WNCGoater

First, I realize I'm not comparing apples to apples here. I just bought my first touring bike, a Marin Four Corners. It came with 40mm Schwalbe Silento tires. When I ordered the bike, I figured I'd be wanting some narrower tires, having been used to riding 25mm on my road bike. So with the bike I ordered some 32mm Continental Sport Contact tires. I rode the Silento's several rides and was very surprised at the comfort and "cushioning" effect of the larger tire.
So I decided to try the Continentals and switched. I rode them today and was surprised at the rough ride in comparison to the Schwalbe's. I mean, they seemed rougher than my road bike tires. Don't get me wrong, it wasn't like I was getting my teeth rattled loose but there was a big difference between the two.

It was however, down in the 30's today. Rarely have I ridden in temps much below high 40's and so I was wondering if cold temperatures affect tires? Seems reasonable to me hot asphalt and warm temperatures would make a rubber tire more pliable and flexible and cold would do the opposite.


FWIW. the 32mm Continental's actual width is a hair over 29, not 32.

fantom1 

Its been a while since I even thought about thinking about physics, but PVnrt would indicate that with colder temperatures, and constant volume and pressure, moles must increase (increasing density) and thus the gas mix is less theoretically less compressible for a given pressure, meaning a harder ride.

At least that is my memory of how gases theoretically work; I could be totally wrong, I do hate physics and math...

Tourist in MSN

I grew up in Minnesota, so I have had some experience with cold weather. But my tires on cars and trucks only got significantly harder in very cold temperatures, like minus 15 (F) or minus 20 (F) or colder If above zero (F) on cars and trucks I never noticed tires feeling harder. Motorcycles, I never drove them when it was colder than about 15 degrees (F) and never noticed tires feeling harder in the cold.

Bicycles, I have not ridden a bike when it is colder than about 5 degrees (F) and most of my cold weather riding is above 20 degrees (F). I have never noticed bike tires feeling harder in the cold.

mackgoo

Temperature goes down, the gas contracts, pressure decreases. No I don't think so.

WNCGoater

75 pounds of pressure would be the same cold or hot wouldn't it?

Anyway yes, reduced pressure would have the effect to make a tire softer feeling, but I was specifically talking about the rubber.

WNCGoater

So I assume I can deduce from that the difference in the ride was in the two tires. My wife's bike needs some tires, maybe I'll put these 32's (or 29's or whatever they are) on her bike.

mackgoo

75#'s at 80 degrees would not be 75#'s at 50 degrees. It would be something less.
Temperature is the average translational kinetic energy of the molecules. More temp more movement thus more space between the molecules. This is inverse for less temp. So for the same volume pressure would go down with temp.
To a lesser degree the rubber may actually feel harder too. Even the molecules of solids move, to a much less degree. This is why in motorsports if they don't warm up the tires first before they get on it they slide around.

WNCGoater

But, but, but... If I pump a tire to 75 pounds at that 80 degrees, and I pump a tire to 75 pounds at that 50 degrees, they both have 75 pounds of pressure do they not?

If it's 38 degrees outside, and my bike is outside in a garage for instance, and I pump the tire to 75 pounds of pressure, it's still 75 pounds of pressure in there just the same as if I did the same thing at 80 degree temperature.
The volume of pressure would not go down unless it was put in at a higher temperature and then cooled down to a lower temperature.

What am I missing here?


edit to add: I think you are envisioning filling the tire at a higher temperature and then not changing anything other than a lower temperature, in which case yes, the pressure would likely drop. And vice-versa though I think the change, considering the volume of a bike tube, would be negligible.

mackgoo

Yes. Pumping up a tire to a pressure at a temperature is the same as pumping the tire to the same pressure at a different temperature.
I must confess I just read your title and then the post after.
Now what you may have experienced is pumping the tire up cold then riding, putting heat in the tire, thus...........

jefnvk

Two separate issues: Tire compound and air pressure.

If you don't top off air pressure, the tire will get softer as the temp drops. After that, yes, 75# is 75#, so long as the gauge reads 75# at the prevailing temp, not the temp pumped up at.

