Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
Old 04-30-2013, 09:07 AM   #1
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
C/D tire

If you run C tire at 80% around 1600 lbs....is there any reason to increase to a D tire?
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Old 05-01-2013, 06:01 AM   #2
Senior Member
 
Join Date: Feb 2013
Posts: 418
Then there is no reason to chanche, is my first impression. You have enaugh reserve to cover , unequall loading R/L and a little overloading.
But to be shure I would have to fill in the data in my caravan/trailer- or CamperR V- tyre-pressure-calculator.
Then I need the maximum load or loadindex of your tires and the reference-pressure ( the yyy in fi maximum load xxxx lbs AT yyy psi( cold)) wich is not the maximum pressure of the tire.
From the caravan or RV I need the GVWR or GAWR's and the number of tires the load is resting on.
jadatis is offline   Reply With Quote
Old 05-01-2013, 06:34 AM   #3
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
In my opinion, if you have enough reserve capacity to increase the required pressure to support the actual weight plus 10 PSI for the speed rating increase, then there is no need to change to a higher pressure tire.

For example, if you have Maxxis ST225/75R/15 C load rated tires and the ACTUAL load on them is 1880 pounds (requires 40 COLD PSI to support that load); then inflating to 50 COLD PSI at that load will increase your speed rating from 65 MPH to 75 MPH.

If your actual load is 2020 pounds per tire (requires 45 COLD PSI to support that load); you would only be able to push the pressure to 50 COLD PSI for a speed rating increase of 5 MPH (70 MPH).

If you are closer than that to your max load, a Load range bump to D would benefit you by a speed rating increase potential as well as a greater strength and excess capacity for road hazard protection.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Herk7769 is offline   Reply With Quote
Old 05-01-2013, 07:12 AM   #4
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
2150 lbs @ 50 psi....GVWR 8786.....GAWR 4000 per axle (2)
Trailer axles 6600 pin 1400 TV 6900 Varible water 0-300 lbs just rear of rear trailer axle moving to balance over axle and slight to front axle in tanks....

Rear trailer tire start somewhere around 1725 going to 1650 as water changes position.....Maybe a litte less depending on black/gray tanks.....usually start trip with 100 lbs h2o fresh rear tank 50 lbs middle gray 50 lbs front black....with water weight moving forward as trip progresses....the intial water weight is included in the 6600......Max addition water weight increase could be 700 lbs with all tanks full...but quickly looking for dump station under that condition...LOL.....so pretty much stay near the 6600.....top speed range is 56 mph to 58 mph.....
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Old 05-01-2013, 07:19 AM   #5
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
Quote:
Originally Posted by sail2liv View Post
2150 lbs @ 50 psi....GVWR 8786.....GAWR 4000 per axle (2)
Trailer axles 6600 pin 1400 TV 6900 Varible water 0-300 lbs just rear of rear trailer axle moving to balance over axle and slight to front axle in tanks....

Rear trailer tire start somewhere around 1725 going to 1650 as water changes position.....Maybe a litte less depending on black/gray tanks.....usually start trip with 100 lbs h2o fresh rear tank 50 lbs middle gray 50 lbs front black....with water weight moving forward as trip progresses....the intial water weight is included in the 6600......Max addition water weight increase could be 700 lbs with all tanks full...but quickly looking for dump station under that condition...LOL.....so pretty much stay near the 6600.....top speed range is 56 mph to 58 mph.....
So that would be a "No, switching to D rated tires would not reap you the benefits that others closer to their max would see."
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Herk7769 is offline   Reply With Quote
Old 05-01-2013, 07:30 AM   #6
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
Thanks herk, I now won t be a concerned about tire and trailer fodder when they pass me going 65-70.....And is nice to know I have a cushion to increase my speed some, if want to get in the race for the last campsite.....but probably will just keep going 56-58 mph and stay at wally world or the VFW if the speedballs get there first.....
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Old 05-01-2013, 07:50 AM   #7
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
Stamped on the aluminum rim is 2150J.....since J is a speed rating.....does that mean the rim is limited to 65 mph? And load max for the rim is 2150? Not sure where to get this info? More help Herk pls.....thanks
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Old 05-01-2013, 08:14 AM   #8
Senior Member
 
