Trek RSL Knit Road Cycling Shoes

The Trek RSL Knit Road Cycling Shoes are stiff, comfortable and airy pro-level footwear with a knitted sock-like construction that makes them extremely breathable. But in spite of those knitted uppers I found them surprisingly hard to get into and I didn't get on with the insole. And there's no getting away from their £400 price either.

> Buy now: Trek RSL Knit Road Cycling Shoes for £399.99 from Trek

RSL stands for Race Shop Limited, which is the designation that the US bike giant Trek gives to its poshest bikes and equipment – the stuff it makes for its pro teams. And although £400 for a pair of kicks isn't exactly unheard of these days, it will still represent a luxury purchase for most.

The Trek RSL Knit shoes have been developed with the pro riders of the Lidl-Trek team, and are a fast shoe for warm sunny days. Or – if you're testing them in early March in the UK after an especially wet winter – best kept covered up.

There are two shoes in the RSL range and these are arguably the most interesting – and definitely the most expensive. They aren't the first knitted cycling shoes – Giro, Fizik, Specialized and FLR have all done so in recent years.

However, the Trek RSL Knits go for the full socks-and-sandals effect, with the knitted layer effectively a fairly snug sock that sits against your actual sock, with BOA-equipped straps over the top. We'll come back to the reasoning behind this, but it does have some convincing thinking behind it.

Let's start at the bottom. The sole is made from 100% OCLV carbon (Optimum Compaction Low Void, the term Trek's uses for its carbon fibre) and is drilled for three-bolt road pedals.

What's that, you say? Is there a stiffness index? Well, yes of course there is – and the RSL Knits score a maximum 14/14 on Trek's scale, and the sole simply doesn't seem to flex at all, either in your hands or when you're going all-out in a sprint.

There's a small non-replaceable heel pad, and a front bumper that wraps upwards and joins a larger plastic piece around the outside of your toes. Four sole vents fore and aft of the cleat are largely cosmetic as only one has any corresponding perforations in the insole, but – as we'll see – sweaty feet are unlikely to be a major issue here.

The carbon sole is shared with the Trek's more conventional-looking RSL road shoes that cost £349, and which we're also reviewing. Above it, the front two thirds are made up of knitted material – it's pretty much a sock – with the knit made up of at least four different patterns, all joined seamlessly to give you yield and airflow where you need it.

A sock on its own wouldn't lock your feet in enough to contain the watts that the likes of Mads Pedersen can put out in a sprint, so there are straps outside the knitted sock layer. The sock and the straps aren't joined to each other but only to the sole. This is very different to the other knitted shoes we've seen it the past, which use knitted outer layers but generally have a more conventional construction.

Trek calls the strap arrangement METNET and it's been designed to allow a tight fit (for those who want it) while removing pressure from the areas of the foot that Trek reckons most commonly cause discomfort – the first and fifth metatarsal head and the fifth metatarsal tuberosity. Yes, I had to Google it – but these are the inner and outer bones of your forefoot and a bony protrusion on the outside of your foot.

The straps avoid these parts altogether so there's only the sock over them – if you've got lumpy feet that don't get on with a lot of cycling shoes, these might just be a game-changer for you.

The knitted sock is thinner than that of just about all the other knitted cycling shoes, some of which have a knitted outer layer covering some padding and an inner layer. As a consequence the Treks are highly breathable and these shoes feel great on warmer days. They wouldn't be my first choice for winter in part because they're not really warm enough, but also because they don't offer any protection against road spray.

On a £400 shoe you'd expect some fancy closures – you can keep your laces, thank you very much – and Trek is absolutely on the money here with a pair of gorgeous BOA Li2 aluminium dials. I think BOAs are the best dial system on the market and the metal Li2 version is the best of its current range of dials.

Unlike the pretty S3 dials on the S-Works Torch, these also have the pull-to-release feature to get you out your shoes quickly at the end of the ride. Well, fairly quickly. They are simplicity itself to adjust while riding, even with overshoes fitted, and they're replaceable too if you damage them.

The mad thing is this: you can literally ride in these shoes with the BOAs completely loose, so well-anchored are your feet. Some of this is down to the aggressively cupped heel but the sock itself is doing a surprising amount of work here too. I found I generally ran the BOA laces much looser on these shoes than any others I've used, and at the end of a long ride it's really nice to be able to slacken them right off without any risk of your feet coming unshod.

