REASONS TO BUY
Grippy rubber soles
Walks well
Solid closures
REASONS TO AVOID
Expensive for performance
Terrible power transfer
Minimal foot protection
Thin footbeds
Sidi SD15 Review
A great concept but poor execution from one of the top mountain bike shoe companies in the business
Sidi SD15
Credit: Sidi
RELATED: Best Mountain Bike Shoes of 2024
Our Verdict
The Sidi SD15 is a clipless mountain bike shoe aimed squarely at the all-mountain and adventure market made by one of the top bike shoe manufacturers in the business. Sadly, the SD15 fell short of the bar set by the other shoes in our selection with the most flexible soles and poorest power transfer of all models tested. The shoe does have many great features, like grippy rubber soles, excellent off-the-bike walking performance, and reliable closures, and may be a good fit for certain types of riders. That said, performance-oriented mountain bikers will probably be much happier with any of the other models in this test — especially similarly priced models like the Giro Terraduro, the Specialized 2FO Cliplite, or the Shimano ME7. All offer equally good traction off the bike and far superior power transfer and performance on your shred sled.
Our Analysis and Test Results
We have to admit that we were excited when we saw the SD15. It seemed like the Italian bike shoe giant Sidi had finally made a mountain bike shoe with a grippy walkable sole, and we assumed that it would have their signature XC style performance that we have come to know and love. Unfortunately, that was not the case. The SD15 fell short of the bar set by all of the other shoes in our test selection. The SD15 was designed with all-mountain and trail riding in mind, and we found it best suited for that style of riding. Due to the more flexible nature of the soles on the SD15, it works best with pedals that have medium or large platforms to help maximize what little power transfer these shoes provide.
Performance Comparison
The SD15 was the least stiff shoe in our entire test, with a sole so flexible we find it hard to believe it's meant to have a cleat mounted to it. Look closely and you can see the sole flexing under pedaling force.
Credit: Jeremy Benson
Power Transfer
Contrary to our expectations, the SD15 failed to deliver the power transfer that Sidi shoes are typically known for. In fact, the SD15 scored the lowest of all shoes tested in that category. As far as we can tell, there is no shank whatsoever in the shoe, and this is evidenced by the fact that you can fold them in half. The shoes flex under power, and you can feel the pedal through the sole of the shoe. This results in foot fatigue, soreness, and cramping. While riding, you could also feel the sole flex laterally around the cleat. This took us off guard, and it is unclear why a mountain bike shoe with clipless pedal compatibility would be made with such little support in the sole, especially for the price.
If you can literally fold a shoe in half then it must not have any sort of shank to provide a pedaling platform. The SD15 provided almost no support and caused fatigue in our feet and legs while climbing and descending.
Credit: Jeremy Benson
Comfort
Off the bike, the SD15 is a reasonably comfortable shoe. The soft Politex Suede synthetic uppers are supple and conform to your feet within minutes of putting them on. The shoe features one of Sidi's Tecno 3 cable closures that crisscrosses over the upper part of the foot while a simple Velcro strap secures it down by the toes. Unfortunately, these shoes aren't just made for walking around in, because they are comfortable for that purpose. On the bike, these shoes are uncomfortable for several reasons.
There is very minimal padding, mainly the tongue and around the top of the ankle opening, as well as Sidi's signature molded plastic heel cup. Otherwise, the shoe offers little to no protection for the feet, and we felt especially vulnerable in these shoes. Just like the Sidi Trace 2, the footbed of the SD15 is wafer thin and offers little support or cushioning. The Sidi “Outdoor Sole” lacks a stiff shank in the sole which allows it to flex under power. The flex of the sole leads to strain and even cramping of the feet both when pedaling and descending. Walking on rocks - one of this shoe's strong points - is even somewhat uncomfortable since you can feel the points of the rocks through the sole. Sure these shoes fit nicely, but that's about where the comfort ends.
The SD15 is a relatively comfortable shoe. It's unfortunate that it's not stiff enough for its intended purpose of mountain biking.
Credit: Jeremy Benson
Traction Walkability
One of the SD15's strongest points is its traction and walkability. We might even go out on a limb and say that this shoe is better for walking than it is for riding. Sidi's “Outdoor Sole” is a full coverage rubber sole with large well-spaced lugs under the heel and the forefoot. The rubber isn't as soft as that found on the Five Ten Hellcat Pro or the Specialized Rime 2.0, but it is still very grippy and offered excellent traction on virtually all surfaces. The wide spacing of the lugs cleared mud, snow, and other debris with ease. The walkability of the SD15 is made even better because the sole offers full flex from toe to heel, much like a pair of running or hiking shoes, so it is not inhibited in any way by a shank or anything similar. The lack of shank in the sole is disconcerting in many ways, and it means that you can feel sharp rocks through the sole when you step on them.
If this were a hiking shoe test the SD15 would have done very well. Its traction and walkability were its best attributes.
Credit: Jeremy Benson
Weight
The SD15 weighs 416g per shoe for the size 44 that we tested. It's by no means the lightest shoe out there, but far from the heaviest. The shoes feel light in your hand and also on your feet. That said, the SD15 weighs about the same as several other shoes in our test selection that offer significantly better power transfer and overall performance such as the Shimano ME7 or our top pick for trail riders, the Specialized 2FO Cliplite. Anyone looking for a lighter and less expensive pair of shoes with far superior power transfer need look no further than the Giro Privateer R.
At 416g per shoe in a size 44, the SD15 weighs similar to the enduro oriented shoes in our test.
Credit: Jeremy Benson
Durability
Despite our general lack of enthusiasm for the performance of the SD15 we have to admit that it appears to be a well-made product. So far there are no durability issues to report. The soles look almost brand new. The stitching is all intact, and there is barely a scratch on the uppers. The closures have also worked flawlessly thus far.
They may not have put a signature stiff Sidi sole in the SD15, but it appears to made with their typical quality construction.
Credit: Jeremy Benson
Value
We do not feel that the SD15 is a good value due to the poor power transfer and on the bike performance. We are a little surprised by this due to Sidi's long-standing reputation as one of the best shoe manufacturers in the business. For the money, we would recommend something else with similar walkability and far superior on-the-bike performance.
We had high expectations for the SD15. Unfortunately, they were not met as this was the poorest performing shoe in our test.
Credit: Jeremy Benson
Conclusion
Our expectations for the SD15 were met with a truly underwhelming performance due to inferior power transfer and on-the-bike performance. While we like the concept of a walkable Sidi mountain bike shoe with a grippy rubber sole, they failed to create one that excels at the shoe's primary task, riding a bike. If only they would glue this sole to the bottom of one of their proven high-performance models, then they would be on to something.
—
Jeremy Benson
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