The rubber compound gets harder as temps drop. It is why winter tires are recommended below 7C/45F regardless of actual snow coverage on cars. A sticky summer tire can become rock hard at freezing.

With bike tires, you also have to look at TPI. Even at the same temp, a higher TPI is generally going to feel less harsh than a lower.

djb

those contis from my memory of helping friends wiht them, is that the sidewall is stiff as a fricken board. I've put a couple of these tires on and off rims for friends, and thats what I remember, just how rigid the sidewall is compared to other tires. This will make a real diff in ride compared to your other tires to a certain degree.

that said, while I have no way to prove it, I ride in cold temps and every year it seems to me that my tires are harsher feeling when its colder--this coiuld easily be all in my head though....
Ive been riding a number of times lately in below freezing temps, down to about -5 or -8c and the thought did go through my mind the other week in these temps.

staehpj1

In addition to the pressure issue and the issues with the rubber compound regarding traction, there is also a difference in sidewall stiffness at different temperatures.

Those of us who value a soft supple sidewall and it's associated road feel (and slightly better efficiency) will notice a reduction of those qualities at lower temperatures.

I should note that some (many?) riders apparently do not value, maybe don't even notice, and possibly don't like if they do notice the difference in ride feel. If that were not the case we wouldn't see so many folks who like tires with super stiff sidewalls (like the Marathon Plus).

indyfabz

You know, I recently had the same experience with a model of Conti tires. I mistakenly ordered the Touring II model in 37c instead of the Top Touring II model in the same size. The ordinary Touring II came labeled as 35c, not 37c, despite being advertised as 37c. Looking at them and taking a rough measurement, no way are they even 35c. More like 32c. I kept them for commuting.

WNCGoater

Thanks for all the info.
My rides are mostly road miles but a lot of that is chip/seal and LOTS of cracked asphalt. I decided to get a steel touring bike for the purpose of bigger tires, more upright ride, overall comfort oriented especially when getting up in the 50-60 mile range.
So, being new at using touring tires, is there a recommended tire that gives a nice cushioned ride and do people use a "winter" tire for cold weather riding?

52telecaster

i have noticed my tires feeling harder when its cold. no science just saying.

Tourist in MSN

It sounded like you liked the ride on the Schalbe 40mm wide tires, not sure why you want to use other tires or what you are trying to achieve. If you could be more specific we might be able to provide some advice.

Maybe you should consider your tire pressure instead of searching for other tires? I usually run pressure that exceeds 15 percent tire drop but some people really like that rule of thumb for rear tire pressure.
https://janheine.wordpress.com/2016/...ure-take-home/

I find that rule of thumb suggests much lower front tire pressures than I think are appropriate, so I usually run a front tire pressure that is about 80 percent of the rear pressure.

jefnvk

Can you define "winter" a bit better? Around me, "winter" implies studs or 3"+.

That said, I have yet to use them in cold, but I've really been liking my Clement USHs. 35mm, plush, and fairly fast rolling (IMO). I've also had Paselas out below freezing, with no noticeable degradation in ride quality.

djb

if you are referring to a regular tire, non studded tire, nope I just what I have on the bike.

whats more important here for you I suspect is the tire pressure you are running. I hope you have an actual gauge or floor pump with a gauge, because with one you could simply note what pressures you are riding with (lets say 75) and reduce it down and you will find a significant increase in riding comfort.

as a reference, on one of my commuters I have 35mm tires, I weigh about 140, and always have rear panniers on with at least 15lbs of stuff probably, clothes, locks, etc etc , and I run these tires at about 40fr and 45 rear. You might not want to go that low if you are a lot heavier, but I highly recommend doing some riding tests at lower pressures and you will find it makes all the diff, cold temps or not.

just to be clear , the diff in tire feel with colder temps can be noticed, but its not a huuuuge thing. Too high pressures are though, and lowering them down will really make a diff, especially in the front tire for your riding comfort.

WNCGoater

HA! Yes "winter" can mean different things to different people! For you guys in the great frozen north, I suspect you'd laugh at what we call winter down here. Multiple days in the 20's is looked on as a borderline natural disaster!

