Sunday, April 23, 2023

Saucony Sinister Multi Tester Review-a technological masterpiece that rejuvenates the racing flat. 9 Comparisons

Article by Adam Glueck and Sam Winebaum

Saucony Sinister ($150)


The Sinister is a super light un plated road racing flat with a single density PWRRUN PB PEBA midsole and a full coverage outsole. At about 5.45oz  / 155 g (US9), it is very light for its 25mm heel / 19mm forefoot stack and outsole. 

Saucony says: “Less weight. Extra snap. Need speed to push you past the finish line sooner? Look no further than the Sinister. A minimalist dream, it comes packed with PWRRUN PB cushioning. No plate. No excess. Just pure agility.”

That is exactly what we found in test as while “minimal” compared to today’s super stacked racers it is by no means too little shoe to be practical for running beyond short races or even just roads as we found it a wonderful short and fast trail shoe as well. 


  • Fun, state of the art race flat that can do more than short road racing: Sam, Adam
  • A very natural riding,flexible, agile, lower stack  ride with road feel that is not punishing: Sam, Adam
  • Versatile! Enough cushion for workouts and tempo in addition to races and light trails speed ready due to agility, upper and stability: Sam, Adam
  • Great choice to work the feet in a rotation of stiffer or plated high stack trainers and racers: Sam, Adam
  • Unplated PWRRUN PB foam midsole is highly responsive, dynamic and also forgiving
  • Incredibly light at 5.45oz  / 155 g with plenty of cushion stack height at 25 mm heel / 19 mm forefoot : Sam, Adam
  • “Strapped in” total lockdown upper that while narrow is comfortable with bonus trail worthy upper hold: Sam, Adam
  • Full coverage rubber outsole for grip and notable stability for such a light shoe.
  • Stable heel and mid foot, flexible toe off : Sam, Adam


  • A bit more substantial heel counter area and platform width for heel strikers : Sam
  • A bit more stack height would make them yet more versatile, extending racing range to at least a half or beyond for me: Sam
  • These are fantastic and the only thing I’d like to see is more variations and shoes in this genre, maybe even with Saucony’s next-generation HG  foam from the Endorphin Elite: Adam


Approx.Weight: men's 5.45oz  / 155 g (US9)  

  Samples: men’s 5.25 oz  / 149g US8.5

Stack Height: men’s 25 mm heel / 19 mm forefoot ( 6 mm drop) 

$150. Available now including at our partners Running Warehouse HERE & Saucony HERE

First Impressions, Fit and Upper

Sam: At first glance the Sinister shouts out it is a race flat type shoe but one with more than minimal cushion as those shoes typically have. Classic optic yellow colors with the black rear area a clear differentiating highlight as is the bold silver, green, and red “Saucony” on the medial heel. 

With the prominent webbing straps at midfoot pointing to security and hold, the Sinister visual design clearly projects serious and fast running business! 

The primary optic yellow upper material is a thin non-stretch ripstop mono mesh with a more extensive external overlay on the front medial side and an internal one of the lateral side. The upper should prove highly breathable and quick draining and drying.

Webbing straps which loop to hold the laces completely lock down the mid foot. As with the front of the shoe, the straps run externally on the medial side all the way down and below the sockliner. How far they extend and if they actually connect all the way to the lateral side I don’t know but they may as the lockdown is total (even for trail use). 

Unlike the medial side the straps pass through the upper part way down towards the midsole. 

I am guessing the reason for this asymmetrical arrangement is to allow the foot to more easily transition forward from landings with the medial side supporting more aggressively to keep things stable. Sure works brilliantly!

The tongue itself is a stretch knit and adequate.

The rear, reminding of the differing front and rear construction of the Ride 16 is a suede type material, also non stretch and rear hold is just as impeccable as toe box area and midfoot. The rear vertical of the heel “counter” is stiffened somewhat with the heel area otherwise pliable. I am guessing the last webbing strap extending rearward is key to the great hold. A bit more heel counter might be in order for heel strikers and for trail use but overall for fast running the rear hold is effective.

There are 2 quite substantial achilles bolsters but otherwise none further the sides.

Fit is true to size with a true high performance fit so don’t come looking for a high volume fit here especially at midfoot. 

The top box is decently accommodating, no pressure on my bunion for one.

Adam:  Out of the box, the Sinister is an aptly named shoe.  It’s an incredibly sleek, modern race flat that looks like it kept all the aggression of earlier designs while bringing modern foams and upper construction to the table.  Sam described the technical aspects of the upper well so I will focus my comments more on the feel.  

