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 — Europe
- 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. Whether you are projecting at your local Kletterhalle, heading to Fontainebleau, or sport climbing on limestone in the Dolomites, Frankenjura, or Siurana, the N23 is built to match your standard.
At €99 EUR, the N23 delivers performance-tier construction at an honest price. 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 limestone across the Alps, Dolomites, and Pyrenees
- Sport climbing — routes at Frankenjura, Arco, Margalef, and other European limestone venues
- Bloc gym climbing — projecting routes in the 6b–7a range at your local Kletterhalle
- Intermediate climbers — Font 5+–6B, 6b–7a 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 — ideal for European climbers who move between the Kletterhalle and the crag.
The N23's downturn profile is optimised for:
- Small edges — crimps and footholds on limestone across Germany, Austria, Switzerland, Italy, and the Nordics
- Slab climbing — smearing and balance moves on granite and conglomerate
- 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 days on the crag, check out the Castiron Grip SWIFT. For Kletterhalle 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 bloc gym resin holds and outdoor limestone, the dominant surface across DACH, the Nordics, and Italy. 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 — Europe
The N23 runs slightly small. Size up 0.5 EU from your street shoe size.
| EU | UK | US Women | US Men |
|---|---|---|---|
| 35 | 2.5 | 5W | 3M |
| 36 | 3.5 | 6W | 4M |
| 37 | 4 | 6.5W | 4.5M |
| 38 | 5 | 7.5W | 5.5M |
| 39 | 6 | 8.5W | 6.5M |
| 40 | 6.5 | 9W | 7M |
| 41 | 7.5 | 10W | 8M |
| 42 | 8 | 11W | 9M |
| 43 | 9 | 12W | 10M |
| 44 | 9.5 | 13W | 11M |
International shipping to Europe — free on orders over €150. 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 across European climbing communities — in Germany, Austria, Switzerland, the Nordics, and Italy — for accessible performance footwear. 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.
€99 EUR. EU 35–44. Free international shipping on orders over €150.
Castiron Grip N23 — Precision Edge Climbing Shoe
Moderate-aggressive downturn · Dual velcro · High-friction rubber · EU 35–44
External Resources
- IFSC — International Federation of Sport Climbing
- Klettern.de — German Climbing Magazine & Route Database
- PlanetMountain — Italian & European Climbing Routes
- Climbing.de — German Climbing Community
- 99Boulders — Climbing Shoe Buyer's Guide
Written by T-K