Tyres: 23c v 25c

open topic, for anything cycling related.

What size tyre do you ride on?

23c
45
48%
25c
38
40%
Other (list)
11
12%
 
Total votes : 94

Re: Tyres: 23c v 25c

Postby warthog1 » Thu Mar 21, 2013 11:45 am

barefoot wrote:
... and you're attributing all of that to the lack of clearance for bigger tyres?

FWIW, as a pipe-smoking cardigan-wearer who has never raced but who has done a bit of CFD in his time... anybody who takes that report seriously is truly clueless.

I'm most impressed by their models showing uniform laminar inflow to the parts of the bike they're interested in. That's funny enough in the first picture, at the head tube, where they have uniform laminar flow coming out of the back of the brake caliper (to demonstrate the amazing benefits of their faired head tube - down tube junction). But it's really really funny in the second picture showing uniform laminar flow hitting the seat tube / chain stay region, as if there's nothing upstream to disturb the flow. ORLY? :lol:

The standard joke in the CFD scene is that it's really an acronym for "Colour for directors". You can use CFD models - however flawed the model - to make pretty colourful pictures that will impress senior management who have no idea about fluid dynamics. Cervelo show us that you can also use pretty CFD pictures to impress bike geeks who want to be impressed.

For all numerical models, the junk-in-junk-out rule applies. That's especially true with CFD, where the detail of your incoming flow is absolutely critical to the results your model will give. If you're really careful with CFD, you can get numerical results that show some correlation with experimental results... but it's not always easy to do. And ignoring upstream obstructions is a really good way to ensure it won't happen.

tim


No I'm not attributing it all to a lack of clearance for tyres. However I would expect that is part of the overall package.

I do a bit of also ran racing and really enjoy tt as my favourite cycling event.
I have a tt bike an aero road bike and a round tubed more traditional road bike.
I first got into tts on the round tubed road bike and ran that std, then with aerobars then deep section tubular wheels and finally as the bug bit a tt bike with disc rear.
I ran the roadie with clip ons in much the same position as the tt bike.
The tt bike was 30 secs per 8 km lap faster than the roadie. I would attribute a fair bit of that to the aerodynamics of the bike, along with rigidity and for me, longer cranks on the tt.
I still have the original bike and now the S5. I race handicap and scratch races with the same guys. I am significantly more comfortable on the S5 during a race than the older bike. I attribute that to the small savings in watts as helping to recover a fair bit when on your limit.
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by BNA » Thu Mar 21, 2013 2:15 pm

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Re: Tyres: 23c v 25c

Postby Aushiker » Thu Mar 21, 2013 2:15 pm

I voted 23 mm but have a 23 mm/25 mm mix on the commuter at the moment. Not really convinced that the 25 mm are adding anything of value, well I cannot notice it anyway.

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Re: Tyres: 23c v 25c

Postby MichaelB » Thu Mar 21, 2013 2:53 pm

warthog1 wrote: .....I still have the original bike and now the S5. I race handicap and scratch races with the same guys. I am significantly more comfortable on the S5 during a race than the older bike. I attribute that to the small savings in watts as helping to recover a fair bit when on your limit.


Sorry, but I call placebo on that.

In theory, there are savings, but I think reality counters a lot of it.

I'm fat and slow, so 25C tyres for me on wider rims.

As I said, there are more and more WT teams running 25C tyres, so what is good for the goose ....
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Re: Tyres: 23c v 25c

Postby warthog1 » Thu Mar 21, 2013 4:01 pm

MichaelB wrote:
warthog1 wrote: .....I still have the original bike and now the S5. I race handicap and scratch races with the same guys. I am significantly more comfortable on the S5 during a race than the older bike. I attribute that to the small savings in watts as helping to recover a fair bit when on your limit.


Sorry, but I call placebo on that.

In theory, there are savings, but I think reality counters a lot of it.

I'm fat and slow, so 25C tyres for me on wider rims.

As I said, there are more and more WT teams running 25C tyres, so what is good for the goose ....


I wasn't talking about the tyres there, I was talking about the difference between the 2 bikes I have running the same wheels and tyres. I have gone OT again :roll: normal for me :oops:
My strava times are all quicker on the S5 v the old girl too.
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Re: Tyres: 23c v 25c

Postby Nobody » Thu Mar 21, 2013 5:16 pm

warthog1 wrote:Once you have that where else are you going to get 20 odd watts :idea:
I don't need the extra 20W (of bought advantage) because I'm aging gracefully. :idea: :P

warthog1 wrote:When Tony Martin, Fabian Cancellara, and Bradley Wiggins start using shorter cranks on their tt bikes I'll look into it again. They are not
But you aren't any of them. Fit is an individual thing.

warthog1 wrote:I did try 172.5's they were slower for me at my much more modest speed. :oops:
This is more telling, but did you adjust your position to get any better aero advantage by using the shorter cranks?
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Re: Tyres: 23c v 25c

Postby warthog1 » Thu Mar 21, 2013 5:48 pm

Nobody wrote:

warthog1 wrote:When Tony Martin, Fabian Cancellara, and Bradley Wiggins start using shorter cranks on their tt bikes I'll look into it again. They are not
But you aren't any of them. Fit is an individual thing.


