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Kool Stop Dura 2s are aftermarket upgrade brake blocks with the dual compound providing good braking performance in a range of conditions and decent longevity too.
Kool Stop are an American brand that specialise in aftermarket brake blocks and pads, and the Dura 2 is their latest road block. It's thicker than their regular Dura block so it lasts longer, and the 7.65mm contact width works well with narrower rims.
They're available in several versions; we've been testing the dual compound type. This mixes their standard black all-weather compound with their salmon compound, which is designed to offer better stopping in very wet conditions. A pair of grooves on the braking surface help to dispel water when riding in the rain.
As with all cartridge brake blocks, they're a doddle to fit and didn't require any adjustment once in place. I swapped out the standard brake blocks (which are made by SwissStop) on a set of SRAM Red calipers and tested them over several months, encompassing all sorts of weather and riding conditions.
In the dry the braking performance was on a par with the standard blocks they replaced. They offer a nice lever feel with good modulation and power, with no grabbing. Where they really impress though is riding in the rain or sodden roads, where they offered noticeably more stopping power over the stock brake blocks.
The durability through this period was good too, with a lower rate of wear compared to the regular blocks, even after riding in some pretty bad weather.
Cut outs reduce a bit of weight, but saving weight on a brake block has never been top of my list of priorities.
Martin Cox has also been using the Kool Stop Dura 2 blocks. He adds:
Swapping them for some well-worn winter-abused pads pads, the effect was noticeable immediately; they brought a new lease of life to the bike. This was especially noticeable on the few occasions they were used in the rain. They gave the brakes a decent level of grip despite the wet stuff, which is always appreciated.
Like most (all?) dual compound pads they attract the grit off the road and it does embed a little too easily for my liking so the risk of rim damage is always there. I find an olive stick removes them quickly though.
While they work effectively in the rain, this level of stone stickiness can be worrisome, so probably best keep them on the dry bike if at all possible.
Solid stopping power in all conditions, but a bit prone to picking up road grit
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Make and model: Kool Stop Dura 2 Dual Compound brake blocks
Size tested: Dual Compound
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?
Kool Stop says:
The Dura2 insert is Koolstop's newly designed road pad. The pad is thicker than our standard Dura type for longer life, has a 7.65 mm contact width for narrow rims and cut outs for reduced weight.
Martin Cox comments: Aimed at those looking to make a step-up from standard stock pads, the Kool-stop Dura 2 Dual Compound pads add excellent performance at a reasonable price. My only concern really is about grit getting embedded a little too easily in the wet.
Tell us some more about the technical aspects of the product?
*7.65 contact width
*6.5mm pad depth (2 mm greater than the normal Dura)
*Rim Friendly Compounds
Great in the wet and mixed conditions
They've held up to around 1,000 miles of usage with very little wear.
Around the £10 mark, give or take 15% depending on the month seems fair.
Tell us how the product performed overall when used for its designed purpose
Great step-up from Ultegra pads, working well across the spectrum of riding conditions.
Tell us what you particularly liked about the product
Good performance in a range of conditions and ideal for this time of year. Well done to the marketing department for adding the spiel about the cut-outs saving weight - that'll tick a box for someone I'm sure!
Tell us what you particularly disliked about the product
Picking out bits of grit after every wet ride.
Did you enjoy using the product? Yes.
Would you consider buying the product? Yes - in Spring.
Would you recommend the product to a friend? Yes.
Age: 31 Height: 180 Weight: 67
I usually ride: My best bike is:
I've been riding for: 10-20 years I ride: Every day I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,
David worked on the road.cc tech team from 2012-2020. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes.