Tires, Wheels and Brakes

Tire and Wheel Notes: (Brakes are at bottom of page)

Update 1/27/18: A reader writes “starting 9-1-17, NHTSA now requires that the tires on any towable RV exceed the axle rating by 10%, Montana installs 7000 lbs Dexter axles, which requires tires rated for at least 7,700 lbs (3,850 per tire)”

Go here for my blog post on Tires and Wheels

Trailer Tires and is the place many recommend to buying tires.

  • Beware – tires have speed ratings. Many are 65 mph top.
    • Many suggested at least 70 mph tires. Seems reasonable given the speed limits are often 70 mph.
    • If I’m reading everything correctly, you have to go with an LT tire for ratings over 65 mph.
    • I’ve found driving under the speed limit is more enjoyable, as others will pass, increased reaction time, less likely someone will drive along side you. We discovered this when driving the rental unit. So 65 mph could also work fine.
    • I found some off brand tires that were STs and rated up to 87 mph.
  • Trailer Tires and Wheels – Heard about this on the Tumbleweed blog. Where they ordered their new tires in 2011. (3/23/15)
  • I also liked the TiresandWheel site when shopping for prices.
  • Mark Bruss blog goes into depth on all of this.
    • Go here for one stop research!
  • RV Dreams always does a good job of explaining stuff.
  • Need to check out “bead balancing of tires” where a bag of beads is placed in the tire before mounting, they break apart.
    • Make sure does not effect warranty.
    • Article that suggests they don’t work and could hurt fuel economy.
    • DynaBeads website.
    • Forum where folks say they work.
    • You have to use a special value stem if you use beads so they don’t clog the valve.
    • They don’t scare me. More than likely the rig we get will not come with bead balancing, so will have to make that decision after the fact.
    • Found one forum where they were talking about them in 2003, I understand this is not a new technology.
  • Goodyear RV Tires web site. Includes helpful videos.
  • Make sure and check the month/year date of manufacture.
    • Replacing tires in 5 to 6 years is often suggested. Lots of factors to consider. My research at this time is limited to just knowing to check the DOT number for the date and know that even a new rig could have one or two year old tires.
      • The numbers appear with the month followed by year. 711 is July of 2011 for example.
  • What about radial tires vs bias?
    • Informal survey of rigs I’m looking at are 100% radial. Bias tires are special use tires like the hard tires used on farm tractors.
  • What about aluminum vs steel wheels?
    • None of the trailers I’ve been looking at use anything but aluminum.
    • Some are rated for lower air than others.
    • One site I visited I noticed the chrome steel wheels were rated higher than the aluminum by about 200 pounds each.
  • Does the wheel have to be rated for a certain tire pressure as well?
    • Yes.
  • What about the number of lug nuts?
    • Lug nut torque is something to watch for.
      • Has to do with maintenance, wonder if I should put a torque wrench on tool list.
      • You also have to be concerned with hole patterns if you change out wheels.
    • Quick example where I looked at the same tire (load rating E) with different wheels and lugs. This was a 10 ply 16″ tire.
      • Modular aluminum with 6 lugs was 3242 pound rating.
      • Modular aluminum with 8 lugs was 3520
      • Spoke aluminum rim with 6 or 8 lugs was 3520.
      • I checked another site and found this example of the highest ratings available.
        • For 16″ wheels
          • 6 lug wheel: 3,580 pounds, max air pressure was 80 pounds. 16″x 6″
          • 8 lug wheel: 3,960 pounds, max air pressure was 110 pounds.  16″ x 6.5″
        • For 17.5″ wheels
          • 8 lug wheel: 4,850 pounds, max air pressure was 110 pounds. 17.5″ x 6.65″
            • Also noticed you can get a commercial truck wheel at 6,000 pound capacity. Everything else was aluminum.
  • What about aspect ratio and tread width.
    • For trailers, the biggest issue of tire aspect ratio is controlling the total diameter of the tire, as diameter is more critical than tread width.
    • I’d have to think this part of the tire size will be someone fixed by the trailer manufacturer unless one changes the suspension system later.
  • May want to include maintenance tips and need to research monitoring systems.
    • For this research topic I’m not including what monitoring system to use – only that I’ll have one.
    • Goodyear tire maintenance chart.
    • RV explains some maintenance items and where to locate the plate that tell you what tires/wheels to have.
    • Good article on weight distribution.
    • What about tire rotation and balancing on a trailer
      • Figure, folks have different opinion on this.
      • Some rotate once a year, many don’t at all because the tires are not used for steering. Some say no need to unless you see uneven wear. Some say they only rotate at the time they would balance tires. Some say weathering will cause you to replace the tire long before the tread is gone.
      • In terms of balance, same answers. Some only balance when they are new. Some say no need to balance a trailer tire. Several said the factory does not balance them so get it done when you buy the trailer.
      • Everyone agrees under-inflation is the big hazard and what kills a tire.
      • Montana Owners Forum has good FAQ section.
  • Will research truck tires as separate blog post.
  • Need to research tire inflation.
    • Here is what Goodyear has to say about it: “Air is what carries a tire’s load. If you run tires with air pressure below the placard recommendation, or below the inflation required to carry the actual vehicle load, nothing but problems will occur. Irregular wear increases, mileage goes down, fuel economy gets worse, and tires may be damaged or destroyed.”
