There was some initial discomfort in the instep area when the laces were tightened. Slight loosening helped and eventually this discomfort disappeared.

Keen Ridge Flex Mid WP Review | Tested by GearLab Keen Ridge Flex Mid WP Review | Tested by GearLab

The Ridge Flex is a lightweight walking boot that uses a combination of leather and synthetic mesh in its uppers.

The boots really do flex very easily with virtually no resistance. I’ve worn trail shoes that are stiffer. I find them easy to walk in and certainly more comparable in comfort to a flexible trail shoe than to most boots. I guess they do save some energy, like all flexible lightweight footwear, though how much I can’t say. Hard-wearing hiking boots that offer all-day comfort, plus the added benefits of Bellows Flex technology Pros and Cons Its innovative and unique (as far as I know) feature is the Keen Bellows Flex section at the base of the laced part of the boot, which is a rubberised area linking the forefoot with the ankle section of the boot, at the point where it flexes during walking. There’s also a narrow bellows strip at the base of the ankle cuff.

Keen Ridge Flex WP Women - idealo Keen Ridge Flex WP Women - idealo

In terms of niggles, the only issue we’ve had so far was some slight fiddliness when lacing the boots up, as the top two pairs of eyelets are located very closely together. We suspect that the eyelets have been positioned as they are to allow a really secure fit of the boot’s ankle cuffs around the ankles, so despite it taking a second or two longer to tie the laces that we’d have liked (so impatient to get out on the trail as we are!), it’s definitely worth it for the extra secure fit you get as a result. The membrane, combined with the leather in the uppers made the Ridge Flex Mid WPs feel quite warm, which was welcome on cool and cold days but less so on longer days when the temperature rose. There were no surprises from the Ridge Flex during testing, with the fit and general feel of the boot being very familiar to us due to previous models that we’ve tested, such as the Targhee and Karraig. Although it’s a well-made boot that’ll stand up to rough trails and general abuse, the walking action is very easy due to the quite soft nature of the sole unit allied to the bellows flex feature. While we couldn’t put a precise number on the energy-saving properties of the bellows flex (let alone the 60% Keen claim) – we can confirm that the Ridge Flex feels light, comfortable and eminently capable of keeping your feet in good shape even after many hours of walking. Things we like about the boot include the well-padded ankle cuffs, which provide not just comfort but excellent support, especially when walking on uneven ground or going downhill. The midsole offers good cushioning, but not so much that you lose the feel of the terrain under foot. The leather in the boots is from a Leather Working Group ethical source, and the durable water repellent treatment is PFC free. The Keen Ridge Flex also have a natural eco odour-control treatment. The Bellows.Flex technology that features on the Ridge Flex and its sibling, the Tempo Flex, came as a result of Keen’s desire to make a boot that enables the user to use less energy when walking. Keen figured that quite a lot of energy is used when your heel lifts and the front of the boot flexes, and that over a period of a few hours this energy adds up considerably. Making the boot flex more easily at the forefoot would save a lot of this energy, but how to do it?My first pair lasted around 10 months before they started to let in water. Partly via the uppers and a small delamination on the sole. These were replaced under warranty. Keen says the boots have ‘million flex goodness’, which I calculate equates to about 1,500km or 932 miles, which will get you from John O’Groats to Land’s End, with a bit to spare. Maybe I have a pair that has a defective peice of FLEX rubber in them..?. You do mention in your review that it is worringly thin, and that also crossed my mind when they arrived..