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Argon 18 Nitrogen vs Felt Nexar UD Carbon STD
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
- Both start at $5,999.
- Our verdict scores the Argon 18 Nitrogen higher overall: 81/100 vs 77/100.
- The Argon 18 Nitrogen comes in 6 sizes, the Felt Nexar UD Carbon STD in 7.
Argon 18 Nitrogen
Felt Nexar UD Carbon STD
| Argon 18Nitrogen | FeltNexar UD Carbon STD | |
|---|---|---|
| Overview | ||
| Brand | Argon 18 | Felt |
| Build | Nitrogen SRAM Force AXS | Nexar Expert Shimano Ultegra Di2 |
| Build notes | Harvest Moon or Cosmic Teal. Argon 18 lists the crank as 'SRAM Force AXS Powermeter 48/35'. Only USD is listed; Argon 18's other regional stores redirect to the US site. | UD Carbon STD frame and fork in Glossy Grey. USD from Felt's US store; Felt's store lists no other currency for this build. |
| Price (MSRP) | $8,599$8,599$8,599 | $6,999$6,999$6,999 |
| Bike weight | — | 7.6 kg16.8 lb |
| Weight measured on size | — | M |
| Model year | 2026 | 2026 |
| Generation | 2025 relaunch | Nexar (2026), successor to the AR |
| Launched | 2025-09 | 2026-03 |
| Discipline | Aero road | Aero road |
| UCI legal | Not stated | Not stated |
| Verdict (out of 100) | ||
| Overall score | 81 | 77 |
| Aero | 88 | 84 |
| Frame | 80 | 76 |
| Components | 80 | 70 |
| Fit | 80 | 78 |
| Practicality | 72 | 66 |
| Price | 84 | 84 |
| Weight | — | 84 |
| Frame & fork | ||
| Frame material | Carbon (Nitrogen 'Elite' layup) | Carbon (UD Carbon STD) |
| Fork material | Carbon | Carbon (UD Carbon) |
| Max system weight | — | 120 kg264.6 lb |
| Frame sizes | XXS, XS, S, M, L, XL | 44 (XXS), 49 (XS), 52 (S), 54 (M), 56 (L), 58 (XL), 61 (XXL) |
| Colours | Harvest Moon, Cosmic Teal | Glossy Grey (Expert), Glossy Black (Race) |
| Also available as | Nitrogen Pro, the higher carbon layup of the same platform | Nexar FRD (FRD 12K Carbon Light frame and fork, same geometry) on the FRD and Pro builds and as a framekit |
| Compatibility & standards | ||
| Brake type | Hydraulic disc | Hydraulic disc |
| Max rotor size | 160 mm | — |
| Wheel size | — | 700c |
| Max tire width | 32 mm | 32 mm |
| Bottom bracket standard | T47 threaded, 85.5 mm shell | — |
| Front axle | 12 mm thru-axle (M12 x 1.5, 119 mm) | — |
| Rear axle | 12x142 mm thru-axle (M12 x 1.0, 167.5 mm) | — |
| Drivetrain compatibility | Electronic groupsets (the assembly guide covers wireless and wired routing only). 2x with 50-57T round chainrings (or oval of equivalent size); 1x up to 56T | — |
| 1x compatible | Yes | — |
| Max chainring | 57T | — |
| Front derailleur mount | Removable front derailleur hanger; plugs fill the holes for 1x | — |
| Cable routing | Fully internal | Fully internal, through the one-piece cockpit |
| Electronic battery location | On the bottom bracket cover / battery holder | — |
| Hydration & storage | ||
| Bottle mounts | 2 | — |
| Bottle mount locations | Down tube and seat tube, with the included ATTEN aero cages | — |
| Fit & adjustability | ||
| Cockpit | One-piece carbon bar and stem (ATTEN CHB-01 Aero) | One-piece carbon bar and stem (Felt Road 1-Piece Integrated Cockpit) |
| Standard stem and bar possible | Yes | — |
| Seatpost type | Argon 18 Nitrogen aero carbon seatpost | Felt Nexar dedicated carbon seatpost, zero offset |
| Aerodynamics | ||
| Manufacturer aero claims | Argon 18's aero claims (24 W faster than the Sum Pro, CHB-01 cockpit and aero-cage savings) were published for the Nitrogen Pro; it doesn't publish separate figures for this layup | 5% less drag than the previous Felt AR (claim made for the Nexar platform) |
| Tube profile | Truncated NACA-based profiles; off-axis head tube with the steerer set back from the leading edge; wide-stance fork; dropped seat stays | — |
| Travel, maintenance & warranty | ||
| Headset bearings | IST3 (Enduro 440C bearings on the complete bikes) | — |
| Derailleur hanger | UDH (SRAM Universal Derailleur Hanger), standard or direct-mount version | — |
| Proprietary parts | ATTEN CHB-01 cockpit, Nitrogen seatpost and clamp, BB cover/battery holder, thru-axles | — |
