Tire question

[MrBond]

Other than the obvious benefit of running a narrower tire for less rolling resistance, what are the pros and cons of running 21, 23, or 25 widths ?

I just saw a pic of an IM guys' bike, and he was running 25s, that goes counter to what I would have expected....

http://www.slowtwitch.com/Products/The_ ... _5079.html

[jonovision_man]

Other than the obvious benefit of running a narrower tire for less rolling resistance, what are the pros and cons of running 21, 23, or 25 widths ?

This used to be obvious - until they found that it's actually wrong!



The more I've read the more I'm inclined to go back to 25mm. Might be a touch heavier and not quite as aero, but less rolling resistance probably makes it a wash.

jono

[MrBond]

Wow, that is interesting - I put 21s on my new bike when I got it, but I think I'll put the 23s back on and see if there's a noticeable difference.

[jonovision_man]

Here's a good article about it:
http://www.competitivecyclist.com/learn/25-vs-23

There was one guy a few years ago that did a bunch of tests where he had people roll downhill on different tires. Wider won, everyone thought he was a nutjob and must have got something wrong. Love it.

jono

[MrBond]

Here's a good article about it:
http://www.competitivecyclist.com/learn/25-vs-23

There was one guy a few years ago that did a bunch of tests where he had people roll downhill on different tires. Wider won, everyone thought he was a nutjob and must have got something wrong. Love it.

jono

Thank you !

[drghfx]

Here's a good article about it:
http://www.competitivecyclist.com/learn/25-vs-23

There was one guy a few years ago that did a bunch of tests where he had people roll downhill on different tires. Wider won, everyone thought he was a nutjob and must have got something wrong. Love it.

jono

Kind of the same old story. People take something as gospel and then are not willing to listen to anything else. The earth is the centre of the universe!

[Wu wei]

Other than the obvious benefit of running a narrower tire for less rolling resistance, what are the pros and cons of running 21, 23, or 25 widths ?

I just saw a pic of an IM guys' bike, and he was running 25s, that goes counter to what I would have expected....

http://www.slowtwitch.com/Products/The_ ... _5079.html

Just go to Tom Anhalt's blog
http://bikeblather.blogspot.ca/

And his spreadsheet
https://docs.google.com/spreadsheets/d/1f398PSxFhSj6Zdsjllo14l5XyhOhcmlkzjvHwfKjNOs/edit#gid=361584932

Still the best mix of aero, low rr, puncture resistance and durability is the original Conti GP4000S 23C with latex tubes of course...

Haven't heard as good of reviews about the GP4000S II's though.

Tire pressure almost makes a difference on rolling resistance. Too high is just as bad as too low.

[MrBond]

"Still the best mix of aero, low rr, puncture resistance and durability is the original Conti GP4000S 23C with latex tubes of course...
Tire pressure almost makes a difference on rolling resistance. Too high is just as bad as too low."

I just run the tire pressure recommended on the sidewall by the manufacturer (checked with a GOOD gauge), should I be doing something else ?

[Wu wei]

"Still the best mix of aero, low rr, puncture resistance and durability is the original Conti GP4000S 23C with latex tubes of course...
Tire pressure almost makes a difference on rolling resistance. Too high is just as bad as too low."

I just run the tire pressure recommended on the sidewall by the manufacturer (checked with a GOOD gauge), should I be doing something else ?

I don't have a tire handy at the moment, but I think sidewalls usually only denote max and/or min pressure... not IDEAL pressure.

narrow inner rim = higher pressure
Wider inner rim = lower pressure

Heavier athlete = higher pressure
lighter athlete = lower pressure

narrower tire = higher pressure
wider tire = lower pressure

smoother roads = higher pressure
rough roads = lower pressure

I run rims with 18mm internal width and 23mm tires. I weigh 62kg.
So, I'm light, riding wide rims, and "average" width tires.
I usually ride around 95psi.
I'll run lower pressure when crit racing for a bit more grip in the corners.
Triathlon and road racing, it's usually course dependent.
Challenge Roth = best pavement ever... ~103psi
Challenge Penticton Half = 40km of road destroyed by studded tires ~90psi.

Generally, I try to get a tire pressure that feels smooth, with no chatter.
And lower tire pressures are better than you think.

Always use latex tubes... they'll save something like 3-4 watts/wheel, and give you a nicer ride, and they are more puncture resistance (if you install them correctly).

And NEVER EVER use Gatorskins for racing. Just don't.

[MrBond]

Thank you again Sir !

I'm going to do some experimenting, bearing in mind that am (ahem) a Clydesdale and fairly new to all this skinny tire business...

[Wu wei]

Thank you again Sir !

I'm going to do some experimenting, bearing in mind that am (ahem) a Clydesdale and fairly new to all this skinny tire business...

As a Clydesdale I would recommend 25mm+ tires for sure! (as long as they fit your frame/brakes) You will be able to drop your psi and see an increase in comfort.

Here's a rough guide to extrapolate from:

[jonovision_man]

Thank you again Sir !

I'm going to do some experimenting, bearing in mind that am (ahem) a Clydesdale and fairly new to all this skinny tire business...

As a Clydesdale I would recommend 25mm+ tires for sure! (as long as they fit your frame/brakes) You will be able to drop your psi and see an increase in comfort.

Here's a rough guide to extrapolate from:

Being north of 180lbs means never having to look at charts.

jono

[Wu wei]

Being north of 180lbs means never having to look at charts.

jono

It's still a rough guide, but yeah. I'll ask my heavier buddies what pressures they use at the bike races this weekend.

I'd ridden tires well under their recommended pressure for CX racing. Minimum 70psi? HA! Try 28psi...

[MrBond]

Thank you again Sir !

Being north of 180lbs means never having to look at charts.

jono

Being north of 180lbs means not worrying about spending obscene amounts of money saving grams on yer bike stuff...

[jonovision_man]

Being north of 180lbs means not worrying about spending obscene amounts of money saving grams on yer bike stuff...

Ha that too.

jono

[Mark.AU]

I've always run 23's at 110 front and 120 back. I've raced at 95-97kg so bigger fella here, too.