Santini's Eureka bib shorts are a warm choice for the colder weather, with a very good seat pad and the bonus of good water repellency.
First, though, it's worth pointing out that although the RRP on the Eureka shorts is £124.99, you can get them for £95 – or as a bundle with Santini's Eureka leg warmers (RRP £41.50) for £125 – from independent bike dealers before the end of October.
The Eureka shorts are made from BeHot yarn that's designed to generate heat as you pedal. The heat generation is said to be a permanent feature rather than something that washes out over time.
'When functional BeHot stretches, it generates heat by decreasing the entropy (disorder or randomness of molecules),' according to Sitip, the company behind it.
Without the same product, in exactly the same weight, made from a different yarn, I couldn't tell you whether the claims made for BeHot stand up, but I can tell you that these are warm shorts with a Roubaix-style brushed back to the fabric. I've been using these comfortably, along with the matching Eureka leg warmers (review to come), in temperatures as low as 7°C on recent autumn mornings. Judging by the level of warmth on offer, I'd say they're good for a couple of degrees lower than that too, depending on your body's internal thermostat.
The fabric has an Acqua Zero DWR (durable water repellent) treatment that causes road spray, fog and light rain to bead up and roll off, even if you're riding in these conditions for an hour or so. Granted, heavy rain does get through. We all know how much difference staying dry can make to warmth and comfort, so these shorts really do make a good case for themselves when it's damp.
After several washes this Acqua Zero is performing as well as ever although, as with any other treatment of this kind, you'll need to reapply eventually.
The fleecy panels extend well up onto your stomach and lower back so there's no danger of any areas being left unprotected. The straps are mesh and I found them wide enough not to put any particular stress on my shoulders.
Silicone gel inserts and two layers of foam mean that Santini's GIT Evo pad provides plenty of cushioning without being too bulky. The layer next to your skin is antibacterial and channels in the padding add to the airflow. I did a four-hour ride in these at the weekend and didn't give comfort a moment's thought. That's always a good sign.
Wide, elasticated grippers with a silicone pattern on the inside hold the legs in place; I didn't find them riding up at all, even over the top of leg warmers. And finally, reflective tabs on the back of the legs help you get noticed at night.
Warm and comfortable thermal shorts with water repellency and a high-quality seatpad
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road.cc test report
Make and model: Santini Eureka Bibshorts
Size tested: Large
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Santini says, "Don't get left out in the cold when the first days of fall hit, Santini has got you covered. Eureka is the perfect bib-short for the first cold snap: Made of Behot Acquazero fleece, this innovative mix of fabrics is light and soft to the touch. The Eureka bib-shorts maintain perfect thermal balance while protecting you from the cold and rain. Eureka winter bibshorts and leg-warmers do not simply insulate you from the cold but, thanks to the Heat Generating Technology of the BeHot fabric and Acquazero treatment, they keep you dry and they generate additional heat – up to 4 degrees C - as your body moves."
Tell us some more about the technical aspects of the product?
SITIP says, "This fabric is made with BeHot functional yarn developed with SITIP Heat Generating Technology and with a special textile construction.
"When functional BeHot stretches, it generates heat by decreasing the entropy (disorder or randomness of molecules).
"BeHot Heat Generating Technology minimises the heat loss and keeps the warmth during exercise on a permanent basis."
These are among the warmest thermal shorts I've ever used.
The GIT Evo pad is a highlight, although these are comfortable throughout.
They're not cheap but there are far more expensive thermal shorts out there too.
How easy is the product to care for? How did it respond to being washed?
They go in the washing machine with the rest of your bike kit. There are no transfers to flake. The Acqua Zero treatment is durable although you'll eventually need to reapply a DWR if you want to retain the water repellency.
Tell us how the product performed overall when used for its designed purpose
These shorts are warm and very comfortable, which is exactly what you want.
Tell us what you particularly liked about the product
The level of warmth and the comfort.
Tell us what you particularly disliked about the product
I didn't dislike any particular aspect.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your score
These are very good shorts made with high-quality materials and an impressive seatpad. They're not the cheapest thermal shorts out there but they're well made and should last so they're still decent value.
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 pushing 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.