Colnago Y1RS Expander Bolt Kit Weight: 49.1 g vs 98.5 g Stock 49.4 g Saved

The Colnago Y1RS expander bolt kit — the complete set of fasteners that secures the fork, handlebar, seatpost clamp, and headset — weighs 98.5 g in stock steel (XS frame, zero spacers). TiNE's Grade 5 Ti-6Al-4V replacement brings the entire set down to 49.1 g, saving 49.4 g. That is the largest single-kit weight reduction in TiNE's entire catalog — over 50% of the stock weight gone in one swap.

Problem: The Stock Expander Is Heavier Than It Looks

On the Y1RS, the expander assembly sits hidden inside the carbon steerer tube above the head tube. It is a three-piece system — shaft, locking ring, and main bolt — that grips the steerer from the inside and provides the anchor for the headset top cap and handlebar. In stock steel, these three pieces alone weigh 55.9 g. Add the ten remaining frame bolts and the total reaches 98.5 g — more than a full Shimano hydraulic bolt kit.

Solution: Expander Core in Titanium

The shaft alone saves 18.0 g — the single largest component in the entire kit. The three-piece expander core accounts for 28.7 g of the 49.4 g total savings.

Frame Bolts: Seven Positions, Ten Pieces

The four handlebar screws save 13.2 g — the second-largest contributor after the expander shaft. These screws are selected by spacer height (0–5 positions), so the total kit weight adjusts with your bar setup.

Sizing: Savings Grow with Frame Size

The Y1RS expander shaft is sized to the frame — larger frames need longer shafts. Each size increment adds 0.4 g to the TiNE titanium shaft and 0.9 g to the stock steel shaft. This means the savings actually grow with frame size: a larger frame shaft saves roughly 0.5 g more per size step than the XS baseline (18.0 g saved).

Material and Finish

Grade 5 Ti-6Al-4V throughout, CNC machined. Eight anodized color options: Gold, Blue, Candy, Silver, Black, Pink, Green, Rainbow. Every bolt is titanium — no mixed-material hardware in the kit.