SDG Formula FX I-Beam saddle review

Firm and robust seating

Our rating 
2.5 out of 5 star rating 2.5
GBP £89.95 RRP | USD $129.99
SDG Formula FX I-Bream saddle

Our review

Light and robust, but having to cough up for a post as well is a downer
Skip to view product specifications

The Formula FX uses SDG’s I-Beam mounting system, with a single rail forming a single moulded piece with the nylon hull. The design was originally devised to get around the problem of conventional saddles popping rails under hard use but has found its way into more cross-country oriented seats too.


You’ll need an SDG post – having to buy into the whole system is a real drawback, though you can get a version of the Formula with normal rails. The profile’s similar to SDG’s Bel Air, but the nose is less droopy. The sides sweep out closer to the nose than most saddles, but they’re also deliberately flexier. Hull flex is limited and there’s no pressure-relieving channel on top – if you like your saddles firm, give this a go.

Product Specifications


Name Formula FX I-Beam (11)
Brand SDG

Description • Lightweight EVA Foam • Dual Density Base Flex cavity • Topeak QR System Bag Mount • One Piece top with embossed/printed graphics • Size - 285mm x 145mm
Weight (g) 241
Available Colours Black Brown White