For such a high performance fit (the Sinister reminds me more of a cross country spike upper than a normal running shoe’s), the upper is remarkably comfortable.  It’s a reasonable width in the toe box, distributes the pressure of the laces over the foot despite minimal padding, and doesn’t slip or blister at the heel.  All of this, as well as the weight of the midsole truly contributes to a shoe you forget you’re wearing. 

On light trails, the upper allows for sharp corners and quick accelerations providing the perfect amount of control without being overly constricting   This upper might struggle for stability on a stiff carbon shoe with a greater stack height, but when combined with the stability of the Sinster’s midsole and outsole, it’s close to perfection as a racing upper. . 


Sam: The midsole is a single slab of Saucony PWRRUN PB, a supercritical expanded pellets PEBA foam. To pressing it is slightly softer than the original PB (Endorphin Pro and Speed 1 and 2) and slightly firmer than the PB in the Endorphin Pro 3, a foam I find too soft in combination with its carbon plate while I find the Endorphin Speed 3 PB with its flexible nylon plate just about right for me. I found the original PB quite firm but here recall no plate to make things harsh and stiff.

The midsole is highly dynamic with very noticeable energy return at toe off. The platform is rigid enough through toe off to keep me stable, aligned and flowing from a surprisingly forgiving landing at the relatively low 25mm heel. There is plenty of stability and rebound for even my heel striking. I have no sensation of the rear bottoming out with the raised medial midsole walls adding a touch of stability.

The Sinister while commendably stable in a natural way through to the front of the shoe, also has a quite snappy front flex point. The shoe is way easier to accelerate than plated shoes be they carbon or nylon. Maybe not as explosive as plated shoes here it is the quick rebound of the foam off the front of the shoe that is felt. While only 19mm in front stack height I found them plenty well cushioned up front for their fast purpose with the forefoot and its low stack and flex in no way “thin” feeling or unstable, the full coverage outsole also contributing.. 

Adam: The midsole of the Saucony Sinister is what elevates it from a fantastic race flat, to a versatile speed shoe I’ll grab for track, road, trail, or hills.  The incredibly low weight of the shoe means that it accelerates in an incredible way.  The ease of turnover feels comparable to a spike to me, in a way that most carbon plated racers can’t hope to match.  

The Sinister has just enough cushion that it never feels like it is fully compressed and harsh, while still feeling direct and responsive.  I’ve taken the shoe at the 10K, and think I could probably go longer. The midsole does get quite narrow in the mid foot but this doesn’t seem to affect its stability too much unless you’re a heavy heel striker, The midsole is dense enough to allow it to feel stable and controlled on light trails.  There’s no rock plate and sharp point to point rock jumps are not advisable, but for dirt and gravel it’s fantastic.  


Adam:  Part of what makes the Sinister, so special, is the fact that it actually has a full coverage outsole.  Initially, this may seem like a mistake, adding weight to a shoe that is clearly focused on lightness and responsiveness, but it actually transformed the character of the shoe.  

Despite having no carbon plate, the stiffness of rubber delivers a beautiful midfoot snappy transition.  This allows the shoe to accelerate quickly, maintain excellent stability even on trail, while still connecting you with the ground you are running on.  The outsole lug pattern is shallow, and doesn’t add a ton of material, but makes a world of difference in grip on wet tracks, and on light, dirt and gravel trails.  

The outside makes the shoe more responsive, versatile, stable, and even makes it competitive with trail shoes like the Salomon S/Lab Pulsar.  Kudos to Saucony for putting enough rubber on the bottom of this.  It is this, so I’m not sure how long it will last.  But for the short distances this shoe was intended for, it’s a good compromise vs.additional  weight.  

Sam: I concur with Adam. The outsole is key to stability and response and blends perfectly with the midsole foam. Grip is excellent on road and light trails and for a racing shoe there is plenty of rubber here to allow for training miles as well.

Ride, Conclusions and Recommendations

Sam: The Sinister is a very special shoe. Very simple in design, incredibly light in weight yet more than adequately cushioned, it leverages state of the art materials very, very effectively.  

It is "refreshing" to have pure PEBA foam power and its dynamic return with no plate in a configuration that is both stable and more than sufficiently cushioned. Bonus, it is fantastic on light trails as well and so much fun to run everywhere. 

No plate, no problem as here the foam return, secure fit and ride, agility all come together beautifully. I raced them for 5K on a mix of every surface: pavement, dirt road, winding single track and beach sand. The two short very steep climbs were handled snappy quick. I plan on running them at Mt Washington with its 7.6 miles of pavement and 4500 vertical feet as there the lightest possible weight traction and just enough cushion are what is called for and I am sure Sinister will deliver!

