Truck tire pressure question

[Texdan]

Picking up my new fiver tomorrow with dry wt. of 9100# and GVWR of 11k. I have a 2013 Chevy 2500HD Duramax with Michelin 18" tires, max pressure rating 80lbs. I normally kept them at 70# when pulling my 7k bumper pull. Should I take the tires up to the max 80# since I'll have an additional 2500-4000#?

[katkt]

You could if you wanted to.
Even at 70psi, the load carrying rating of the tire may be well above what you're fixing to put on it. Check the manufacturers website for the tires, and there will more then likely be a chart showing pounds of weight and suggested inflation. Figure out how much will be riding on the tires total, compare to the Manu's chart, and proceed accordingly.
Just do your inflation checking and adjusting on cold tires.

[The Big Toe]

I carry one of these with me at all times. It works a LOT better than the old plug-in to your cigarettle lighter junk.

If you shop, you can get one at Homely Depot on the sooper-cheap sometimes. I've also got the driver, the impact, leaf blower and a couple other things I forget right now.

That way, if you're on the road and you don't like how your rig is handling, pump up the tires a bit. (I also have extra batteries) If you gotta change or plug a tire.....

I don't leave home wihtout them.

But to answer your question, put the 80 PSI in the rear tires. If you don't like it, let some out at your next stop.

[The Evil Twin]

I would. That is what I do with our TH. They will run cooler and squirm less.

[Thomas ho]

I run what is on door panel . 5th wheel trailer or no trailer. Running Michelin xts tires. 2nd truck i have run like that perfect tire wear. Sidewall construction is top of line i have found. Not Defender tires top of the line michelins . Around $1,400.00 for 4. Never had defenders by michelin but i would say it is a real good quality tire .

[Texdan]

Originally Posted by katkt

You could if you wanted to.
Even at 70psi, the load carrying rating of the tire may be well above what you're fixing to put on it. Check the manufacturers website for the tires, and there will more then likely be a chart showing pounds of weight and suggested inflation. Figure out how much will be riding on the tires total, compare to the Manu's chart, and proceed accordingly.
Just do your inflation checking and adjusting on cold tires.

Well, here's what's on Michelin's site (and max info on my tire):


3180/6190@65#; 3360/6720@70#; 3530/7060@75#; 3640/7280@80#


I'm figuring my pin weight will be around 2k give or take 100#. So I'm thinking tire pressures could be any of these? Payload is 2800.

[Theo]

One option would be to take your rig to the Cat Scales and do the 3-pass weighing routine. You'll have good data from that exercise to answer a number of weight-related questions. Then, check the loads on the steer & drive axles. Use those weights to look up the tire pressure/loading data on the tire manufacturer's website and set the pressures accordingly.

[Texdan]

Originally Posted by Theo

One option would be to take your rig to the Cat Scales and do the 3-pass weighing routine. You'll have good data from that exercise to answer a number of weight-related questions. Then, check the loads on the steer & drive axles. Use those weights to look up the tire pressure/loading data on the tire manufacturer's website and set the pressures accordingly.

I plan on doing that in the near future. Gotta look up how to do it first.

[katkt]

Originally Posted by Texdan

Well, here's what's on Michelin's site (and max info on my tire):


3180/6190@65#; 3360/6720@70#; 3530/7060@75#; 3640/7280@80#


I'm figuring my pin weight will be around 2k give or take 100#. So I'm thinking tire pressures could be any of these? Payload is 2800.

So roughly 4000, plus whatever weight is on the truck axles(gross curb weight of the truck) without the pin weight, divided by four.
Payload is everything you throw in the truck, including warm bodies. So that'll add to whatever the above is.

I think I'd put them at #80 cold. That'll give you some margin until you can cross a scale, and see what's on each axle(something everybody should do for a real education). After you determine what's what, you can come off the max a bit for a slightly improved ride...if.
If you do let them down a bit and the squirm seems to increase, go back up.

