The Shimano Dura-Ace R9270 C50 is 98 g lighter (1,461 g vs 1,559 g claimed per pair); the Zipp 404 Firecrest costs €20 less (€1,379 vs €1,399) at our October 2026 price check. The rim depth is 50 mm on the Dura-Ace R9270 C50 and 58 mm on the 404 Firecrest, the internal width is 21 mm on the Dura-Ace R9270 C50 and 23 mm on the 404 Firecrest and the listed tyre range is 25–32 mm on the Dura-Ace R9270 C50 and 28–35 mm on the 404 Firecrest.
Drag the handle to switch between the Dura-Ace R9270 C50 (left) and the 404 Firecrest (right) on a Canyon Aeroad CF SLX 8 AXS. Black tyres shown for context.
General context for the specifications where these two differ. Numbers in superscript link to the sources below each topic. How much each point matters depends on your riding, tyres and bike.
Weight: what the grams mean
The Dura-Ace R9270 C50 is 98 g lighter per pair (1,461 g vs 1,559 g, manufacturer claims).
Dura-Ace R9270 C501,461 g
404 Firecrest1,559 g
On a steady climb only total weight counts: a gram in the wheels costs the same as a gram in the frame or a bottle.1 A common rule of thumb is about 2 seconds per 100 metres of climbing for every kilogram, so 150 g works out at roughly 3 seconds on a 1,000 m climb.2
Rim weight matters somewhat more when you accelerate, because the rim spins as well as moves forward; physically that effect is at most about twice that of frame weight, and only while speeding up.1 Claimed weights are measured differently from brand to brand: some include rim tape and valves, others do not, and tolerances of around ±30 g are common.3 Independent weighing usually lands close to the claim once tape and valves are accounted for.4
Rim depth: 50 mm on the Dura-Ace R9270 C50, 58 mm on the 404 Firecrest.
Cross-sections drawn to scale from the catalogue values for outer width, internal width and depth; hooked rims show the bead hook. Simplified shape, not the manufacturer's exact profile.
Deeper rims generally reduce aerodynamic drag, which pays off most at higher speeds on flat or rolling roads, but they tend to weigh more and can be more affected by gusty crosswinds. In a BikeRadar comparison, 60 mm aero wheels were about a second per kilometre faster on the flat but slower on steep climbs than a considerably lighter set.1
How a wheel behaves in crosswinds depends on the rim shape as well as its depth,3 which is why TOUR measures steering torque in the wind tunnel, not just drag.2 Shallower rims are generally easier to handle in gusts, something lighter riders and riders on exposed roads tend to notice first.1
Internal rim width: 21 mm on the Dura-Ace R9270 C50, 23 mm on the 404 Firecrest.
Dura-Ace R9270 C50 · internal21 mm
Dura-Ace R9270 C50 · external28 mm
404 Firecrest · internal23 mm
404 Firecrest · external28 mm
A wider internal rim spreads the tyre beads further apart, so the same tyre mounts wider and with more air volume: roughly 0.4 mm of tyre width per extra millimetre of rim width.1 A tyre labelled 28 mm can measure around 30 mm on a 21 mm rim,2 so check frame clearance against the measured width, not the printed one.4
Typical road rims have moved from about 19 mm internal width around 2020 to 21–25 mm, together with wider tyres. A wider rim also raises the narrowest tyre you may fit and, on hookless rims, comes with pressure limits.3 Brands usually shape the rim around a target tyre width for aerodynamics, so the fastest combination is not simply the widest tyre.5
Shimano recommends tyres from 25 mm to 32 mm for the Dura-Ace R9270 C50. This is a recommendation, not an approved limit. Zipp approves tyres from 28 mm to 35 mm for the 404 Firecrest.
Dura-Ace R9270 C5025–32 mm
404 Firecrest28–35 mm
An approved tyre range is the span of tyre widths a manufacturer permits for a rim, based on the ETRTO/ISO tables for tyre and rim combinations.2 Not every brand publishes one: some give a recommendation only, or no maximum. The lower end is the narrowest tyre that fits that internal width safely; the upper end shows how far you can go towards wider, lower-pressure tyres for comfort and grip on rough roads or gravel, provided your frame has the clearance.4
In TOUR's tests, wider tyres at a pressure matched to their width roll about as easily as narrower ones on smooth surfaces and add comfort and grip on real roads, while a tyre much wider than the rim costs some aerodynamic drag.1 Pressure calculators such as Zipp's take the rim's internal width into account as well as the tyre.3
A hooked rim has a small lip on each sidewall that grips the tyre bead; a hookless rim has straight inner walls.1 Under the ETRTO/ISO standards, road tyres on hookless rims must not be inflated above 5 bar (72.5 psi),2 there are minimum tyre widths for each rim width, for example 29 mm on a 25 mm internal rim,5 and most wheel makers publish lists of approved tyres.3
Manufacturers cite precision, strength and lower weight for hookless rims; independent coverage describes the weight saving as modest. Hooked rims accept a wider choice of tyres and higher pressures.4 Both work within the standards: check the rim maker's tyre list and the pressure you like to ride before choosing tyres.
Warranty: 3 years on the Dura-Ace R9270 C50, a lifetime warranty on the 404 Firecrest; crash replacement is listed only for the 404 Firecrest.
Dura-Ace R9270 C503 years · crash replacement no
404 FirecrestLifetime · crash replacement yes
A warranty covers manufacturing defects; damage from a crash or impact is usually excluded.4 Crash replacement programmes cover that case, either free of charge or as a discount on a replacement. Hunt's H_Care is one example;2 Roval repairs or replaces crash damage free for two years on US purchases and at a discount of 20–35 % elsewhere, for up to five years.3 Some brands, Zipp among them, also include riding damage in their lifetime warranty.1
Terms differ widely: many programmes apply only to the original owner, need registration within a deadline and proof of purchase, may charge shipping or fees, and depend on the region you bought in.23 Check the current conditions on the manufacturer's page before relying on them.
How much lighter is the Shimano Dura-Ace R9270 C50 than the Zipp 404 Firecrest?
98 g. The Shimano Dura-Ace R9270 C50 has a claimed pair weight of 1,461 g, the Zipp 404 Firecrest 1,559 g. Both figures are manufacturer claims.
Which has the wider tyre range?
Both ranges are equally wide but start at different widths. Shimano recommends tyres from 25 mm to 32 mm for the Dura-Ace R9270 C50. This is a recommendation, not an approved limit. Zipp approves tyres from 28 mm to 35 mm for the 404 Firecrest. Check the manufacturer's guidance for your exact tyre and pressure.
What is the price difference between the Shimano Dura-Ace R9270 C50 and the Zipp 404 Firecrest?
€20 at our October 2026 price check: the Shimano Dura-Ace R9270 C50 cost €1,399 and the Zipp 404 Firecrest €1,379 per pair. Prices change; check the current offer with the retailer or manufacturer.
Which of the two has hookless rims?
The Zipp 404 Firecrest uses hookless rims, the Shimano Dura-Ace R9270 C50 hooked rims. On hookless rims, use tyres the manufacturer approves for hookless use.
All values come from the Show My Bike catalogue, the same records used on the product pages. Prices checked October 2026. Some model-specific details were reviewed against the manufacturer pages. Manufacturer claims are identified as such. No independent product test is claimed, and no winner is declared.
