I wish to put 2 new tires for my travel trailer. Current tires are 205-75-14. Load range b. Max inflation is 35 psi. I would like to get 2 new tires prior to hunting season. We travel about 20 miles of good gravel road. I am thinking of getting 2 195-75-14 load range D. They inflate to 65psi and have a load rating of 1,710# each. My trailer gross max weight is 7k. Question is, is it advisable to mix-n-match tires? I'd put one on each side. So I'll at least have 2 that I can count on. These are BFG-KO's. Only size available in 14". And within an inch overall diameter of the 205's. In all the years of off roading we've never had a failure with these tires.

I myself wouldn't mix size's even 1in is a huge difference your putting more weight on the 2 older tire's, more presure on your bearing's, and more presure on your suspension. Even if they hold more air the height difference is still there. Now if you not going far like a few mile's and not going interstate speed and not have her loaded down. Then you'd be ok I just don't like mixing size's

Doesn't the suspension adjust to varying heights of load? I've seen the suspension adjust to a flat on one wheel. Not sure I agree that an inch of tire height will add additional load to the other tire?

Just speaking out of experience and hope no one has to go through this but, we have a 16ft bumper pull car trailer that had a front tire that had began to dry wrought so we threw on a spare set of 215/75/16 and left the 235/75/16 on the back and loaded my mom's 2001 dodge carvan on it total weight maybe 4,000 pd's not sure but after only 15 or so mile's we had to pull over because the bearing's were shot in the rear axel and nearly blew out the rear wheel's which was to hot to touch. Cause they were carrying a majority of the weight even if the tire's are both on the ground does not mean the load is equally on each tire and we alway's keep everything greased and have Bearing buddie's on all 7 of our trailer's. Just my opinion and it sucks to be on the road changing the bearing's when 18 wheeler's are wizing by lol I been there

For a small price I would just change all four tires on the trailer knowing that they are equal sized and equal load capacity. I wouldn't suggest mixing age of tires (new vs. old) and mixing sizes. Like I've got just cheap ST Tires on the RV now and understand they are a 65 MPH limit tire. Knowing this I will not travel faster than 55 MPH with the RV in tow. Not worth damaging the RV or having blowout from pushing the tires to the breaking limit of blowout. I will typically check hub and tire temps when I stop for fuel or to rest. So I'm always aware of tire and axle condition. As for trailer axles I pack the bearings by hand every spring of the year. I only paid $350 for all four tires on the RV. TowMax S/T (225/75 R15) I'm in my 3rd year on them and zero problems!

I think I'm going to upgrade to 15" rims. Currently 14. The tire selection is so much better in 15. Plus the load rating increases.

I think I'm going to upgrade to 15" rims. Currently 14. The tire selection is so much better in 15. Plus the load rating increases.

Thats probably the best solution. And try to get away from the ST tires, for the life of me I just can't understand why they can't engineer a tire to at least withstand the posted legal speed limits on the highways. I tow fairly frequently and I will only drive as fast as I feel is safe given the road, weather, and traffic conditions regardless of the posted speed limit. With that being said limiting your speed to 65 mph (which is at the MAX speed rating of the tire and a red flag in my book) when your on a freeway with a posted speed limit of 75 mph and traffic is realistically driving 80 to 85 mph, is a hazard in itself and an accident waiting to happen.

I'm thankful of living in Idaho there is only 2 highways in the state with speeds up at 75 MPH. Most other roads are 55-65 MPH. As for the ST tire it going to be tough to beat being that switching to LT (Light Truck) tire the weight capacity typically goes down but the speed rating goes up then visa-vera with ST (Special Trailer) tire where the weight capacity goes up and the speed rating goes down. Now there is more ST tires typically have stronger side wall construction compared to LT which is not designed for scrubbing of the tires when turning tight with dual or triple axles which ST is designed for. You could spend more money and get a better speed rated tire like a Q Speed rating (99 MPH) but of course it going to be more expensive. I personally loved my previous set of tires on my truck they where a set of Solid-Trac by Voma which where ST Tires (ST 235/85 R16's) with a weight capacity of 3,750# at 110 PSI and they where a Load Range G tire (14 ply) with a Speed Rating of Q (99 MPH). Now find that tire in a 15" for your size and your set forever! http://www.bigotires.com/Tire-Detail/VOMA/SOLID-TRAC-RADIAL-A-S-TRAILER/23024

Don't ST tires typically have a short "shelf life" so to speak?

All tires should be replaced in 5 year period. But no... ST tires have just as much shelf life as any other tire. It just most people abuse the tires with too much weight, too fast of speed, under/over inflated tire pressures, etc. So ST's tend to get a bad rap for failures. After running 3 years on ST's on my truck and never had a single failure not even a flat tire it just proves that if you do you homework and purchase the proper tire for the purpose it will not fail regardless if it a ST tire or not. A matter of fact I kept the use ST tires for spares...

Interesting.... I've always been under the impression they are only good for 3 to 4 years. I remember reading an article by Michelin that stated after 3 years an ST tire has lost 1/3 of it's integrity, and the average lifespan of an ST tire should not exceed 5000 to 10,000 miles depending on the type of use the tire had.As for your tires on your truck, you went way overkill with a G rated tire which is probably why you got away with it. You increased the safety factor. If you would have been running on a set that was rated closer to the max GVW (or within the recomended 20% cushion) you may have had a lot different experience. Go buy a G rated truck tire and it will last you 80k+ miles and alot more than 3 years.....It's all personal preference based on past experience, I'm just not a fan of ST tires.

I bought my travel trailer a year ago. 1998 and original tires. Might be overdue for replacement. Load rating B, 2 ply and 32psi inflation. Firestone beauties with like new tread.

You can look at the DOT information on the tire to get the week/year on the tire and know how old it really is.

Like this tire was manufactured in the 51st week of 2007.