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Inov-8 Road-X 233 Running Shoe Review

Inov-8 Road-X 233Over the past two years I’ve run in shoes made by most of the major running shoe manufacturers, with only a few notable exceptions. This review eliminates one of those exceptions – UK based shoemaker Inov-8. It’s somewhat surprising that it’s taken me so long to run in an Inov-8 shoe given the fact that they are one of the more minimalist-friendly shoe companies out there. I think the main reason why I’ve avoided them for so long is that until recently most of their shoes have been designed for trail and fell running, and they have a reputation for being fairly narrow in terms of fit.

Recently, Inov-8 released a new line of shoes called the Road-X series. The Road-X line differs from other Inov-8 shoes in being specifically designed for road running (which is my most frequent running surface), and they are built on an anatomical last that provides a roomier fit, particularly in the forefoot. There are currently 3 shoes in the men’s Road-X line (one female shoe for now), and they present a gradation from less to more minimal. I like this approach a lot, as it gives people options for where they would like to jump into a more minimalist style shoe, and allows for a very gradual transition for those who plan to take it very slowly. Below are the three current Road-X shoes, with stats and descriptions provided by Running Warehouse:

Inov-8 Road-X 255

Inov-8 Road-X 255

Description from Running Warehouse:

“When efficiency counts, run natural in the Inov-8 Road-X 255.  Utilizing a 9mm difference from heel-to-toe, this shoe offers runners a mild transition into the realm of midfoot style running. This low-to-the-ground performance trainer uses an ample amount of underfoot protection, which allows it to be worn as a daily trainer or racer. The Road-X 255 is lightweight, super comfortable and offers a responsive ride.”

Weight: 9.7 oz (size 9)

Stack Height: Heel (21mm), Forefoot (12mm) = 9mm drop

Inov8 Road-X 233 White

Inov-8 Road-X 233

Description from Running Warehouse:

“Inov-8, the original minimalist trail shoe brand, now makes great lightweight road shoes. The Road-X 233 is best suited for the runner who wants to move toward the less is more concept. With a 6mm heel-to-toe height difference and a low-to-the-ground foot position, the Road-X 233 is a big step toward minimalist road running without being at the extreme end of the spectrum.”

Weight: 8.8 oz (size 9)

Stack Height: Heel (17mm), Forefoot (11mm) = 6mm drop

Inov-8 Road-X 155

Inov-8 Road-X 155

Description from Running Warehouse:

“The Inov-8 Road-X 155 is a lightweight, natural running shoe that offers the utmost in proprioception for the minimalist or elite runner. Unlike other Inov-8 models, the Road-X 155 doesn’t incorporate Dynamic Fascia Band but rather relies solely on foot strength from the runner. The Road-X 155 offers a 5mm heel-to-toe height difference that allows the runner to run in a smooth natural running style.”

Weight: 6.1 oz (size 9)

Stack Height: Heel (10mm), Forefoot (5mm) = 5mm drop (Inov-8 lists it at 3mm drop, not sure why the discrepancy)

My initial thought when considering which of the Road-X shoes to buy was to go for the 155 since it has the lowest heel differential and weighs the least – in other words, it would best suit my personal taste. However, one of the most common shoe questions I get asked in emails is for a comparable alternative to the Saucony Kinvara. The Kinvara tends to be a bit narrow in the forefoot for some people, and durability has been an issue for some as well. Some also don’t like the softness of the Kinvara’s sole. The 155 has no rubber on the sole, and is much closer to the ground, and is thus a step further toward the minimal end of the shoe scale from the Kinvara. Thus, for comparative purposes, I opted instead for the Road-X 233, knowing in advance that the heel differential would be just a tad higher than I typically like.

Inov-8 Road-X 233 Side

Inov-8 Road-X 233 Medial

My first impressions of the Inov-8 Road-X 233 was that it was a good-looking, well-built running shoe. The upper of the 233 is made of a synthetic mesh, with overlays welded from the sole to the laces on either side to provide a snug fit around the midfoot. Aside from a flexible heel counter, there are no other noticeable stability elements in the upper.

Internally, the sockliner is thin, and there is only a small amount of contour under the region of the arch. The inner lining of the upper is soft and comfortable and allows for sockless running. My one complaint regarding internal comfort is the fact that the sockliner is perforated (you can see this in the photo below), and this causes some rubbing under my big toe (I have noticed the same problem with other shoes that have extensively perforated sockliners – e.g., the Scott T2 Comp). Swapping out the sockliner with one from another shoe is an easy fix for this.

Inov-8 Road-X 233 Top

In terms of fit, the last of the Road-X 233 matches my foot quite well. The forefoot is plenty roomy, and does offer a bit more space than that of the Saucony Kinvara, which makes this a viable alternative for those looking for a moderate-drop, transitional shoe with a bit wider forefoot. Among shoes I have worn, I’d say the fit is most similar to the New Balance Minimus Road or New Balance MT101 (perhaps just a bit narrower) – the latter is among the most comfortable shoes that I own.

