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07-12-2013, 12:50 PM
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#21
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Senior Member
Join Date: Sep 2009
Location: Lexington, NC
Posts: 2,621
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Quote:
Originally Posted by pt1655
I must be an old fart but I choose to tow at 60mph. I like knowing towing at that speed is easier on tires, suspension,the truck and myself. My 2012 Dodge Ram1500 4X4 5.7L Hemi with Husky weight distributing hitch and tow package is tow rated at 8500lbs and our 25' Surveyor SP220 weighs 5000lbs loaded so I am a bit over half of our rating so I feel comfortable at that speed. Sorry if I don't do 75 or 80 like some of my friends here in Az towing their 40foot fifth wheels on our 75mph posted highways. One friend in particular has had 2 blowouts at those speeds recently on his 38' fifth wheel on relatively new trailer tires and wonders why.
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You won't see MY 220 passing YOUR 220 because I do the same thing. Never over 60. I try to make it a point not to be in a hurry when I'm in the process of going camping.
__________________
2018 Coachmen Apex 249 RBS
2010 Silverado LT 5.3 V8
The world is a great book, of which those who never stir from home
read only a page. - St. Augustine
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07-12-2013, 12:53 PM
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#22
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Senior Member
Join Date: May 2013
Location: Corvallis, Oregon
Posts: 415
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me too
Amen to that!
__________________
2013 Forest River Surveyor SP220 Sport 25'
2012 Ram 1500 4X4, 5.7L Hemi quad cab
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07-12-2013, 05:07 PM
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#23
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
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For the record: I am in the 60-65 (when legal) camp.
My opinion (only) of the verbiage on the Goodyear flyer is that the added 10 PSI is on top of the maximum rated load for the correct tire pressure at that load.
So for example a ST225/75R15 D rated tire (using the attached Maxxis charts) at 55 PSI has a "maximum rated load" of 2270 pounds per tire. IF the load on that tire IS 2270 pounds, the speed rating is 65 MPH. IF an additional 10 PSI is added to that tire (65 PSI - the sidewall pressure), AND the load stays the same (2270 pounds); the tire can be safely spun to 75 MPH without damage.
Again, no tire expert, but that is how I read that...
No where does it say the sidewall pressure can be exceeded.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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07-12-2013, 05:36 PM
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#24
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Mod free 5er
Join Date: Mar 2008
Location: Concord, NC
Posts: 24,702
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Quote:
Originally Posted by herk7769
For the record: I am in the 60-65 (when legal) camp.
My opinion (only) of the verbiage on the Goodyear flyer is that the added 10 PSI is on top of the maximum rated load for the correct tire pressure at that load.
So for example a ST225/75R15 D rated tire (using the attached Maxxis charts) at 55 PSI has a "maximum rated load" of 2270 pounds per tire. IF the load on that tire IS 2270 pounds, the speed rating is 65 MPH. IF an additional 10 PSI is added to that tire (65 PSI - the sidewall pressure), AND the load stays the same (2270 pounds); the tire can be safely spun to 75 MPH without damage.
Again, no tire expert, but that is how I read that...
No where does it say the sidewall pressure can be exceeded.
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That's the way my feeble mind grasps it Lou. Thanks.
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07-12-2013, 05:44 PM
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#25
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Senior Member
Join Date: Jul 2012
Posts: 1,258
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Quote:
Originally Posted by herk7769
So for example a ST225/75R15 D rated tire (using the attached Maxxis charts) at 55 PSI has a "maximum rated load" of 2270 pounds per tire. IF the load on that tire IS 2270 pounds, the speed rating is 65 MPH. IF an additional 10 PSI is added to that tire (65 PSI - the sidewall pressure), AND the load stays the same (2270 pounds); the tire can be safely spun to 75 MPH without damage.
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And from what I gather, if the load is only 2000 lbs per tire, one theoretically would be allowed to go 85 mph at 65 psi. That is the GVWR rating on our camper, so the D-rated tires provide a very large margin of safety.
We seldom go over 65 mph, and prefer to go about 60, as on downshift the engine doesn't rev so much.
Tire discussions can get off track so quickly, but in this case there has been a sharing of great info on this tread.
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07-12-2013, 05:51 PM
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#26
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Site Team - Lou
Join Date: Oct 2009
Location: South Eastern PA
Posts: 23,268
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Quote:
Originally Posted by bakken
And from what I gather, if the load is only 2000 lbs per tire, one theoretically would be allowed to go 85 mph at 65 psi. That is the GVWR rating on our camper, so the D-rated tires provide a very large margin of safety.
We seldom go over 65 mph, and prefer to go about 60, as on downshift the engine doesn't rev so much.
Tire discussions can get off track so quickly, but in this case there has been a sharing of great info on this tread.
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The flyer only allows a 10 PSI/10 MPH addition for speed rating, but I get your drift.
__________________
Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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07-12-2013, 06:03 PM
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#27
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Senior Member
Join Date: Apr 2013
Location: Cincinnati Ohio
Posts: 464
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Quote:
Originally Posted by mjones12
You won't see MY 220 passing YOUR 220 because I do the same thing. Never over 60. I try to make it a point not to be in a hurry when I'm in the process of going camping.
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Ok I might pass you in my 220 if we are going downhill . Actually my wife and I had this same discussion on the way down tonight (our first highway trip with a camper). I remembered herk saying he goes 5 under and so that was what I did but I found I needed to speed up to 70 for short stretches in the hills to get a run so I could stay in 5th gear.
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07-12-2013, 07:05 PM
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#28
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Senior Member
Join Date: Jul 2012
Posts: 1,258
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Quote:
Originally Posted by herk7769
The flyer only allows a 10 PSI/10 MPH addition for speed rating, but I get your drift.
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My angle came from an email response from maxxis to the poster wmtire, from another thread;
" The speed rating on for the Maxxis M8008 ST Radial is "Q", which is 99 MPH. However, according to the Tire and Rim Association the inflation pressures and load specifications in general for all ST Radial trailer tires, regardless of the manufacturer, are designed and rated at 65 MPH. If the speed is higher than 65 MPH, the pressure and load need to be adjusted according to the following guidelines:
From 66 to 75 MPH – the tire inflation pressure needs to increase 10 PSI (not to exceed the maximum PSI the tire is rated for) but requires no load adjustment.
From 76 to 85 MPH – the tire inflation pressure needs to increase 10 PSI (not to exceed the maximum PSI the tire is rated for) and load should be reduced by 10%.
We hope this information is helpful. Thanks for your email and interest in Maxxis Tires.
Best Regards,
The Maxxis Support Team
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So, if that is correct, I should have a speed capability of 85 mph, although that would be pushing the limits.
What it does do though, is make me wonder why they put load range "C" tires on my fifth, as there was virtually no safety margin whatsoever.
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