No, but they are the fastest road cyclists in the world. If short cranks were the go for tt's they'd be using them.

Nobody wrote:
warthog1 wrote:I did try 172.5's they were slower for me at my much more modest speed. :oops:
This is more telling, but did you adjust your position to get any better aero advantage by using the shorter cranks?


Yes I did. There wasn't much in it but neither was there much time difference between myself and the bloke I was trying to beat.
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Re: Tyres: 23c v 25c

Postby Nobody » Thu Mar 21, 2013 6:39 pm

warthog1 wrote:No, but they are the fastest road cyclists in the world. If short cranks were the go for tt's they'd be using them.
Well OK, but I think they would still be the fastest riders in the world if they had shorter cranks. Especially since TT is primarily about aerobic capacity and aerodynamics. If they were the best track sprinters it might point harder at crank length being an issue due the nature of the event. But I see (as usual) we'll just have to agree to disagree on this point. :)
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Re: Tyres: 23c v 25c

Postby brawlo » Thu Mar 21, 2013 9:13 pm

Crank length, from everything I've read relating to track, is a moot point. Shorter cranks allow you to spin a little faster in an easier gear, while longer cranks allow you to push a harder gear for theoretically the same pedal rotation speed. The difference between crank lengths is taken up by the variation in gearing.

Having a quick read through this aero stuff has me thinking though. If getting lower allows for a more aero position, then shorter cranks may in fact be better because your legs don't come up quite as far on the upstroke, thus allowing you to get your upper body lower, and theoretically more aero...... But that is in my professionally inexperienced opinion...

Oh yeah, and 25mm ride over the roads that send up small vibrations better. Other than that, I've not really noticed a big difference after using both
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Re: Tyres: 23c v 25c

Postby twizzle » Thu Mar 21, 2013 9:40 pm

cyclotaur wrote:
Angus wrote:23mm front and back. Many moons and kilos ago I used race on 19mm, so the 23mm is like a comfort tyre now! I bought a new bike 6 months ago which had 25mm tyres on it, and I didn't like the feel of them cornering. Not terrible, but when they wore out I changed to 23mm and they feel better for me anyway.

Wow - you wore out a new set of tyres in less than 6 months !! :D


Ride more.

I get seven or eight weeks out of a rear tyre (about 1800 - 2000 k's).


Sent from my iThingy...
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Re: Tyres: 23c v 25c

Postby barefoot » Thu Mar 21, 2013 9:53 pm

twizzle wrote:I get seven or eight weeks out of a rear tyre (about 1800 - 2000 k's).


I was a bit alarmed when I took a good look at my rear tyre the other day.

It's been on since Christmas (when I built the bike) , and is only just going to clock 1000km this weekend. But it's significantly worn already. I wouldn't be surprised if it's due for replacement by 2000km at this rate.

That's a Maxxis Detonator. I think I'll replace it with something more durable next time.

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Re: Tyres: 23c v 25c

Postby Angus » Fri Mar 22, 2013 4:45 am

twizzle wrote:
cyclotaur wrote:
Angus wrote:23mm front and back. Many moons and kilos ago I used race on 19mm, so the 23mm is like a comfort tyre now! I bought a new bike 6 months ago which had 25mm tyres on it, and I didn't like the feel of them cornering. Not terrible, but when they wore out I changed to 23mm and they feel better for me anyway.

Wow - you wore out a new set of tyres in less than 6 months !! :D


Ride more.

I get seven or eight weeks out of a rear tyre (about 1800 - 2000 k's).


Sent from my iThingy...


Less than 2000k's is pretty low. Do you ride racing tyres? I'm almost 100kgs so load the tyre up and still get about twice that.
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Re: Tyres: 23c v 25c

Postby Aushiker » Fri Mar 22, 2013 9:56 am

Angus wrote:Less than 2000k's is pretty low. Do you ride racing tyres? I'm almost 100kgs so load the tyre up and still get about twice that.


I am normally getting around 4,000 to 5,000 km from Continental GP4000s which I rotate from the front to the rear to the bin.

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Re: Tyres: 23c v 25c

Postby boss » Fri Mar 22, 2013 10:58 am

Aushiker wrote:
Angus wrote:Less than 2000k's is pretty low. Do you ride racing tyres? I'm almost 100kgs so load the tyre up and still get about twice that.


I am normally getting around 4,000 to 5,000 km from Continental GP4000s which I rotate from the front to the rear to the bin.

Andrew


I got 4500 from a rear before it wore through the indicators. I'm a lightweight though.

Still had heaps of life on the front tyre but I took it off as I wanted to try 25mm tyres. So it's just sitting as a spare. At a guess I'd say a front tyre would be good for 6000km or maybe 5000km if you rotate it to the back after 4500.
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Re: Tyres: 23c v 25c

Postby twizzle » Fri Mar 22, 2013 11:35 am

Angus wrote:Less than 2000k's is pretty low. Do you ride racing tyres? I'm almost 100kgs so load the tyre up and still get about twice that.


