The best 15-inch spare trailer tire is one that matches your trailer’s tire size, load requirement, and wheel bolt pattern. For a common ST205/75R15 or ST205/75D15 setup, the eCustomRim assemblies offer a ready-to-use Load Range C option, while ROCKMAN’s ST205/75R15 tires provide a Load Range D alternative. The picks below include black, white, and silver wheel styles; confirm the specifications on your trailer before choosing.
| Product | Best For | Key Detail |
|---|---|---|
| eCustomRim Black Load C | Common 5-lug fitment | ST205/75D15; 5 on 4.5-inch |
| ROCKMAN Silver Load D | Higher load-range option | ST205/75R15; 8-ply rated |
| eCustomRim White Load C | White-wheel replacement | DOT-approved assembly |
| ROCKMAN Black Load D | Black wheel and radial tire | 8mm tread depth stated |
| Free Country Black Load C | Load C radial option | ST205/75D15; 5 on 4.5-inch |
eCustomRim Black Load C Assembly
This complete ST205/75D15 bias-ply tire and wheel assembly is best for buyers who need a spare with a 5-lug, 4.5-inch bolt pattern. Its 15-by-5-inch rim has a 3.19-inch center bore. The tire is Load Range C, rated for a maximum load of 1,820 pounds and maximum pressure of 50 PSI, according to the supplied product details.
The listed assembly includes a tire, wheel, and valve stem, and is described as DOT-approved. It also lists a two-year manufacturer’s warranty with roadside assistance. Choose this if your trailer’s size and wheel measurements match. Its limitation is the Load Range C rating, so verify that its capacity meets the trailer’s requirements.
ROCKMAN Silver Load D Radial Assembly
This ST205/75R15 assembly is best for shoppers seeking a Load Range D, 8-ply-rated option with a silver mod rim. ROCKMAN lists a 5-by-4.5-inch bolt pattern, load index 107, and M speed rating, stated as up to 81 mph. The maker also describes an 8mm tread depth and a full nylon cap ply overlay across the tread area.
Choose this if the trailer calls for the radial ST205/75R15 size and the D-range specifications suit its load needs. The listing does not provide the same detailed rim width and center-bore measurements as the eCustomRim products, so confirm those details before purchase.
eCustomRim White Load C Assembly
This white-wheel version is best for owners replacing or carrying a spare for a compatible ST205/75D15 setup. The bias-ply tire is Load Range C, with a stated maximum load of 1,820 pounds and maximum pressure of 50 PSI. The 15-by-5-inch rim has a 3.19-inch center bore and 5-lug, 4.5-inch bolt pattern.
The product is described as a DOT-approved tire, wheel, and valve-stem assembly, with a two-year manufacturer’s warranty and roadside assistance. Select it when the white wheel appearance and listed fitment match your trailer. As with other Load C options, it may not meet requirements for a trailer that needs a higher load range.
ROCKMAN Black Load D Radial Assembly
This ROCKMAN option is best for buyers wanting an ST205/75R15 radial tire with a black mod rim and Load Range D construction. Its listed specifications include 8-ply rating, load index 107, M speed rating up to 81 mph, and 8mm tread depth. The product description also identifies a full nylon cap ply overlay across the tread area.
Choose this over a Load C option if the trailer’s required size and load specifications call for this D-range assembly. The stated bolt pattern is 5-by-4.5 inches. A limitation is that the supplied details do not include rim width or center-bore measurements, so check fitment with the seller or trailer specifications.
Free Country Black Load C Tire
This Free Country ST205/75D15 option is best for buyers comparing a Load Range C tire with a black mod rim. It is listed as 6-ply rated, with load index 101 and L speed rating up to 75 mph. The product details specify a 5-lug, 4.5-inch bolt pattern, zero offset, and 7.4mm tread depth.
Choose it if those specifications match the trailer and you want a black-wheel assembly. The listing does not state a maximum load or pressure in the supplied information, so verify both against the trailer’s requirements before relying on it as a spare.
Buying Guide: How To Choose A 15-Inch Spare Trailer Tire
Which tire size should the spare match?
Check the size printed on the trailer’s existing tire and follow the trailer manufacturer’s requirements. ST205/75D15 and ST205/75R15 are both 15-inch sizes, but the letter indicates different tire construction. Do not assume that any 15-inch tire is interchangeable.
How should load range affect your choice?
Match or exceed the load capacity required for the trailer, while following its specifications. The listed eCustomRim Load C models state a maximum load of 1,820 pounds per tire. The ROCKMAN options are Load Range D and 8-ply rated, but buyers should verify the complete load requirements for the specific assembly.
What wheel measurements matter?
Confirm the bolt pattern, wheel diameter and width, center bore, and offset where provided. A 5-lug wheel does not automatically fit every five-lug hub. Compare the measurements with the trailer’s original wheel or documentation.
Should you buy a tire-only spare or a complete assembly?
A complete tire-and-wheel assembly can be useful when a ready-to-mount spare is needed, but only if its wheel fits the trailer. Check whether the listing includes the components you expect. Never select by wheel style alone.
Frequently Asked Questions
Can I use a 15-inch spare on any 15-inch trailer wheel?
No. Tire size, bolt pattern, wheel dimensions, load capacity, and other fitment requirements must match.
What does ST mean on a trailer tire?
ST identifies a special trailer tire. Use the tire type and size specified for the trailer rather than choosing solely by diameter.
Is Load Range D always better than Load Range C?
Not automatically. The correct load range is the one that meets the trailer’s requirements and fits its wheel setup.
Should a spare tire’s speed rating matter?
Yes. Follow the tire’s stated speed rating and the trailer manufacturer’s guidance when towing.