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Storck Aerfast.4 Pro vs Winspace T1550
Pick up to 4 bikes. Rows line up component by component. Highlighted rows differ, and green marks the best value where lower or higher is clearly better.
Key differences
- Our verdict scores the Winspace T1550 higher overall: 78/100 vs 75/100.
- Tire clearance: up to 28 mm on the Storck Aerfast.4 Pro vs 32 mm on the Winspace T1550.
- The Storck Aerfast.4 Pro comes in 6 sizes, the Winspace T1550 in 5.
Storck Aerfast.4 Pro
Winspace T1550
| StorckAerfast.4 Pro | WinspaceT1550 | |
|---|---|---|
| Overview | ||
| Brand | Storck | Winspace |
| Build | Aerfast.4 Pro 105 Di2 | T1550 Gen2 Ultegra Di2 |
| Build notes | Colour Radioactive Green. Price with DT Swiss PR 1600 Spline 32 alloy wheels (size M); carbon wheels cost extra. Prices from Storck's own web shop (EUR only). No power meter. | Winspace's weight is about 7.7 kg in size M without pedals. Sold in USD only; shipped from the China, EU or US warehouse, plus a $100 complete-bike shipping fee outside Asia. Bikes from the EU warehouse may come with an 11-30 cassette, Shimano SM-RT10 rotors, a Selle Italia Novus Boost saddle and 28 mm Michelin Power Cup tyres. Winspace says all cranksets currently ship with 52/36 chainrings. |
| Price (MSRP) | €4,499€4,499€4,499 | $4,849$4,849$4,849 |
| Bike weight | — | 7.7 kg17 lb |
| Weight measured on size | — | M |
| Model year | 2026 | 2026 |
| Generation | Aerfast.4 (fourth generation) | 2nd generation |
| Launched | 2021 | 2025-01 |
| Newer generation | Aerfast.5 (2024) | — |
| Discipline | Aero road | Aero road |
| UCI legal | Yes | Yes |
| Verdict (out of 100) | ||
| Overall score | 75 | 78 |
| Aero | 86 | 80 |
| Frame | 74 | 74 |
| Components | 66 | 70 |
| Fit | 72 | 70 |
| Practicality | 58 | 72 |
| Price | 93 | 95 |
| Weight | — | 82 |
| Frame & fork | ||
| Frame material | Carbon (CFR/UD), Pro grade | Carbon (Toray T1000 and T800; the complete-bike pages list T800/T1000/M46) |
| Fork material | — | Carbon (Winspace T1550 fork) |
| Frame weight | 950 g33.5 oz | 828 g29.2 oz |
| Fork weight | 500 g17.6 oz | — |
| Frameset weight | 1,900 g4.19 lb | — |
| Weight measured on | Storck's 'from' weights on its Aerfast.4 Platinum and Pro frameset pages (frame, fork, one-piece cockpit; frameset includes seatpost and headset); not split by grade or size | Frame, size M, unpainted (±35 g). The complete-bike pages give about 855 g for a painted size M frame. |
| Max system weight | 120 kg264.6 lb | — |
| Frame sizes | XS, S, M, L, XL (XXL for the Final Edition) | XS (440), S (470), M (490), L (520), XL (550) |
| Colours | Radioactive Green (Pro), Imperial Blue Chrome (Final Edition), Pink/Black (SRCT Edition) | Flavoured Black, Retro Blue, Black and White, Silver and White, Panda, Silver Red, Vuelta Tribute, Turbulent Blue, Tropical Green, 2025 Team Edition, Black Viper, Chameleon White, Cosmic Purple, Carnival, Neon, Blue Silk, Stardust (frameset); complete bikes also list Clover |
| Also available as | Aerfast.4 Platinum, Pro, Comp and Red Edition (frame classes of the same design, same geometry); succeeded by the Aerfast.5 | — |