Inov-8 Road-X 233 Sole

The midsole of the Road-X 233 rides a bit closer to the ground than that of the Kinvara, and is considerably firmer. As a result, ground feel in the Road-X 233 is better – not at all spongy like the transitional shoes made by Saucony. The 6mm heel lift is noticeable, and if I had one complaint about the shoe it would be that there almost seems to be a a slight increase in firmness under the front half of the heel. This firmer area puts pressure on the region near where the plantar fascia attaches to the heel bone, and is quite noticeable when standing in the shoes.

Inov-8 Road-X 233 FrontThe outsole of the Road-X 233 is ample and I would expect durability to be very good – unlike the Kinvara, there is plenty of rubber under the lateral forefoot to reduce wear in this region for forefoot strikers. Sole flexibility is good, particularly in the forefoot where the outsole is divided by what Inov-8 calls the “meta-flex” region.

In preparing my review of the Road-X 233 I took an unusual approach (for me) by running exclusively in this shoe for 2 consecutive weeks (about 50 miles). Overall, the experience was positive, though I found myself wishing the midsole was a tad softer. I actually prefer the softer midsoles of the low-drop Saucony shoes, but that is likely just a personal preference. If a shoe is going to be very firm, I prefer very little midsole at all (think Merrell Barefoot, Vibram Fivefingers, or Vivobarefoot Neo). If you like a firm midsole, then this shoe would be a great choice. Again, my only major complaint is the odd feeling firm region under the front half of the heel.

Inov-8 Road-X 233 Heel CounterI view the Inov-8 Road-X 233 to be a competitor to shoes like the Saucony Kinvara, New Balance Minimus Road, and more traditional racing flats. In fact, in terms of feel it is much more similar to the Saucony Grid Type A4 than it is to the Kinvara, though the Road-X is a lot more roomy than the A4. It’s also a more flexible in the forefoot than the Minimus Road. Thus, if you are looking for a firm, reasonably flexible shoe with a moderate heel-forefoot drop and a fairly roomy fit in the forefoot, the Inov-8 Road-X 233 fits the bill nicely.

The Inov-8 Road-X 233 is available for purchase at Running Warehouse.

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About Peter Larson

This post was authored by Peter Larson. Pete is a biology teacher, track/soccer coach, and dad (x3) with a passion for running, soccer, and science. If you'd like to learn a little bit more about who I am and what I do, click here, or visit


  1. Thanks for the review Pete. The X-255’s have been in my rotation for about 2 months and they are the most firm shoe I own, including the NB Minimus Road and Minimus Trail. Construction is very good and the sole durability is outstanding. Mid-foot strike is very easy to achieve, but unforgiving if you miss, or when form breaks down.

    They do have US customer support (out of the northeast), which I have used and the individual was very helpful.

    Regards – Britt

  2. I’ve been running the F-lite 195 on my home trails for quite a while now. Could be used as road running shoe as well and exhibits only 3 mm drop. Seems more durable than the X-155. Though cut narrow it is only a snug fit and no resctrictive fit (I have wider feet). May be an alternative from Inov-8. The sticky outsole offers great traction.

    However, for my taste those shoes all lack some sort of cushioning for long distance road running. Can’t wait for the moment when at least one major shoe brand brings out a reasonably cushioned zero-drop shoe. Everything that’s offered so far is either too minimalistic or too much drop. A Road X-255 with zero drop would have been nice.

    • Have you given the Altra Instinct a look?

    • Pete Larson says:

      Somnio Runaissance or Saucony Hattori might also fit the bill along with the Altras.

      • Thanks for the suggestions:

        * Altras –> not available here in Europe (and from what I could gather always out of stock in the U.S.)
        * Hattori –> as a forefoot runner I was disappointed deeply with durability of the Kinvaras. Hattori seems to be similar. Nice attempt by Saucony but this shoe has still too many flaws. Didn’t like the fit either.
        Somnios –> haven’t had them on my radar. However, getting them here in Europe seems tricky, too.

        I really wished one of the major companies with their distribution networks came up with a decent model.

        • Pete Larson says:

          Merrell and New Balance have zero drop road shoes coming. Until then, old shoe + hacksaw to the heel is always an option…

  3. I’ve been running x-155 for the past 2 week and I liked it a lot. It feels a little softer and bit more comfortable on the road than trail shoes x-195. I just ran in them at Hottest Half marathon in Dallas this past week with no problem.  I look forward to those zero drop shoes from Inov in a few months. 

  4. Bach Vuong says:

    Pete, thanks again for the review.  6mm drop is a bit excessive for a minimal/natural running shoe.  I’d like to see the shoe a little lighter as well.  

    You mention that the midsole is a bit stiff, that sounds a bit appealing to me, as I’m not a fan of the cushioned feeling of my Hattori’s.  Is the entire interior cushioned in the same fashion?  I prefer a flexible, but uncushioned ride.  

