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INSPECTORBOB · 03-22-2023, 07:45 AM

Hello all. I'm running 6 ST718 245/70/19.5 "F" load, 3 year old Sumi tires on a Class A, 21,500# 35' Itasca. The tires have less than 1,000 miles on them. We are low-mileage rv'ers, and generally replace tires about every 6 years due to age, not wear, 2 at a time.

I've had some erratic readings with my tpms, so while in storage, I took the sensors off to test them at home. I made the mistake of not putting caps on the valve stems, and about 2 weeks later when I returned to the storage lot, I found my front left tire completely flat, and it had popped the bead. I assume it must have leaked at the valve with no cap

.

I first tried to set the bead and air the tire with no luck. I am concerned for safety, so I decided just to remove the wheel and take it to a tire shop and replace the tire. I don't know if this is really necessary, but with the tire was so smashed, I thought it best.

I called around for a replacement, but found that the ST718 is no longer made in that load range/size. They now make the ST719. The differences are that the ST719 is a G-rated 14 ply tire, vs the ST718 F-rated 12 ply tire. Dimensions are all basically the same, within 1/10".

I assume I can't mix the two model tires, so I guess my options are to (1) replace just the one tire with a different brand, but with the same specs, assuming I can find one; (2) repla

ce the 2 two tires with the newer ST719 Sumi. However, when it comes time to replace the rears, would I need to replace all 4 at one time, rather than 2 at a time? (3) Other options? I can't afford to be extravagant, but would like to get good, safe tire(s).

Any thoughts would be appreciated!

HarryStone · 03-22-2023, 09:34 AM

As long as the size is the same, and the tread pattern at least similar, I don't see why you can't use the 719

bentjm · 03-22-2023, 10:01 AM

The difference in the load rating would probably necessitate different pressures in the two front tires if you mixed them. Replace both.

theroc · 03-22-2023, 12:41 PM

I too would replace both front positions with the ST719 at this time. When it comes time to replace the rear, I think --and I'm not an expert-- that you could still replace two at a time with the ST719 but putting them in the same position on opposite sides. You're going up in load range so I don't see a problem with that but those with more knowledge might disagree.

So, in other words, replace the two front positions now with the ST719. When it comes time to replace two rear positions, replace the two outside duals with the ST719. Then when you want to change the inside duals, put the identical ST719 on the inside position. At that point, you will have changed out all six positions with the ST719.

You will be running for a short period of time, two different model of Sumitomos on the rear but they will be the same brand and same size with different load ranges (again, you'll be going up a step in load range so it won't be going down a step from what you have now). Again, lets see what the experts say if this would be feasible.

However, if I were in your shoes, I'd most likely want to replace all four rears together with the ST719 when it comes time.

vicwhit · 03-23-2023, 07:33 AM

The air leaking from the valve stem slowly and gently deflated the tire. The tire was never really stressed in any way or run white flat. The tire shop can easily get the bead back in place and reinflate the tire.
You still have 3 more years of use, going by your normal tire scheme.

SavnTheWales · 03-30-2023, 12:24 AM

I also replace my steer tires from the ST718 with ST719. No issues. I did take the opportunity to add Centramatics and love them. It seems to have help eliminate the cupping problem I was seeing. I found the tires on Walmart.com since nobody local could find them. Saved a ton, enough to pay for the Centramatics.