How wide is too wide? The 48mm Switchback Hill is the widest 650B tyre that Compass makes, and too wide it ain't. It's super-comfortable, fast-rolling, tubeless-compatible, off-road-capable and light. There's really not a lot wrong here. At a time when people are doing roll-down tests to see if it's worth switching to 28mm tyres from 25s, my advice would be to skip a few sizes and fit a pair of these, if you can. They're great.
Compass has all its tyres made in Japan by Panaracer to its own specifications. I've heard plenty of times that these tyres are just 'rebadged Panaracers'; they're not, although they do share the same facility. The Switchback Hill is a 48mm, 650b road/gravel tyre that's available in a standard or an extralight carcass (the one that we have) that saves 65g.
Our test tyres weighed in at 412g either end, which is very light for such a big tyre; lighter indeed than the 40mm Schwalbe G-One Speed tyres that I swapped them out for.
Fitting the Switchback Hill tyres tubeless isn't hard exactly, but it did require a specific workflow to make them seal. If you bung them on the rim and just try to blast them on with a tyre booster or a compressor, you'll be out of luck. Well, I was anyway. In the end I removed the tubeless valve, fitted an inner tube, pumped them up nice and hard to pop both beads in the rim, deflated them, unhooked one bead, removed the tube, fitted the valve and then used an Airshot to pop the unhooked bead back on. Et la.
If that sounds like a massive faff then yes, it's a more drawn-out process than fitting the G-One Speeds that they replaced which you can bung on with a track pump, but those are a bit heavier and more rigid, and keep their shape better when deflated. The carcass of the Switchback Hills – these are the Extralight ones, after all – is a lot more flexible and doesn't pop out to the bead on its own. Anyway, bottom line: you need an hour, but it's not hard.
I was fitting them to a set of the excellent Reynolds ATR 650b wheels, and I stuck them on my first-generation Tripster ATR. That's as big a tyre as that frame will take; there's about 2mm of grace either side. Most modern gravel bikes will squeeze them in. More road-orientated adventure bikes will struggle.
Once they were up, they went down. The first time, anyway; that was because I was a bit stingy with the sealant. I needed 60ml in each tyre (I used Orange Seal, which is what Compass recommends) to make them stay up. You need to use latex sealant as they don't have a buytl liner; the lack of a liner is what makes the carcass of the tyre so light and flexible, but it's not airtight off the production line and the sealant needs to find all the little holes. The best thing to do is get the bike in a workstand and keep spinning the wheels from time to time to slosh the sealant around.
With an eye-watering 40psi in the Switchback Hills it was time to take them out on the open road. And what lovely tyres they are. I've completed plenty of riding on the Switchback Hills, including a 300km weekend to and from North Devon on a Sven Pathfinder (with lightweight tubes), and lots of shorter rides on my Tripster ATR around Bath (running tubeless).
They're massive, and they only weigh 412g a piece; the extralight casing is super supple and they thrum along on tarmac with no obvious penalty over something much, much narrower. I've checked my Strava times; that's not conclusive, but there's no trend to suggest I'm slower, and they don't ever feel slower. They really are quick, these tyres. Compared to the same bike, on the same routes, with 'wide' 30mm Schwalbe G-One Speed tyres, I can't discern any meaningful difference. I'm a bit quicker on my race bike (on 28s), but that's my race bike. It's 3kg lighter.
Take this ride for example: going fairly hard up a 10-minute back-lane climb I was only half a minute off my best time, and that was set on my race bike in a group, rather than on my Tripster, on my own. Further into the ride I bagged fifth overall on a short, punchy fire road climb, for which the prerequisite for a good time is basically to be able to carry plenty of speed on the preceding gravel descent. The Switchback Hills are exceptional at that.
Compass doesn't recommend the tyre for 'truly technical terrain' and indeed I'd be wary of chucking the thin sidewalls at anything that was especially rocky, but on gravelly unsurfaced paths they're almost as quick as they are on the tarmac, floating over imperfections with aplomb, especially if you drop the pressure a bit.
On the road they allow you to be a lot less choosy with your line, and in a group you have to remember to point out holes and other imperfections that you can glide over on 48s but might easily pinch-flat a 25. Grip is exceptional, with the tyres deforming around imperfections and hugging the tarmac on steep climbs and tricky descents.
They really come into their own on any surface that's less than smooth; that can be gravelly back lanes or a main road with a surface in need of repair. Basically, round here, it translates as: nearly any road.
Those are the main reasons to fit a tyre like this: versatility over a range of surfaces, grip, and comfort. Compass recommends a maximum pressure of 55psi. My sweetspot was about 38 in the front tyre and 40 in the rear; I'm about 92kg so lighter riders will be going lower. That's a bit above what the all-knowing Berto chart of tyre width vs. optimal pressure would suggest is ideal for a 15% compression of the tyre (36/28psi), but it felt good to me on a bike that's predominantly used on the road.
Overall, I'm really impressed with the Switchback Hills, as you can tell. We've tested the Steliacoom TC and the Barlow Pass TC previously, and both of those tyres received high praise from reviewer Mike Stead and these are no different. Aside from the fact that they're a bit of a pain to fit, there really is no downside to a big tyre like this if you're doing anything other than racing.
Exceptional, super-light, big chamber tyres that roll fast on tarmac and gravel alike
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road.cc test report
Make and model: Compass 650B x 48 Switchback Hill Extralight TC
Size tested: 48mm wide
Tell us what the product is for
Compass says, "At 48 mm wide, the Switchback Hill is our largest 650B (27.5') tire yet. Switchback Hill is the first and only named climb on the 360 mile Oregon Outback gravel ride/race. The gravel is quite loose in places, and the extra floatation of the Switchback Hill tires gives you more speed and security when the going gets really rough.
30% of the Oregon Outback is on pavement, so we designed this tire to roll as fast and grip as well as a good racing tire. With this tire, you truly have the best of both worlds.
The Switchback Hill also can transform the performance of your 27.5' mountain bike on gravel or paved roads. However, it is not intended for truly technical terrain, and with its supple sidewalls, it will not climb out of ruts like a stiff mountain bike tire.
The Switchback Hill is tubeless-compatible in both standard and extralight casings. When used with tubes, we recommend the SV13 or SV14A tubes."
Tell us some more about the technical aspects of the product?
Clincher, folding bead
Ultra-light, ultra-supple casing
Choice of black or tan sidewalls
Further improved comfort
Ultra-low rolling resistance
Clincher tires with the ride of a good tubular
Maximum pressure with tubes: 55 psi (3.8 bar)
Maximum recommended pressure – tubeless: 55 psi (3.8 bar)
Slight wobble in the carcass around the seam on one of the tyres, otherwise all fine.
Yes to big tyres. Fast, light and comfy.
Holding up well. They are a very thin carcass, so I wouldn't expect them to last forever, but there's plenty of tread and they're wearing well.
412g for a 48mm tyre is pretty impressive.
They are super comfy. The comfiest tyres.
They're pretty expensive, but they're good value considering the performance.
Tell us how the product performed overall when used for its designed purpose
Tell us what you particularly liked about the product
Fast, light and comfy.
Tell us what you particularly disliked about the product
They're a bit of a faff to run tubeless.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? If they had a frame with enough clearance, definitely yes.
Use this box to explain your overall score
Gosh what lovely tyres these are. You get a few funny looks from the roadies but you'll be able to keep up just fine...
About the tester
I usually ride: whatever I'm testing... My best bike is: Kinesis Tripster ATR, Kinesis Aithein
I've been riding for: Over 20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.