    • Pete Larson says:

      I’d say it’s firm but flexible. This is the middle shoe in the Inov-8 Road-X line, so if you want less heel rise and a lighter shoe look at the 155. The interior of the shoe feels great.

  5. Sam Winebaum says:

    Echo Britt’s comments on Road X 255. I have been running in the X Road 255 for a couple of months. I am actually using them as much on trails as roads. Utah hardpack trails are handled with aplomb with no slippage and great trail feel. It’s a firm but reasonable road ride with less mushy feeling in the forefoot than Kinvara. The full forefoot outsole has small cuts which open on foot flex. No visible wear to date.  The upper is outstanding. Great forefoot room yet the midfoot is well wrapped and secure. Noticed the lace area and forefoot are actually 2 separated units of upper stitched more or less across the last lace hole, a bit different construction than Pete’s 233’s.

  6. Owning the 155s for 3 months and 233s just shy of 1 month, I can say they are both fantastic, but I have trouble pushing the 155s for distances over 4 miles.  My lower calves and achilles are just not  up to the task quite yet.  The 233s however have just enough lift and the addition of the dynamic fascia band to make longer distances trouble free.  More cushioned soles caused ankle pain for me, while the firmer soles of the Inov-8 shoes are bliss on my joints.

  7. Pete,

    In the shoe reviews of yours that I’ve read you never mention if a shoe is slip lasted, combination lasted, or board lasted.  Why?  From your review of the Inov8 Road-X 233 I would guess its combination lasted (firm heel, flexible forefoot).  Next time your wife is away and you feel like cobbling, try removing the board in the heel.  It should make for a softer feel and drop the heel by a mm or so.


    • Pete Larson says:

      Honestly, I’ve never paid any attention to the lasting. Should look into that…

      • I try not to be biased about the lasting until after I decide to buy or not to buy a shoe, then I peak under the sock liner to see what it is.  It turns out I usually buy slip lasted shoes.  

  8. Peter Ebro says:

    Hi Pete.

    Great review!

    If I like the NB Minimus Trail in terms of feel underfoot and fit. Which one would you suggest to try, the X-155 or X-233? 


  9. Inov-8 only seem to make one really good trail running shoe – the 3/4 mid-top Terrafly™ 343 GTX. But even they say it’s for walking. Plus the sole grip’s a bit flat.… 

    • Arve Bersvendsen says:

      Uh?  Inov-8 started as a trail shoe company, and apart from the road-x and bare-x line, I think you will find they are all excellent trail shoes. The f-lite line for hard-packed trails, and a large variety for more technical trail, with the bare-grip and x-talon line tending to the minimalist.

  10. Arve Bersvendsen says:

    When you’re noting a 2 mm discrepancy between your own measured data and what Inov-8 provide themselves, are you measuring with or without the insole? I seem to have read somewhere that it has 2mm lift.

  11. Do i need to be ordering a half size bigger shoe (allowing for foot expansion) if using these as a marathon training shoe?

  12. Are there different colours in the road X 233.  And are they unisex.  I’m female.  I have a red pair and was wanting a second pair hopefully in a different colour.

  13. precision engineers says:

    Take it from someone who has been TIG welding for over 30 years and has sharpened electrodes every way imaginable including using a cutting torch. That’s right I said cutting torch.

  14. from the pictures of the Inov-8 Bare-X 150 (orange and blue) looking at the lace system, it seems they can be a good option for triathlon? anyone has used them as a triathlon shoe?

  15. Hi Pete,
    I bought Inov8 Road-Xtreme 138 recently and really liked it that how light weight it is and has zero drop and small cushion for a low miles speed work upto 6-7 miles.

    I was wondering to add another shoes for half marathon to marathon long runs and have following choices. Road X-treme 178 (3mm drop), Road-X lite 155 (3 mm) and Bare-X lite 150 (zero drop but no cushion) and finally Road-X 233(6 mm drop). When running 15-20 miles I feel some level of firm cushion helps a lot as I use my merrell bare access 2 for my most long runs. What do you think would be an ideal choice for my requirement? Any help/suggestion is always appreciated.

    • Pete Larson says:

      For long distance the 233 probably makes most sense, maybe the 155. I haven’t tried the other 2. The 155 has decent cushion for a low drop shoe, maybe similar to the Merrell Bare Access but a bit softer.

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      • Thanks Pete for the quick reply. Really appreciate that!

        Here is what I found from Running warehouse specs:
        Forefoot stack height for each shoes –
        Road-X-Treme 178 : 11 mm

        Road-X Lite 155 : 6 mm

        Road-X 233 : 12 mm

        Bare-X Lite 150 : 7 mm

        So it seems to me, Road-X 233 & Road-X-Treme 178 has more forefoot stack height which is here I would be pounding anyways and they are more closer to Merrell’s Bare Access 2’s forefoot stack height of 14 mm. I wondered if they are measuring stack height with or without footbed which can be 3mm to 6mm depending on the shoe type per Inov8 website. Do you think going up to 6mm drop (from zero drop merrell) is wise to keep my gait and form correct?

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