AlTheKiller

cliffs: fatter tires are better.

except when they're not.

And sometimes they amount to about the same, but different.

Also, vague physics problems are pointless.

Andy_K 

I think you need to take a more existential view of this thread. Yes, nearly everything that has been said here is entirely pointless, but in order for the thread to continue each of us must choose how we will participate in the conversation, not necessarily with a goal of bringing the thread back around to something useful but just to manifest ourselves in the reality that is this thread.

mikeybikes

That's deep.

AlTheKiller

Edit: totally quoted wrong image which would have looked insulting

Gresp15C

Well, I still appreciate the comments, though the thread has taken an amusing turn. Perhaps I should have admitted that I have somewhat of a personal compulsion to understand how things work. I appreciate that there are many layers of complexity to be uncovered when digging into the physics, and a point where it's no longer going to be fruitful to dig any further. For instance the "all things being equal" kinds of generalizations can be useful (if true), especially if they dispel misconceptions. But it appears that an accurate quantitative model that covers all of the possible parameters, e.g., sidewall construction and tread pattern, probably doesn't exist in any accessible form.

I've decided to shelve this particular project idea for now.

Joe Minton

Gresp154c:

I am sorry that you have not gotten any sort of useful answer to your query. There are too many folks here who are looking for some excuse to prove their superior knowledge, which usually works the other way around.

I can only give opinions based on my experience, which includes my own plus that of others with whom I have had conversations/interviews.

My Advice:
Consider only your own particular needs:
1) If going fast is your goal, then you need to consider smaller, higher pressure, tires.
2) If your goal is comfort, then you need to consider larger tires with less pressure.


I, personally, use highly- puncture proof tires (Conti "Touring Plus") w thin Panasonic liners. I haven't driven my car for five months+). My other bike, Cannodale "Synapse" is also fitted with Conti ("Gatorskin") & Panasonc tire liners.

Haven't had a flat in over a year (3+ thousand miles).

Joe

tedi k wardhana

i've been commuting on 700x38, 16x1.50/1.75, also 29x2.1
and i love 29x2.1 so much.
maybe this is because the roads here are not always smooth.

takenreasy

I commute on 700x38 and 26x1.75 and since I don't care how fast I go it works out great.

acidfast7

Have you been to Kansas?

Gresp15C

Oh, no problem. I figure that I can sort out the physics myself, but was just trying to get an impression of whether my proposed project was worthwhile, i.e., if the difference is likely to be big enough to bother with in the grand scheme of things. As I mentioned, my present plan is to do nothing until at least I've worn my present tires to oblivion.

AlTheKiller

We've come around to this point again. The old addage of thinner and higher pressure being faster is very arguable. And is kind of the purpose of this thread. You CAN have both. Just because most people who get fat tires either get cheap wire beads, or something loaded to the gills with flat protection, doesn't mean the very idea of higher volume = slower. In practice, sure, you get a blow out and need a new tire ASAP, if you get a 700x35 or bigger, it's probably also heavy and not supple. Unless you happen to get a flat in Walnut Creek near the Rivendell shop where you can get some Jack Browns.

I think the main physics point people were arguing, unsuccessfully, was if higher volume in and of itself is in any way slower. I think most people arguing that they are always slower, have never experienced a fast and fat tire. And I think most people (or at least me) arguing that fatter might lose very little to thin and racey, are probably people who ride in a more relaxed style.

I think the main point from me is that it's quite easy to get thin, high pressure tires which ARE slow. I've had 700x23 tires that weigh nearly twice as much as my Jack Browns which measure 35mm wide. Every rock slows you down on those, like on most high pressure/thin tires, and they don't even accelerate quickly like a good 23 would.

Maybe the question should be, "Are crappy tires worth the trouble?". I say no

Get a nice, thin tire, or a nice, thick tire. And you'll probably be happy. A fast guy on a slightly thicker road slick might lose a tenth of a percent of snappy speed going from the normal 700x25, to a nice 35. A slower guy might notice even less of a difference, since snap acceleration doesn't register on his commute. And that fatter tire might keep his speed up on certain roads, translating to a "faster" tire.

Andy_K 

Joe Minton

Viewpoints:
As some of you may know, I currently ride two bikes.

One is my ‘car’; I use it for most things (shopping, appointments and so on) accounting for most of the miles I ride. After missing a doctor’s appointment because of two ‘goathead’ flats, I switched to Conti “Touring Plus” tires and made them larger while I was at it (37mm front & 42 rear). I also fitted light tire liners. The price I paid was: A stiffer ride from the stiffer sidewalls and a less ‘lively’ feel. It was completely worth these minor limitations --- I no longer worry (so much) about ‘getting there’ on time. Today, for instance, I rode this bike nine miles each way for a doctor’s appointment without significant concern about getting a flat. Still, I started early enough to fix one and still make it on time.

My other bike is a light road bike and is currently fitted with Conti “Gatorskins” (25 & 28mm). Since I do not ride this bike to anyplace that is time-sensitive, these tires are more than good enough. When they wear out, I’ll probably fit 28mm Conti 4000s II front & rear (wish I could get 32mm versions).

I intend to ride several light touring trips next year (rather short: 100 & 450 miles). I’ll use the light bike (Cannondale Synapse) & pull a trailer (“Extrawheel”). Given the clean & smooth road I’ll be traversing, PCH from San Francisco to LA, the Synapse with its Gatorskins should do just fine.

I have done a fair job of considering my needs and ambitions and think that my choices adequately reflect my needs. I am six-two and weigh 16-stone (224#); for comfort, I need/want bigger tires.

Racing has way too much influence on what we buy, ride & do. --- Forget those genetic deviants ;o) --- Only consider your own comfort, riding conditions and goals.

Your needs & results may vary --- and that, my friends, is why we must consider and choose for ourselves. There may be reasonable upper & lower limits but we need to make sure our particular, actual, needs are met before we consider any ‘universal’ or fashionable rules about our tire choices.

Always: Rubber side down,
Joe