Ratio Astrum CSD review

Super-curvy new Italian model

Our rating 
3.0 out of 5 star rating 3.0
GBP £3,399.99 RRP | USD $5,502.20
Ratio Astrum CSD

Our review

Good ride, weight and spec but fussy design won't appeal to all and a stiffer fork would improve handling
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Ratio are a new Italian company founded by Pancrazio Centola. Centola may not be a household name, but he has a wealth of experience from working at 3T and Deda Elementi, and he’s now brought this to bear on his own range of components and framesets. 


The only tube on the Astrum free of swoops and bends is the seat tube – a curved seatpost presumably being a step too far even for Centola. The result is certainly striking. The claimed 1,080g frame and 370g tapered fork are topped with Ratio’s Tacto carbon bar and seatpost, and carbon-wrapped alloy stem. Titanium bolts, carbon seat clamp and headset caps save a few more grams. Our test bike was built up with Shimano Ultegra, Pro-Lite wheels and Ratio’s own kit, but the frameset is available on its own for £1,299.99 or £1,199.99 in a raw finish.

On the road, first impressions are promising, with excellent shock absorption over some poorly surfaced roads. Despite the S-shaped stays, the rear end remains responsive, the frame’s sprightly acceleration testament also to the BB30 bottom bracket shell and Pro-Lite’s Bracciano wheels. The bar’s slight backwards sweep makes for a relaxed grip, with multiple comfortable positions, and the wrapped stem dulls road buzz well. the Control Tech Module carbon railed saddle also deserves praise, with its unusual laterally rocking rear structure increasing comfort.

Pressing on, the bike’s character begins to surface. Its cosseting nature can disguise the fact that it’s travelling quite quickly, though while it’s efficient at picking up speed, it lacks the zing of a racing thoroughbred. A short head tube gives a racy position and a feel that’s somewhere between outright racer and sportive special. Tidy handling gets the job done, but the fork lacks the lateral stiffness required for ultimate cornering precision. Seated climbing is swift, but out-of-the-saddle efforts feel less planted, as the muscular head tube area isn’t matched by a similarly buff fork.

The Astrum has undoubted quality of design and construction, with some classy in-house components. It’s a machine for the non-racer looking to go fast and long in comfort, and who’s not afraid to do so on an original-looking machine.


This article was originally published in Cycling Plus magazine, available on Apple Newsstand and Zinio.

Product Specifications


Name Astrum CSD (12)
Brand Ratio

Fork Full carbon monocoque
Fork Weight 370
Frame Material Carbon monocoque
Frame Weight 1080
Front Derailleur Shimano Ultegra
Handlebar Ratio carbon
Rear Derailleur Shimano Ultegra
Rims Pro-Lite Bracciano
Saddle Control tech module
Seatpost Ratio carbon
Shifters Shimano Ultegra
Stem Ratio carbon-wrapped
Weight (kg) 7.2