tire width & rolling resistance

[Catrin]

I am not very fast. My average speed at the end of a ride is finally breaking 13 mph :) It is basically that low of an average because of hills. On flatter terrain, unless there is a strong wind, I can get up to 16-18 mph pretty easily, and that might improve as I clip in :)

Of course part of the equation is my bike, Ms. Explorer is a touring bike, she is built for comfort, not for speed. She also has 26 x 1.5 tires...

If I were to decrease the rolling resistance a bit by going to a slightly more narrow tire, would this give me a little more speed? I am just thinking about my brevet next month. I don't want to decrease it much because I am very happy with how she handles rough pavement and chip-seal roads.

I've no idea what kind of roads will be on my brevet yet - but this seems worth considering if it would help my speed significantly without being too expensive. I am a little concerned that my speed won't be enough to finish in time, but on paper it looks like I am fast enough. On paper, that is.

I am also moving next month, so the cost just may be prohibitive anyway - I love my Conti Travel Contacts and if I do this would like to stick with the same tire, just a little more narrow.

[Catrin]

If you change I suggest staying with tires that have decent tread and screw the rolling resistance.

The tires are great and still look almost new even though they have 1,200 miles on them :) The tread is great, just wondering about the rolling resistance and speed. I wouldn't drop the width much if I do this - a quarter inch?

Will ask my LBS to show me how to check for wear when Ms. Explorer comes home today sporting her new fenders.

[Thorn]

This is one of those bike religion questions. I'll try not to cross the relgious boundary.

Tread is not necessary for road bikes. Bikes don't hydroplane; road bikes aren't chomping through dirt (well, unless you drop off road).

Wider tires are more comfortable. They absorb more shock. Over the longer distances, feeling less road fatigue can keep you riding harder longer.

If you can find 28mm tires that take the same pressure as their 23mm counterpart, the theory goes you'll be more comfortable without an increase in rolling resistance.

There is a current thread on wide tires on bike forums' long distance forum (unlike their open threads, the long distance forum is female friendly).

[Becky]

In my experience, changes to tire width don't have a whole lot of effect on speed and rolling resistance. Wider tires are definitely more comfortable though, due to the increase in volume.

If you like the tires that you have, and they're wearing well, I wouldn't sweat it. JMHO though....

[Catrin]

In my experience, changes to tire width don't have a whole lot of effect on speed and rolling resistance. Wider tires are definitely more comfortable though, due to the increase in volume.

If you like the tires that you have, and they're wearing well, I wouldn't sweat it. JMHO though....

Becky - thanks - that is exactly what I needed to know - thanks!

Thorn, I think I saw that thread on Bike forums - the LD/Rando forum is really the only one I visit there. Will check it out for my edification - thanks!

[OakLeaf]

1/4" is a LARGE change. Think about it, it's over 6 mm.

You may have a small decrease in rolling resistance due to a smaller contact patch, but you will have a LARGE decrease in weight.

Weight of the tires, tubes and rims is the most significant weight on your bike, because it's rotating weight with a very large diameter. A couple of hundred grams in your tires will make an enormous difference that you will feel right away.

The question is what tires will fit on your rims without distorting the profile. That's a question for your LBS. I really don't know what's available in 26". Is that the same as 650?

[Becky]

I really don't know what's available in 26". Is that the same as 650?

Nope. ISO bead seat diameter for 26" wheels is 559 mm vs. 571 mm for 650c wheels.

[Catrin]

Thanks everyone, Ms. Explorer is coming home from the LBS this evening so will ask about this. Probably not in my budget anyway unless my tires are showing signs of wear (I think they are fine) but it is worth considering. Hadn't thought about weight... I don't know if my wheels can even take a skinnier tire...