# Assos S9 — Six Years of Development for a New Generation of Bib Shorts

> After six years of development, Assos unveils the S9 generation. A-Lock Engineering, the rollBar strap system and the Butterfly cut pattern replace the S7. The biggest change to Assos shorts since 2013 — available from January 2019.

- Published: 2018-09-14

In September 2018, Assos announces the [S9 generation](https://www.bikeworldnews.com/2018/09/14/assos-announces-major-generational-update-to-bib-shorts-the-s9/). This is more than an update — it’s a generational shift. The S7, on the market since December 2013 and an industry standard within five years, is being replaced. The new Equipe RS S9 hits stores in January 2019.

## What changes

**A-Lock Engineering** is the core concept. Every fabric panel, every strap and every seam is designed to keep the shorts and chamois in position — even when the rider gets out of the saddle, accelerates out of the saddle or leans into a descent. That sounds obvious, but it wasn’t. Pad slipping and shifting is the most common problem with bib shorts.

The **rollBar** is the most visible part of this solution: a stabilising element in the straps that restricts vertical movement of the pad. It works together with the **ergoBox** — a three-dimensional construction in the crotch area — and the [**Butterfly cut pattern**](https://road.cc/content/tech-news/248323-assos-equipe-rs-s9-shorts-launched-all-new-padded-insert-and-short-design), which uses just two main panels. One large panel wraps both legs and converges at the back.

## Two variants: RS and RSR

The [**Equipe RS**](https://swindoncycles.co.uk/blogs/news/assos-s9-launched) offers the full A-Lock system with rollBar. The **Equipe RSR** does without the rollBar to save weight — for riders who prioritise maximum lightness over maximum stabilisation. Same textiles, same pad, different strap system.

## Assessment

The S7 shaped the modern bib shorts market: goldenGate, Memory Foam, floating chamois. The S9 answers a different question — not “how does the pad feel?” but “does it stay where it belongs?”. Six years of development for an answer you feel within the first ten minutes of riding.

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Source: https://kilometro.ch/en/articles/assos-s9-six-years-of-development-for-a-new-generation-of-bib-shorts