Mavic's Ksyrium Pro Thermo shoes are almost fantastic – they're warm, comfortable, easy to slip on and off, and decently stiff for pedalling. Unfortunately, the waterproofing only works to make things worse, as heavy rain or spray quickly makes its way in and then can't get out. For cold, dry rides they're excellent, but that's obviously way short of what Mavic promises.
Early in this test, I hobbled indoors, let my sopping socks splat to the floor and poured a tablespoon of water from each shoe as my toes cold-welded themselves to the floorboards. Let me tell you, my wife was as delighted as I was.
Mavic says the Ksyrium Pros "simplify your winter weather setup without having to wear booties over your shoes", but in that they fail. And that's a shame, because in every other area (all the dry ones), these shoes are great.
The sizing is accurate for a close but comfy fit in thick socks, which is good as the entire upper is pretty rigid and will not give. A large rubber bumper protects the toe, and they feel substantial enough to actually protect your feet in a crash (and also to survive it in pretty good condition).
Non-replaceable hard rubber bumpers protect the toe and heel from wear while walking, and the sole features wide, raised alignment marks that actually work.
The Ortholite insole has good arch support and no pressure spots that I encountered. The only issue you might find is if your feet are particularly wide, as these are on the narrow side and, as I said, pretty unbending.
The single Ergo dial cinches a well-padded tongue down comfortably and with excellent security, and there's lots of room for getting in and out – the splash cover zips up tightly once you're in, before two large, well-positioned Velcro tabs seal it around your leg. There's a bit of stretch around the top, so they feel unrestrictive and getting a tight seal is easy. It's just a shame it doesn't work.
Even with the cuffs done up tight and hidden underneath full-length tights, rain and heavy spray soon makes its way in. Wet roads under clear skies will have your feet noticeably damp and cold after 10 miles. An hour of normal rain is enough to leave you with socks like you've walked into the sea. An admittedly horrible storm with sheeting rain and level-with-your-pedals floodwater filled them with water that then couldn't get out.
Clearly rain isn't getting in through the bottom, despite what look like (blocked) vents in the heel and toe, or through the side of the upper, despite surface perforations to allow the membrane to breathe. Otherwise it would drain out. The Gore-Tex outer and efficient nylon-fibreglass composite sole – which is surely being braced for extra stiffness by that rigid-sided upper – do a great job of being impervious.
I'm actually a little mystified as to how these so squander that Gore-Tex membrane and emerge quite so vulnerable to water. Mavic says the neoprene ankle cuff is only 'water-resistant', so perhaps water is actually soaking right through your instep and/or the rear. A quick and dirty test pooling water inside the cuff saw nothing soak through within a few minutes, but just how resistant it is depends on the size of the gas bubbles within the fabric itself. Mavic doesn't specify that. It's possible the cuff will wet through with longer exposure, but post-ride everything's equally soaked, so I can't say for sure.
One last problem, presumably a result of the insulation, is that the Ksyriums take ages to dry. It took two days to get them dry after that storm, and at least 24 hours after more normal rain. They're not ideal for multi-day rides.
Avoid water that's either falling or just lying around on the road looking for a toe to freeze, and everything is admirable – the build and finish are excellent, with the complex pattern of fabrics and shapes having been sealed together with impressive accuracy and strength. Details, such as the large textured rubber gripper on the Velcro, the quality of the dial and the subtle reflective highlights, impress. On dry rides they're great.
Unfortunately for the Ksyriums, there are more effective options available for similar money. Northwave's excellent Flash Arctic GTX winter boots are £210 and as waterproof as you can realistically expect, while Fizik's Arctica R5s are £190, warm and – yes – waterproof. In fact, Northwave's fantastically warm, £140 Flash TH winter shoe appears to cope better with water than the Kysriums, despite lacking any sort of cuff or claims beyond mere water repellence.
If you live somewhere that's regularly cold and dry, the Mavic Ksyrium Pro Thermo shoes will make your riding far more pleasant. If, however, there's any chance of water during your rides, the Pro Thermos will be unable to keep your feet either dry or warm.
Warm, comfortable and really well made winter shoes, but definitely not waterproof
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road.cc test report
Make and model: Mavic Ksyrium Pro Thermo shoes
Size tested: 44
Tell us what the product is for
Mavic says: "This warm, waterproof shoe keeps your feet dry and protected from the cold during your toughest winter rides.
"With a Gore-Tex outer, neoprene ankle gusset and water-resistant zipper, you can simplify your winter weather setup without having to wear booties over your shoes. "
Tell us some more about the technical aspects of the product?
The company lists these features:
Ergo dial system provides precise and easy adjustment, so you can stay comfortable on longer rides.
OrthoLite ergonomic insole delivers superior cushioning and unmatched comfort.
Energy Comp Outsole is constructed from a combination of fiberglass and nylon for stiffness and pedaling efficiency.
Index Energy Transfer: 50
Neat, accurate and tough build.
Warm, comfy, stiff for good pedalling, and splashproof – but definitely not waterproof.
Strong build bodes very well.
Reasonable for warm boots, but they get noticeably heavy when waterlogged.
They're a similar price to other winter boots and shoes, but don't match them (or cheaper ones) for waterproofing. Fantastic for cold, dry riding, but you'll still need waterproof overshoes, and those can be expensive.
Tell us how the product performed overall when used for its designed purpose
Very well – so long as it doesn't rain.
Tell us what you particularly liked about the product
Comfort, warmth, stiffness, great build, looks.
Tell us what you particularly disliked about the product
Rapidly let water in and don't let it out.
Did you enjoy using the product? Yes, when it was dry.
Would you consider buying the product? Yes, if it never rained.
Would you recommend the product to a friend? Yes, if they lived somewhere it never rained.
Use this box to explain your overall score
These are warm, comfortable and really well built – on cold, dry days they work extremely well. If Mavic's claims ended there the Ksyriums would be a solid 8. But not only are they not waterproof, as Mavic claims they are, they're not even particularly splashproof, and they get cold when they're wet. If they weren't such good quality and effective in the dry, they'd be lower still than a 6.
About the tester
I usually ride: Vitus Zenium SL VR Disc My best bike is:
I've been riding for: 10-20 years I ride: A few times a week I would class myself as: Experienced
I regularly do the following types of riding: general fitness riding, mtb,