USFS National Forest System Trails · Black Hills National Forest · South Dakota · Updated June 2026
Rimrock Spur B (USFS trail 79B) is a 0.8 mi trail in Black Hills National Forest, South Dakota. Mountain bikes are designated as allowed year-round, with no Class 1 e-bike designation on record.
Can I bike Rimrock Spur B?
| Use | Status | Season on record |
|---|---|---|
| Mountain bike | Allowed | year-round |
| Class 1 e-bike (pedal-assist, 20 mph) | — | |
| Class 2 e-bike (throttle, 20 mph) | — | |
| Class 3 e-bike (pedal-assist, 28 mph) | — |
Zooming out: across Black Hills National Forest, 34% of rideable trail miles are open to mountain bikes — a Bike Access Grade of C.
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About this trail
In Black Hills National Forest, South Dakota, Rimrock Spur B (USFS trail 79B) covers 0.8 mi of National Forest System trail. This profile summarizes what the official US Forest Service trail record says about riding it: how long the trail is, what it's built on, how steep the route grades out, and which forms of bike use the agency has designated. Underfoot, the trail is recorded as native material. Based on slope, this is a Advanced trail (grade band 12-20%); that reflects steep gradient and is not the same as a technical MTB difficulty rating. Bike use is designated as allowed year-round. The agency lists no Class 1, 2 or 3 e-bike designation here; absent a local order to the contrary, that means e-bikes are not an allowed use on this trail. The route is mapped as USFS Trail Class 3 on the agency's 1-to-5 development scale, where 1 is the most primitive, minimally maintained tread and 5 is the most developed. For day-of certainty on closures or seasonal orders, check directly with the ranger district, since this reflects the USFS data as of the latest refresh.
Frequently asked questions
- Can you mountain bike on Rimrock Spur B?
- Yes. Mountain bikes are designated as allowed on Rimrock Spur B in Black Hills National Forest, year-round, per USFS data.
- Are e-bikes allowed on Rimrock Spur B?
- No e-bike class (1, 2 or 3) is designated on Rimrock Spur B in the USFS data.
- How long is Rimrock Spur B?
- Rimrock Spur B measures about 0.8 mi in total, summed across its mapped National Forest System segments.
- What is the surface of Rimrock Spur B?
- USFS data records the tread surface of Rimrock Spur B as native material.
- How difficult is Rimrock Spur B?
- Its grade-based difficulty is Advanced (grade band 12-20%), derived from USFS slope data. This reflects steepness, not technical mountain-bike difficulty.
How we read this data
Grade-based difficulty above is the USFS grade (route steepness), not a technical mountain-bike rating — a gentle-grade trail can still be rocky or technical, and vice versa. Bike and e-bike status come verbatim from the USFS managed-use fields for this trail; we never infer access we can't cite. See our methodology for how the dataset is built and what each field means.
Where it is
Approximate location of Black Hills National Forest (USFS trail geometry isn't mapped).
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