A winter with more than three snows exceeding 4-6" will be talked about for decades.

Darth_Firebolt

colder air is also more dense, so if you inflate to 75 psi at 50F, there will be more air molecules in your tires than if you put 75 psi at 80F. the tire inflated at a lower temperature will be heavier than one inflated at a higher temperature. mostly insignificant in a bicycle tire and with these temperature differences, but still true.

saddlesores

there might be an insignificant, barely measurable, difference.
but more likely any perceived change is due to the effects of
cold on your human body.

how cold is cold? here in bangkok, when the mercury drops to a
frigid 80°F, the locals start wearing insulated jackets backwards
whilst riding their scooters.

WNCGoater

Not sure how to answer. I HAD ridden some 28's on my road bike and so I knew I wanted a bigger tire for this touring bike.
When I ordered the bike, being used to riding 23-25mm, I just envisioned big fat, almost mtn bike-like tires with 40mm so I ordered some 32's. Maybe I had a fear of a slow ride or negative aesthetics. Reality is, 40's aren't that big. And so, I'm not disappointed in the 40's, on the contrary I'm impressed with the feel of the ride. I was just a bit shocked, and a little disappointed, at the difference when I put on the 32's.

I have by habit, just inflated my road tires at or near max pressure, always running around 100+psi in them. It really never crossed my mind to run these 32's lower to add a bit of cushion. It may be the simplest answer or solution is staring me in the face. Thanks!

cyccommute 

There are a number of factors to consider with regard to ride quality. Some have more impact and others not so much.

Let's get the "gas" thing out of the way to start. The temperature differential is too small for there to be much pressure difference from 70°F to 30°F. It would be a few psi at best and probably not even a "few". I'm going to be lazy and not do the calculations but from past posts, going from 70°F to 150°F results in less than 10 psi difference. It's tiny.

As for fantom1 comments, they are just wrong. Sorry but they are. The tires are a closed system. You can't increase moles of gas unless you put in more gas. A tire is a closed system that in volume constrained so the change in pressure is dictated by Guy-Lussac's law where you only consider the direct proportional relationship between pressure and temperature. The only proviso is that the temperature has to be in Kelvin for the equation to work.

Other factors to consider are pressure...was the new tire pumped up harder than the old one? You should also consider the casing of the tire. The Continental is a suppler tire with more threads than the Schwalbe but it is also a narrower tire.

But, in this case, I would say that the main impact on the ride quality is the weather. The cold makes the rubber stiffer and less flexible. Basically, the tire is harder and so would transmit more impact to the rider.

There is also a bit of a psychological impact that I've noticed when riding in cold weather, especially if you haven't done it in a while or don't do it regularly. Cold can magnify annoyances. Little things that you wouldn't notice on even long rides in warm weather like foot pain or an uncomfortable saddle become much bigger issues when you are cold. When you are miserable...and while cold riding can be fun, there is still some misery involved...you notice everything. We're still little tropical monkeys and we don't really like cold. Where would you rather be in December...Hawaii or Michigan?

pdlamb

Fully agree with @cycocommute's points on gas molecules, air pressure, and psychological impact. (FWIW, back of my envelope says 8.7% difference between 75 and 32F.)


However, I suspect the difference is in the tires rather than rubber temperature. I'm not familiar with the Schwalbe Silentos, but the Continental Sport Contacts are pretty rigid, regardless of how many threads they claim. I suspect thick, heavily cross-linked rubber on the sidewalls of the Contis. Either way OP is comparing apples to oranges.


To be sure would require the sacrifice of halving a ride (or doubling it!). Ride on one set of tires for a while, loop back by the house and change tires, then head back out for the same ride at close to similar temps.

fietsbob

Physics; cold air is more dense than warm air, so why would semi solids like butyl rubber, act differently..

There are non studded winter tires using a rather soft rubber compound, that is able to be a little grippier in cold weather..

I have hard compound studded tires , they are super long wearing, and since where I live it does not freeze that often

It's an occasional not a seasonal occurance.. my Nokian tires are still good , 25 years on...





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