• Discontinued
  • Terrain


    Shoes best for road, track and light gravel. See the best road shoes.


    Shoes best for trail, off road, mountains and other unstable surfaces. See the best trail shoes.

    Good to know

    As long as you stick to the road or path, and if you want just one running shoe, buy a road running shoe.

  • Arch support

    Neutral / cushion / high arch

    Shoes for runners who do not need any additional arch support (Around 50% of runners). Best for people with normal, high or medium high arches. See the best neutral shoes.

    Stability / overpronation / normal arch

    Shoes for runners who need mild to moderate arch support (Around 45% of runners). Best for runners with a low arch. See the best stability shoes.

    Motion control / severe overpronation / flat feet

    Shoes for runners who needs a lot of arch support. Best for runners with flat feet. See the best motion control shoes.

    Good to know

    - Rule of thumb: If in doubt, buy neutral shoes to avoid injuries.
    - More about arch support in this video.
    - Find your arch type by following steps from this video.

  • Use

    Daily running

    Cushioned shoes for your daily easy running. Great comfort. See best shoes for daily running.


    Lightweight shoes good for races, interval training, tempo runs and fartlek. Here are the best competition running shoes.

    Good to know

    If you want just one pair of shoes, buy a shoe for daily running.

  • Price
  • Weight
    Men: 10.9oz
    Women: 8.9oz
  • Heel to toe drop
    Men: 4mm
    Women: 4mm

    The height difference from the heel to the forefoot, also known as heel drop, toe spring, heel to toe spring or simply drop.

    There are many opinions about what a good heel drop is. We do not recommend any in particular. Lean more in this video.

  • Heel height
    Men: 19mm
    Women: 19mm
  • Forefoot height
    Men: 15mm
    Women: 15mm
  • Width
    Men: Normal
    Women: Normal
  • Release date
Show more facts


A top rated Road running shoe

Expert Reviews

Experts are runners, who post reviews at youtube, directly at RunRepeat or at their own websites. Each expert is categorized from level 1 to level 5 based on expertise. See stats on expert reviews and how we calculate scores here.

Are you an expert? Apply to contribute here.

82 / 100 based on 5 expert reviews

  • 75 / 100 | Runblogger | | Level 5 expert

    If you want to put in the effort to try an change your gait, then these again might be a good shoe choice.

  • 88 / 100 | Feed the Habit | | Level 3 expert

    If you already like Newtons and want a more durable, rugged version, rejoice! However, if you’re not comfortable with forefoot running or uninterested in transitioning your running style, this probably isn’t the shoe for you.

  • 83 / 100 | GearJunkie | | Level 3 expert

    They are comfortable and indeed more forgiving than other Newtons I have tried.

  • 93 / 100 | Best Running Tips | | Level 1 expert

    They have helped me change my running style for the better, I feel better after my runs and do not have the same issues with the running injuries again.

  • 88 / 100 | The Long and Winding Road | Level 1 expert

    I love these shoes. They have helped me truly learn more about my body and how to run. However, they are overpriced. 

Become an expert

  • The Newton Sir Isaac is a training shoe that features systems and components that offer pronation support. Performance-wise, this shoe delivers because it keeps the runner moving forward in a well-guided way. Beveled lugs give a springy and more enabled lift, especially when tackling the forefoot lifts. This is a reliable shoe to take to the roads.
  • The upper unit of this Newton shoe uses durable yet comfortable materials to make sure that the runner feels safe and secure. A closed construction is intended to keep small debris out, but it’s still very breathable. Stitched-on overlays make sure that the fit is more customizable and responsive to the adjustments made to the lacing system.
  • The mid-sole unit features systems and platform technologies that ensure the foot is comfortable and well-supported at all times. A high-rebound foam gives bounciness with each step, while the support chassis adds stability to the stance of the foot.
  • A carbon rubber outsole keeps the sole unit protected from the abrasive nature of the asphalt. The Action/Reaction™ technology moves the platform like a trampoline that propels the runner upward for a smoother and more enabled stepping motion.

The Newton Sir Isaac has a regular running shoe length. The sizes that are available for men and women follow the standard measurements. The heel, mid-foot and forefoot sections have medium widths, so this shoe accommodates the runner who has a medium sized foot. Its semi-curved shape allows the wearer to acclimate well to it.

Carbon Rubber is a strong compound that’s used for the outsole unit of the Newton Sir Isaac. It is placed in critical sections where wear and abrasion are most likely to happen. It also gives effective traction over the roads, giving the runner dependable surface control.

Beveled Lugs are placed in the external sole unit. They guide the foot towards a smoother and springier performance. They also allow a stable feel in the forefoot section.

The Action/Reaction™ Technology is applied to the surface lugs of this shoe. It causes these units to absorb energy and give it to the runner, essentially enabling a more propelled and boosted lift of the foot.

A single-density, high-rebound EVA serves as the main platform on which to rest the foot. It is very responsive and it even adds a bit of bounciness to the underfoot experience. It doesn’t wear off easily, so it stays efficient even after many uses.

A Midfoot/rear support chassis allow the foot to be more stable when running. It balances the foot and guides it to a more effective and stable ride.

The upper unit uses a closed mesh material. Though it has a closed construction, it still encourages air to enter the shoe and keep the foot cool & dry. It also prevents any debris from entering the shoe, thus keeping the interior clean and free from any hazards.

The Enhanced Sock Liner adds more cushioning to the wearer. It also has a mildly bouncy nature, so energy is given back to the foot for more energized performance all throughout.

The overlay system has been stitched onto the upper unit. They allow a more customizable fit because they cause the upper unit to follow with the tightening and loosening of the shoelaces.