The Hunt 4AM Limitless is 276 g lighter (1,283 g vs 1,559 g claimed per pair); the Zipp 404 Firecrest costs €580 less (€1,379 vs €1,959) at our October 2026 price check. The rim depth is 49.5 mm front / 47 mm rear on the 4AM Limitless and 58 mm on the 404 Firecrest and the listed tyre range is 28–50 mm on the 4AM Limitless and 28–35 mm on the 404 Firecrest. Both share the internal width (23 mm).
Drag the handle to switch between the 4AM Limitless (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 4AM Limitless is 276 g lighter per pair (1,283 g vs 1,559 g, manufacturer claims).
4AM Limitless1,283 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: 49.5 mm front / 47 mm rear on the 4AM Limitless, 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
The 4AM Limitless (49.5 mm front / 47 mm rear) uses different rim depths front and rear.
Some wheelsets use a different rim depth front and rear, and brands disagree on the direction. Roval's Rapide CLX II paired a shallower front with a deeper rear to favour stability.1 The newer Rapide III uses a slightly deeper front than rear, and Roval argues most of the aero benefit comes from the front wheel.2 Zipp's 454 NSW rim itself varies in depth along its circumference.3
Treat a split depth as a design choice of the brand rather than an advantage in itself. If crosswinds concern you, the front rim depth is the figure to look at.
Hunt approves tyres from 28 mm to 50 mm for the 4AM Limitless. Zipp approves tyres from 28 mm to 35 mm for the 404 Firecrest.
4AM Limitless28–50 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.
Spoke count front/rear: 20/24 on the 4AM Limitless, 24/24 on the 404 Firecrest.
4AM Limitless 20 front / 24 rear · steel404 Firecrest 24 front / 24 rear · steel
Fewer spokes save weight and can reduce drag slightly,1 but each spoke then carries more load and a broken spoke is more likely to leave the wheel unrideable.3 Wheels with low spoke counts usually state a maximum system weight;2 compare it with your own weight plus bike and luggage rather than judging by spoke count alone.
Warranty: 3 years on the 4AM Limitless, a lifetime warranty on the 404 Firecrest; crash replacement is offered for both.
4AM Limitless3 years · crash replacement yes
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 Hunt 4AM Limitless than the Zipp 404 Firecrest?
276 g. The Hunt 4AM Limitless has a claimed pair weight of 1,283 g, the Zipp 404 Firecrest 1,559 g. Both figures are manufacturer claims.
Which has the wider tyre range?
The Hunt 4AM Limitless. Hunt approves tyres from 28 mm to 50 mm for the 4AM Limitless. 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 Hunt 4AM Limitless and the Zipp 404 Firecrest?
€580 at our October 2026 price check: the Hunt 4AM Limitless cost €1,959 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 Hunt 4AM Limitless 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.
