New Tire: Pumpkin Ridge 650B x 42 mm

Many cyclists dream of a dual-purpose tire that rolls smoothly on paved roads, but has knobs that dig into the surface when it gets slippery. In the past, combining these two qualities in a single tire has been elusive. Usually, the knobs were too squirmy for good performance on pavement – especially when cornering hard – and yet the knobs were spaced too closely to shed mud when the going got rough.

When we designed our first knobby tire, the 700C x 38 mm Steilacoom, we made the knobs big enough so that they don’t squirm, but left enough space in between to clear mud. We distributed the knobs so that the tire always is supported by the same amount of rubber, whether it’s rolling forward or leaning into a turn. This gives you uniform grip at all times.

Does it work? Even we were surprised how well the Steilacoom rolls and how hard you can lean it into corners (above). If it weren’t for the (unavoidable) noise of the knobs, you’d soon forget that you were on knobby tires at all. I am aware that this sounds too good to be true, so I gave the Steilacooms to other riders to test. Mark’s initial comment was: “Why would I ride knobbies on a paved ride?” When he rode the tires, he was surprised how “un-knobby-like” they felt on pavement. And gravel racer Matt Surch found that he had no trouble keeping up with fast road pacelines on Compass knobbies. Both these riders confirmed that the Compass knob pattern works exceedingly well on pavement.

What about mud? After all, the whole point of a knobby isn’t just to ride on pavement, but to provide extra traction when conditions get slippery. A full season of cyclocross, including the single-speed world championships, have shown that the knobs have no trouble shedding mud. Your bike will get dirty, but your tire tread stays clean – as it should be. And the knobs are tall enough to dig into the surface and provide excellent traction.

With so many Allroad bikes running 650B wheels these days, it made sense to offer the same tread pattern in a 650B tire with a little more volume. Enter the Pumpkin Ridge 650B x 42 mm. We named it after Pumpkin Ridge, a quiet paved road near Portland, Oregon, that has a number of promising dirt spurs heading toward the Tualatin Mountains. Past explorations failed to reveal a connection, but filled our fenders with mud. We wished for knobby 650B tires that would not get bogged down in the mud, yet would also roll well on pavement. Imagine where you might go with these tires….

The Compass Pumpkin Ridge is designed for rides that mix pavement, gravel and muddy dirt. “Road” tires quickly reach their limits here, yet if you ride knobbies, the paved sections of the ride aren’t much fun. The Pumpkin Ridge performs equally well on all these surfaces. And of course, if you race cyclocross on 650B wheels, like BQ Team rider Steve Frey, there finally is a tire that offers the ultimate in performance in that wheel size.

The Pumpkin Ridge is now in stock, in Standard and Extralight casings. Click here for more information or to order.

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into high-performance components for real-world riders.
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18 Responses to New Tire: Pumpkin Ridge 650B x 42 mm

  1. ew742 says:

    Hi Jan,

    is there a chance to see a 29″x2,1″ tire of this kind?

    Thanks
    Christoph

  2. Steve says:

    Hi

    It would be fun to make a 650b version narrow enough to use on a bike with fenders that would normally have babyshoe pass tyres fitted.

    Steve

  3. Kevin McGrew says:

    I would love to hear more about racing CX on 650B wheels. I tried this myself using the BG Rock and Road setup tubeless and found more cons than pros. The higher volume tire seemed to only help a small amount of time when the course had chunky, rocky sections. I found the Rock and Road very unpredictable on wet grass – this put me on the ground more often than my previous experience using normal CX tubulars. Perhaps the worst problem was the reduced BB height of the smaller wheels creating more opportunity for pedal strikes during off camber sections.

    • Most previous “dual-purpose” knobbies spaced the knobs closely to roll OK on the road, but they didn’t clear mud, so they weren’t really useful for ‘cross. I think you’ll find these much better. Of course, they won’t change the lower BB height if your bike originally was designed for 700C…

    • Steve Frey says:

      I tried racing cyclocross on 650b not so much because I thought it would offer any advantage, but because I wanted to dip my toe into CX without having to buy a new bike. My Rawland Stag did the job reasonably well, but limited tire choice was the biggest drawback. I’m looking forward to giving the Pumpkin Ridge tires a go!

  4. Dr J says:

    These look great but does Compass have any plans to release 650B tires wider than 42-48mm? Something around 55-58mm maybe?

  5. Jonathan Pearson says:

    I am so thrilled every time I see the line of tire options expand. It means your business is growing and that I can enjoy my compass tires for a long time.

    That being said, I am obsessed with my Rat Trap Pass tires and would love to see a 26×2″ tire like this. It would help me continue the off-pavement tours in our soggy PNW winters. Any chance that someday this could come in a 26″ option?

    If not, maybe I’ll just have to build a 650b wheelset and ride some pumpkin ridge tires.

    • Alex says:

      Without wishing to undermine Compass tires (I own more pairs than I can list & I love them): I own Rat Trap Pass tires, & I favor Continental Race King 55-559 (important: in the RaceSport version!!) on almost all off road rides here in Berlin / Brandenburg on my All Road Enduro bike. It all depends on the surface you ride on (I ride OFF road, not gravel roads, as there aren’t many gravel roads here), but these tires might just fit the bill for you: fast, high volume (they are taller than wide & thus hold significantly more air than RTP) a low profile, & very supple.

  6. igxqrrl says:

    Huh. I live on Pumpkin Ridge. Guess it’s time to build up some 650b wheels for the Gravel bike.

    • Awesome! That may be a first – most of our other tires are named after passes that are far from the next human habitation. Except Steilacoom, which is a town where one of the most iconic cyclocross courses in the Pacific Northwest is located.

  7. Max Sievers says:

    Please consider a studded tyre. All available today are ultra heavy and stiff. I live in Switzerland and need tyres which can cope with ice and snow.

    • huges84 says:

      Look into a product called GripStuds that will let you add studs to this tie. Just note that you need to be careful with how far you screw them in or you will pierce the tire casing and will then need to make a protection belt to keep from puncturing the tube.

      http://www.gripstuds.com/

  8. Lou says:

    It might be possible to add your own studs to the outer knobs, so the studs only make road contact when pressure is reduced.

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