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The Castelli Diluvio UL Shoecovers are made from waterproof neoprene to keep your feet dry, they extend high to make sure your ankles stay warm in most conditions, and they're very stretchy for a close and comfortable fit.
Castelli offers a whole load of different overshoe designs – 13 at the last count, if you include the Toe Thingy – the Diluvio models being designed to keep your feet dry as well as warm ('diluvio' means 'downpour' in Italian).
Ash reviewed the Diluvio Pros (now £60) a couple of years ago and rated them highly. Whereas the Diluvio Pros are made from 4mm-thick neoprene, the Diluvio ULs are 3mm thick, as are the Diluvio C (£45) and the Diluvio 2 All-Roads (£45).
First things first: do the Diluvio ULs keep the water out? This might make or break the deal, particularly for UK readers. The good news is that water doesn't get through the neoprene at all and the seams are sealed. Fabulous; we're up and running!
Whereas the Diluvio Pro mentioned above has a water-resistant zip at the back, the Diluvio UL has a standard YKK zip, although double layer neoprene flaps behind it help to minimise ingress there.
As with any other overshoes I've ever used, water can eventually get in if it's persistent. A shiny section of fabric that Castelli calls a neoprene skin around the top edge is designed to form a seal, but if you're wearing full-length tights inside your overshoes, rain can soak into the fabric and gradually migrate south. You can't argue with physics (although you can position the ankles of water-repellent tights outside the overshoes to minimise this effect).
You can fit the Diluvio UL overshoes so that the bottom edge slightly wraps around to the sole of your shoes to stop water getting in there.
The bottom of the overshoe is open but for a Velcro closure that allows you to adjust the width. That Velcro has a super-tough backing and the same is true of the section underneath your toe. Both are still looking in excellent shape despite having been in contact with stones and gravel on the way to and from the bike every day for several weeks. I mean, go hiking in your cycling shoes and these areas are going to get damaged, but in normal circumstances they're going to stand the test of time.
Overshoes such as the Diluvio Pros that Ash reviewed and the Diluvio C, where the neoprene extends around to cover part of the sole, provide a little more insulation but the fabric inevitably gets scuffed sooner or later, no matter how careful you are.
I've used the Diluvio ULs with various types of shoes and they've worked well with all of them. I've had to persuade the Velcro closure to sit neatly between the heel tread and the forefoot tread of some gravel shoes, but it has always been possible.
One thing that's really noticeable when you put the Diluvio ULs on is that they extend higher above your ankle than most other overshoes out there. This is A Good Thing for making sure that road spray stays out. There's no Velcro strap to adjust them up top, so what you see is what you get when it comes to tightness around the calf. I can't say that was an issue for me, and if you have chunkier legs than me, the neoprene is plenty stretchy enough not to feel restrictive.
Reflective fabric at the heel provides highly noticeable visibility and the Castelli name that's plastered across the side in big letters (well, it actually says 'Caste' on one overshoe and 'Stelli' on the other) is reflective too.
Castelli says the Diluvio ULs are suitable for temperatures from 2-14°C (with the slightly thicker Diluvio Pros getting a range of 0-14°C). I've been using these on some cold mornings over the past few weeks and I'd say that's about right in normal winter-weight socks. I've not given a thought to chilly toes in these temperatures, although you might want something thicker in frosty conditions. Sure, there are overshoes out there that provide more insulation, but these do the job promised.
Winter-weight neoprene overshoes start at about £30, with many sitting in the £30-£50 price bracket. Castelli's own Diluvio C overshoes are £5 cheaper than the Diluvio ULs at £45, although they're a simpler design without such a sculpted fit, and they don't extend so high above the ankle.
There are plenty of more expensive overshoes out there too. The BioRacer One Tempest Protect Pixel Overshoes that Liam reviewed earlier in the year were £56, for example, and the Assos Assosoires Winter Booties that were £70 when we reviewed them are now £80.
The reason I'd usually be reluctant to pay £50 for overshoes is that I know how quickly I go through them. However, these perform well and they'll last longer than most, so I reckon they're a good buy.
Overall, these are pretty hardwearing and work well with various types of cycling shoes. The neoprene keeps the water out well and provides enough for warmth for most, but not quite all, conditions.
Hardwearing overshoes that do a good job of keeping your feet dry and warm
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road.cc test report
Make and model: Castelli Diluvio UL Shoecovers
Size tested: L/XL
Tell us what the product is for
Castelli describes the Diluvio UL shoecover as "a hard-wearing all-around neoprene bootie that features our premium 3mm high stretch neoprene, sealed seams, skin-out top edge to seal against the foot, and adjustable opening under the foot to work with any shoe."
Castelli says, "We've taken our best-selling Diluvio C and Diluvio Allroad booties and modified, improved and combined them into the all-new Diluvio UL. With improved fit and a better seal thanks to the neoprene enclosure at the top, large reflective rear tabs for visibility, and the flexibility to accommodate any type of cycling shoe, there's little this bootie can't handle."
Tell us some more about the technical aspects of the product?
Castelli lists these features:
* 3mm neoprene for water protection and warmth
* Velcro closure under foot for perfect fit
* Bottom opening accommodates road, gravel or MTB shoes
* Sealed seams
* YKK zipper
* Neoprene skins at cuff to keep water out
* 2°-14 °C / 36°-57°F
The water resistant zip found on the Diluvio Pros would be good, although it would doubtless increase the price too.
They're cut with a seam just higher than the top of your shoes. This gives them more shape than a lot of cheaper overshoes.
I really like the higher than normal cut; 3mm neoprene isn't quite as insulating as 4mm, but it's more flexible.
The tough central strap and panel under the toe mean these will last longer than most, increasing their value.
How easy is the product to care for? How did it respond to being washed?
I know some people chuck their overshoes in the washing machine but I'm a good boy and follow the manufacturer's instructions to wash them by hand in the sink. Hang them up to dry and they're good as new.
Tell us how the product performed overall when used for its designed purpose
Really high level of performance. The neoprene is waterproof and it's warm enough for most conditions.
Tell us what you particularly liked about the product
The tall cut, the fact that the neoprene lets no water through.
Tell us what you particularly disliked about the product
How does the price compare to that of similar products in the market, including ones recently tested on road.cc?
Many winter-weight neoprene overshoes sit in the £30-£50 price band. Castelli's own Diluvio C overshoes are £45, although they're a simpler design without such a sculpted fit, and they don't extend so high above the ankle.
The BioRacer One Tempest Protect Pixel Overshoes that Liam reviewed earlier in the year were £56, for example, and the Assos Assosoires Winter Booties that were £70 when we reviewed them are now £80.
These overshoes are pretty hardwearing so they'll last longer than most, helping to justify the price.
Did you enjoy using the product? Yes
Would you consider buying the product? I would.
Would you recommend the product to a friend? Yes
Use this box to explain your overall score
These are an 8 all day long thanks to a strong performance and very good durability.
About the tester
I usually ride: My best bike is:
I've been riding for: Over 20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding,
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.