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MRR

Tow vehicle concern

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Folks, I have a new Redwood 5th wheel. Dry weight is 13,400 pounds. We will start living in it by the end of the year. I bought a new Ram 3500 SRW to pull it. The truck is rated to pull 17,080 pounds. And max payload is 3,950 pounds. Hitch weight is 2,450 pounds. Pulling the 5th wheel with the truck is fine and stable feeling. But suddenly, after several trips, I started worrying about having only two wheels back there. What if a tire blows. I've got the rear tires filled cold to 80 pounds. Driving home in the heat the other day, the pressure on the rear tires read 90 pounds. It freaked me out. If it wasn't for me worried about tire failure, I don't think I would be thinking about switching out this new truck for a DRW. Help me out guys. Should I be trading now while the truck is almost new??????

Edited by MRR

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It is normal for the tire pressure to increase from 80psi to 90psi as the tires heat up. 

What you need is a TPMS (Tire Pressure Monitor System) on both the truck and trailer. 

Search this forum for TPMS or just tire pressure for a number of discussions and info about TPMS.  

BTW, if you start the day at 70 degrees and 80psi on the rear tires of the truck and then by the afternoon, pulling the trailer, you are on the interstate at 60mph and 95 degrees, your tire pressure will be 95-100psi.  That is normal.  The tires are built to handle this. 

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About the dully tires versus SRW.  

--  I would not change trucks as long as you do weigh your axles at a CAT scale to be sure you are not near to being overweight. To find a scale go here to find a scale location near you.

--  We pulled our 35' Hitchiker with a SRW truck and didn't have a problem.  Many others do as well. 

--  It is probably safer with a dully.  But keep your speed down and use a TPMS and you will be fine.

But keep in mind even with a dully, if you don't have a TPMS and you loose air in one tire you won't know it and then you are likely to blow the remaining good tire.  Especially if you like to drive at 65-70mph or higher. Not recommended!

 

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It would be helpful if you provided the GVWR for the trailer and the max weight for the rear axle of the truck.  Also the model number of the trailer and the numbers/letters from the trailer tires, would be helpful.  Looking for the entire string of numbers from the tire.  Example:  ST225/75r15 109S and the load range of the tire like LR-E

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Welcome to the Escapee forums!  

I'm not a fifth wheel owner but doubt that I'd trade just to get dual rear wheels. The big reason most want them is for stability, especially in a cross wind. 

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27 minutes ago, Kirk Wood said:

Welcome to the Escapee forums!  

I'm not a fifth wheel owner but doubt that I'd trade just to get dual rear wheels. The big reason most want them is for stability, especially in a cross wind. 

I don't know, Kirk. When we moved from SRW to DRW, we certainly benefited from stability and the added safety of having a backup tire on each side, but the main reason we did it was to move from a rear axle rating of 6,200 lbs. to 9,000 lbs. Now I don't have to tell my wife, "No - we can't put anything else in the basement!"

Rob

Edited by Second Chance
I misspelled Kirk's name... of all things!

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We have had two dually trucks since 2005.We did have a inside dually tire lose air and go flat one time while pulling the 5th wheel. Wife was driving and said something did not feel right pulled into a truck stop and sure enough the inside right dually was flat From the right seat I did not know anything was wrong .No damage and a tire repair had us on the road again. We got the dually  for the added Carry capacity in regard to pin weight.TMPS sensor will not report on the inside dually tires on our F-350 Fords.

 

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1 hour ago, richfaa said:

... TMPS sensor will not report on the inside dually tires on our F-350 Fords.

 

The TireMinder TPMS we use for both truck and trailer reports on both inside tires on the back of the truck (10 tires total with truck and trailer). Perhaps those sensors are being relayed through the "booster" unit mounted in the front compartment of the fifth wheel.

Rob

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2 hours ago, Al F said:

It is normal for the tire pressure to increase from 80psi to 90psi as the tires heat up. 