In addition to the full coverage outsole with its great multi surface grip, credit for the versatility (and for trails too) here must be given to the upper. Yes, it has a race fit but a comfortable one.  The mesh and overlays really lock down the foot with the real secret the “straps” at midfoot and the medial raised sidewalls. I don’t think there is a light race upper out there which is as locked down and secure.

Bottom line: for speed workouts, moderate length, fast tempo, 5K to half racing, easier terrain park and trails speed and racing, working the feet in something other than stiff high stack or plated shoes , the Sinister is one versatile, fast and fun shoe. Yes, $150 is steep but the value is strong. I might only wish for a bit more stack height to extend its range to a half marathon for me.

Sam’s Score: 9.6 /10

Ride: 9.7 Fit: 9.7 Value: 9.2  Style: 9.1


The Sinister is a re imagination of why thin, light, race flats can be, and why they should continue to exist in an age of high stack height, carbon plated super shoes. 

It is the best feeling shoe for light trail climbing I’ve ever tested, cruises up to 4:10 pace on the track while staying composed and snappy, and leaves my legs feeling less sore the next day than any other shoe with its weight and stack height. 

Sam said it well, that it is refreshing to have a shoe like this that innovates on the upper, midsole, and outsole without trying to put a stiff plate inside everything labeled for racing.  I’m not going to be running a marathon in these anytime soon, but every time I pick up the Sinister to go for a run, I am excited, and ready to go fast.  With the versatility to cover hills, track, short, racing, light trails, and fun tempo days, the Sinister is the technological masterpiece rejuvenating the racing flat genre.  

8 Comparisons

Index to all RTR reviews: HERE

Salomon S/Lab Pulsar (RTR Review):

Adam:  These shoes feel surprisingly similar to me.  And for true more technical trails, I’d take the Salomon due to the heel stability and outsole, but the foam on the Saucony is more efficient and propulsive for everything else.

Sam: Agreeing with Adam.  The Pulsar weight about 0.6 ounces more and has the same stack height as the Sinister. It is for trail as the Sinister is for road about the lightest shoe out there with a strong weight to cushion ratio. Either is great but if you do more road than trail go Sinister. If you lean trail more strongly but also need a short distance fast road shoe Pulsar. 

Saucony Kinvara (RTR Review):

Adam:  I’ve always been impressed by the upper and light weight of the Kinvara, but disappointed by the outside grip, and the harshness and lack of responsiveness of the cushioning.  The Snister fixes each of those, though the upper of the Kinvara would actually be better suited to longer distances. 

Nike Streakfly (RTR Review)

Sam: At  6.0 oz  / 170g (US9) with a 32mm heel / 26mm forefoot the Streakfly is about 0.5 oz heavier but more cushioned by 7mm front and back. While it is at race flat weight and marketed by Nike as “5K-10K”,  I found it to actually be a super light trainer more than a racer. More mellow all around despite a mid foot rigid shank it is super pleasant, decently fast and ZoomX lively and soft. 

As a short racer it does not compare to the Sinister and for sure I would not take them to trails as I would the Sinister as its outsole is pure road and not nearly as grippy or capable. It does provide a flexible option for a trainer racer as does the Sinister. It does also have a bit more generous if less secure fit than the Sinister.

Topo Cyclone 2 (RTR Review)

Sam: Sinister is 1.5 oz / 41g  lighter with 3 or so mm more stack height of cushion. Sinister is quicker feeling and snappier while the Topo is a bit more easy going all around including of course in fit. 

New Balance FuelCell SC Pacer (RTR Review)

Adam:  The Pacer is a low stack carbon plated racer.  That carbon leads to very high responsiveness, high speed snap, and a slightly harsh ride.  I think that the Sinister was better for not having a plate, since its outsole still allows for a responsive snap without the harshness and with an ever faster turnover.  

Sam: Agree with Adam. With a 28mm heel, 20mm forefoot stack the Pacer has a bit more cushioning at the heel and about the same at the forefoot but.. adding a plate to such a relatively low stack of softer foam leads to a rough, stiff quite harsh ride for me. For short and fast, Sinister all the way and I would never dare take the Pacer on any trail. 

adidas adizero Takumi Sen 7 (RTR Review)

Sam: Sadly replaced by the very different TS8,  the TS7 is in many ways very similar to the Sinister in being a low slung fast race flat with a great outsole and similar race fit upper that can range over to light trails. Where they differ is at the midsole. The adidas with its firm Lightstrike and midfoot plastic Torsion plate is far firmer with lots of quick response but less energy return or cushion. Takumi Sen 8 is a completely different shoe than the TS7 with a rigid rocker profile and more stack height designed for elites at the 5-10K distance. Wouldn't dream of trails in them as I would the TS7 and Sinister.