Join Date: Feb 2013
Posts: 418
Then I made 2 pictures, one with the 6600/1400lbs as you gave, wich gives 42 psi as advice, and one for 8786GVWRand 10% pinload.
Shows a poor reserve for the full loaded, but yust slightly .
Other thing is, if they are Specialtrailer-tires(ST) those are calculated in their maximum load for a lower speed,and often give problems.
Better then would be to chanche to the same sises in LT tires, wich have lower maximum load but can carry that up to higher speed.
The reason for ST to give problems, is that they mostly have off-road like profile wich cover a part of the sidewal, so that may deflect lesser then the deflection the tire-maker used to calculate the maximum load, probalby you have to substract even 20% of that maximum load, printed on the sidewall.
And then things change and you better do swich to D-load/8ply to have enaugh reserve.
But asuming your tires are calculated right, and the loads are right, use 42 minimum psi. If it apears that your loads are at the level of maximum for the 5thwheeler, use even 51 psi minimum ( see 2nd picture), and this is within the 10psi the tire maker allows ( so under 60 psi ).
Attached Thumbnails
Click image for larger version

Name:	forestriverCD.GIF
Views:	108
Size:	47.3 KB
ID:	29395   Click image for larger version

Name:	forestriverCDfullloaded.GIF
Views:	82
Size:	47.2 KB
ID:	29396  
jadatis is offline   Reply With Quote
Old 05-01-2013, 08:31 AM   #9
Site Team
 
wmtire's Avatar
 
Join Date: Nov 2010
Location: Northeast Louisiana
Posts: 33,736
Quote:
Originally Posted by sail2liv View Post
stamped on the aluminum rim is 2150j.....since j is a speed rating.....does that mean the rim is limited to 65 mp
h?
Usually J is a common bead profile/rim contour designation.......but it's usually stamped where the rim diameter/width is like 15 X 7 J .....but I guess it could be placed anywhere.

Let me go see if we have any trailer wheels still in stock to look.
__________________
2011 Flagstaff 831 RLBSS

A 72 hour hold in a psych unit is beginning to intrigue me as a potential vacation opportunity.
wmtire is online now   Reply With Quote
Old 05-01-2013, 08:35 AM   #10
Senior Member
 
Join Date: Feb 2013
Posts: 418
Quote:
Originally Posted by sail2liv View Post
Stamped on the aluminum rim is 2150J.....since J is a speed rating.....does that mean the rim is limited to 65 mph? And load max for the rim is 2150? Not sure where to get this info? More help Herk pls.....thanks
You read right so yes that is what it means.
But it does not write maximum psi so 65 psi might be ok.
In Europe we also have 3,75 bar/ 55psi tires so inbetween C- and D-load.
They are also called C-tires for Comercial, and is the European term for LT.
C-load/6ply and Dload/8ply are also called C-tires in europe and LT in America.

They could have that 2150 lbs max load with on road profile so max load written is what it is. That the tires have higher speedrating then J would be now problem then, but you still are restricted to the 65m/h maximum speed, because of the rimms.
jadatis is offline   Reply With Quote
Old 05-01-2013, 09:15 AM   #11
Site Team
 
wmtire's Avatar
 
Join Date: Nov 2010
Location: Northeast Louisiana
Posts: 33,736
Here are some pics below of various trailer rims. As you will notice, they all have the rim contour designation of J or JJ in various places on the stampings. These are just some we had in the shop.

Here is a link to better explain bead profiles/rim contours: It's near the bottom

Technical Information: Wheels and Tires

Here is another with the explanation near the middle:

Car Bibles : The Wheel and Tyre Bible Page 4 of 4

Here is Goodyears chart on approved rim contours. Common trailer sizes are on page 1 and 2:

http://www.goodyear.com/truck/pdf/databook/misc.pdf
Attached Thumbnails
Click image for larger version

Name:	trailerims 001.jpg
Views:	77
Size:	51.7 KB
ID:	29399   Click image for larger version

Name:	trailerims 002.jpg
Views:	80
Size:	51.0 KB
ID:	29400   Click image for larger version

Name:	trailerims 003.jpg
Views:	95
Size:	58.2 KB
ID:	29401   Click image for larger version

Name:	trailerims 004.jpg
Views:	87
Size:	55.8 KB
ID:	29402  
__________________
2011 Flagstaff 831 RLBSS

A 72 hour hold in a psych unit is beginning to intrigue me as a potential vacation opportunity.
wmtire is online now   Reply With Quote
Old 05-01-2013, 09:26 AM   #12
Senior Member
 
