Road Cycling - Tire question...

Is there an advantage to using a 700x23 tire over a 700x25? I ask cause I have an extra set of tires that I want to use that are 700x25...and my current ones are 700x23.. I assume it means they are wider therefore maybe a little slower? I also noticed that the "23's" say to inflate to 120psi, while the others say 100psi...


Thanks for any input :)

yes, the 25's will be slower, i think its the friction caused by the tires on the road, but i do not know.

yes, the 25's will be slower, i think its the friction caused by the tires on the road, but i do not know.


Noticeably slower to the average rider?

more surface area = more friction = more drag = slower

Physics works.

That being said, realistically 25's for training will hold up significantly better than 23's especially if you as a rider carry any heft (aka 225+)

I'm a larger rider and I have a hard time keeping 23's inflated for one reason or another on most any ride. I used train with 23's and I had a flat a week. Rocks, glass, potholes, rr tracks you name it. Switched to Conty Gatorskins in 25 and life has been good. The difference in speed is only slightly noticable to me, but worth it to be riding flat free months in a row. One man's opinion.

more surface area = more friction = more drag = slower

Physics works.

That being said, realistically 25's for training will hold up significantly better than 23's especially if you as a rider carry any heft (aka 225+)

I'm a larger rider and I have a hard time keeping 23's inflated for one reason or another on most any ride. I used train with 23's and I had a flat a week. Rocks, glass, potholes, rr tracks you name it. Switched to Conty Gatorskins in 25 and life has been good. The difference in speed is only slightly noticable to me, but worth it to be riding flat free months in a row. One man's opinion.

Yeah I had the 25's on my old wheels... one flat (huge piece of glass) in over 1000 miles... Got new wheels with 23's on 'em and I've gotten about four flats in about 100 miles... I guess with the lighter wheels and same old tires, it will still be an improvement over what I had...

Is there an advantage to using a 700x23 tire over a 700x25? I ask cause I have an extra set of tires that I want to use that are 700x25...and my current ones are 700x23.. I assume it means they are wider therefore maybe a little slower? I also noticed that the "23's" say to inflate to 120psi, while the others say 100psi...


Thanks for any input :)

Take a good look at a millimeter ruler. Two millimeters isn't very much is it? That's all the difference we are talking about either way. I doubt you'll subjectively feel any difference.

In general wider tires are also a little taller and have a greater cross section. As a result they give a more cushioned ride and are more resistant to pinch flats. Narrower tires have less frontal area so they are more aero. At equal air pressure they will pinch flat more easily and they have more rolling resistance because they deform more as they rotate. Fortunately, since they have less internal surface area, they can tolerate more air pressure before blowing off.

While it's true that every little bit counts, once you get over about 12 MPH the air resistance of your body on the bicycle outweighs everything else to such an extent that small differences in the amount of aero drag and rolling resistance from the tires doesn't really matter much.

Okay here is another question related to the first... The 23's say to inflate to 120psi, the 25's say 100...at 100 the 25's feel a little low (compared to the 23's at 120..) so do I just do what the tire says, or put a little more air in there? I don't want to overinflate them.. they just seemed a little soft... I'm 165lb btw..


Thanks!

Okay here is another question related to the first... The 23's say to inflate to 120psi, the 25's say 100...at 100 the 25's feel a little low (compared to the 23's at 120..) so do I just do what the tire says, or put a little more air in there? I don't want to overinflate them.. they just seemed a little soft... I'm 165lb btw..


Thanks!


Are you sure they are the same tire from the same manufacturer? The exact same tire should have the same max inflation for 23's and 25's. You must have two different brands of tires.

Are you sure they are the same tire from the same manufacturer? The exact same tire should have the same max inflation for 23's and 25's. You must have two different brands of tires.

Same brand, but different tires.. Bontrager race x lites, (23) and bontrager select (25)

Same brand, but different tires.. Bontrager race x lites, (23) and bontrager select (25)

That's why the pressure is different. Probably constructed different internally.

That's why the pressure is different. Probably constructed different internally.

So I assume its best to stay with what it says on the tire? :)

Yeah, on very smooth roads the 23's may be faster than the 25's, BUT on rougher roads the 25's will actually be faster! On a long 100 mile race you may be talking only a couple of seconds depending on whether the roads are very smooth or very rough. If your commuting or training on surface streets the wider tires will be safer with less tendancy to drop in to ruts and groves on street surfaces plus they will stop a tad faster.

Yes, wider tyres are definitely safer and more comfortable, but there's no way i would ever ride a 25. I actually race and train on Conti 20s with 160psi in them!! they hurt your ass a bit, but on smooth roads they FLYYYYYYYYYY

So I assume its best to stay with what it says on the tire? :)

respected people in the biking world like sheldon brown and jobst brandt (sp?) would advise you to ignore the manufacturers rating... rather, set the pressure based on your weight and tire size... i wouldnt think that any modern <25mm tire would NOT be able to hold up 120psi

Okay here is another question related to the first... The 23's say to inflate to 120psi, the 25's say 100...at 100 the 25's feel a little low (compared to the 23's at 120..) so do I just do what the tire says, or put a little more air in there? I don't want to overinflate them.. they just seemed a little soft... I'm 165lb btw..


Thanks!

You could probably pump them up to 140 - 150 with no problems. I regularly ride with my Ultras at 150, just to stop my fatbutt from putting the rims on the ground

If i was a rather lg guy,i'd use 25's instead of going over the max psi on a 23.
Jakey,put the 25's on and ride for a week and see how it is,nothing to lose.

Which tyre will be slower? The 23 or the 25? Could this be relative slowness be determined by which tyre has the least rolling resistence? Is the air preesure of the tyre a factor in determining slowness? Inquiring minds want to know. Check this out:
http://sheldonbrown.com/tires.html#rolling

Its the engine.

Its the engine.

and this has no relavence at all to what we were talking about. if you are in good shape, sure, you will be faster then someone who is in bad shape. however, we were talking about tires, and he was asking if there is a difference in how different tires feel.

25s will feel different, and probably not as fast. I can notie a definite difference in my old 25s vs. my newer 23s. the biggest difference, though, is gonna be in the quality of the tire. the x-lites are lighter and more flexible, which will yeild a faster, smoother ride at a given pressure. the selects are decent tires, but they are more training tires, and so they will not be as light, and will not have as flexable a casing. generally, the more flexible a tire's casing the faster it will roll at a given pressure.

I've used both and noticed no difference except a bit better ride. Does that answer suit you or do you want another. He's got both fricken sizes. Put the dam things on and find out for youself,better then any of your or my answers.