[Texdan]

Originally Posted by katkt

So roughly 4000, plus whatever weight is on the truck axles(gross curb weight of the truck) without the pin weight, divided by four.
Payload is everything you throw in the truck, including warm bodies. So that'll add to whatever the above is.

I think I'd put them at #80 cold. That'll give you some margin until you can cross a scale, and see what's on each axle(something everybody should do for a real education). After you determine what's what, you can come off the max a bit for a slightly improved ride...if.
If you do let them down a bit and the squirm seems to increase, go back up.

Thanks, that's kinda what I'm thinking at least for the maiden voyage.

[Theo]

Originally Posted by Texdan

I plan on doing that in the near future. Gotta look up how to do it first.

Basically, here's the 3-Pass weighing overview. Prepare by picking a time when you are on your way to a campsite and you are fully loaded with people, pets, propane, H2O and your other cargo.

• Pass 1: Disconnect the TT and weigh your fully loaded TV (keep the uncoupled hitch in the receiver). The Cat Scale will report your "steer" and "drive" axle weights. Together, these weights are your uncoupled TV's GVW weight.
• Pass 2: Hook up the TT to your WDH but DO NOT connect the bars. Weigh your rig by making sure each of the three axle sets are as close to the center of the scale segments as is possible. The Cat Scale will report your steer, drive and "trailer axle" weights. Together, these weights are your whole rig's GVW weight without any WD compensation.
• Pass 3: Connect the WDH's trunnion/spring bars and weigh as in Pass 2. You'll notice the rig's GVW is the same as in Pass 2, but that weight is distributed to the axles differently; usually, weight is distributed from the TV drive axle to the steer and trailer axles.

Now, with this data you can check all kinds of things to make sure your rig is safe and doesn't exceed various weight ratings. It's also good for any adjustments that you may be considering for your WDH. Finally (and specifically germane to this thread), you can easily find the load on each of your axles by referencing the Cat Scale tickets.

Remember that the axle load is distributed between the two tires on the axle. The Michelin loading/pressure charts usually represent the combined tires' loading. The minimum pressure would be the pressure at which the combined load rating is at (no margin of error) or is comfortably above the highest Pass 2/3 axle weight (highly recommended).

I've found the Cat Scale worksheets developed by Jeffrey Boyer for his book "Are You Ready to RV" to be particularly useful. Among other topics, his book also describes how to use Cat Scales and provides ~15 worksheets for all kinds of RV configurations. He has a website with PDF versions of his worksheets that can be downloaded for buyers of his book.

HTH

[Texdan]

Originally Posted by Theo

Basically, here's the 3-Pass weighing overview. Prepare by picking a time when you are on your way to a campsite and you are fully loaded with people, pets, propane, H2O and your other cargo.

• Pass 1: Disconnect the TT and weigh your fully loaded TV (keep the uncoupled hitch in the receiver). The Cat Scale will report your "steer" and "drive" axle weights. Together, these weights are your uncoupled TV's GVW weight.
• Pass 2: Hook up the TT to your WDH but DO NOT connect the bars. Weigh your rig by making sure each of the three axle sets are as close to the center of the scale segments as is possible. The Cat Scale will report your steer, drive and "trailer axle" weights. Together, these weights are your whole rig's GVW weight without any WD compensation.
• Pass 3: Connect the WDH's trunnion/spring bars and weigh as in Pass 2. You'll notice the rig's GVW is the same as in Pass 2, but that weight is distributed to the axles differently; usually, weight is distributed from the TV drive axle to the steer and trailer axles.

Now, with this data you can check all kinds of things to make sure your rig is safe and doesn't exceed various weight ratings. It's also good for any adjustments that you may be considering for your WDH. Finally (and specifically germane to this thread), you can easily find the load on each of your axles by referencing the Cat Scale tickets.

Remember that the axle load is distributed between the two tires on the axle. The Michelin loading/pressure charts usually represent the combined tires' loading. The minimum pressure would be the pressure at which the combined load rating is at (no margin of error) or is comfortably above the highest Pass 2/3 axle weight (highly recommended).