93Kg. 380W FTP. Panaracer Race Type D. Best puncture protection I've found, lousy tyre life. But I'd never gotten more than 2.5K k's out of a tyre before something put a big hole in it anyway.
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Re: Tyres: 23c v 25c

Postby Mulger bill » Fri Mar 22, 2013 6:59 pm

Got and mounted my 25mm Re-Fuse tyres for the FG today. Skinny looking things compared to the nominally 25mm ProRace that was there before.

Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?
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Re: Tyres: 23c v 25c

Postby Nobody » Fri Mar 22, 2013 7:47 pm

Mulger bill wrote:Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?
I read it's about how much the manufacturer thinks the tyre will expand during its lifespan. Schwalbe say they use bigger casing now since they developed a casing with less stretch.
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Re: Tyres: 23c v 25c

Postby find_bruce » Fri Mar 22, 2013 7:54 pm

Mulger bill wrote:Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?

Sheldon says it is a big chunk of dishonesty, aka marketing
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Re: Tyres: 23c v 25c

Postby toolonglegs » Fri Mar 22, 2013 8:38 pm

schwalbe durano 25's ... 6000 ( maybe 8000 ) kms for a rear tyre ( big rider, plenty of power, rough as guts roads, no glass ) ... race on them when I can't be bothered swapping to race tyres.
80-100 psi depending on how often I pump them ( latex tubes ).
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Re: Tyres: 23c v 25c

Postby warthog1 » Sat Mar 23, 2013 7:51 am

toolonglegs wrote:schwalbe durano 25's ... 6000 ( maybe 8000 ) kms for a rear tyre ( big rider, plenty of power, rough as guts roads, no glass ) ... race on them when I can't be bothered swapping to race tyres.
80-100 psi depending on how often I pump them ( latex tubes ).


That is really good mileage from a rear tyre for a big rider :) . How many k's do you get out of a GP4000S on the rear?
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Re: Tyres: 23c v 25c

Postby toolonglegs » Sat Mar 23, 2013 4:52 pm

Tried them many years ago and never liked them. They certainly didn't last as long as these things do... I buy two sets a year for training.
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Re: Tyres: 23c v 25c

Postby warthog1 » Sat Mar 23, 2013 7:14 pm

Thanks. I really like the GP4000S but only get about 3k out of a rear tyre. I'm lighter and putting out less power than you, so the durano must be a fair bit more durable.
I've got a durano 23 on a back wheel I haven't been using. I'll chuck it on when my Gp wears out
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Re: Tyres: 23c v 25c

Postby Mulger bill » Sat Mar 23, 2013 10:20 pm

Mulger bill wrote:Got and mounted my 25mm Re-Fuse tyres for the FG today. Skinny looking things compared to the nominally 25mm ProRace that was there before.

Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?


So I got the calliper out and measured 'em across the widest part of the carcase...
Pro Race 25mm:27.6
Re-Fuse 25mm:24.8
Kenda Whatevers 23mm:22.3
'Gator 28mm 27.8

Good work in the sizing department lads :roll:
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Re: Tyres: 23c v 25c

Postby toolonglegs » Sat Mar 23, 2013 10:35 pm

Mulger bill wrote:
Mulger bill wrote:Got and mounted my 25mm Re-Fuse tyres for the FG today. Skinny looking things compared to the nominally 25mm ProRace that was there before.

Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?


So I got the calliper out and measured 'em across the widest part of the carcase...
Pro Race 25mm:27.6
Re-Fuse 25mm:24.8
Kenda Whatevers 23mm:22.3
'Gator 28mm 27.8

Good work in the sizing department lads :roll:


Did you measure the volume of each?
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Re: Tyres: 23c v 25c

Postby jacks1071 » Sat Mar 23, 2013 11:36 pm

twizzle wrote:
Angus wrote:Less than 2000k's is pretty low. Do you ride racing tyres? I'm almost 100kgs so load the tyre up and still get about twice that.


93Kg. 380W FTP. Panaracer Race Type D. Best puncture protection I've found, lousy tyre life. But I'd never gotten more than 2.5K k's out of a tyre before something put a big hole in it anyway.


I need a lead-out man with your dimensions and power output :-)
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Re: Tyres: 23c v 25c

Postby Nobody » Sun Mar 24, 2013 7:34 am

Mulger bill wrote:
Mulger bill wrote:Got and mounted my 25mm Re-Fuse tyres for the FG today. Skinny looking things compared to the nominally 25mm ProRace that was there before.

Is there such a thing as a standard for bike tyre sizing or do makers just eye the moulds and say "She'll be right"?


So I got the calliper out and measured 'em across the widest part of the carcase...
Pro Race 25mm:27.6
Re-Fuse 25mm:24.8
Kenda Whatevers 23mm:22.3
'Gator 28mm 27.8

Good work in the sizing department lads :roll:
Were these on the same wheel with the same pressure? I've found both make a difference.
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