| UCI frame approval | On the UCI list of approved framesets as 'AERFAST.3 / AERFAST.4' (code STOR-AEF), approved 8 Feb 2023 in sizes XS-XXL (6) (UCI list version 2026.10.02); the list doesn't distinguish the grades | Winspace states the T1550 Gen 2 frameset is UCI approved. The UCI list (version 2026.10.02) has a 'T1550' frame and fork approved 27 Sep 2017 (sizes 410-550, code WINS-T15-RD) and no separate entry for the second generation. |
| Compatibility & standards | ||
| Brake type | Hydraulic disc, flat mount (160 mm rotors front and rear as built) | Disc, flat mount |
| Wheel size | — | 700c |
| Max tire width | 28 mm | 32 mm |
| Bottom bracket standard | Press-fit, 41 mm bearing bore x 86.5 mm | T47 threaded (internal, symmetric 85.5 mm) |
| Front axle | — | 12x100 thru-axle |
| Rear axle | — | 12x142 thru-axle |
| Drivetrain compatibility | — | Mechanical and electronic: Shimano Di2, SRAM eTap/AXS and Campagnolo EPS routing |
| Mechanical shifting possible | — | Yes |
| Front derailleur mount | — | Braze-on |
| Cable routing | Internal through the one-piece cockpit | Fully internal through a 1.5 in ACR (Aerodynamic Cable Routing) headset |
| Fit & adjustability | ||
| Cockpit | One-piece Storck RBSU Aerfast.4 bar and stem, one size per frame size | One-piece carbon bar and stem (Winspace Zero SL) on the complete bikes; the frameset comes without a cockpit |
| Seatpost type | Storck Aerfast.4 carbon aero seatpost | Proprietary carbon aero seatpost (Winspace S23 VCLS), 0 or 15 mm setback (0 mm on XS-S, 15 mm on M-XL in the geometry chart) |
| Fit notes | Each frame size comes with one cockpit size, from 380 mm bar / 90 mm stem (XS) to 440 / 120 mm (XXL). Storck says a computer mount and triathlon extensions can be retrofitted, and lists its TT kit as compatible with the Aerfast.4. | Five sizes. Compared with the first T1550 the head tubes are about 10 mm longer on average and the stack-to-reach ratio is 1.40 or more. The Zero SL one-piece cockpit is sold in 380, 400 and 420 mm widths with 85 to 135 mm stems ($290 on its own); the complete-bike pages don't say which size is fitted. |
| Aerodynamics | ||
| Manufacturer aero claims | Storck says the Aerfast.4 measured 199 W at 45 km/h in TOUR's wind-tunnel test; TOUR's own figures were 201 W for the Pro Disc and 202 W for the Comp Disc | Winspace publishes no drag figures. It says the fully hidden ACR cable routing lowers drag. |
| Testing method | Wind tunnel | — |
| Tube profile | 80 mm wide aero fork with a camtail trailing edge | — |
| Travel, maintenance & warranty | ||
| Headset bearings | — | 1.5 in (No.55R), ACR integrated headset included |
| Derailleur hanger | — | Direct-mount derailleur hanger (a spare comes with complete bikes) |
| Proprietary parts | RBSU Aerfast.4 one-piece cockpit, Aerfast.4 seatpost and headset | Aero seatpost, ACR headset and Zero SL cockpit |
| Frame warranty | — | 3 years on the frameset from arrival at the original buyer (wheelsets 2 years); not transferable |
| Sold via | Direct from Storck's web shop and Storck stores | Direct online from Winspace (shipped from China, EU or US warehouses) and through authorized dealers |
| Drivetrain | ||
| Groupset | Shimano 105 Di2 R7100 | Shimano Ultegra Di2 R8100 |
| Launched | 2022 · current generation | 2021 · current generation |
| Speeds | 12-speed | 12-speed |
| Electronic | Yes | Yes |
| Drivetrain | 2x | 2x |
| Shifters | Shimano 105 Di2 ST-R7170 | Shimano Ultegra Di2 ST-R8170 |
