Jonathan Hanson 

But does this source also cite figures from a tightly woven cotton shirt? I suspect a synthetic shirt woven like a "thin T-shirt" might not perform much better. For example, I commonly wear tightly woven, all-cotton Filson Feather Cloth shirts while pedaling. Even after weeks of exposure to full sun on a ride the length of Israel, I exhibited zero—zero—signs of sun exposure where the shirt covered me, with sharp "farmer tan lines." It's difficult for me to discount such obvious long-term field results.

gauvins

In this academic paper reported SPF ratings for different types of natural (not dyed) cotton range from 3.8 to 19.2 . SPF rating goes up to more than 50 for dyed (indigo) heavy cotton, which is probably similar to what is achieved by synthetics (I didn't find explicit comparisons -- will report if I get lucky)

The authors write that the protection afforded by cotton is good.

So, yes, it depends on thickness and color.

J.Higgins 

Wear what you like. Like what you wear. Common sense is king.

Jonathan Hanson 

That makes more sense. I know for sure I find cotton much more comfortable in warm or hot weather!

KraneXL

That's vanity, not common sense.

DropBarFan

UPF 50 shirts are becoming quite popular, almost all are synthetic & some are pretty cheap. Locally a moot point since there's not enough sun for the weeds to grow.

afrowheels

I've been thinking a bit about cotton vs synthetics in hot weather (e.g. cycling South America) and found this thread. On my last long tour many years ago - 5months in East Africa, often very hot - I mostly used synthetic materials top and bottom. The plus was what is usually referred to: easy to dry, easy to wash and didn't retain dirt much. Downside: got heat rash, did not feel particularly cool, got saddlesores (though that was at least as much bike setup but I don't think the synthetics helped).

So for my potential upcoming tour I am seriously considering reverting to cotton clothing or at least blends that are majority cotton, with a couple of synthetics to compliment that off the bike or offer an alternative. E.g. in rainy weather I like the fact that synthetics won't hold much moisture. But I would be interested in any more recent developments with materials in the last 4 years that I might not know about and weren't covered above.

staehpj1

I don't think a lot has changed since this thread was new. Possibly some of the antistink treatments built into the synthetics are better in some cases.

Some like wool. More power to them if it works for them. I found it held a lot of moisture, dried slowly, and didn't deliver on the no stink promise for me (I don't doubt it does for others, maybe I have a weird body chemistry of something).

FWIW, I have not found that I like cotton or wool at all for touring or riding in general. I tend to use synthetic regardless of the season. Some synthetics tend to be better than others with regard to how well they manage to be odor free. This seems to be on a garment by garment basis rather than something you can predict by the material listed on the tag. As a result I just take the ones that I have found to be good in that regard. I just wear regular bike shorts or bibs (I like medium high end Peal Izumi ones). For shirts I prefer running shirts or other tech tees rather than jerseys for touring. I used to be a daily trail runner so I own a bunch. I'd buy them cheap when I'd see top running brands (Nike etc.) on sale at Marshals or whatever. Also I'd buy North Face or similar if they were deeply discounted at REI or other outdoor suppliers. So I paid $6-12 for most of them. I tend to wear short sleeves in hot weather, but have both long and short sleeved ones.

Maybe off topic a bit, but my favorite insulation layer to wear over them is a kayaking sweater from decades ago (Immersion Research). I don't think they make one like exactly mine any more, but it is warm, dries fast, and doesn't hold much moisture, .

pdlamb

Well, when it's "very not" most clothes that didn't just come wet out of a refrigerator are going to feel "particularly cool."

If you've got some time before starting this next tour, you might want to try cotton and see how it works for you. A popular vote on BF might be informative, but really can't replace your personal choice and decision.

staehpj1

About the only thing that might not tell you is what it is like day in and day out all day on the road. Some of that will depend on your style of touring. Things like how many changes of clothing you carry and how often they get washed will impact that. Someone who has one set of on bike clothes and rinses them out daily (or less) and only really washes it once in a while will have very different experiences and and needs than someone who carries lots of clothes,wears stuff once, and always manages to fully launder before wearing again,

Yes setting some expectations based on what works at home is the way to go, but they will not fully duplicate the experience at home so some notes from others experiences may help them consider what criteria to apply. Their own experiences ultimately are the bottom line though.

staehpj1

Just an aside... This thread made me think how much I hate hot weather. I tend to try very hard to tour when/where it isn't too hot. It never seems to work though since I seem to manage to find unseasonable record heat. That said, one bit of advice I will give that has noting to do with clothing, is to ride at hour when it is coolest. Early morning, even before daylight, can be wonderful. Watching the sun rise over the road ahead when I have a couple hours of riding in is my idea of a nice morning, but I am naturally an early bird. Getting hours in then might allow for hours off during the hottest hours of the day. The evening can be nice too, but the heat often lingers in many places and I prefer to settle in early most of the time.

Pratt

This summe,r riding around Quebec for a couple of weeks, I wore 50/50 cotton/polyester tee shirts by Carhartt. Each afternoon, I would shower and wash the shirt. It was sunny, breezy and low humidity most of the time and the shirts would be dry and clean enough the next morning to wear again.

StarBiker

Nylon Cargo Shorts, White T Shirt......wore that combo for a decade with no tree canopy in blast furnace mid Atlantic Heat, and Humidity. Keen Sandals with footy socks.