What you need is a TPMS (Tire Pressure Monitor System) on both the truck and trailer. 

Search this forum for TPMS or just tire pressure for a number of discussions and info about TPMS.  

BTW, if you start the day at 70 degrees and 80psi on the rear tires of the truck and then by the afternoon, pulling the trailer, you are on the interstate at 60mph and 95 degrees, your tire pressure will be 95-100psi.  That is normal.  The tires are built to handle this. 

Thanks much. Appreciated. I tried Googling this subject of tire pressure increasing. I did see mentions of expecting a 10 percent increase. That would put pressure at 88. On the latest trip, I actually saw 91. 

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2 hours ago, Al F said:

About the dully tires versus SRW.  

--  I would not change trucks as long as you do weigh your axles at a CAT scale to be sure you are not near to being overweight. To find a scale go here to find a scale location near you.

--  We pulled our 35' Hitchiker with a SRW truck and didn't have a problem.  Many others do as well. 

--  It is probably safer with a dully.  But keep your speed down and use a TPMS and you will be fine.

But keep in mind even with a dully, if you don't have a TPMS and you loose air in one tire you won't know it and then you are likely to blow the remaining good tire.  Especially if you like to drive at 65-70mph or higher. Not recommended!

 

Thanks Al. I've got TPMS on truck but not trailer. Working on that one. Have to figure out what exactly to buy.

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2 hours ago, Al F said:

It would be helpful if you provided the GVWR for the trailer and the max weight for the rear axle of the truck.  Also the model number of the trailer and the numbers/letters from the trailer tires, would be helpful.  Looking for the entire string of numbers from the tire.  Example:  ST225/75r15 109S and the load range of the tire like LR-E

I'll dig all that out this weekend. Thanks so much.

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2 hours ago, Al F said:

About the dully tires versus SRW.  

--  I would not change trucks as long as you do weigh your axles at a CAT scale to be sure you are not near to being overweight. To find a scale go here to find a scale location near you.

--  We pulled our 35' Hitchiker with a SRW truck and didn't have a problem.  Many others do as well. 

--  It is probably safer with a dully.  But keep your speed down and use a TPMS and you will be fine.

But keep in mind even with a dully, if you don't have a TPMS and you loose air in one tire you won't know it and then you are likely to blow the remaining good tire.  Especially if you like to drive at 65-70mph or higher. Not recommended!

 

Thanks Al. Okay, newbie found a CAT scale 3 miles away. Now, what exactly should I be doing? Hold my hand a bit longer on this one please.

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Put your front axel (wheels) on the front scale, your rear axel (rear wheels) on the second scale and your trialer axels on the third scale.  Press the button and when they answer just tell them you want to weigh for personal use.  They'll ask you for a number....you can just tell them 1 or 100.

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4 minutes ago, JCZ said:

Put your front axel (wheels) on the front scale, your rear axel (rear wheels) on the second scale and your trialer axels on the third scale.  Press the button and when they answer just tell them you want to weigh for personal use.  They'll ask you for a number....you can just tell them 1 or 100.

Then pull off the scales and go in and get your weight ticket and pay the $12 (I think) fee.  Drop your trailer and take the truck across the scales alone.  Tell the weigh master you are doing a re-weigh and give them the number from the bottom of your original ticket.  Once done, pull off the scales, go inside and pay the $2 (I think) fee for your second ticket.  You will now have the ability to calculate your truck's weight hitched and unhitched and your trailer's total weight and pin weight.  This will let you know if you are within specs on your truck's axle ratings and GVW as well as the trailer's axle ratings and GVW and finally your GCWR.  It won't give you individual wheel weights, so the axles could be overloaded sided to side potentially, if you are close on your ratings.

You should go across the scales fully loaded as if you are traveling.  This includes full fuel, all passengers, water in the fresh water tank, full propane, all your gear in the truck and trailer, etc.

