tire sizes

[Larryjb]

Perhaps I just missed it, but I couldn't find anywhere on this site that tells you what tire sizes you can put on. There seem to be two common 14" sizes out there: 205/75-14 and 215/75-14. Do both sizes fit the rims safely? If so, is one better than the other with regards to blowout possibilities?

I know it's better to upgrade to 15" wheels/tires. But we've had an expensive year and may get more expensive. If I get a trailer and need tires I will probably keep the rims for this time, then upgrade to 15" on a cross Canada trip.

[Padgett]

What you need is a load range D tire (over 2k lbs) with a nylon overlay or cap. Doesn't really matter if 14 or 15 but some mfrs do not offer a cap in a 14.

[Larryjb]

Fountain Tire has Endurance tires on sale. They are telling me the 225/75/r15 is way overkill, and I might tend to agree. The other Endurance size is 205/75/r15. Is this a reasonable size?

[Gapopper]

Fountain Tire has Endurance tires on sale. They are telling me the 225/75/r15 is way overkill, and I might tend to agree. The other Endurance size is 205/75/r15. Is this a reasonable size?

I just purchased 205/75/r15 Powerking Towmax with a nylon overlay.

[Padgett]

The key is the load rating, for a 2001 without a lift kit, 215x75x14 or 205x75x15 is the tallest that will fit but you need at least a Load Range D (LRD) and I would not buy a trailer tire that did not have a nylon cap or overlay.

[Bill]

Fountain Tire has Endurance tires on sale. They are telling me the 225/75/r15 is way overkill, and I might tend to agree. The other Endurance size is 205/75/r15. Is this a reasonable size?I'm not sure what you consider reasonable. According to the Goodyear site, the Endurance specs are

o ST205/75R15 2150 pounds, MSRP $110
o ST225/75R15 2830 pounds, MSRP $121

Since the starting point is a 14" Marathon rated at 1870 pounds, and many of us considered this to be an inadequate tire (that's the whole reason for the upgrade), I don't think I would stop with a 280-pound upgrade just to save $11. But then, I am a belt-and-suspenders guy.

Bill

[Larryjb]

I hear you Bill.

When I look at the side clearance of my 215R14, I do question how well the 225's would fit. The other issue is how much extra am I paying to get rims that will support the tire pressure for a 2830# tire. Also, we have to remember that 280 pound upgrade is per tire, giving a 560 pound upgrade overall.

FountainTire was reluctant to give me the 225's, claiming it was way overkill. I'm also thinking that the required tire pressure for these tires would make for an extremely harsh ride unless I'm loading up the trailer that much.

I'm still mulling things over. I have until Friday to make a decision (when the sale ends).

[Padgett]

Yes the stock tire was a 14" marathon (max inflation 50 psi) but even TM realized it was inadequate.

[Larryjb]

Yes the stock tire was a 14" marathon (max inflation 50 psi) but even TM realized it was inadequate.

I know the stock tire on the newer TM is 15", but what is the stock load rating tire they're using now? I can't find that information.

[gonzo628]

I know the stock tire on the newer TM is 15", but what is the stock load rating tire they're using now? I can't find that information.

The stamp on my 06 3124kb with 15in rims is Load range D...

[Larryjb]

When I took a look at the clearance between the tire and the fender skirt on my 215/75r14's, there is maybe 1/2" clearance or so. Those of you who put on 225/75r15's, how did you get them to fit?

[gonzo628]

you mention clearance between tire and fender skirt. What about clearance on the backside (between tire and wheel well) Perhaps those running the other tire have a rim with a different offset?

[Bill]

There isn't much clearance, but I don't think there needs to be. I have about 3/4 inch on my 225's. But a 215 is only slightly wider than a 205, and only half of the increase is on the outside, against the fender skirt. If you are concerned, the sketch in post #1 here may (or may not) help.

http://www.trailmanorowners.com/forum/showthread.php?t=6245

Bill

[Larryjb]

Thanks for the link Bill. It does help a lot. I remember seeing it at one time, but couldn't find it again. I "missed" out on the sale because the shop was discouraging me from even going LRD. I'm working with another shop that understands the need to avoid pushing limits. The other shop was trying to tell me that most flats are due to under inflation. While that may be true, it seems obvious from lots of other stories that there are other reasons for blow outs, including pushing limits of the tire.

[tentcamper]

I hear you Bill.

The other issue is how much extra am I paying to get rims that will support the tire pressure for a 2830# tire. Also, we have to remember that 280 pound upgrade is per tire, giving a 560 pound upgrade overall.


I'm still mulling things over. I have until Friday to make a decision (when the sale ends).

You don't have to air them up to e rating, which then will not require the rims. Air them up somewhere north of what the GY chart list for PSI to Tire Load.

The way I look at it; is an E Rated tire has structure equal to 4 more ply's then a C rated tire. Much tougher. When I pickup the NTU camper, I'm planning to install the 225x75x15 endurance tires, but will air up to about 56 PSI. I like to go up to 10 extra PSI than what the GY chart has listed. This give me the plus 10 PSI that GY call for in the service bulletin for traveling over 65 MPH. These tires at that PSI will give me a softer ride, but are much stronger tire.

GY tire PSI chart, see page 9: http://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf

GY plus 10 PSI: https://www.tirerack.com/images/tires/goodyear/Marathon_Special_Trailer_Applications.pdf