And like the poster above I hate heat. I really hate summer!

Ron Damon

Hot & humid, cotton sucks. Hot & dry, it's fine.

Yan 

The problem with cotton is not about whether it protects you from the sun. The problem is it dries slowly after getting wet. It doesn't dry when you're wearing it, and it refuses to dry overnight. After a couple of days of moist fermentation, you're wearing donkey diarrhea.

Pratt

^That is why I chose 50% cotton, 50% polyester. It did dry overnight, and so I was able to wash it daily and mostly dry it hanging from a picnic table in the afternoon breeze. Granted, it was pretty low humidity which helped.

greatbasin

Cotton is a fantastic fiber for woven fabrics to be worn loosely in hot weather.
Knit cotton fabrics (the 'jersey' material used in 't-shirts') worn tight-fitting performs terribly.

Woven cotton fabrics can also be outstanding for extreme dry cold.

The way cotton fails is when it is knit into a cheap fabric and worn tight against the skin and in cold wet climates.

Even in hot wet climates, cotton isn't the worst if it is used in a woven fabric and worn loosely. Think about what people wear in jungles and where there are monsoons -- it's not Lycra.

The problem for cycling is that people have become obsessed with aerodynamics. Lowering aero drag demands tight-fitting clothing. Cotton won't work. First, the woven fabrics (canvas, twill, oxford, etc.) won't stretch much. That's one of the qualities that makes them good for both hot and cold climates. Because they won't stretch, they will create a lot of airspace between the skin and the fabric. This encourages ventilation and evaporation for cooling. In cold climates, it allows insulating layers to keep their loft so the dead air space retains heat. Use a tight-fitting, stretchy, knit cotton fabric like jersey and the fiber looses all its benefits. It's just cheap.

For tight-fitting garments that need to stretch, the natural fiber choice is merino and knit merino fabrics are a great traditional choice for cycling.

I've toured in hot dry climates (Western US) and I did it in oxford cotton shirts and cotton duck canvas or twill trousers. Provided I kept the speeds around 10 mph or less, they performed incredibly well. I didn't tour Death Valley, but I did tour the Owens Valley (adjacent valley to the west of Death Valley). Had I wanted to average closer to 15 mph or more, these fabrics would have created a lot of unwanted drag. Frankly, they would be like a parachute. As it was, they provided great sun protection. I kept totally dry. I was cool. I did still get dirty and the fabric is bulkier than synthetics to stow changes of clothing.

I have a lot more backpacking experience than cycle touring. In backpacking, the problem with cotton is the backpack doesn't allow it to fit loosely. It could be fine on the legs, but it's heavier and bulkier than alternatives and weight and bulk are a bigger deal backpacking than cycle touring.

Skiing, I tend to be in pretty wet conditions. I wish it were colder, but a lot of areas in the western US where snow is customary are getting warmer and warmer and we're grateful just to have a few powder days a year and then it just hovers around the melting point. Wool is far better in this environment because of the insulation, breathability, and because it's not so affected by dampness. In dry, arctic-cold regions (well below zero), cotton can work great as an outer layer over wool or down insulation.

For cycling, I just resolved not to go fast. I'm not in a hurry, especially when touring, so I just go slow. I think when I started, I was averaging 10 to 12 mph. Now, I average about 7 mph, and loose-fitting woven cotton is by far my preferred fabric. I'll wear wool when it's cold.

StarBiker

Interesting comments about White T's. Who would wear them tight?

In the heat what was my sweatiest area? My crotch. I have done away with the type of underwear I did wear. Still cotton but much thinner, and fits better.

I don't know how you avoid sweaty butt. I have vented Selle SMP Saddles.

I just don't ride much in heat anymore.

afrowheels

Thanks, this came in at a good time: I was walking past a sale and picked up an Under Armour t-shirt 60%cotton 40%synthetic that I am now trying out.

afrowheels

Yeah, that's another issue. I had read that advice before but I am not a natural morning person and on my last tour I slogged through midday heat (40C+ in southern Malawi!). I can do it so long as there's enough water and sun protection, have done long distance hiking under similar conditions, but I think I will need to be more deliberate about avoiding heat if I get this tour off the ground.

afrowheels

I would say my experience of synthetics in hot & humid conditions is worse than my experience of cotton in the same circumstances... Sure, synthetics wick and dry but they also stick to the skin in a different way and I think that was how I got heat rash the first time.

staehpj1

I think that you should use what works for you, but I will just add that synthetic garments vary widely even with the same nominal fiber and most of the very most comfy shirts are not cycling specific garments. Some of my very favorite ones are from North Face or Nike or other non cycling brands and are sold as running, hiking, or general outdoor wear. You just might still find synthetic fabric joy with a bit more experimentation

All that said, I have a hard time imagining wanting to put up with cotton in humid conditions unless you are carrying multiple changes of clothing to change into dry ones daily and be able to launder and dry the old ones before wearing them again. Even then I wouldn't, but at least I could see it. The way I tour, cotton would never be dry, other than once and a while when it was put through a washer and dryer, unless the humidity was very low. Also even when on a hot tour I usually have come chilly conditions at altitude at some points along the way. Deaing with damp cotton would be a ***** if the trip included those conditions. But that is me and the conditions I tend to ride in.