DAVE: Let’s cut right to the chase. For many, the adidas SL20 will be the missing piece of the puzzle that completes the Boston series and the Ultraboost lineup.
Quick sidenote: I’m a longtime, diehard fan of the Boston line, especially the last two versions. For me, it simply works with my stride and provides effortless miles. I’m always pushing the shoe as an option to my athletes who are looking for something smooth, so when I was pitched with the option to test a beefed-up version of it, I was tuned up like Charles Mingus.
The SL20 comes in at 7.8 ounces (222 grams) for a US M9. For a shoe marketed to be a stouter Boston, it’s very light on the foot. It also makes use of the new adidas Lightstrike midsole compound. Compared to Boost, Lightstrike feels like it’s a little asleep at the wheel. Not completely, but you do have to toe-off a bit harder in it and give it a honk to get it up to speed.
All that is to say, the SL20 is reppin’ a fresh look, a good wrap of the foot and a fit true to size.
JEREMY: The SL20 is advertised as a lightweight shoe for fast running and racing––similar, but slightly heavier than the Adios 5. For me, this shoe is more like a trusty Swiss army knife: Its versatility makes it usable for everything from easy days to speed workouts to long runs.
The shoe features Lightstrike foam which feels pretty firm but still has a little spring to it. In the midfoot, there’s a torsion system designed to create a springy toe-off, while also reducing any unwanted movement. The upper is a simple design that’s breathable but also snug enough to keep your foot locked down and in place. The SL20 reminds me of a firmer Nike Pegasus Turbo, sans some of the bouncy fun.
DAVE: Fit: I have a narrow foot and a high arch. The prototypical Adi foot. I rock a ton of adidas Originals as well (shoutout to Ian Brown of The Stone Roses), so most of the run lineup fits like a glove. The SL20 has a nice step in feel to it, and it wraps the foot well for a daily trainer. I’d say it runs best for the narrow to average foot type, but there is some wiggle room in the toe box. For a shoe to be effective for me (or really for anyone for that matter) it needs to fit well. As runners, sometimes I think we get a little midsole happy and forget the importance of a good lockdown. I know I’m guilty!
Moving onto the midsole. I debated whether to put the Lightstrike foam in the good or the stinking bad. It’s going to land here for now. After two long runs and a good amount of weekly mileage, it woke up a bit. Here’s the deal: It’s smooth for my easy days and some of my medium-long runs, and I could definitely run 20+ miles in it as well. But did Lightstrike make me want to drop the hammer? No. It’s missing the powerful toe-off of an Adios 4 or a Boston and it doesn’t have their rockin’ Boost foam either.
So if you want to use this as a Tempo shoe, or even race in it, I’d tell you there are plenty of better speedsters out there (even from Adi). Jeremy may disagree, but he’s younger and still fast. For fast days, including this week’s 14 x 70-second hill rep session, my Adios 4 was still as good as gold.
Heel Lock: Locked and loaded with no slippage. Perfect. You’re not going anywhere.
Outsole: Continental Rubber. Grips like gravy on those Southern California sidewalks full of doobie roaches and human urine. Yeah, welcome to sunny SoCal.
JEREMY: There’s a lot to like about this shoe. The fit is perfect for keeping your foot snug and secure with everything in place. Like Dave said, the Continental rubber outsole had zero issues gripping and keeping traction on the rainiest days.
The foam was firm but had some bounce while keeping the shoe relatively light. I tend to enjoy lightweight shoes, even for easy days, so I really appreciated the feel of these. In addition to easy days, I took these shoes out for a progression long run and honestly they felt light in the first half and cushioned enough for the back half where I progressed down to marathon pace to finish out a 20-miler.
Another run where the speed of these shoes was apparent to me was a hilly tempo run I did, averaging around 5:15/mile and feeling pretty comfortable! While some may enjoy the firm feel of these shoes, they’re a bit old school (like Dave’s references) ––especially with lightweight cushioned trainers and racers selling like hotcakes right now.Shop adidas SL20 – US
DAVE: Lacing: It has since broken in a bit, but the lacing is tough. Like, literally, as in the laces themselves. They’re not only tough to work with, but they’re also a tad on the thicker side, meaning it takes a few tries to get the damn thing perfect. But once laced, the SL20 doesn’t get wiggly with it and that’s a huge plus.
Fun Factor: Like I said earlier––a pretty smooth shoe, great for easy days and some of your long runs. But it just doesn’t want to go fast. Like anyone who’s had a few too many drinks during a night out, these babies like to settle. I found the SL20 to be best suited at 6:50-7:45. When I tried a fast finish two weeks ago on a long run, it got stuck a bit below 6:00 pace. The transition time became much more forced. So much so, that wearing them on a tempo day meant I had to turn around and change shoes.
JEREMY: The tongue of the shoe is abrasive and extends up too far for low-cut socks (everyone knows too much tongue is never a good thing). I was getting some painful irritation of my skin just from the repeated rubbing against it. Swap out for some taller socks and you’ve got an easy fix, fortunately.
As mentioned above, these are firm shoes. So if you prefer a more cushioned bounce, I’d look somewhere else because these are probably not the best choice for you.
Finally, while these shoes are lightweight, I wouldn’t describe them as an extra fast shoe (they would not be my choice for race day). They just don’t have the foam that pops like other competing race day shoes.Shop adidas SL20 – US
DAVE: Look, it’s a pretty decent shoe. Its weight is nice, it cruises along at moderate speeds, and it fits well. Even so, it lacked some of the pop I like in faster offerings. It’s not going to the graveyard, but it does have its place. So even though it’s not an uptempo or a race day shoe, I’m still pulling it on occasion, and I did so this morning.
I’ll be completely honest. Midsoles have ruined me. Pick your poison– Hyper Burst, PWRRUN+, or ZoomX– they all leave this aftertaste in your mouth, and like a shoe tweak you’ll always be jonesing for that pop. I fully admit that I need to be more open-minded, but given the way the game is being played right now, you better bring your best foam. Anything else and you’ll get left behind.
I’d recommend the SL20 for the runner looking for a quick easy day shoe with the option to put in some marathon pace work.
JEREMY: If you’re looking for a lightweight trainer that could be used for every kind of run, this is your shoe. In all seriousness, if I was forced to train in just one pair of shoes every day this would make the shortlist for me, alongside options like the Pegasus Turbo 2 or the Hoka Clifton (I know, totally different shoes in terms of cushion).
That said, while everything about this shoe is good, it just doesn’t quite stack up to the firepower of the competing lightweight trainers coming from the likes of Nike, Hoka, and Skechers. It works for a lot of things, but it doesn’t really excel at any of them––like a jack of all trades, but a master of none.
You can pick up the adidas SL20 at Running Warehouse (featuring free 2-day shipping and 90-day returns) for $120 by using the shop link below.Shop adidas SL20 – US