Today we're going to take a look at the Castle Rock ST225/75R15 radial trailer tire in a load range D on this 15 inch white modular steel wheel with the 6 on 5-1/2 bolt pattern. Now this inaudible 00:00:16 wheel inaudible 00:00:16 ideal for RVs, campers and trailers. Now this one is nitrogen filled and maintains your tire pressure longer than just standard air. And the way you can tell that is if you see the green valve stem cap on the valve stem that identifies that this tire is filled with nitrogen. The nitrogen helps prolong the life of the tire and the wheel. The wheel is a sturdy steel wheel.
This is the modular design, and when I say modular design, that's the one that has these round holes all the way around the wheel. They use a white powder coat finish over an eco primer on this to help resist rust and corrosion.They do use the beveled stud holes here where your lug nuts go to help keep the wheel securely in place on your trailer hub. This eliminates the need for constant re-tightening of your lug nuts. Now the tire that's mounted on this wheel is a Castle Rock radial tire. It is constructed with double steel belts, double nylon plies.
It's a radial ply tire, which is great for highway use, and they do use a nylon tread firming belt overlay around the whole tire to help prevent tread separation. They do offer the tread wear indicators like you have on your passenger car tires that give you a quick visual indication of how the tire tread is wearing. Now if you look at the tread blocks, they do have these cuts in the blocks that's called siping, and what that does is it helps channel water away from underneath the tire to help improve traction during wet, snowy or icy conditions.This is an ST tire, which stands for special trailer. Has the sturdy sidewalls, so it can handle heavy loads. It is created specifically for trailers, not intended for use on any other vehicles.
They do offer a complimentary roadside assistance for two years, flat tire services available 24/7 anywhere in the U.S., Canada or Puerto Rico. This whole assembly does meet the DOT Department Of Transportation specifications. The tire will meet the Federal Motor Vehicle Safety Standard specs, and the wheel meets the SAE J1204 standards. Now the center cap, that is not included. If you do want a center cap, you can purchase those.
We sell those separately on our website. You do want to make sure that you buy a center cap that has the diameter of 4.27 inches. That's the diameter here of the pilot hole.Give you a few measurements on this. The diameter of this wheel, which will be measured inside the inside is 15 inches. The width on just the wheel, it's going to be six inches wide. Bolt pattern on this wheel is a 6 on 5-1/2 inch bolt pattern. And if you want to measure that bolt pattern on a wheel that's an even number of lugs in this case six, it's pretty easy because the holes are right across from each other. So you just pick any hole, let's say this one. And you'll measure from the center of this hole directly across to the center of the hole right across from it. So on this wheel, it'll measure 5-1/2 inches. So it's six log 5-1/2 inch bolt pattern. Does use a wheel lug size of a 1/2 inch by 20. Weight capacity on just the wheel by itself is 2,850 pounds.We had mentioned the pilot hole diameter here is 4.27 inches. Now the tire size, which is stamped on the sidewall. ST for special trailer, 225/75R15. The R means that it's a radial design tire. Section width is 8.8 inches. Overall diameter from the bottom to the top when it's inflated is 28.3. And this tire has a load range D, which means it's an eight ply rated tire. Has a maximum load of 2,540 pounds at 65 PSI. And the last thing I do want to mention is most all the new trailer tires are coming through with a speed rating on them. And where the speed rating is usually if you look where the load range is indicated. Right over here, it'll have two numbers for the load index and then a letter at the end. This one's a speed rating L, so that means it's a 75 mile per hour rated tire. But that should do it for the review on this Castle Rock ST225/75R15 radial trailer tire in a load range D on the 15 inch white modular steel wheel with the 6 on 5-1/2 inch bolt pattern..