Hands-On Review of the Kinvara 8
Being the second lightest and having one of the smallest heel-to-toe discrepancies among the traditional shoes, this is a top contender for favorite shoe to take out when we have a tempo run or local road race planned, especially anything fast and hard over six or eight miles where true minimalist and barefoot shoes tend to tear up the forefoot and toes, calluses be damned.
Some of the top racing flats: Adizero Boston 6 (left), Saucony Kinvara 8 (middle), and Nike Free RN (right).
Typically the most responsive models feature a springy midsole and internal stability structures that help the midsole snap back and return energy. These shoes have half of that equation with a tall EVA midsole that includes the EVERUN topsole, meant to increase the energy return with each stride, which it does beautifully.
We rate these near the top of the responsiveness category alongside most of the stability shoes, like the Saucony Hurricane ISO, whose internal structures and stiff soles give the kick back.
The new model still comes in near the top for landing comfort. It doesn't need much breaking in and is ready to roll with high out-of-box comfort. With just a 4mm drop in the heel-to-toe, Saucony created a smooth and natural landing that utilizes full ground contact similar to many of the other models in this lineup.
About a third of the shoes in our test group have at least a 10mm discrepancy from the heel-to-toe. The 4mm offset of the Kinvara 8 facilitates a natural running gait, forcing the runner to heel strike less and land on the midfoot, creating a more efficient landing. This puts less shock on your joints but will in turn make some of your leg muscles work harder.
Thick padding and a wide landing platform give the Kinvara 8s superior landing comfort.
The updated seamless upper is not as perfectly snug and sock-like as its predecessor, but it remains much more comfortable than the average shoe - not just out of the box and walking around the store, but where it counts… miles after you pulled out your credit/debit card. They also retain their FlexFilm upper that stretches and adapts to the form of your foot.
In addition to the EVERUN heel insert from the previous model, they also include an additional EVERUN layer near the top of the midsole, called the EVERUN Topsole, which the company says gives back 83 percent of the energy put into it. The EVERUN inserts seem to make a difference, creating a lovely, natural-feeling cushion all along the foot. Without the insert, the shoe's construction made it a very comfortable shoe, but the new layer and larger tongue seem to crowd the foot and don't have the natural form-fit that made the 7 such a fantastic offering.
The Kinvara 8 features a thicker padded tongue and leaner upper.
Having a fully seamless and ventilated upper, the Kinvara 8 receives our second highest rating in breathability, second only to the Top Pick for Lightweight Racing Flat winning On Cloud and New Balance Minimus 10v1. An extremely minimal and lightweight yet functional upper is used in the 8. Other than the seamless outer mesh layer, there is only a single thin foam layer lining the inside of the upper. This shoe won't protect your foot much from the harsh winter elements, but will definitely help you finish your run faster to get back inside and warm up those feet.
Scoring similarly, the Adidas Adizero Boston 6 has moderate padding and lightweight, tight mesh. This works to pull moisture from the shoe and allows airflow. Based on breathability alone, it is difficult to parse these shoes apart. Runners looking for lightweight, breathable neutral shoes should know that they are looking at the top of the stack with these models and should look for other qualities they value, like style and comfort, but based on this metric alone, one would be obliged to choose between the On Cloud and Minimus 10v1.
Out comparing notes with runners during a side by side with the Minimus (John, front), Kinvara 8 (author, middle), and Nike Free RN (Tomasz, back).
At 17.6 oz. in a size 11, this model comes in lighter than almost all of the rest of the group, just behind the 17.2 oz. Minimus 10v1 and 17.3 oz. On Cloud. One significant way Saucony cut down on weight is by only using high density rubber in high wear areas of the shoe. This is also an ideal shoe for the road racer doing 5k distances and it is comfortable all the way up to the marathon distance. If you want a lighter neutral shoe with comparable cushioning, take a look at the Top Pick for Lightweight Road Flat, the On Cloud.
We like to envision these flats as a Formula 1 car tire. It won't be able to take the same miles as the tires on your commuter car, but the miles it does take are amazing. That said, we notice the tread does wear away faster than happens with many of the other shoes in our test group, despite their iBR+ rubber placed in the high-wear areas.
Don't expect to log as many miles in this shoe as some of the other road trainers we tested. We logged a little over 15 miles in our pair before we noticed slight wear on the outsole, but it's hard to say what they'll look like at a few hundred miles. The seamless upper is nice, though we assume it probably won't last as long as many of the heavier designed uppers.
The author (middle, On Cloud) out comparing notes on some of our top racing flats with runners John (front, Kinvara 8) and Tomasz (back, Pegasus 34).
Don't be surprised if you set a PR in local group runs and 5Ks all the way to your big marathon. This is the ideal shoe for race day or if you're looking to gradually make the switch to minimal road shoes.
Less shoe equals more performance, with the retail value around $110, we think this is a good price for this extremely versatile, fast feeling shoe. The Kinvara 8 has one of the lowest prices in our lineup, which is another reason we think it earns its place near the top of the group. But because its design accommodates many different running styles while maintaining its lightness and comfort, we feel it would be a bargain even at higher prices.
We think you should absolutely consider this speedy road shoe if a low-drop, highly cushioned minimal shoe works with your running style. This shoe has a great balance of minimalism and plentiful cushioning.