# $600.00 Mod



## mrw3gr (Feb 19, 2006)

Just made a "major" mod to my truck. I bought a set of Goodyear Wranglers to replace the factory rubber that was on the Silverado. According to the labels on the tires, the carrying capacity is 3042 lbs @ 80 psi. I currently have 35 psi in them. When I hook up to the "caboose" do I need to increase the psi in the tires to the max, leave them at 35 or go somewhere in between?
Thanks,


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## mountainlady56 (Feb 13, 2006)

mrw3gr said:


> Just made a "major" mod to my truck. I bought a set of Goodyear Wranglers to replace the factory rubber that was on the Silverado. According to the labels on the tires, the carrying capacity is 3042 lbs @ 80 psi. I currently have 35 psi in them. When I hook up to the "caboose" do I need to increase the psi in the tires to the max, leave them at 35 or go somewhere in between?
> Thanks,


The tires should have a "recommended inflation" on them. I would run them at that recommended amount, whatever it is, for gas mileage and even wear.
Darlene action


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## tdvffjohn (Mar 10, 2005)

You purchased higher load rated tires than the originals. I run mine at what the tires recomended pressure says on the sidewall. When not towing you can go lower for a better ride but not 35.


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## PDX_Doug (Nov 16, 2004)

mrw3gr,

Good question! Those are some heavy duty tires you have there ('E' rating?), and are actually way more than you probably need in your application. The bottom line is that they only achieve the maximum load rating (3,042#) at the maximum inflation pressure (80PSI). At the current 35 PSI they will be nowhere close to that.

The question in your case, is how much do you need? Certainly more than 35PSI, but as you are unlikely to be loading the tires to anywhere close to 3,042# each, you could get by with less than the 80PSI. Unfortunately, I can't tell you how to calculate that. It may or may not be a linear scale.

I guess to be on the safe side, I would say inflate them to the full 80PSI, although that may be a tad skittish and harsh on the road. For what it is worth, my 'D' rated tires (2,540#) reach maximum capacity at 50PSI, and even that is probably more than you are dealing with.

The only way to really know for sure, would be to get an actual weight on each rear tire when fully loaded, and then contact Goodyear. It would be interesting to hear what they have to say.









Happy Trails,
Doug


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## rnameless (Jun 30, 2005)

I run 78 psi in the rears and 70 psi in the front when towing. michelin e rated truck tires they are stiff but i don't want to take any chances


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## mrw3gr (Feb 19, 2006)

I went to Goodyear's web site and stumbled across this document: www.goodyear.com/truck/pdf/databook/loadinflation.pdf It had some interesting info. Best I can figure out is with my tires at 35 psi, my load rating drops to around 1900 lbs but it still didn't answer my question as to the recommended tire pressure while not towing (and it's not on the tire). I sent them an e-mail so we'll see what they suggest. I know my door pillar says 35-40 but I think that was for the original tires.


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## Insomniak (Jul 7, 2006)

Split the difference and try around 50-55 psi when towing. The best you'll probably be able to do is experiment and see what works best for you.


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## tdvffjohn (Mar 10, 2005)

Remember all those Ford rollovers. It was mostly about tire pressure. Under inflated tire pressure.

I will be interested to learn from your e mail to Goodyear


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## Dan V (May 21, 2006)

I just put new 10 plys on my TV , max pressure is 80 lbs. but not neccessary for my weight of trailer , 5000 lbs. loaded . Got the tires at Les Schwab Tires and the recommended 60 lbs for my application and 40 lbs as minimum so you don't screw up the side walls . Tried driving them around at 60 a day or two before our vacation , oh what a rough ride . Let them down to 40 and my smooth 1500 Silverado ride is back , also was told that running the higher pressures unloaded was ok , but would be rougher !

Dan


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## 7heaven (Jun 4, 2005)

My tire dealer inflated my new.Bridgestone E rated tires to 60 psi when not towing.


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## huntr70 (Jul 8, 2005)

I run my E range tires at 55 psi not towing and the full 80 when towing.

Even at 80 psi, with the load on them, the develop a little belly, so I would run them full.

They are definitley stiff if you don't drop them between towing.

Steve


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## HootBob (Apr 26, 2004)

I run my tire to the max rating on the tires
beside if the air goes below 42lbs. the low tire pressure light comes on

Don


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## Oregon_Camper (Sep 13, 2004)

Inflate to mfg's recommended pressure...


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## GlenninTexas (Aug 11, 2004)

7heaven said:


> My tire dealer inflated my new.Bridgestone E rated tires to 60 psi when not towing.


