortable in using them. The rigs and tires are subjected to rigorous testing combining higher than rated speeds with running them thru large holes and ditches. There have been some failures, but they have been rare. These brave test drivers are called delivery haulers:)

04-01-2015, 04:19 PM
Excellent point. Time is money for those drivers and the rig ain't theirs so run as hard as possible

Artemus Gordon
04-01-2015, 04:52 PM
Dick: I read your post twice. Lol. Yes those guys do damage on their own. I was told by an RV dealership that his product comes less than 200 miles from the factory, and he sees evidence of road abuse!

04-02-2015, 03:18 AM
Michael, I look at it just the opposite. Keystone insists that E rated tires are fine for their units coming out of the factory because when the units are unloaded they probably are close to "fine". They can get them delivered with those tires on the rigs and after that it is not their problem if you or I load 2,000 pounds of personal property into the rig and actually go camping. I think Keystone RV, if they were defending themselves in a lawsuit reference not installing the correct tires, would immediately question how much weight the buyer had added to the FW and how fast they were pulling it.

So I don't think your old email is a smoking gun at all, I think it is kind of a "that is my story and I am sticking to it" by Keystone.

04-02-2015, 07:57 AM
JandC... I agree with your last sentence very much!

I think the letter pretty much reiterates since they've matched the rig to those tires, I don't think they've specifically tried to go outside those tires. It's about cost of development. If the tires are spec'd correctly, why waste time and effort to allow another better tire if they are trying to keep R&D costs down to keep the cost of development down. The letter doesn't imply they tried any other size and what for, if that tire meets their specs.

As a former transporter of trailers, I agree that most other drivers are in a hurry and will drive faster than the tire specifications. I could probably argue that many RV transporters don't even know that tires have a speed rating because they drive way too fast and sure seemed like they didn't care. I was religious about staying under 65MPH, and witnessed "too many to count" other RV Trailer transporters BLOWING by me on the roads in the West.

Then there was the time one tire on my tow bubbled after about 100 miles of being towed right from the factory at less than 65mph the whole trip. It was a late pickup when we (DW accompanied me) had to stop for the evening (limited by on-duty hours. That night's check looked fine, but in the morning, prior to continuing, there was that large softball sized bulge on the sidewall and I was amazed it didn't pop. Changed out the 'you guessed it', Goodyear Marathon and we continued on with NO spare per the manufacturer's instuctions.

My average tow distance was about 550 miles, NOT 200 miles (and therefore included an overnight stay enroute). I could only take 3 months of this. The persons on either end of the job could be some real jerks (obviously not happy with their jobs) or the dispatchers were clueless on what it takes to do this. All sad signs for the trailer industry and why some of us can be downright religious about caring for our rig's tires, but not realizing they could have already been abused before we purchased our tons of fun.

On my Montana, I had good luck with my Marathons, but I was the only transporter of my RV when I bought them new as replacements for my prior Missions that didn't last a year before one started to bulge. And after just 6 years they were traded out for Maxxis STs and we now fulltime over short distances.

Artemus Gordon
04-02-2015, 09:03 AM
Joe in the world of contingent liability, you never admit to "testing" and your own engineering as bases for selecting a component.. I was in manufacturing business you take in as little overall liability as possible. In a real life legal situation "Keystone" just put the responsibility squarely in their lap. I ran this by my close friend who won the famous "Jeep Roll" over case. He found those statements to be fascinating. The way they should have responded was to say, "our engineers" "specifications" were provided to our suppliers and we followed their recommendations! If anything the email puts the liability back on Keystone! The only thing Keystone can posdible do is say the author overstepped their bounds. That however is not going to cut it! Keystone also better be prepared to show what "testing" they did and if no extensive testing was done" end of game. Instead of shifting liability for a "component" used in manufacturing they, by virtue of independent analysis made the choice. In addition they further complicated things by telling me, I was not given any "option" to have my unit delivered with a better tire. I got all they offered or recvomendeded. As far as over weight, a parade of experts will come forward to state, that the manufacture by virtue of experience knew it or should have known, "overloading happens", yet manufacturer failed to factor it into their calculations.

04-02-2015, 08:42 PM
Reading that response from Keystone reminds me of watching Josh Earnest at the podium during the daily White House press briefing.

04-03-2015, 07:31 PM
Hmmm, lets see the specs. The E rated tires have a load capacity in the 3,000 PSI range. The sticker on the door of my 3750 FL states the "dry" weight at 12,430. So to start with, we are at the maximum load range for the tire (4 Tires X 3,000 PSI each). But let's say as an owner, I put in 2,000 pounds of clothes, food, dishes, blankets, etc... Now we are at 14,430 pounds. But that is just sitting still. As we all know, as we pull the trailer, there will be "bouncing" with an uneven road.

With heavy bouncing, achieving momental inertia of 5,000 PSI on a tire is not uncommon.

Here is a short excerpt about tires:
Pacejka has developed a series of tire design models over the last 20 years. They were named the 'magic formula' because there is no particular physical basis for the structure of the equations chosen, but they fit a wide variety of tire constructions and operating conditions. Each tire is characterized by 10-20 coefficients for each important force that it can produce at the contact patch, typically lateral and longitudinal force, and self-aligning torque, as a best fit between experimental data and the model. These coefficients are then used to generate equations showing how much force is generated for a given vertical load on the tire, camber angle and slip angle.[4]

The Pacejka tire models are widely used in professional vehicle dynamics simulations, and racing car games, as they are reasonably accurate, easy to program, and solve quickly.[5] A problem with Pacejka's model is that when implemented into computer code, it doesn't work for low speeds (from around the pit-entry speed), because a velocity term in the denominator makes the formula diverge.[6] An alternative to Pacejka tire models are brush tire models, which can be analytically derived, although empirical curve fitting is still required for good correlation,[7][8] and they tend to be less accurate than the MF models.[9]

The general form of the magic formula is: R(k) = d \cdot sin \{ c \cdot arctan [ b(1-e)k+e \cdot arctan(bk) ] \} \, where b, c, d and e represent fitting constants and R is a force or moment resulting from a slip parameter k.

In layman's terms, there are a LOT of forces working on a tire, causing major stress, ie. speed, weight, road conditions, lateral movement, turning torque, braking, accelerating, etc... Even the torque of the lug nuts can affect a tires performance.

Bottom line, those E tires are designed for an empty, motionless 3750FL, nothing more. Keystone is being negligent on the tire side of things, especially for their longer units. Personally, I think any fifth wheel over 35 feet and/or over 10,000 pounds, should have three axles. We love our Montana, but the tires are inefficient for it. Hello G14s!!

Artemus Gordon
04-03-2015, 07:37 PM

04-04-2015, 01:43 AM
Lost me on the math but got the bottom line!

04-04-2015, 04:14 AM
My attorney will quote what N2Bch said above but Keystones attorneys, cause they will have a bunch of them, will quote the basic specs.....then the court will have to decide who is right.....guess it will depend on who has the smoothest talker.....

04-04-2015, 10:56 AM
My thinking is that Keystone is saying the E rated tires are within specs based on the GVWR minus 20% of that weight that is carried as pin weight in the bed of the truck and not on the four E rated tires.