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10 hours ago, Chad Heiser said:

Then pull off the scales and go in and get your weight ticket and pay the $12 (I think) fee.  Drop your trailer and take the truck across the scales alone.  Tell the weigh master you are doing a re-weigh and give them the number from the bottom of your original ticket.  Once done, pull off the scales, go inside and pay the $2 (I think) fee for your second ticket.  You will now have the ability to calculate your truck's weight hitched and unhitched and your trailer's total weight and pin weight.  

The re-weigh without the trailer isn't really necessary unless you're simply curious. For most of us a single quick trip across the scale hitched up is all that we need to obtain the critical axle weights.  Taking the time to unhitch, re-weigh, and then re-hitch isn't critical. 

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11 hours ago, Chad Heiser said:

Then pull off the scales and go in and get your weight ticket and pay the $12 (I think) fee.  Drop your trailer and take the truck across the scales alone.  Tell the weigh master you are doing a re-weigh and give them the number from the bottom of your original ticket.  Once done, pull off the scales, go inside and pay the $2 (I think) fee for your second ticket.  You will now have the ability to calculate your truck's weight hitched and unhitched and your trailer's total weight and pin weight.  This will let you know if you are within specs on your truck's axle ratings and GVW as well as the trailer's axle ratings and GVW and finally your GCWR.  It won't give you individual wheel weights, so the axles could be overloaded sided to side potentially, if you are close on your ratings.

You should go across the scales fully loaded as if you are traveling.  This includes full fuel, all passengers, water in the fresh water tank, full propane, all your gear in the truck and trailer, etc.

Chad is spot on .. weigh without the trailer and with the trailer.  This will give you your pin weight (rear axle weight with/without the trailer difference is the pin weight).  The chances are VERY GOOD that you have exceeded both the rear axle weight rating and the GVWR of the truck.  I had a lighter 5th wheel and a SRW F350 and that was my situation.  I traded the SRW for a DRW to get "legal".  You will find that a DRW truck will be more stable when 18 wheeler's pass you and their bow wake hits the side of your rig.  With the SRW truck there was a little push-pull and wiggle.  With the DRW truck I almost don't feel the 18 wheeler's bow wakes anymore.

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A very good reason to do the re-weigh is to insure the hitch weight is from about 18% to 22% of the trailer weight.  20% is ideal. 

If you are 15% you will experience some handling problems.  Such as significant sway from passing trucks and cross winds.  Also if you ever need to make a sharp maneuver to avoid something in the road you may loose control. 

Sway is a very serious problem.  Once it starts it can be hard to stop.  One way to stop the sway is to grab the handle on your trailer brake controller and manually apply the trailer brakes. 

If your hitch weight is 25% or more you probably exceeding the max rear axle weight on the truck. 

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Kind of back to the original question:  "Should I sell my new SRW truck and buy a DRW truck?" 

You are going to take a big hit on the cost of selling, then buying a new truck.  Some $15,000 to maybe $25,000 maybe.  Just a guess on my part. 

You are going full time living in the 5th wheel.  So I would expect you are not likely to "need" to put yourself in the position of needing to make a trip where you have to cover 500 mile in a day and there by want to drive at 65-70mph. 

Keep your speed in the 60mph range or perhaps 55-58mph, put the cruise control on and sit back and relax.  Plan on covering 150-250 miles in a day.

Subscribe to the rule of "2's".  That is: only drive 200 miles in a day, off the road by 2pm, stay 2 nights before traveling again.  I, personally, subscribe to the rule of 2's. 

However we have been making an annual round trip of about 2300 miles from Texas to Portland, OR for the last 6 years.  On these trips we do drive 350-400 miles in a day.  It does make for a long day, since I find it hard to average more than about 40-45mph for a full days travel.   That includes fuel stops, bio-breaks, and lunch stop.  I seldom drive over about 62-63mph on the interstates. Less on 2 lane roads.  Only once have we covered the 2300 miles in 6 days.  The rest of the 12 round trips we will drive the 300-350 miles in a day for 2-3 days and then spend a few days, either in one spot or a couple of days and then move 50-100 miles for another 1-3 days.  We have taken as long as 30 days to make the trip from Texas to Oregon. 

