Darth Lefty 

I got a pair of those Costco pants Sunday and wore them yesterday. Very light, very synthetic stretchy fabric. In light of the stretchy fabric, the elastic waistband that slides through the pockets seems a little gimmicky. Mesh lining in the pockets that reminds me of the stuff used for swim trunks liners, catches on my calluses and badge clip.

Fit: I'm just fat enough for the 36. (In Levi's 511 I wore 3 different pairs of 38's that ranged individually from loose to tight). Wife says they fit me, but they feel pretty relaxed fit if so. I think the 34's would be too tight, though. Had to peg the cuffs to ride. I'm usually between 28 and 30 for leg, these with 30 leg seem a little bit too longer than usual. I'm interested to see how they do after a trip through the washing machine and dryer.

RHETTORIC

Get yourself a pair of joggers. They stretch for comfort and movability, but are slim fitted and tight at the ankle to avoid the chain/gears and other bike parts. I got a few pairs at Cotton On online.

Skipjacks

I wear long shorts for all warm weather riding. Nothing special. Just any shorts that come to the mid knee. Anything shorter and they ride up as I pedal.

In cold weather I wear long synthetic workout pants. Again nothing fancy. Just keep my legs warm.

I have no need for any padding in the seat.

Theycallmegio

+1

I can't stress enough that riding in your work clothes (even for a casual Friday or something) will ruin said work clothes in no times.

KraneXL

Makes the most sense...except for cotton. Technical fabrics look better, breadth, are more durable over time and tend to stave off microbes.

Darth Lefty 

Another trip to Costco and got the 34's to try. They seem to fit a whole lot better though the elastic waist is obviously a lot tighter.

LPcreation

Thanks for this suggestion. I'm 5'10 190 and the 34x30 are just about perfect for me. I commute 6 miles each way and today was my 1st morning riding in these pants. Temp was around 58F and I wasn't too cold or too hot. I think these will be fine until I start seeing temps in the low 40's.

CrewFan

Best part about the Costco pants is they're fairly cheap, so you don't have to worry about snagging them on something or staining them!

Orkun KnighTR34

I'm wearing jeans for commuting and if rains, wearing raincoat pants with shoe covers on my jeans. I'm not wearing suits because I'm student.

Bikewolf

Rain pants, maybe something packable, can be very useful too when it is not raining.

There are days when you may wake up with only a few degrees above zero, to end the day with +15 degrees or so — getting too warm to wear long pants. So then I choose to wear shorts. But (chilly me) in the morning, I simply put on my rain pants for wind protection.

Brofessor

Got a second pair of these yesterday:

https://www.macys.com/shop/product/l...g%26slotId%3D1

The most comfortable pair of pants I have worn for riding.

schiavonec

CO commuter here too. It was in the low 40s all week on the ride in. I shoot for at least 3 days a week depending on family obligations. I am fine in shorts into the 40s, but have used wind block fronted cycling/ xc ski pants in the cold. . I keep clothes (Khakis, oxfords, etc.) at the office to change into. YMMV

Ironfish653

For clothes to ride in, that i can still wear at work, i tend to go inexpensive, since i'll usually want to have 2-3 pair. That way i can ride back-to-back days without having to wash the same pair of $50 'expedition pants' every night.

Similar to the Costco is the SwissGear 'Tech Pant' I found at W*almart. Khaki and black, with good breathability and lots of stretch. Which is good, because they're an 'athletic' fit. I had to size-up to get my Q's in them without looking painted-on.

Dickies also has a line of rip-stop work pants, in cargo and 'carpenter' styles, fit is typical 'relaxed-cut' jeans, with a little bit of stretch. I like them for errand-running and casual riding.
Both are less than $20/pair

My commute is about 1 hour of 'moderate effort' so I tend to go with the more technical stuff. If it's above 70* i usually wear MTB shorts, and bring a change of long pants.

EdwinHeadwind

I discovered SWRV brand last year, and love their trousers and jeans for both commuting and working. Well worth their price, and you often get a discount coupon when you order a pair.

autonomy

I've been eyeing these for a while, though they're quite pricey. How is the hem on these for cycling, doesn't get into the pedals? Not too hot? I have a pair of Columbia softshell pants I love, they're just the perfect stretchiness, length, and hem width to flex in my knee and cover the ankle without moving up or flopping. Alas, too warm to bike in above 40 degrees.

clengman

I got a couple pair on sale last fall. I think they were $50-60. I thought that was reasonable for a quality pair of pants. I usually roll them up a little on the drive side, just to keep them from getting stained by the chainwheel. I've never had any problem with any pants getting caught on the pedals.

The regular guide pros are nice, lightweight, breathable and a little stretchy. Very comfortable on the bike. I'm thinking about getting a pair of the lined guide pros for winter.

Archwhorides 

I use a reflective ankle tape on the ankle, just to be sure, as @clengman notes they may be fine without.

rcsting

I've been wearing these pants from REI for commuting and have no complaints. Wind proof and water resistant. Very comfortable too.

https://www.rei.com/product/136583/c...ing-pants-mens

autonomy

Eddie Bauer is having a 40% off sale right now, so I went to the store to take a look at the colors and try on some sizes. I've been looking for pants that I can wear comfortably on the bike (slimmer fit, stretchy fabric, not too tech looking) and then continue around the office (very casual dress code). I like Eddie Bauer's philosophy of multi-use travel/work pants.
The Guide Pros run about true to size but the hem is a bit too wide for my liking; I have a 32in inseam and I would want to have these in 34 so that it doesn't flop around and get in the chain (I have a velcro ankle wrap but would prefer not to be reliant on it).
I actually liked the Horizon Guide Chinos more and ended up getting a pair, also in length 34. These run a little bigger, so I had to size down in waist. There's a slim version too, which I thought would be perfect for the bike, but even the website doesn't seem to have my waist size and the color choices are meh. The material is light & stretchy but not too light - seems like they will stay on the ankle while pedaling. They also don't have the thigh pockets, like the Guide Pro, which are not a must-have for me. I haven't tried them on the bike yet.

A while back I was at Sierra Trading Post and found a pair of Gramicci pants that were almost perfect; I never heard about this company before. I poked around a bit and found these: https://www.sierratradingpost.com/gr...r-men~p~223jm/
They don't have my size, but the slimmer fit seems to be exactly what I would want in a bike commuter pant.

Update: the Horizon Guide pants aren't great for commuting due to a wide hem (the Guide Pros have a similar hem). The mobility and comfort are great but you have to either use an ankle strap or roll up the bottom, which are not ideal for me in lower temperatures.