Alright Guys-- On the front axles I have a P195/75/R14 M&S on the other side is a P185/70/R14 M&S (Brand Unknown) on the rear axles are a P205/75/R14 Yokohamas and the spare is a B 78 13. All running tires have about 1/2 tread left. Should I rush right out and buy 4 new P205 6ply trailer tires and switch my spare to a 14" set up? or am I good for about 1,000 miles?

just speaking from an automotive standpoint I would be most concerned with the differing size on the same axle. Although not ideal to have different sizes from 1 axle to the next I don't see it as a major crisis. JMHO.

Harry

I would concern with running different size tires, it may put uneven stresses on the frame and may cause it to twist. The tires should be trailer rated (not automotive rated) I believe the sidewall of the tire is manufactured differentlly
LES

Thanx for the replies... Can anyone tell me what are the bolt patterns (5 hole) on my 1984 Funchaser? Chevy Ford Chrysler? I currently have 14" Centec Chrome Wheels....

Hi Reed,

Guide for torquing patterns can be found at the following website: adaptitusa.com/wheellugnuttotquing.aspx

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1967 17' Hi-Lo Bon Voyage (1967-1969)
1969 19' Hi-Lo Bon Voyage (1969-2011)
2004 27' Hi-Lo TowLite (2010-present)
2015 Chevy Tahoe LTZ

Reed,

If you experience fishtailing at higher speeds (55 plus) and have determined its not caused by improper trailer loading, or other obvious causes. It could be due to tire mismatch... I had this problem years ago with a tandem axle utility trailer. I've also learned (from experience) that certain tires not designed for trailers, can cause fishtailing when used on a trailer, even when the tires are matched. Hope this helps.

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1967 17' Hi-Lo Bon Voyage (1967-1969)
1969 19' Hi-Lo Bon Voyage (1969-2011)
2004 27' Hi-Lo TowLite (2010-present)
2015 Chevy Tahoe LTZ

1. if the tires are not an ST (a designation specifically for trailer tires) and at least a load range "C" i would be concerned.

2. if the b78 13 shows the size like b78-13 it is a bias ply tire and is Illegal to run on the same axle as a radial tire, they handle the load differently.

3. most camper/rv's are close to max load on the tires they come with from the factory. my recommendation would be put the proper sized tires with the highest load range available!

And Reed, going back to your first post - trailer tires are not good until they run out of tread. If the tire has been on the trailer for about 4-5 years, it needs to be replaced - regardless. I'd replace them with a matched set of ST rated tires, and I'd try to get Load Range D ones (if you can find them). I'd also mount a spare tire of the same size and load rating with a matching 14" rim.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System
2014 F150 Platinum 4x4 3.5L EcoBoost SCrew

I have a similar dilemma. On my 78-BON Voyage,on the back axle are 2 - P205/75D14 on the front axle is 1 - T2-76205 & 1 - ST205/75D14 & no spare. They all were on it when i bought it,it did 70mph for 200 miles on the way back from buying it and road fine,but i'm almost ready to take it out for the first time camping and am wondering about running 3 different size 14's .I already know the risk of no spare.I have to wait $ flow is low (i cant afford 4 new tires right now ) so i'm going to chance it but will be camping closer to home than i wanted.All i can say is i myself wouldn't chance it,it feels a lot better knowing your wearing the right shoe's, and since your going camping to have a good time. Who needs the headache or worse an accident.

Mismatched tires are a recipe for disaster, mixing radial with bias is the biggest no no, they are designed differently to deal with side wall flexing (keeping the tread on the ground, one gives the other does not
Mixed matched tire sizes really doesn't cause any frame problems since the suspension deals with that. The problem is weight carrying capability, just think what is you get a flat in a spot where you must drive quite a way to get to a safe spot to change, like in the mountains or a bridge, the weight that tire carried is now displaced to the other three.
Also ST tires have a little stronger sidewall but the main difference is in the materials used to make it, the rubber is produced to deal with the sun also the rubber is a little tougher. Many people use car tires in lieu of trailer tires provided the tire is rated to handle the weight.