  • RV Tire Safety is a good resource.
    • Roger is active on the IRV2 forum as a tire engineer
    • Lots of links to tire information.  Another single source place to go to.
  • What about using nitrogen in tires for air?
    • Nearly 100% of posts in this forum say nitrogen is a sales gimmick.
    • I don’t want to carry a spare tank of nitrogen around.
    • I looked at the stated benefits (less change in air pressure and no moisture) and think I’ll pass on it.
    • Here is a good article on the subject of nitrogen.
  • Huge forum post on the subject of tires.
  • Another forum post to read through.
  • Did an informal survey by checking to see what several trailers come standard with such as from the top fulltimer brands I’ve been researching.
    • There is a difference by load ratings of trailer. Seems there is a mix based on if you have 7,000 or 8,000 pound axles.
      • 8,000 pound axle for heavier generally go with an H rated tire, aluminum wheels and 17.5 inch.
        • Plenty recommending the Good Year G114’s load range H
      • 7,000 pound axle generally go with G rated tire, aluminum wheels and 16 inch.
    • Radial tires were popular, with 8 lug wheels. All the Goodyear brand came up more than not.
    • Heavier duty tires and wheels would be an over-kill without a matching suspension system, brakes and more. For example if you are limited by 7,000 pound axles. The reality of it all is that we may not be able to afford anything outside the 7,000 axle range if we buy new. 8,000 if we buy used. Heavier units = more expensive in many cases.
    • The reality of it is a simple question. Will we feel comfortable with the tires the trailer comes with. If not, how much should be budget to replace them while staying with the manufacturers size limits.
    • Cost to replace tires and/or wheels:
      • Popular Goodyear G114 17.5 inch is $500 each
      • Popular Michelin XPS Rib 16″ is $380 each
      • Plus aluminum wheels at another $120
      • So you are looking at anywhere from $1,430 to $2,000 for tires and another $480 for wheels.  Or a range of $2,000 to $2,500 for the combo.
      • I suspect if we buy new they will try and put the minimum tire on the trailer. I want to have a safety margin.
      • RVSEF (RV Safety and Education Foundation) is a good reference.
  • Always wondered what the best tire gauge would be.
  • LT vs ST tires – What’s the difference?
    • Forum thread suggests LT (light truck/trailer) tires are rated for faster speeds. Not sure if you would have to change out the wheels if going to an LT tire over the more standard ST (special trailer) tire.
    • LT tires are rated for steering and designed at a higher standard because of it. STs are for trailer tires only while LT tires are rated for any position.
    • After reading forums for three hours – LT tires seem to be the one to go with. They may have a lower weight rating than an ST tire but hold up better with a higher PSI rating (110 pound vs 80 pounds for example). The air carries the weight.
    • Talked to the owner of the shop where I have my car worked on. He hauls cars all over the country with a large goose neck trailer. He said he has not had good luck with ST tires. He only had a blowout with an LT tire once, after he loaned the trailer to a friend who damaged the sidewall. He says just watch the load rating on the LT, as they are rated lower than STs because LTs are designed to haul passengers.
  • Most preferred brands to buy.
    • Michelin, Goodyear, Saliun, Hankook
      • Here is an excellent video on Saliun brand.
      • Have to assume just because its a Goodyear does not make it good. Lots of people were bad mouthing the Goodyear Marathon tire for example.
      • Michelin XPS Ribs
      • Goodyear G114
  • Most suggested brands to avoid.
    • Even the preferred brands have tires that are not as good as others within the same company.
  • How much safety margin should the tires have.
    • Such as 15-20% more load capacity than when trailer is at full Gross Weight.
  • What about valve stems? Do you have to change to steel valve stems for the higher tire pressures?
    • Steel/metal seem to be always used with 100 psi rates.
    • Most say never mind the pressure, get metal. You need them to support weight of tire monitoring system and more durable if you brush up against something.
  • How to calculate minimum tire load rating? I believe this is done by taking the gross trailer weight less the pint weight divided by the four tires.
    • For example a 16,500 pound gross trailer less say a 3,000 pound pin would be 13,500/4 tires means each tire must support 3,375 pounds. Add 20% safety margin brings the weight for each tire to 4,050 pounds.
    • The above measuring may not be accurate in that the actual weight at any one tire could have a different load than the other tires as weight in the trailer is not distributed evenly. Suppose the safe option is to have the trailer weight checked at each tire and make sure the tire rating all around is right.
  • Should the tire rating be one that allows for 14,000 pound loads because of 7,000 pound axles or 16,000 pounds in the case of 8,000 pound axles? I have to assume one should not max out the weight anyway.
  • Don’t forget about the effects of UV rays and other things on tires. I’ll have covers when we are parked for a long time. Some tires have built-in chemicals to protect against weathering.
    • Here is what Goodyear includes: “The Goodyear Unisteel® G670 RV® has technology that helps guard against the effects of ozone and UV rays.Anti-oxidant and anti-ozonant compounds throughout the tire help protect against weather cracking.”
