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Ribble Ultra-Aero SL R vs Storck Aerfast.4 Pro
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 Storck Aerfast.4 Pro higher overall: 75/100 vs 73/100.
- Tire clearance: up to 32 mm on the Ribble Ultra-Aero SL R vs 28 mm on the Storck Aerfast.4 Pro.
- The Ribble Ultra-Aero SL R comes in 5 sizes, the Storck Aerfast.4 Pro in 6.
Ribble Ultra-Aero SL R
Storck Aerfast.4 Pro
| RibbleUltra-Aero SL R | StorckAerfast.4 Pro | |
|---|---|---|
| Overview | ||
| Brand | Ribble | Storck |
| Build | Ultra-Aero SL R 105 Di2 | Aerfast.4 Pro 105 Di2 |
| Build notes | Prices are the full ("was") prices Ribble showed in November 2026 (GBP and USD); its end-of-season sale, ending 2 November 2026, offered it at £3,149 / $4,460. In October 2026 Ribble's full prices were lower (see the price history). No euro price found: Ribble's German site showed the US-dollar store from our location. Built to order with inner tubes fitted; pedals not included. Options at extra cost include a 4iiii power meter crankset and Mavic Cosmic carbon wheels. | 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. |
| Price (MSRP) | $5,705$5,705£3,749 | €4,499€4,499€4,499 |
| Bike weight | 9.5 kg20.9 lb | — |
| Weight measured on size | M | — |
| Model year | 2026 | 2026 |
| Generation | First-generation Ultra SL R (2021) | Aerfast.4 (fourth generation) |
| Launched | 2021-08 | 2021 |
| Newer generation | — | Aerfast.5 (2024) |
| Discipline | Aero road | Aero road |
| UCI legal | Yes | Yes |
| Verdict (out of 100) | ||
| Overall score | 73 | 75 |
| Aero | 82 | 86 |
| Frame | 70 | 74 |
| Components | 72 | 66 |
| Fit | 62 | 72 |
| Practicality | 70 | 58 |
| Price | 86 | 93 |
| Weight | 70 | — |
| Frame & fork | ||
| Frame material | Carbon (T1000 and T800 blend, with more T1000 than the Ultra-Aero SL) | Carbon (CFR/UD), Pro grade |
| Fork material | Carbon | — |
| Frame weight | 1,200 g2.65 lb | 950 g33.5 oz |
| Fork weight | — | 500 g17.6 oz |
| Frameset weight | — | 1,900 g4.19 lb |
| Weight measured on | Ribble's figure for a medium frame only | 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 |
| Max system weight | 120 kg264.6 lb | 120 kg264.6 lb |
| Frame sizes | XS, S, M, L, XL | XS, S, M, L, XL (XXL for the Final Edition) |
| Colours | Ultra Black; Ribble Custom Colour also available | Radioactive Green (Pro), Imperial Blue Chrome (Final Edition), Pink/Black (SRCT Edition) |
| Also available as | Ultra-Aero SL: same design with a cheaper carbon layup | Aerfast.4 Platinum, Pro, Comp and Red Edition (frame classes of the same design, same geometry); succeeded by the Aerfast.5 |
| UCI frame approval | Approved 19 Jan 2022 as 'ULTRA SLR' (frame and fork), sizes XXS-XL (6), code RIBB-USLR (UCI list version 2026.10.02) | 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 |
| Compatibility & standards | ||
| Brake type | Hydraulic disc | Hydraulic disc, flat mount (160 mm rotors front and rear as built) |
| Wheel size | 700c | — |
| Max tire width | 32 mm | 28 mm |
| Bottom bracket standard | BSA 68 mm threaded | Press-fit, 41 mm bearing bore x 86.5 mm |
| Front axle | 12 mm thru-axle (M12 x 1.5 x 125 mm) | — |
| Rear axle | 12 mm thru-axle (M12 x 1.5 x 173 mm) | — |
| Cable routing | Internal | Internal through the one-piece cockpit |
| Hydration & storage | ||
| Bottle mounts | 2 | — |
| Bottle mount locations | Down tube and seat tube, shaped for Ribble's aero bottle cages | — |
| Fit & adjustability | ||
| Cockpit | One-piece bar and stem (Ribble Ultra-Aero integrated carbon bar) | One-piece Storck RBSU Aerfast.4 bar and stem, one size per frame size |
| Clip-on aerobars possible | Yes | — |
| Seatpost type | Proprietary aero carbon seatpost | Storck Aerfast.4 carbon aero seatpost |
| Fit notes | The steerer is cut to length when the bike is built and comes with 30 mm of spacers, so the bars can be lowered but not raised later. | 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. |
| Aerodynamics | ||
| Manufacturer aero claims | At launch: 11.6 W saved at 22 mph (average of 5 and 10 degrees yaw) against Ribble's Endurance SL Disc, about 75 seconds over 40 km. Ribble says the current Ultra-Aero bar has 2.1% less drag than its RI-2 integrated cockpit. | 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 |
| Testing method | CFD, wind tunnel and real-world testing, optimised for 5-10 degrees of yaw | Wind tunnel |
| Tube profile | Truncated aerofoil tubes; flared down tube; brake calipers mounted inboard of the fork | 80 mm wide aero fork with a camtail trailing edge |
| Travel, maintenance & warranty | ||
| Headset bearings | Upper P16 40 x 52 x 7 mm 45x45°, lower ACB 40 x 51.8 x 8 mm 45x45° | — |
| Derailleur hanger | Ribble SL R/SL disc hanger | — |
| Proprietary parts | One-piece Ultra-Aero bar, aero seatpost, derailleur hanger, UCI fork brake adapter | RBSU Aerfast.4 one-piece cockpit, Aerfast.4 seatpost and headset |
| Frame warranty | Lifetime frame and fork warranty for the original owner | — |
| Sold via | Direct from Ribble (online and showrooms), built to order in the UK | Direct from Storck's web shop and Storck stores |
| Drivetrain | ||
| Groupset | Shimano 105 Di2 R7100 | Shimano 105 Di2 R7100 |
| Launched | 2022 · current generation | 2022 · current generation |
| Speeds | 12-speed | 12-speed |
| Electronic | Yes | Yes |
| Drivetrain | 2x | 2x |
| Shifters | Shimano 105 Di2 ST-R7170 | Shimano 105 Di2 ST-R7170 |
| Notes | — | Combined shift and hydraulic brake levers |
| Crankset | Shimano 105 R7100 | Shimano 105 R7100 |
| Chainrings | — | 52/36 |
| Crank length | 165 (XS) / 170 (S, M) / 172.5 (L, XL) | — |
| Crank lengths available | — | 170 mm (XS-S), 172.5 mm (M-L), 175 mm (XL-XXL) |
| Bottom bracket | Shimano BB-R60 | Storck Press-fit 41 x 86.5 mm |
| Standard | BSA 68 mm threaded | Press-fit, 41 mm bearing bore x 86.5 mm |
| Front derailleur | Shimano 105 Di2 R7150 | — |
| Rear derailleur | Shimano 105 Di2 R7150 | Shimano 105 Di2 R7150 |
| Cassette | Shimano CS-HG710 | Shimano 105 R7101 |
| Range | 11-36 | 11-34 |
| Speeds | 12-speed | 12-speed |
| Chain | Shimano CN-M7100 | Shimano CN-M7100 |
| Brakes | ||
| Brake levers | Shimano 105 Di2 ST-R7170 | — |
| Brake calipers | Shimano 105 BR-R7170 | Shimano 105 |
| Type | Hydraulic disc | Hydraulic disc, flat mount |
| Notes | — | 160 mm rotors front and rear |
| Rotors | Shimano RT-CL700 | — |
| Front rotor | 160 mm | — |
| Mount | Center Lock | — |
| Wheels & tires | ||
| Wheelset | Mavic Ksyrium 30 | DT Swiss PR 1600 Spline 32 |
| Front rim depth | — | 32 mm |
| Rear rim depth | — | 32 mm |
| Material | Aluminium | Aluminium |
| Hubs | Center Lock | — |
| Notes | — | Base wheels; Zeitjaeger Platinum, Pro and Comp and DT Swiss ARC 1400 Dicut wheels cost extra |
| Tires | Vittoria Rubino V TLR G2.0 | Continental Grand Prix 5000 S TR |
| Tire width | 30 mm | 25 mm |
| Set up tubeless | No | — |
| Cockpit | ||
| Handlebar | Ribble Ultra-Aero Integrated | Storck RBSU Aerfast.4 |
| Type | One-piece bar and stem | One-piece bar and stem |
| Integrated stem | Yes | Yes |
| Widths available | Hoods/drops 360/400 mm with an 80 mm stem (XS), 100 mm (S, M, L); 380/420 mm with a 110 mm stem (XL) | 380 mm / 90 mm stem (XS), 400/100 (S), 420/100 (M-L), 420/110 (XL), 440/120 (XXL) |
| Tops | Aero (wide wing-shaped tops) | — |
| Cable routing | Internal | — |
| Material | Carbon | — |
| Headset | — | Storck Aerfast.4 integrated headset |
| Saddle & seatpost | ||
| Saddle | Selle Italia Model X Light | Fizik Vento Argo R5 |
| Seatpost | Ribble Ultra-Aero SL R/SL Setback Carbon | Storck Aerfast.4 Carbon |
| Material | Carbon | Carbon |
| Bar tape | — | Storck Microfibre |
| Notes | — | Black |
| Geometry (smallest – largest size) | ||
| Sizes | XS, S, M, L, XL | XS, S, M, L, XL, XXL |
| Rider height min | 160–185 cm5′3″–6′1″ | 152–188 cm5′0″–6′2″ |
| Rider height max | 165–191 cm5′5″–6′3″ | 166–190 cm5′5″–6′3″ |
| Stack | 506–583 mm19.9–23″ | 482–576 mm19–22.7″ |
| Reach | 379–410 mm14.9–16.1″ | 362.5–418 mm14.3–16.5″ |
| Seat tube angle | 73.3–75° | 73° |
| Head tube angle | 72–73.5° | 70–72° |
| Head tube length | 105–180 mm4.1–7.1″ | 85–170 mm3.3–6.7″ |
| Effective top tube | 515–590 mm20.3–23.2″ | 510–595 mm20.1–23.4″ |
| Seat tube length | 470–560 mm18.5–22″ | 458–583 mm18–23″ |
| Chainstay | 410 mm16.1″ | 410 mm16.1″ |
| Wheelbase | 975–1,014 mm38.4–39.9″ | — |
| BB drop | 69 mm2.7″ | — |
| Fork offset | 45–53 mm1.8–2.1″ | — |
| Front centre | 518–613 mm20.4–24.1″ | — |
| Wheel size | 700c | — |
| Crank length | 165–172.5 mm6.5–6.8″ | 170–175 mm6.7–6.9″ |
| Stem length | 80–110 mm3.1–4.3″ | 90–120 mm3.5–4.7″ |
| Handlebar width | 400–420 mm15.7–16.5″ | 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).