Join Date: Feb 2013
Posts: 418
So I was wrong with the J for up to 65 m/h and it only stands for the rimm contour. Always confusing when you use the same letters for different things.
jadatis is offline   Reply With Quote
Old 05-01-2013, 09:55 AM   #13
Site Team
 
wmtire's Avatar
 
Join Date: Nov 2010
Location: Northeast Louisiana
Posts: 33,736
Quote:
Originally Posted by jadatis View Post
Always confusing when you use the same letters for different things.
Welcome to the tire business. They don't make anything as simple as it should be.
__________________
2011 Flagstaff 831 RLBSS

A 72 hour hold in a psych unit is beginning to intrigue me as a potential vacation opportunity.
wmtire is online now   Reply With Quote
Old 05-01-2013, 10:23 AM   #14
Mod free 5er
 
Join Date: Mar 2008
Location: Concord, NC
Posts: 24,702
For me, going from a C lr to a D lr doesn't involve that much money and is worth it to get away from all the worry and hassle of whether the trailer is loaded right or whether I can go 55mph or 60 or 65 and not have to worry about overheating the tires and inflating or deflating them accordingly. Just not worth the effort IMO.
__________________
OldCoot is offline   Reply With Quote
Old 05-01-2013, 12:37 PM   #15
Senior Member
 
spierce617's Avatar
 
Join Date: May 2012
Location: Minnesota
Posts: 259
If you go from a C load range to a D load range will you need to replace the rims? The D's require or should be run at 65 psi and most of the C rims are only 50 psi. Is this right or wrong?
__________________
2005 Winnebago Adventurer 38R
Workhorse 8.1/Allison Transmission
Old 2005 Forest River Cherokee Lite 28A
spierce617 is offline   Reply With Quote
Old 05-01-2013, 12:53 PM   #16
Mod free 5er
 
Join Date: Mar 2008
Location: Concord, NC
Posts: 24,702
Quote:
Originally Posted by spierce617 View Post
If you go from a C load range to a D load range will you need to replace the rims? The D's require or should be run at 65 psi and most of the C rims are only 50 psi. Is this right or wrong?
You need to look on the inside of the rim to determine that. It is usually stamped on them or call the mfg.
__________________
OldCoot is offline   Reply With Quote
Old 05-01-2013, 01:03 PM   #17
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
Per FR you can go up one time.....ie C to D....when I took delivery of the new trailer it had 3 C s and 1 D on it.....in my reading all 4 are suppose to be the same, so they replaced the D with a C.....so they use the same rims on larger 5 ers....and the larger ones come with D s.....so the weight will be appropriate....I also talked with lionshead the tire supplier for FR....they made mention that the J was tire contour/bead related....they said CTP was to maintain shape of tire so it has proper contact with the ground...ie draw a chalk line across the tread and see if it wears even.....or use the chart....he felt the J on the rim was the bead letter....but I am skeptical to a point because the 2150J with 2150 being the max wt of C tires....anyway....I will never have over 1800 lbs per tire....1700 or less will be the norm....and will probably never tow the 5 er over 60 mph.....so I will see how the C s do and make a decision when they near end of life (date on tire)....thanks for all the input.....It is all very helpful.......
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Old 05-01-2013, 03:04 PM   #18
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
My steel rims (which came with OEM 50 PSI C rated tires) are stamped 60 PSI max. I run my D rated tires at 58 PSI which is 10 PSI over my Load required pressure.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
Herk7769 is offline   Reply With Quote
Old 05-01-2013, 04:14 PM   #19
Senior Member
 
sail2liv's Avatar
 
Join Date: Apr 2012
Location: NC
Posts: 295
From rim spoke...P.C.D.=4.50 2150 lbs P.C.D.= 5.50 2830 lbs Next spoke DOT M3 06 15x6J ET Next spoke HISPEC WHEEL & TIRE patent pend.

Another wheel had a DOT-T 06 15x6J ET and no visible PCD = so looking for what DOT M3 means and DOT-T means.....

For the moment thinking C tire will be the 2150......and D or E will be the 2830 lbs will have to refer to chart but think D around 2550 so 2830 may be E so possibly the rim on my trailer will handle c d or e..tires.....since FR said you can go up one size...

Anyway I am fine since I am lite wt.....but for those who pull heavier might be good info to have.....
__________________

2011 Silverado 2500HD 6.0 Gas 3.73
2013 Flagstaff 8524 RLWS
1978 Cape Dory Ketch
sail2liv is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 08:18 AM.