Another Question about tires.

[rvhavingfunyet]

So here's my first post, hello everybody. I am so thankful there is a forum like this. Recently I bought a 79 Sunrader and my girlfriend and I are having a blast. Unfortunatly the tires are pretty weather checked. I can't afford to buy new tires right now but.....there are some on CL right now.

Here's the dillema, the old tires are Kelley-Springfield E78-14 with a max load of 1440 lbs single, 1270 Dual. 10 ply.

The CL ones are Prime Well p205/75/R14 with a max load of 1532. 6 Ply

I know I shouldn't put 6 ply tires on an RV but they can hold more weight. Am I crazy? Are they even compatible? I have an 18 ft model.

Utterly Confused in South Dakota.

[Derek up North]

Here's the problem with the tires you've found, They're too wide, which will probably lead to the two rear tires rubbing together. This will lead to sidewall failure in pretty short order. What you should look for are 185R14 Load Range C (6 ply) or Load Range D (8 ply). 195/75R14 will probably work without rubbing too.

[McShank]

Utterly Confused,

Make sure the tires you get are rated 8 ply, weight rating D. The difference in the C and D is an additional layer on the sidewall - our top-heavy motorhomes place a lot of stress on the sidewall even when driving in a straight line; passanger car tires do not need that extra strength. Safety first. When I bought my Sunrader it had barely used C rated tires on it and upon inspection the sidewalls had already shown some bubbling and cracking. Don't just look at how many pounds it is listed to hold, look for 8PR "D". 185's or 195's works, but the 205 size will rub together on the dual axle. I replaced all my tires with Nexen 185's, but you can also find Hankook and Continental.

Seamus McShank

[Derek up North]

With radial tires, even though the tire might be marke 6 or 8 Ply Rating, they don't actually have 6 or 8 plies in the sidewall. It's just a 'hold-over' from the 'good 'ole days'. I don't see why Load Range C tires wouldn't support the weight of a Toyota motorhome, if inflated properly. How old were the 'C' rated tires you saw the problems on. That said, there's not much difference in price between C & D, so why not?

"Today's load range/ply ratings do not count the actual number of body ply layers used to make up the tire's internal structure, but indicate an equivalent strength compared to early bias ply tires. Most radial passenger tires have one or two body plies, and light truck tires, even those with heavy-duty ratings (10-, 12- or 14-ply rated), actually have only two or three fabric plies, or one steel body ply."

http://www.tirerack....e.jsp?techid=55

P.S. What Seamus said. I'd overlooked the 'P' in the tire designation. Passenger radial tires tend to bulge out even more so the likelihood of interference is even greater.

[WME]

The correct tire could be marked 8ply rating or Load range D or 100-102Q Serv Desc. They are all the same tire.

P.S. You may also see something like LT 185/14C, the C is not the load range but is the Euro designation for Commercial or light truck (LT)