Nobody likes being too cold. Nobody likes being too hot either. We all want to be just right. Like a bunch of two-wheeled Goldie Locks, mountain bikers love when our gear meets in the middle. My favorite example this season has been thermal 3/4-length bibs. Full-length tights tend to be built for the dead of winter, and normal bibs are usually made for the dog days of summer. But that leaves out the best time of the year. So what to wear?

Pearl Izumi Pro Escape Thermal ¾ Tight : $185

These aren't very far from those dead-of-winter full tights. The Pro Escape's thermal lining surrounds you on all sides while the Specialized and Gore offerings put their fleece in a few strategic places. This makes sliding on the Pro Escape Thermals a bit like climbing into a wetsuit. You'd better be ready to get out in the cold as soon as you're wearing them. They can heat up too quick if you're in the wrong conditions. For morning rides when you might want to turn on the A/C come about 9:15, you won't be able to. So, choose wisely. I found they were the most comfortable in the low- to mid-40-degree range and were passable in the low- to mid-50s, depending on my energy output. They do a good job managing moisture. If I warmed up enough to sweat, it took a while for them to start feeling muggy.

Keep in mind, my acceptable temperature range is coming from a Californian who’s long forgotten his Midwest roots. Thicker-skinned riders could easily use the Pro Escape Thermals when it's close to freezing outside. And as is the case with all 3/4 length bottoms, you can always opt for long, thick socks for full coverage and even more warmth.
And the Pearl bibs hold onto that warmth. No matter the speed and no matter the wind, you won’t feel the breeze.  Even the chamois is made to keep you toasty. It doesn't have the contoured lines and varied thickness of higher-Tech pads, but it’s wide and thick and keeps you very comfy, and of course very warm.
A couple features on the Elite Thermals are higher tech then the rest of the test. The cuffs transition to a thinner, more flexible material for more comfort and have traction pads for less slip. And the shoulder straps are by far the best-feeling of any thermal lower I've ever worn. Possibly of any bib I’ve ever worn. The wide, sheer material distributes pressure so evenly and so softly, you barely know they're there.

pearlizumi.com/proescapethermaltight

 

Gore Oxygen Partial Thermo Bibtights : $180

Cold weather gear is what Gore is known for, but the Oxygen Partial Thermo Bibtights sit somewhere in the middle of the three options I tested with regards to warmth. Nearly all of their inner panels are lined with fleece, but a few are left as standard Lycra. A 1-inch- to 3-inch-wide perimeter around the chamois is designed to be a little more breathable and a little more flexible than the rest of the short. The thinner material also extends up the back, where wind is not an issue. These are the spots where a little ventilation is the most welcomed. It kept me from overheating as much as I did in the Pearl Izumi Pro Escapes. Even when wrestling up slow-speed climbs, I wouldn't overheat until the temperature got into the high 50s. But they still won't quite carry you into moderate temperatures as well as the Specialized Swat Thermals do.
And they aren't ideal for super-cold temperatures like the Pearl Izumis, but they do just as good a job at stopping the wind. So, if your body is generating enough heat, the Thermo Bibtights will keep you plenty comfortable in the high 30s.

The chamois itself is pretty minimal. It's plenty thick, but it doesn't extend past the footprint of the saddle. This, again, helps a lot with breathability. There's very little extra material to trap heat and moisture where they would normally build up the most.
The Oxygen Bibtights measure relatively short. I'm up there at 6'2", so your results may vary, but they end just below my kneecap. And without any rubberized traction patches around the cuffs, they would sometimes bunch up behind my knee while pedaling.
Lastly, the unique shoulder straps are made of two layers of thin breathable fabric with supportive piping on the outside edge. For those who doubt to the durability of the paper-thin material used to hold up the Pearl Izumi bibs, this would seem like a perfect compromise. But if I paid attention, I could feel that one strip of piping more than I could do more traditional straps of the Specialized SWAT bibs, which are supported on both sides. But if you're generally not bothered by bib straps, you won't be bothered by these.

gorewear.com/us/cycling/

Buy them here.

 

Specialized Therminal Mountain Bib Knickers With SWAT : $110

These are the perfect early spring or late fall addition to your wardrobe. We were first introduced to the specialized SWAT Therminal bibs during this past Bible of bike tests in Marquette, Michigan. It happened to be unseasonably warm there this past October, but not at 7 AM. It made it a lot easier to get out of bed knowing that when we faced the cold, we'd have these babies to protect us.
Unlike the Gore and Perl Izumi offerings, the SWAT Therminal bibs apply their fleece very sparingly. It reinforces only the front panel above the chamois and the front panels of the legs, leaving more traditional material everywhere else. After using all three of the offerings you see here, the SWAT Therminal bibs are the most versatile. But I'll admit that in the coldest of temperatures, I'd rather have on the Gore or Perl Izumis for the first moments after I get out of my truck at high altitudes or leave my house for my very early morning commute. Those options are perfect for cold days while descending or pedaling lazily. But if you're going out in the SWAT bibs while the temperature is in the low 40s, it's best if your heart rate is in the high 140s.

But what that means is that as the day warms up alongside you, the SWAT Therminal Bibs won't make you sweat. Back to the Bible of bike tests, those days that started in the high 30s would sometimes peak in the high 60s. In Most testers were perfectly happy wearing the Specialized bibs all day.
The chamois they use is pretty standard. Thinner than Pearl or Gore, but a little wider and more contoured. Most of the other design touches are pretty standard as well. The shoulder straps are reinforced on each edge, and the leg cuffs feature some minimal rubber traction pads. But there's also the design touch, the SWAT pockets. One pocket hugs on the side of each leg while three hang from the back like the pockets on the back of a traditional jersey. They add to the Specialized bibs' versatility advantage. They're not good for the coldest temperatures but they're good for almost everything else.

specialized.com/us/en/therminal-mountain-bib-knickers

Related:

The 2018 Bible of Bike Tests — The Goods

Review: Specialized SWAT Pro Bibs

Review: Assos T.Rally Shorts_s7