Best steer tires for DP

[mccoll62]

I’m in need of replacing my steer tires due to excessive wear on inner edge (cupping and rivering).  What is the better tires for the steer application on the smaller DP?  My coach is the Newmar 3434 with 12 k front axle.  I weighed the coach and from memory I believe the front totaled around 10-11k loaded.  I have read the Goodyear is known for rivering issues and the Michelin have sidewall cracking issues, are either of them problems corrected?  I can get deep discounts with either of the two brands but want my investment to last.

Im currently running the 275/70R22.5 and thought about going to the 275/80R22.5.  I read they ride and handle better, anyone change their size?

 

The Goodyear seem to ride a bit rough when inflated to get the swaying out and the feeling of loosing control,  I run 110 in front and 100 in rear.  I have run lower pressures but ride didn’t improve but had the feeling of skating on ice.

[richard5933]

Welcome to the forum. Glad to have you here.

A couple of thoughts, although I am by no means a tire expert.

First about the size issue. My gut tells me that it's best to stick with the manufacturer's recommended size. Lots of issues can crop up when changing size, even if the outside diameter stays the same. There are clearance issues with the fender and wheel well to consider as well as handling issues. If your manual doesn't list the new size as recommended, then I'd call the manufacturer to ask before changing size. Also would be necessary to find out if it was okay to run one size in front and another in the rear.

Second, if you have excessive wear on the inner edge I'd recommend getting that taken care of before doing anything with new tires. Is there a steering or front end issue? Alignment issue? Tires should wear evenly, so if they are not then something is wrong.

About the tires themselves, we've got Firestone on our bus and we're quite happy with them. Looks like they have one in the 275/70r22.5 size.

[mccoll62]

Richard thanks for the information.  I found my ride height off last year and adjusted it within specs, it was set about 1/2” to high.  The adjustment helped with the handling and I wondered if it caused the wear on the inner edge.

[wolfe10]

If solid front axle, very doubtful that 1/2" of ride height would change tire wear.

If IFS, a completely different matter.

[mccoll62]

It’s the solid front axle.

[wildebill308]

The first thing I would do is have an all wheel alignment done loaded like you were leaving on a trip. I went with 275/80/22.5 instead of the original 255/80/22.5 size. I used the Continental from the tire program. I saved over $100.00 each off the Michelin discount price.

Bill

[manholt]

I have had 315/80R, for steer and 295/80R, for drive & tag since 2014...love it.  My next set, will be 315 & 305's!  Yes, my coach is bigger and heavier than yours, but the concept is the same.  As stated above, get your alignment, toe in/out and caster's, looked at first.

[manholt]

No matter what brand you get, the sidewalls will go, long before your treads wear down!  I replace mine every 6 to 7 years...you can't go by how long your car tiers last.

[mccoll62]

Thanks everyone for the good information 

[tireman9]

As the resident tire engineer. I really don't like the "Best tire" questions. IMO that's almost like asking what is the "best" Pizza or "Best" beer.

All the major tire manufacturers make good tires. People may have individual issues and many times think it is a design or manufacturing problem but most, not all but most issues are a function of the specific coach and how it is maintained and loaded.

I agree with the suggestions to get the alignment checked and set first. See if you can get a "4 wheel" check too, just to be sure your rear tires are pointed in the right direction and you have no "dog tracking" as is sometimes seen in HD truck/trailer situations. You can do a rough check with a long tape measure and help from a friend. Confirm the wheelbase on both sides of the RV measures out to be identical.

Sounds like it has been a while since you checked your weight. Even if you can't get a "4 corner" weight at RVSEF or Escapees you can get on a truck scale and compare current axle loads with the last "4 corner " numbers. We all need to get on a truck scale once a year to confirm not too much "weight creep"  You know, a bit like waistline creep we see over the years.

You mentioned ride height and its effect on handling. The suggested tire size change would affect ride height and could affect handling too so you need to be careful about that.

 

[wildebill308]

10 hours ago, tireman9 said:

You mentioned ride height and its effect on handling. The suggested tire size change would affect ride height and could affect handling too so you need to be careful about that.

No, actually it doesn't alter ride height what it alters is how high the coach sets. Ride height refers to the height of the body over the suspension. This is controlled by valves that are adjustable.

Bill

[manholt]

High end 45' coach's come out of the factory, with 315/80 steer and 305/80 drive/tag.  Or 360/80 & 315/80!  My Jeep fits "Tireman9", description!  I changed my size, after speaking to Allied Tech.

[kaypsmith]

On ‎9‎/‎4‎/‎2018 at 4:16 PM, mccoll62 said:

Im currently running the 275/70R22.5 and thought about going to the 275/80R22.5.  I read they ride and handle better, anyone change their size?

I'm surprised that no one else has pointed this out, going from 275 70 to 275 80 will increase the height of the sidewall by 10%, 275 width is pretty close to 11 inches, which means that adding 10%, is pretty close to 1.1 inches, which increases the diameter to close to 2.2 inches. So you must compensate the clearance around the tires, be sure to check if there will be enough room for this excess height and width. Also as Bill said this will not effect the ride height but will increase the overall height by about 1.1 inches, also will cause the top of the tire to be that 1.1 inches closer to the chassis. Also will change the circumference by about 6.9 inches, being 0n a steer tire will not effect speedometer reading, but will if you ever want to move them to the drive axel. The extra height could possibly help ride because of the ability to flex the sidewall a little more.

[richard5933]

1 hour ago, kaypsmith said:

I'm surprised that no one else has pointed this out, going from 275 70 to 275 80 will increase the height of the sidewall by 10%, 275 width is pretty close to 11 inches, which means that adding 10%, is pretty close to 1.1 inches, which increases the diameter to close to 2.2 inches. So you must compensate the clearance around the tires, be sure to check if there will be enough room for this excess height and width. Also as Bill said this will not effect the ride height but will increase the overall height by about 1.1 inches, also will cause the top of the tire to be that 1.1 inches closer to the chassis. Also will change the circumference by about 6.9 inches, being 0n a steer tire will not effect speedometer reading, but will if you ever want to move them to the drive axel. The extra height could possibly help ride because of the ability to flex the sidewall a little more.

Which is why I mentioned early on that I wouldn't change tire size without confirming with the manufacturer it's a good idea. We can look all we want at these things to check for clearance and other issues, but we'll never be able to consider all the factors involved in changing tire size. Everything may look good when the rig is sitting still, but hit a big bump while taking a tight turn and the tire might suddenly (and catastrophically) hit the frame.

Since tires in the current size are available in a variety of styles and load ratings I'm not sure what the advantage to changing size would be other than reading somewhere that they ride better. Not that design engineers never make mistakes, but if something as simple as using a different tire size would have enabled the coach to ride and/or handle better you'd think they would have either put them on at the factory or made them an option.