I wouldn't count on that being the best pressure. I thionk most of these guys just put some air in until it looks right. I doubt if they even check the pressure.

For what it's worth, when towing my fifth wheel, I run 50lbs front and rear. when not towing I run 50 front/45 rear.

Regards, Glenn


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## jgerni (Nov 10, 2003)

Before you air them up to 80psi make sure your rims can handle that presure. Your rear Axle is probably only rated at 4000lbs so airing them to 80 is a waste anyway. You probably donâ€™t need to go over 50 even when towing.

For me towing I do 50 front 75 rear and not towing 50 front and 50 rear.


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## biga (Apr 17, 2006)

The Tacoma brand tires on "big red" are E rated tires with max press of 80psi (I think). I have been running 40psi not towing (which is pretty much 0), and 40psi front and 50psi rear. I am going to try 60/70 on my next trip because we still felt a little bouncy on our last trip.


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## campmg (Dec 24, 2005)

biga said:


> The Tacoma brand tires on "big red" are E rated tires with max press of 80psi (I think). I have been running 40psi not towing (which is pretty much 0), and 40psi front and 50psi rear. I am going to try 60/70 on my next trip because we still felt a little bouncy on our last trip.


Just curious why different psi front and rear if you don't pull a 5th wheel? If using a w/d hitch spreading the weight front and back, wouldn't you want equal tire pressure on all 4 corners?


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## LarryTheOutback (Jun 15, 2005)

mrw3gr said:


> I went to Goodyear's web site and stumbled across this document: www.goodyear.com/truck/pdf/databook/loadinflation.pdf It had some interesting info. Best I can figure out is with my tires at 35 psi, my load rating drops to around 1900 lbs but it still didn't answer my question as to the recommended tire pressure while not towing (and it's not on the tire). I sent them an e-mail so we'll see what they suggest. I know my door pillar says 35-40 but I think that was for the original tires.


This is exactly the document you need. Weigh the truck in it's non-towing configuration, divide by four, look that weight up in the table and inflate to that pressure.

Then, weigh the truck when towing, divide by four, look that up in the table and inflate to that. Ideally you would weigh each wheel individually, but the divide by four is pretty close.

The load-inflation table is useless unless you know your towing and non-towing weights.

BTW, someone else on this thread told you to inflate to maximum. That could be dangerous in the short-run (too little tread on the road) and expensive in the long run (poor tire wear). This would especially be true with the load-range E tires that I think you have, as the maximum pressure is likely much higher than needed for your vehicle weight. Whatever happens, stick with the load-inflation table.

Ed


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## biga (Apr 17, 2006)

campmg said:


> The Tacoma brand tires on "big red" are E rated tires with max press of 80psi (I think). I have been running 40psi not towing (which is pretty much 0), and 40psi front and 50psi rear. I am going to try 60/70 on my next trip because we still felt a little bouncy on our last trip.


Just curious why different psi front and rear if you don't pull a 5th wheel? If using a w/d hitch spreading the weight front and back, wouldn't you want equal tire pressure on all 4 corners?
[/quote]

With my current setup, I am loading the rear of the truck more than the front. I'm still dialing in the Equil-I-zer, so I am also playing with tire pressures. That was the last configuration I used, and has worked best so far.


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## NJMikeC (Mar 29, 2006)

Couple of things. LT tires are probably one of the best mods you can do and probably one of the first you should do so good going. I think that if the people driving P-Tires ever tried LT's then there would be no P's. They are not good, and they are designated P for a reason.

Don't worry about load range so much. Even P's can get you beyond 8000 #'s. Larry set you up with that load table but I myself don't go under 50 #'s for the simple fact that I don't want to compromise all the gains I got going with LT's in the first place. I run 50ft and 60 Rr. Towing I go to 70 Rr. If I haul a ton or more of stone or dirt in the back then I'll bring it up to 80. It won't bounce with a Ton in the back


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## PDX_Doug (Nov 16, 2004)

mrw3gr said:


> I went to Goodyear's web site and stumbled across this document: www.goodyear.com/truck/pdf/databook/loadinflation.pdf It had some interesting info. Best I can figure out is with my tires at 35 psi, my load rating drops to around 1900 lbs but it still didn't answer my question as to the recommended tire pressure while not towing (and it's not on the tire). I sent them an e-mail so we'll see what they suggest. I know my door pillar says 35-40 but I think that was for the original tires.


