Adidas Adistar Windproof Tights
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These are my favorite winter tights. The Adidas Adistar Winter tights are cut looser than most other tights. They are windproof in the right areas and are not bulky. The thin fleece fabric does not feel like they'd keep you warm but they do by keeping the chilly wind off your thighs, knees and shins. The 4-way chamois is nothing spectacular and suits my preference of less-bulky chamois pads. They did take a few rides to adjust to the pad and tend to bunch at times causing the "sit-up and pick" routine during a ride. When the temps get below freezing, I've worn knee warmers underneath just for added warmth. My current pair are on their 3rd winter. MSRP at the time was around $100. These tights paired up with the Adidas Adistar winter jacket and you're set for those blustery 30 degree base mile rides all winter long.
Castelli Cardio Bib Tights
I just recently picked these up off of Chainlove for cheap. Not having worn Castelli before, I didn't realize they were cut
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The chamois is fantastic - not too thin and doesn't bunch. They claim the chamois keeps your temp (down there) at a 98 degree range. I wasn't about to plug any thermometers anywhere down there but they did feel cooler than other winter tights.
Champion System Fleece Bib Knickers
If your team kits come from Champion Systems, you know they are not the high end of kits. However, the bib knickers are fleece lined and the chamois pad is decent. The bib straps are very comfortable. I like these on those 50-60 degree days in the fall/winter/spring and mountain biking in the winter.
Performance Ultra Bib Knickers (Discontinued)
Performance house brand Ultra line of shorts are my favorite shorts to ride in. When they came out with the knickers a few years back, I picked them up on sale ($50). The knickers have a heavier lined material than their Ultra shorts but are not fleece lined. They still give you the compression and warmth when riding in cool conditions. These are my go to bottoms in the 60 degree days when not wearing the team kit.