| Sold via | Through Argon 18 dealers | Through Felt dealers |
| Drivetrain | ||
| Groupset | SRAM Force AXS E1 | Shimano Ultegra Di2 R8100 |
| Launched | 2025 · current generation | 2021 · current generation |
| Speeds | 12-speed | 12-speed |
| Electronic | Yes | Yes |
| Wireless | Yes | — |
| Drivetrain | 2x | 2x |
| Shifters | SRAM Force AXS E1 | Shimano Ultegra Di2 ST-R8170 |
| Crankset | SRAM Force AXS E1 Power Meter | Shimano Ultegra R8100 |
| Chainrings | 48/35 | 52/36 |
| Power meter | SRAM Force AXS E1 Power Meter | — |
| Launched | 2025 · current generation | — |
| Bottom bracket | SRAM T47 | Shimano BB-R60 |
| Standard | T47 threaded | — |
| Notes | Listed by Argon 18 as 'T47 BB' without a brand | — |
| Front derailleur | SRAM Force AXS E1 | Shimano Ultegra Di2 R8150 |
| Rear derailleur | SRAM Force AXS E1 | Shimano Ultegra Di2 R8150 |
| Cassette | SRAM Force XG-1270 E1 | Shimano Ultegra R8100 |
| Range | 10-33 | 11-30 |
| Speeds | 12-speed | 12-speed |
| Chain | SRAM Force E1 | Shimano CN-M8100 |
| Brakes | ||
| Brake calipers | — | Shimano Ultegra BR-R8170 |
| Type | — | Hydraulic disc, 2-piston |
| Rotors | SRAM Paceline X | Shimano RT-MT900 |
| Front rotor | 160 mm | 160 mm |
| Rear rotor | 140 mm | 140 mm |
| Mount | Center Lock | Center Lock |
| Wheels & tires | ||
| Wheelset | Scope R6.A | Vision SC45 |
| Front rim depth | 65 mm | 45 mm |
| Rear rim depth | 65 mm | 45 mm |
| Internal rim width | — | 23 mm |
| Material | Carbon | — |
| Tires | Vittoria Corsa N.EXT TLR | Continental Grand Prix 5000 S TR |
| Tire width | 30 mm | 28 mm |
| Cockpit | ||
| Handlebar | ATTEN CHB-01 Aero | Felt Road 1-Piece Integrated Cockpit |
| Type | One-piece carbon bar and stem | One-piece bar and stem |
| Integrated stem | Yes | Yes |
| Widths available | 360 or 380 mm, each with 80-130 mm stems (12 sizes) | 360/400 mm with 90 mm stem (44, 49), 380/420 mm with 100 mm stem (52, 54, 56), 400/440 mm with 110 mm stem (58, 61); widths at the levers/drops |
| Bar drop | — | 120 mm |
| Flare | — | 8° |
| Cable routing | — | Fully internal |
| Material | Carbon | Carbon |
| Weight | 320 g11.3 oz | — |
| Notes | Stock size by frame: 360 x 80 (XXS), 360 x 90 (XS-S), 380 x 100 (M), 380 x 110 (L), 380 x 120 (XL). Integrated computer mount with Garmin and Wahoo inserts and 3-12° tilt shims. Weight for 380 x 100 mm. | — |
| Headset | Enduro 440C (IST3) | — |
| Saddle & seatpost | ||
| Saddle | Repente Quasar 2.0 | Prologo Nago R4 PAS T2.0 137 |
| Seatpost | Argon 18 Nitrogen | Felt Nexar Dedicated SP |
| Offset / setback | — | Zero offset |
| Material | Carbon | Carbon |
| Notes | — | 250 mm long on the three smallest sizes, 330 mm on the others |
| Bar tape | Ciclovation Leather Touch Tornado Gloss | — |
| Geometry (smallest – largest size) | ||
| Sizes | XXS, XS, S, M, L, XL | 44, 49, 52, 54, 56, 58, 61 |
| Rider height min | — | 142–188 cm4′8″–6′2″ |
| Rider height max | — | 155–196 cm5′1″–6′5″ |
| Stack | 486–607 mm19.1–23.9″ | 515–631 mm20.3–24.8″ |
| Reach | 370–409 mm14.6–16.1″ | 350–405 mm13.8–15.9″ |
| Seat tube angle | 72.5–75° | 73.5–75.5° |
| Head tube angle | 71.2–73° | 70.5–74° |
| Head tube length | 81–192 mm3.2–7.6″ | 90–215 mm3.5–8.5″ |
| Effective top tube | 502–601 mm19.8–23.7″ | 485–604 mm19.1–23.8″ |
| Seat tube length | 395–595 mm15.6–23.4″ | 425–570 mm16.7–22.4″ |
| Chainstay | 410 mm16.1″ | 408 mm16.1″ |
| Wheelbase | 967–1,020 mm38.1–40.2″ | 960–1,013 mm37.8–39.9″ |
| BB drop | 71–79 mm2.8–3.1″ | 70–75 mm2.8–3″ |
| BB height | — | 265–270 mm10.4–10.6″ |
| Fork length | 376 mm14.8″ | 380 mm15″ |
| Fork offset | 45–49 mm1.8–1.9″ | 44–50 mm1.7–2″ |
| Trail | — | 52–67 mm2–2.6″ |
| Front centre | — | 559–616 mm22–24.3″ |
| Standover | 682–848 mm26.9–33.4″ | 723–855 mm28.5–33.7″ |
| Saddle height min | 565–765 mm22.2–30.1″ | — |
| Saddle height max | 715–915 mm28.1–36″ | — |
| Wheel size | — | 700c |
| Crank length | 165–172.5 mm6.5–6.8″ | — |
| Stem length | 80–120 mm3.1–4.7″ | 90–110 mm3.5–4.3″ |
| Handlebar width | 360–380 mm14.2–15″ | 360–400 mm14.2–15.7″ |
| Handlebar drop | — | 120 mm4.7″ |
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).