Rock Machine Lukk: geometry and sizes
Rock Machine may sell more than one frame under the Lukk name, each with its own geometry. These are the ones in the database. Each shows stack and reach for the smallest and largest size. The numbers for every size are on the model page.
The tables show the smallest and largest size, each with stack / reach in millimetres. Both terms are explained in the glossary.
Current Rock Machine Lukk versions
| Version | Smallest | Largest |
|---|---|---|
| Lukk (alloy) 2026 gravel · aluminium | S · 585 / 357 | XL · 623 / 384 |
| Lukk CR (carbon) 2025 gravel · carbon | S · 554 / 366 | XL · 600 / 386 |
The same size label on two versions doesn’t mean the same frame. And stack and reach only describe the frame: where the bars end up also depends on the stem, spacers and bars.
There’s no sizing by height here. Everything starts from your position. Enter your position and I’ll work out which versions and sizes match it.