  • It’s something that for my entire adult life I just replaced the tires with what the car manufacture suggested. Now I find myself worried a trailer might come with something rated for less than what the trailers max load is.
  • Here is some legislation that came out in 2016 regarding rating of ST tires. This excerpt is from RV Business Report. “The National Highway Traffic Safety Administration (NHTSA) has published a final rule amending federal tire safety standards to make it clear that specialty trailer (ST) tires are allowed on new trailers with a gross vehicle weight of 10,000 pounds or less.Also, according to a Tire Business Report, trailers installed with ST tires are exempt from a testing requirement that a tire must stay on its rim when subjected to a sudden loss of air pressure and brought to a controlled stop from 60 mph, the agency said.”
  • What about wheel alignment?
    • There is more to it than just aligning tires. The axle has to be in alignment as well. Seems reasonable to watch for uneven wear on tires and then decide what the problem could be. A good time to do this is when you have the brakes/bearings or whatever checked.
    • Lippert builds the Correct Track system which is used to:
      • “correct a misaligned trailer suspension system. Misaligned axles and suspension are caused by lateral, unbalanced weight. When the RV foundation is assembled, the bulk of the weight of the coach has not yet been placed on the axles and chassis. Slide-out rooms, appliances and cargo added by the consumer can cause un-lateral unbalance within the coach”.
Brake System Notes:
  • One point I want to start off with, just in case I’ve wrongly suggested anything different at any time, is the ” I believe trailer brakes stop the trailer and truck brakes stop the truck.”
  • Will be checking out the Nev-R-Lube bearings which is a Dexter product. Dexter has been around a long time.
    • This is part of the axle.
    • Post where others don’t recommend the Nev-R-Lube bearings because if they go out they destroy the axle.
    • Here is what a trusted source wrote me ” Oh, you need a lot more info on the Nev-R-Lub bearings. They are good and bad. It depends. I don’t have them and I’ll explain why starting with 3 Nev-R-Lub failures… But for some it is the only choice. It does depend.”  Thank you to Bill!
  • In 2015 heard from a 25 year Rver that DRV was installing the morryde suspension where they caused brake line damage. He lost his brakes. Have to check into that.
  • What about disc vs drum?
    • Disc – decision is made.
  • Do another informal survey by looking at what rigs in the 16,000 pound and above range have based on my list of manufactures.
    • Seems like the axle and brakes appear often in the same sentences when discussing options.
    • Disc brakes were nearly always used and if you include them as an option than 100% use disc.
    • It’s not about brakes but the EZ Lube hubs were frequently used.
    • Had a hard time finding which ones were using hydraulic or electric brakes. Read in the past folks upgrade to hydraulic actuators.
    • Mobile Suites was the only one I found in that price range with the Kodiac disc brakes.
    • Self adjusting brakes were popular. As was the Dexter Nev-R-Adjust brakes.
      • Okay, these are drum brakes.  Disc brakes don’t have to be adjusted. The explains why some companies posted they use disc brakes and others said self-adjusting (rather than admitting they use drum brakes I’m guessing).
    • It’s again not about brakes, but noticed the correct track system was listed at times.
    • Here is a note from a trusted source “Dexter are OK but they have had a major issues with their pads. We ent to Kodiak as has MOR/ryde as their offered product. They will do Dexter, but are now recommending Kodiak.”
  • What about braking systems folks refer to as the “trailer brakes” which is controlled in the truck?
    • RV Dreams just upgraded their truck brakes. What did they go with a why. After all, the truck is part of the braking.
    • Think I’ll cover this topic when I research tow vehicle stuff.
  • Read this IRV2 forum.
  • 11949870832001967505estrella_01_svg_thumbRoads Less Traveled has a good article. Go here for a one stop place to learn about braking systems for a trailer.11949870832001967505estrella_01_svg_thumb
  • RV Dreams upgrade to Dexter hydraulic brakes.
    • Seems like with all their upgrades they should have started with a heavier unit that came with all that already. hydraulic brakes, 8,000 pound axles, independent suspension, 17.5″ tires.
  • Kodiak Brakes link – been around since 1989 but claims to be leader in hydraulic brakes since 1994.
  • Dexter Axle Company – been in business for 50 years.
  • Pretty much Kodiak and Dextar are what everyone was writing about during my research. I’ll have to watch for other systems while I walk-though units to see what else is out there.
  • Here are the three types of brakes which include air brakes.
  • This topic is boiling down fast.  Decisions appear to be:
    • Electric or hydraulic disc breaks. And Dexter vs Kodiak
      • Kodiak is a leader on the hydraulic side.
  • Article that explains why disc brakes are hydraulic. Also the disadvantage of drum brakes that are common in electric brakes.
  • Have to check into the need to have the brake controller in the truck to be compatible with the type of trailer brakes used. I assume, but will investigate, what systems trucks come installed with. I’d like to avoid an aftermarket brake control.
  • Exhaust brakes on the truck with an on/off switch would be nice. Helps keep the trucks speed down when going down hills.
  • Brake controllers, proportional and time delayed.

Comments are Appreciated

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s