I've found the Cat Scale worksheets developed by Jeffrey Boyer for his book "Are You Ready to RV" to be particularly useful. Among other topics, his book also describes how to use Cat Scales and provides ~15 worksheets for all kinds of RV configurations. He has a website with PDF versions of his worksheets that can be downloaded for buyers of his book.

HTH

Thanks Theo. Guess you missed the part that I have a fifth wheel (fiver). Would think its same theory though?

[dbledan]

Originally Posted by Texdan

Thanks Theo. Guess you missed the part that I have a fifth wheel (fiver). Would think its same theory though?

Same theory. Only 2 passes. One with the trailer one without unless you find you need to move a bunch of things around or know the weight of your truck without the trailer.

[Texdan]

Originally Posted by dbledan

Same theory. Only 2 passes. One with the trailer one without unless you find you need to move a bunch of things around or know the weight of your truck without the trailer.

So I could take the 1st pass with everything hooked up like this?
1. Scale 1 front truck axle
2. Scale 2 rear truck axle
3. Scale 3 trailer hitched


Then reading 2 I could just raise the trailer pin off the hitch and take another reading?

[Texdan]

Well, picked up my Reflection 29RS yesterday for my first ever fiver tow. I put front tires (80# max Michelin E) at 70 front and 80 back. Truck sticker on stock 17" E is 65 front 80 back. Anywho, I am a little disappointed in that I seem to get a little chucking while driving with my 2013 Chevy 2500HD Duramax. I have a graphite plate on the pin box and greased the hitch jaws and put white lithium grease on the hitch base rubber thingies where the hitch head sits. Any ideas or is that normal? My thoughts:

1. Harder ride due to tire pressure?
2. Would truck air bags eliminate this?
3. ?????

Other than that we are already loving the fiver even in the driveway!

[Herk7769]

I talk to the CAT scale operator at my local truck place. I ask a safe place to temporarily drop my camper for a second weigh. ($1.00 same day).

I get in line and weigh as a combination; then get off the scale to let others use it while I am in that safe area to drop the camper and get back in line if there is one.

Weigh the truck and then pick up the camper; pay on the way out.

[Texdan]

Originally Posted by Herk7769

I talk to the CAT scale operator at my local truck place. I ask a safe place to temporarily drop my camper for a second weigh. ($1.00 same day).

I get in line and weigh as a combination; then get off the scale to let others use it while I am in that safe area to drop the camper and get back in line if there is one.

Weigh the truck and then pick up the camper; pay on the way out.

Wondering if there is no line if I can just raise my fiver off the hitch an inch of so while still there as long as the front trailer jacks are on the 3rd pad?
Oh, and I created and account at www.weighmytruck.com and downloaded the app on my phone. Now I can get readings online and also pre-pay with CC. Easy peasy!

[Thomas ho]

So you never pulled a fithwheel trailer! Bucking is something you will get used to. Roads have up and downs. If you wanted a velvet ride ,,,you expect too much. or get a travel trailer "SMALL, LIGHT". 😆😆😆

[Texdan]

Originally Posted by Thomas ho

So you never pulled a fithwheel trailer! Bucking is something you will get used to. Roads have up and downs. If you wanted a velvet ride ,,,you expect too much. or get a travel trailer "SMALL, LIGHT". 😆😆😆

Ha, selling my TT today! I thought everyone says fivers pull nicer? Didn't know about bucking/chucking but definitely noticed no sway or bouncing.

[Herk7769]

Originally Posted by Texdan

Wondering if there is no line if I can just raise my fiver off the hitch an inch of so while still there as long as the front trailer jacks are on the 3rd pad?
Oh, and I created and account at www.weighmytruck.com and downloaded the app on my phone. Now I can get readings online and also pre-pay with CC. Easy peasy!

I think you will not be allowed to unhitch on the scale.

If something when wrong you might tie up their scale for a LONG time and could be sued for lost revenue at a minimum. Not to mention being beat up by ticked off truckers.

Trying to remember if my camper's landing gear would clear the drive axle's plate, and I don't think so. It would depend on your wheel base.

If you have a long bed crew cab it may just make it.