Those dimpled sidewalls are now iconic. Everyone knows what Zipp wheels look like. Those dimples are made to improve airflow and add stability. While that’s fine and dandy with their 700c road-specific designs, what about the Zipp 303 Firecrest 650b wheels with fat gravel tires?
Zipp 303 Firecrest 650b Disc Tubeless Wheelset Features:
- Versatile 45mm depth for all-around use
- ABLC dimple pattern
- 21mm internal width // 28.9mm max outer width
- Sapim CX-Ray bladed spokes & Secure Lock nipples
- Utilizes Zipp 77D/177D hubs
- Includes endcaps for QR, 12mm and 15mm thru axles
- XDR driver available separately
- Handmade and assembled in Indianapolis, IN
- Weight: 1450 grams (pair, stated)
- MSRP: $2500 pair
Small wheels = big grins
Going with small wheels has been a revelation this year. I’ve come to prefer 650b wheels/tires for gravel and have found it to still remain fun and nimble on the road. Yes, you could maximize your tire width on a 700c tire, but there’s something playful about going with higher-volume tires.
Zipp has a good thing going with their venerable 303 wheelset, so it makes sense that they would shrink it down for both road and gravel use. On the road side, some smaller frame sizes are built around 650b and just about every gravel bike on the market can certainly handle smaller wheels. While the wheels remain smaller, those high-volume gravel plus tires still roll long with confidence and offer superb handling and agility in the dirt.
Throughout my summer gravel rides in Colorado, Minnesota and South Dakota, the Zipp 303 650b wheelset delivered. With a generous 21mm internal width, the WTB Byway 47’s feature a round profile and were run tubeless exclusively. Throughout my testing, I also used the WTB Venture 47 and Sendero 47 tires. Each set of tires seat up nicely and remained locked in place throughout several months of testing.
Standing sprints are rewarded with superb lateral stiffness and quick engagement. Even during extended standing climbs, the wheels remained laterally-stiff and tracked along just fine. Roll-to-stop tests reveal that these will roll just slightly farther than the average wheelset and on par with what I’d expect. Ceramic bearings would certainly add to their rolling abilities, but for a pretty penny.
While the Firecrest dimples are touted as an aero advantage, they do add to the overall durability of the rims. Repeated impacts by flying rocks and debris have done nothing to these wheels in all my miles of testing on rough terrain. I will say that when I swapped tires from the Byway to Venture’s, I did notice some micro carbon fiber particles bouncing around inside the rim’s interior. I was able to get most of them out of the valve hole and none were more than 2mm in diameter, but I was left wondering where the pieces came from. Perhaps the interior carbon compaction wasn’t as smooth as it should have been?
While these still offer the classic Firecrest dimples, aero benefits are minimal with such large tires leading the airflow. Going with 700c 303 Firecrest and a narrower gravel tire could help aerodynamics. As it stood, you’ll notice that large, tires combined with the 303’s profile did show a touch of crosswind stability issues. That’s as expected due to the large tire and medium-depth rim profile. That said, it’s still pretty minimal and I really only noticed it during slow efforts in classic Midwest crosswinds on long gravel stretches.
The 303 Firecrest 650b’s are 100% made and assembled in Zipp’s Indianapolis HQ using the highest-quality parts and manufacturing process. With that, we’re talking Sapim CX-Ray bladed spokes, proprietary Zipp 77D/177D hubs and Firecrest dimpling pattern using top-grade carbon fiber . Throughout my tests, I’ve been using SRAM Red eTap AXS and an XDR driver. You can certainly get a standard SRAM/Shimano driver if that’s your thing.
- Easy tubeless right out of the box
- Playful, fun size
- Perfect for gravel racing
- Durable and laterally-stiff
- 303’s remain in rarified territory — even in mini size
- Don’t expect significant aero benefis
- I prefer Centerlock hubs
Buy Now: Zipp 303 Firecrest Tubeless Disc
Zipp’s small-diameter 303’s are an excellent choice for today’s high-end gravel bikes like the Open UPPER or 3T Exploro. They spin up quickly, are highly-serviceable and set the industry standard for durability.
Buy Now: Available at CompetitiveCyclist.com
Zipp's 303 Firecrest 650b wheelset adds their famous dimpled pattern to small wheel sizes for gravel adventures. With a 45mm depth and 21mm internal width, these wheels are a great choice for all-out gravel speed. The hubs roll nicely and it's easy to change between endcaps or cassette drivers to suit your needs.