Bill,

Where on the Goodyear site did you find the inflation table? The address you hav provided is not working for me, and I can't seem to find my way to it through the site.

Happy Trails,
Doug


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## campmg (Dec 24, 2005)

I agree with NJMIke on the worthwhile upgrade to LT tires.

I recently paid over $20k for a nice set of LT's but it came with a free Yukon XL 2500.


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## Thor (Apr 7, 2004)

I run mine the same as Don. Mfg suggested pressure. My tire monitoring system complains if the pressure is too low or too high.

Thor


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## mrw3gr (Feb 19, 2006)

Based on responses, I went ahead and raised the psi to 50 both front and rear. Thought I would
road test that number for a couple of days to see how many fillings I jar out of my teeth


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## Mgonzo2u (Aug 3, 2004)

I know this will come off as though I am not smart enough to be allowed behind the wheel of a TV and TT but I have to ask this because I am now confused about where to set my TT tire PSI.

Do any of you have any advice on tire pressure for those of us pulling the smallest 21RS versions?

My Mission Radials indicate a PSI of 50 on the sidewall but what does that mean? Does it mean that is the Max PSI or does it mean that is the recommended PSI or what?

Btw, I have been running my TT tires at about 38PSI and it seems to do just fine. But I want to make adjustments if others who are more experienced have differing knowledge.

Any feedback is greatly appreciated.


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## NJMikeC (Mar 29, 2006)

Mgonzo,

38 is too light on the trailer. It says max is 50lbs @6500GVWR right on the side of the trailer. I like 45 # myself for my reasons as in PV=nRT. But I suppose you don't want to go there.

As for the truck ,first stop is the owners manual. It will tell you the max pressure for the truck which you are most likely pretty closely to with your setup. The "little 21RS weighs around 5200# "ready to go camping, no water. Next stop is what type of Tires P or LT. Printed on the side of the Tire is a number that begins with either of the two. If they are P tires then you owners manual told you everything. If they are LT which I doubt then the URL that the author of this thread pointed us to is the correct place.


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## campmg (Dec 24, 2005)

Mgonzo2u said:


> I know this will come off as though I am not smart enough to be allowed behind the wheel of a TV and TT but I have to ask this because I am now confused about where to set my TT tire PSI.


That's a perfectly fine question. They should reflect 50 max psi on the sidewall. If so, inflate them to 50. This will help carry the max load of the trailer and anything less makes it harder to tow.


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## Sluggo54 (Jun 15, 2005)

mrw3gr said:


> Just made a "major" mod to my truck. I bought a set of Goodyear Wranglers to replace the factory rubber that was on the Silverado. According to the labels on the tires, the carrying capacity is 3042 lbs @ 80 psi. I currently have 35 psi in them. When I hook up to the "caboose" do I need to increase the psi in the tires to the max, leave them at 35 or go somewhere in between?
> Thanks,


I run my "E"'s at 60 front, 80 rear. The time I'm not towing is too insignificant to bother dropping them, but if I were, it would be to 55 front, 45 rear.

As for the proper pressure being the recommended pressure for the weight of the truck divided by four - um, I don't think so. The weight slip for my truck, full tank and my fa, shows almost twice as much on the fronts as the rear.

Sluggo


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## PDX_Doug (Nov 16, 2004)

Mgonzo2u,

I would inflate the Outback tires to the maximum air pressure listed on the tire (50 PSI). Be sure to do this when the tires are cold, and you will be fine. Anything less starts to put stress on the sidewalls. Even though the tires may seem to be fine at a lower inflation, sometimes the first sign you get that they are not fine is when the tire fails (as in blows out








).

Happy Trails,
Doug


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## cookie9933 (Feb 26, 2005)

tdvffjohn said:


> You purchased higher load rated tires than the originals. I run mine at what the tires recomended pressure says on the sidewall. When not towing you can go lower for a better ride but not 35.


Agreed. For a tire that has a max inflation of 80 psi, 35 psi is only 43%. That's too little pressure. Nothing wears a tire, and potentially damages it, more than severe underinflation.

Bill


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## Mgonzo2u (Aug 3, 2004)

Thanks to all of you that provided feedback regarding my TT PSI question.

I will amend my TT PSI accordingly (closer to max of 50 PSI than at 38 PSI).


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## Oregon_Camper (Sep 13, 2004)

Mgonzo2u said:


> Thanks to all of you that provided feedback regarding my TT PSI question.
> 
> I will amend my TT PSI accordingly (closer to max of 50 PSI than at 38 PSI).


Glad you got your question answer to your liking...


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