| Notes | Combined shift and hydraulic brake levers | — |
| Crankset | Shimano 105 R7100 | Shimano Ultegra R8100 |
| Chainrings | 52/36 | 52/36 |
| Crank lengths available | 170 mm (XS-S), 172.5 mm (M-L), 175 mm (XL-XXL) | — |
| Bottom bracket | Storck Press-fit 41 x 86.5 mm | Token T47 |
| Standard | Press-fit, 41 mm bearing bore x 86.5 mm | T47, 85.5 mm |
| Bearings | — | Steel |
| Front derailleur | — | Shimano Ultegra Di2 R8150 |
| Rear derailleur | Shimano 105 Di2 R7150 | Shimano Ultegra Di2 R8150 |
| Cassette | Shimano 105 R7101 | Shimano Ultegra R8100 |
| Range | 11-34 | 11-34 |
| Speeds | 12-speed | 12-speed |
| Chain | Shimano CN-M7100 | Shimano CN-M8100 |
| Brakes | ||
| Brake calipers | Shimano 105 | Shimano Ultegra hydraulic disc |
| Type | Hydraulic disc, flat mount | — |
| Notes | 160 mm rotors front and rear | — |
| Rotors | — | Shimano RT-CL800 |
| Front rotor | — | 160 mm |
| Rear rotor | — | 140 mm |
| Mount | — | Center Lock |
| Wheels & tires | ||
| Wheelset | DT Swiss PR 1600 Spline 32 | Lún Hyper 3 |
| Front rim depth | 32 mm | — |
| Rear rim depth | 32 mm | — |
| Material | Aluminium | Carbon |
| Notes | Base wheels; Zeitjaeger Platinum, Pro and Comp and DT Swiss ARC 1400 Dicut wheels cost extra | — |
| Tires | Continental Grand Prix 5000 S TR | Michelin Power Cup |
| Tire width | 25 mm | — |
| Cockpit | ||
| Handlebar | Storck RBSU Aerfast.4 | Winspace Zero SL |
| Type | One-piece bar and stem | One-piece bar and stem |
| Integrated stem | Yes | Yes |
| Widths available | 380 mm / 90 mm stem (XS), 400/100 (S), 420/100 (M-L), 420/110 (XL), 440/120 (XXL) | 380, 400 or 420 mm, with 85 to 135 mm stem (sold separately in these sizes; stock size not stated) |
| Cable routing | — | Fully internal through the ACR headset |
| Material | — | Carbon |
| Headset | Storck Aerfast.4 integrated headset | — |
| Saddle & seatpost | ||
| Saddle | Fizik Vento Argo R5 | Selle Italia SLR Boost Superflow |
| Seatpost | Storck Aerfast.4 Carbon | Winspace S23 VCLS |
| Offset / setback | — | 0 or 15 mm setback |
| Material | Carbon | Carbon |
| Bar tape | Storck Microfibre | — |
| Notes | Black | — |
| Geometry (smallest – largest size) | ||
| Sizes | XS, S, M, L, XL, XXL | XS, S, M, L, XL |
| Rider height min | 152–188 cm5′0″–6′2″ | 152–182 cm5–6′0″ |
| Rider height max | 166–190 cm5′5″–6′3″ | 165–192 cm5′5″–6′4″ |
| Stack | 482–576 mm19–22.7″ | 504.7–585.7 mm19.9–23.1″ |
| Reach | 362.5–418 mm14.3–16.5″ | 363–397 mm14.3–15.6″ |
| Seat tube angle | 73° | 73–75.1° |
| Head tube angle | 70–72° | 70.7–72.9° |
| Head tube length | 85–170 mm3.3–6.7″ | 105–180 mm4.1–7.1″ |
| Effective top tube | 510–595 mm20.1–23.4″ | 497.3–576.1 mm19.6–22.7″ |
| Seat tube length | 458–583 mm18–23″ | 440–550 mm17.3–21.7″ |
| Chainstay | 410 mm16.1″ | 408 mm16.1″ |
| Wheelbase | — | 969.1–1,002.7 mm38.2–39.5″ |
| BB drop | — | 72 mm2.8″ |
| BB height | — | 271 mm10.7″ |
| Fork length | — | 370 mm14.6″ |
| Fork offset | — | 44–50 mm1.7–2″ |
| Trail | — | 57.7–65 mm2.3–2.6″ |
| Standover | — | 731–832 mm28.8–32.8″ |
| Wheel size | — | 700c |
| Crank length | 170–175 mm6.7–6.9″ | — |
| Stem length | 90–120 mm3.5–4.7″ | — |
| Handlebar width | 380–440 mm15–17.3″ | — |
Geometry overlay
Pick a size for each bike to see frames and arm-pad ranges on top of each other.
Drawn to scale (how to read it).