Mountainsmith Zerk 40 vs Mountainsmith Scream 55
Quick take: The Mountainsmith Scream 55 costs $65 less; the Mountainsmith Scream 55 carries more (55 vs 51 liters); the Mountainsmith Zerk 40 is lighter (1.81 vs 2.81 lbs).
| Spec | Mountainsmith Zerk 40 | Mountainsmith Scream 55 |
|---|---|---|
| Price | $225 | $160 |
| Rating | — | 5★ (2) |
| Type | Ultralight Pack | Traditional Pack |
| Frame Type | Internal Frame | Internal Frame |
| Capacity | 51 L | 55 L |
| Weight | 1.81 lbs | 2.81 lbs |
| Max Load | Not specified by the manufacturer | ~35 lbs (tested) |
| Torso Fit | See manufacturer sizing | One size, 20 in torso; hipbelt 30-45 in |
| Material | 210D recycled Extreema ripstop | 210D Robic Dynajin nylon ripstop |
| Back Panel | Removable frame sheet | Framed suspension; construction not published |
| Adjustable torso | No | Yes |
| Ventilated back | No | No |
| Raincover included | No | No |
| Hipbelt pockets | Yes | Yes |
| Removable lid | No | No |
| Hydration sleeve | No | Yes |
| Fits BV500 bear can | No | No |
| Warranty | Manufacturer warranty; terms not published | Manufacturer warranty; terms not published |
Pros & cons
Mountainsmith Zerk 40
- ✓The removable frame sheet means one pack covers both framed and frameless use.
- ✓51 L of measured volume against a 40 L badge is unusual -- most packs here measure well under.
- ✓210D recycled Extreema ripstop is a tough woven fabric that repairs easily.
- ✓$225 is mid-range for the segment and below most cottage packs of similar volume.
- ✓Mountainsmith is a mainstream brand, so returns and support are simpler than cottage brands'.
- ✓1 lb 13 oz is competitive with dedicated ultralight packs.
- ✓Hipbelt pockets included.
- ✓Widely available rather than made to order.
- ✗No published maximum load figure.
- ✗A removable frame sheet is less effective at load transfer than stays or a hoop.
- ✗No adjustable torso.
- ✗Not waterproof, unlike the laminate packs at this price.
- ✗Mountainsmith has less ultralight credibility than the cottage brands it competes with.
- ✗The 40 L badge understates the pack, which makes cross-shopping confusing.
- ✗Fewer configuration options than a made-to-order pack.
- ✗Limited presence on long trails, so fewer real-world reports.
Mountainsmith Scream 55
- ✓Sub-3 lb for 55 L at $160 is the best weight-to-price combination in this catalog.
- ✓210D Robic Dynajin ripstop is a genuinely durable fabric at this weight.
- ✓Undercuts the Osprey Exos 58 by $125 while weighing about the same.
- ✓The hipbelt spans 30 to 45 inches, which is broad for a one-size pack.
- ✓55 L covers most multi-day trips without excess volume.
- ✓Mountainsmith is a mainstream brand with normal returns and support.
- ✓Around 35 lb of usable capacity is solid for a pack this light.
- ✓Hipbelt pockets included.
- ✗One torso length only, at 20 inches, with no adjustability -- the single biggest limitation.
- ✗Anyone outside roughly a 19-21 in torso should not buy this pack.
- ✗The max-load figure is inferred from testing, not stated by Mountainsmith.
- ✗No rain cover included.
- ✗Only one volume is offered.
- ✗No ventilated back panel.
- ✗Mountainsmith has a thinner backpacking reputation than Osprey or Gregory.
- ✗Bear-canister fit is not stated.