New Balance FuelCell Rebel v2  (RTR Review)

Adam:  I like the Rebel V2 a lot, as a lightweight trainer. It uses the same foam as New Balance’s best racing shoes, with a lightweight, uncomfortable, upper, and unplated flexible midsole.  Although I think the Rebel V2 is more suitable for longer and easier training runs, the superior outsole grip and snappiness of the Sinister means that it feel good and controls much faster paces than the Rebel can manage comfortably for me.  I wouldn’t pick the rebel to race in, I would pick the Sinister

Reebook Floatride Run Fast Pro (RTR Review)

Sam: The original super foam race flat 2018 Pro was lighter yet in its v2 at a mere 3.88 oz / 110g and with a low 16.5mm heel / 12.5 mm stack height, 8.5 mm less at the heel and forefoot..  That lower stack was felt.. And the Fast Pro was limited to a max 5 mile race for me although our contributor Michael Ellenberger set his half PR of 1:07 in them. Both share outstanding outsoles that are multi terrain. Interesting side note, the current director of all run product at Saucony, Ted Fitzpatrick, was also responsible for creating the Fast Pro. He has not forgotten the value of such a more flexible super light shoes in the mix of plated and max cushion racers and trainers.

Available now including at our partners

Saucony HERE

Running Warehouse HERE

Tester Profiles

Adam Glueck is an endurance athlete (cross country and AT skiing, running, mountain and gravel biking) who formerly competed at the NCAA’s in cross country skiing while studying at Dartmouth College.  He can run a 4:43 mile, 16:20 5k, 1:23 half, and grew up running in the White Mountains of New Hampshire.  He’s currently working as an engineer in the Bay Area and exploring trails from Santa Cruz to Tahoe.  You can follow him at on Strava

Sam is the Editor and Founder of Road Trail Run. He is 65 with a 2018 3:40 Boston qualifier. 2022 was Sam’s 50th year of running. He has a decades old 2:28 marathon PR. These days he runs halves in the just sub 1:40 range if he gets lucky,, training 30-40 miles per week mostly at moderate paces on the roads and trails of New Hampshire and Utah be it on the run or nordic skis. He is 5’9” tall and weighs about 164 lbs, if he is not enjoying too many fine New England IPA’s.

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Samples were provided at no charge for review purposes. RoadTrail Run has affiliate partnerships and may earn commission on products purchased via shopping links in this article. These partnerships do not influence our editorial content. The opinions herein are entirely the authors'.

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Anonymous said...

Running shoe expert reviewing a racing *flat* with a 25mm(!) stack: "Needs more stack". Enough already! Stack-o-sexuals...

Anonymous said...

Thanks for the review! Appreciate your informative and detailed format with factual specs on stack, drop, weight, midsole, etc. Also value the subjective multiple comparisons at the end of each review (there’s usually one or two in the list which are familiar and useful for personal comps), as well as thoughts on ride, fit, etc. Constructive observation: reviewing a purposefully designed low-stack shoe like this and stating one of the cons is that you’d personally (“for me”) prefer more stack height is analogous to reviewing a cayman gt4 and commenting that you’d personally prefer it if had a taller ride height or tires with a taller profile like an accord or camry (misses the use-case & suggests a propensity for design towards the middle/masses). If the midsole/stack design bottomed out at your particular weight/form then that’d be constructively useful info. Back to the positives, grateful for the review & observations on the outsole, esp.for LD trails. Used to run the a4’s on trails in CO (fun, fast & nimble) and will likely order a pair of these Sinisters for the same purpose thanks to ur review. Speaking of fun, nice job with the outsole & banking turn pics in this review! Steppin up ur game! Also like the recent Salomon trail shoe comp vid which had all the shoes on a table (instead of a porch railing), this provided a quick & easy visual comp of toe boxes, form factor, etc. Nice! RTR = best place for shoe reviews. Thanks & best wishes!

Sam Winebaum said...

Thanks for the kind words! If you try them out please let us know what you think.

Sam, Editor

Anonymous said...

What's it like compared to the Brooks Hyperion Tempo?

Ward Sullivan said...

My thoughts exactly! :)

Luc said...

Helo Sam,

I completely agree with your opinion: “Endorphin Pro 3, a foam I find too soft in combination with its carbon plate”.

So for mainly racing (5/10k, rarely 1/2 marathon) the Sinister is better.

Do you know other alternatives then the Endorphin Pro 3 with a firmer foam?