Estimated reading time: 12 minutes
Table of Contents
- What Is the Castiron Grip N23?
- Who Is the N23 For?
- Moderate-Aggressive Downturn — The Edging Advantage
- Dual Velcro Closure System
- High-Friction Rubber Sole
- Sizing Guide — USA & Canada
- N23 vs the Castiron Grip Line
- Formerly Rock Planet — Now Castiron Standard
- Verdict
What Is the Castiron Grip N23?
The Castiron Grip N23 is a precision edge velcro climbing shoe built for intermediate climbers who need accuracy on technical face routes without the foot punishment of a fully aggressive shoe. Moderate-aggressive downturn, dual velcro closure, and a stiff edging platform that locks your foot in position on small holds. This is the shoe for climbers stepping up from beginner flats who want to start projecting harder routes at Red Rock, Rifle, or their local gym.
At $109 USD, the N23 sits alongside the PR23 in the Castiron Grip performance tier — same price, different discipline. Available in EU 35–44.
Who Is the N23 For?
The N23 is built for intermediate climbers who have outgrown flat beginner shoes and need a precision tool for technical terrain. Specifically:
- Technical face climbing — small edges, crimps, and slopers on vertical and slightly overhung routes
- Sport climbing — limestone and granite routes where footwork precision matters more than toe power
- Gym climbing — setting and projecting routes in the 5.10–5.12 range
- Intermediate climbers — V3–V6, 5.10–5.12 on routes
If the PR23's aggressive downturn is too much for your current climbing style but you've outgrown a flat shoe, the N23 is the right step up.
Moderate-Aggressive Downturn — The Edging Advantage
Where the PR23 is built for overhangs and pockets, the N23 is tuned for precision edging. The moderate-aggressive downturn gives you enough toe power for technical moves without forcing your foot into the painful curl of a fully aggressive shoe. This makes the N23 wearable for longer sessions and more versatile across different route styles.
The N23's downturn profile is optimised for:
- Small edges — crimps and footholds on vertical limestone and granite
- Slab climbing — smearing and balance moves where a flat platform helps
- Technical face — routes where footwork precision matters more than raw toe power
Dual Velcro Closure System
Like the PR23, the N23 runs a dual velcro closure for fast on/off between routes. Two independent straps let you dial in forefoot and ankle fit separately — critical for edging shoes where a precise fit directly affects how your foot loads the hold.
If you prefer lace-up micro-adjustability for longer sport climbing days, check out the Castiron Grip SWIFT. For gym sessions and single-pitch sport climbing, the N23's velcro system is the faster, more practical choice.
High-Friction Rubber Sole
The N23 runs the same high-friction rubber compound as the PR23 — optimised for indoor gym walls and outdoor limestone and granite. The edging platform is stiffer than the PR23's, giving you more support on small footholds and reducing foot fatigue on longer technical routes.
Sizing Guide — USA & Canada
The N23 runs slightly small. Size up 0.5 EU from your street shoe size. Women should size up 1.5 from men's US sizing.
| EU | US Women | US Men | UK |
|---|---|---|---|
| 35 | 5W | 3M | 2.5 |
| 36 | 6W | 4M | 3.5 |
| 37 | 6.5W | 4.5M | 4 |
| 38 | 7.5W | 5.5M | 5 |
| 39 | 8.5W | 6.5M | 6 |
| 40 | 9W | 7M | 6.5 |
| 41 | 10W | 8M | 7.5 |
| 42 | 11W | 9M | 8 |
| 43 | 12W | 10M | 9 |
| 44 | 13W | 11M | 9.5 |
Free shipping on US orders over $150. Ships from our US warehouse. Standard delivery 5–8 business days. Expedited 2–4 business days.
N23 vs the Full Castiron Grip Line
Not sure which model is right for you? Here is how the full lineup stacks up — click any model to go straight to the product page.
| Model | Closure | Downturn | Best For | Level |
|---|---|---|---|---|
| PR23 | Dual Velcro | Aggressive | Bouldering, overhangs | Advanced |
| N23 (this shoe) | Dual Velcro | Moderate–Aggressive | Precision edging | Intermediate |
| SWIFT | Lace-Up | Moderate | All-round, sport climbing | Beginner–Intermediate |
| Little ALIEN | Slip-On | Flat | Kids beginner | Youth Beginner |
| ONE | Velcro | Flat | Youth development | Youth |
| HUG | Velcro | Flat | Kids first shoe | Kids Beginner |
→ Browse the full Castiron Grip collection
Formerly Rock Planet — Now Castiron Standard
The N23 was formerly available under the Rock Planet brand — same construction, same last, same proven rubber compound. Rock Planet built a strong reputation in the US and Canadian climbing community for accessible performance footwear, and that DNA carries directly into the Castiron Grip line. If you climbed in Rock Planet shoes, you already know what the N23 delivers.
The Castiron Grip line represents the next chapter: unified brand standards, expanded sizing, and a next-generation model lineup arriving in 2027. The N23 is the current generation — and it is the same shoe that earned Rock Planet its reputation.
Verdict
The Castiron Grip N23 is the precision edging tool for intermediate climbers who want to step up their technical footwork without committing to a fully aggressive shoe. Moderate-aggressive downturn, dual velcro, high-friction rubber — the right shoe for the next grade.
$109 USD. EU 35–44. Free shipping on US orders over $150.
Castiron Grip N23 — Precision Edge Climbing Shoe
Moderate-aggressive downturn · Dual velcro · High-friction rubber · EU 35–44
External Resources
- USA Climbing — National Federation
- Climbing Canada — National Federation
- IFSC — International Federation of Sport Climbing
- Mountain Project — Route Database USA & Canada
- 99Boulders — Climbing Shoe Buyer's Guide
Written by T-K