The heel cup isn't knitted, but consists of a type of alcantara (a synthetic suede-like material) on the outside and a directional 'cat tongue' material on the inside. There's no pull loop, but it extends up just about enough for you to be able to grab on it – and you'll want to do this, as getting these shoes on and off is uniquely demanding.

Unlike most shoes, there is no tongue so the opening has a fairly fixed circumference, through which you need to be able to fit your foot. I could, although I wouldn't describe the process as easy. My road.cc colleagues Dave Atkinson and Stef Marazzi have similar-sized feet to me, and Dave couldn't get these shoes on at all, whereas Stef could get into them without too much of a struggle.

Trek's size chart recommends a size 46 as the right size for a UK size 12, and on the basis of length I'd agree – once on, these were the right size for me. The knitted material doesn't have a whole lot of give around the opening, however, so I found wearing thinner socks were a better bet and I'd seriously consider investing in a shoe horn if I'd bought these.

There was no sign of any damage from the strain of putting them on or off, but this much huffing and puffing makes me a bit concerned for the longevity of the stitching around the opening.

Once you've got them on, they feel unlike any other cycling shoes I've used. The knitted layer hugs your feet without any pressure points – it is snug but very comfortable. If you do tighten the BOAs then they're still comfortable, I wasn't aware of any pressure from where the BOA's laces run over the sock.

The one disappointment when it came to comfort was the insole. It's made from 'Rise by BLOOM', which Trek describes as a bio-based EVA foam alternative made using waste algae from water pollution. Avoiding the use of oil-based plastics for the foam is a great idea, but unfortunately I found the resulting insole thin, hard and lacking arch support.

I'm not the only one to have found these insoles to offer insufficient arch support, and swapping in 10-year-old insoles from my Scott race shoes offered me an immediate improvement. Other manufacturers include footbeds that can be customised to suit different feet, and at this price point I would like to see something better here. Trek does have a range of three Bontrager inForm insoles for varying arches, so for another £25 you can get something that should suit your feet.

White knitted shoes, especially with the socks-and-sandals aesthetic, are a bold choice and – in my opinion – not necessarily a good one for British roads. I found I was able to get most of the grime off with a very hot shower jet, but not all – once they're dirty they won't ever again look like now. Happily, there's also a black version with – take my money now, Trek! – gold dials.

So, if you're in the market for some shoes with a few hundred quid burning a hole in your pocket, should you go for these? For me it all boils down to the conditions where and when you ride, as well as how comfortable you find other cycling shoes.

These are – and I'm in no doubt about this – very comfortable shoes, once you've got insoles that work for you, but I can also get pretty comfy in shoes from the likes of Scott, Shimano, SIDI and Specialized.

I ride all-year round and when I buy cycling shoes I'd want ones that I could use for most of the year. That means a bit more warmth, a bit more spray resistance, and less effort to keep them clean. If you have a 'best bike' you only ever bring out on balmy summer days and want some top-end shoes to go with it, then these deserve serious consideration. I've certainly never used shoes that held my feet so firmly, and comfortably, without even being done up tight.

Value

Of course, if you're prepared to pay up to £400 you can find all manner of really good alternatives.

The Specialized S-Works Ares Road Shoe that Anna Marie reviewed is another pro-level product with a partially knitted construction and they'll cost you £25 less.

After some knitted kicks at a lower price point? The FLR F-XX Knit shoes make do with a single ATOP dial and are half the price of the Treks – though the white shoes Ed tested were as hard to keep clean as the Treks.

If you're not fussed about knitting, then the Shimano S-Phyre RC9 (RC903) Shoes have long been a popular choice around these parts – Steve certainly thought so – and they're £50 cheaper.

Suvi was similarly positive about the Bont Vaypor shoes, which come in £30 less expensive than the Treks.

You'll find other top choices in our best road cycling shoes buyer's guide.

Conclusion

Top-notch kicks that deliver stiffness, comfort and – thanks to their knitted design – excellent breathability. But you are paying a lot of money for that sort of performance and I did find them surprisingly hard to put on.

Verdict

Minimalist knitted shoes that deliver astonishing foot retention combined with real comfort – best for warm, dry days