One additional comment.  The truck will by your mode of transportation while staying someplace.  A SRW truck is easier to maneuver and park than a DRW truck.  Especially if you explore gravel/dirt roads in the National Forests, National Parks, BLM land, etc.  

Having made the above statement, I have seen lots of comments in the forums over the years of folks saying they have no problems taking their DRW trucks on drives.  Also others have stated they have no problems using their HDT trucks for transportation.  It really depends on your life style.

There is no reason in my mind to not just keep the SRW truck.  After 6 months or a year of travel you will be in a much better position to decide if the SRW truck is right for you.

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A DRW is nice to have but not critical. As far as tire pressure my Tireguard shows the trailer PSI gaining up to 25PSI when rolling down the road. I had an experience with the morning PSI checked at 110 PSI and during the hot afternoon was reading 135+ psi. Within the next 30 days, I had 3 of the tires get bubbles on the sidewalls which I believe was caused from that hot day. Now I have new tires and run them at 95PSI  cold which shows 115-120 rolling PSI. The tread wear seems even and with 110 PSI rated tires and rims, I feel that the 115-120 rolling PSI is doable.

I never heard of anyone being checked for legal weight on a private vehicle, unsafe condition maybe due to a way overloaded trailer axle that was bending in the middle and swerving.

Greg

Edited by gjhunter01

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MRR,

Assuming all your weight and load ratings check out, try switching to nitrogen in your tires.  They will run cooler and remain at pressure longer than air.

The TPMS advice is one to take.  The one thing I did not see mentioned is tire age.  If your tires have aged out, replace them. Doesn't matter how good they look.  Shelf life varies by manufacturer.  Typical is 5-7 years.

Brad

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5 hours ago, Flying Finn said:

...try switching to nitrogen in your tires.  They will run cooler and remain at pressure longer than air.

Considering "air" is already almost 80% nitrogen... it's a complete waste of money, IMHO. Running cooler is pure myth for the standard vehicle, RV or tow package. Whatever gas is inside has no impact on road friction to rubber for the average Joe. It's true they will hold their gas a little longer than standard air. Properly sealed "air" tires typically lose 1/2 to 1psi per month, however, having pure nitogen filled does not negate the need for regular checks and maintanence.

Edited by Yarome

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^^^^I agree with that regarding the nitrogen.  I looked into that a couple of years ago. The nitrogen in a nitrogen tank is only 95-96% pure, which means the difference between air and nitrogen fill is just 15-16%.

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4 hours ago, Yarome said:

regarding the nitrogen.....................it's a complete waste of money,

Absolutely!

Edited by Kirk Wood

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My next truck will be a SRW if it has the carrying capacity I need.  There are times a dually is more of a pain than they are worth.  In 6 yrs of traveling, I have yet to feel any kind of crosswind that would give me pause to tow with a SRW.  If the winds are that bad, find a campground and sit for a few days. 

Duallies do NOT come with TPMS.  IIRC, SRW 1-tons do come with it.  I have had a TST 507 Flow Thru system on my trailer for a few years.  I plan to get them for my truck, too.  Already have the metal valve stems.  Just have to install the flexible steel extensions on the rear wheels.  That is an added pain of duallies, but at least it is only a 1-time pain.

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Nitrogen does have benefits.  It is an inert gas and will not support combustion, so it eliminates tire fires.  It also will run a little cooler and not experience as much pressure loss over time.  The first point (non combustible) is an important factor in many heavy duty applications.  No, it isn’t “magic” ... but to dismiss it as “worthless”, seems misinformed.  It isn’t a huge improvement over regular air, but it is better.

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