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Which tyres best to use??


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Hi all...

 

Which tyres best to use 700c x??

 

there is alot of types of tyres.

 

700c x 19

700c x 20

700c x 21

700c x 22

700c x 23

700c x 25

 

and so on ...

 

if u use 700c x 20 is that means the tyre is smaller than 700c x 23??

 

thanks guys.

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the 19, 21, 23, etc measurement is supposed to be the width in mm. But plenty of research shows that different tyre manufacturers measure small or wide (depending on their motive for doing so)....

 

"Standard" width is 23mm. 90% of the clincher tyres out there are 700x23. But they will often put out a 25mm version, and a 21mm as well.

 

Unless you have a specific reason to go either way, I would just get 23mm. Plus, the 23mm tyres often have awide range of coulours too if that makes a difference........... :lol:

 

Cheers,

Abby

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Measure the width of the front race wheel rim and use the same width to get a nice aero transition , you can put silicone in the gap to smooth it more but that will be messy if you need to change it (you probably will at some point) the bigger the number the more comfort, especially at the back on a disc

Edited by latman
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Plenty of research floating around on the subject but when I last bothered to go into it in any depth (about 10 years ago) the theory was that 23's were no slower than 19/20/21's but more comfortable to ride on.

 

Given I'm 194cm and 93kg, Latmans theory of tire aerodynamics probably don't appy to me

 

Currently running 23's on both the road and track bike.

Edited by -- AJ --
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20mm wide smaller wheel diameter than 23mm

 

20mm less cushioning than 23mm

 

19mm slices through the air nano x more than 23

 

need to recalibrate bike computer for diff width tyres

 

23mm most popular for our roads

 

23 prob more available

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Out of interest, Hed says the following about the relationship between rim and tyre widths in their marketing spiel for the Jet 9 C2 wheel:

 

What makes the Jet 9 so good, and so much better than its predecessor? It is all interrelated. The new wheel is more aero, it has lower rolling resistance, it corners and handles better, and it more comfortable – all increase speed, and all are a result of our C2 rim technology. The C2 rim is 23mm wide; and that fact alone does not make it revolutionary, and by itself a 23mm rim width is not “technology”. What we did with a 23mm rim width, and what it allows for aerodynamics, rolling resistance, and bike handling are what make the C2, and the new Jet wheels revolutionary.

 

First, the rim itself. With exacting CAD design and the resulting extrusion dies that can be machined from the instructions in a CAD file, we can make a 23mm wide rim that weighs no more than the 19mm rims that were standard for the industry (including HED) for years. The additional width actually makes the C2 rim stiffer laterally than a 19mm version.

 

With a better rim to start from, the Jet wheels are faster. Jets are made for 23mm tires. Larger tires have lower rolling resistance than smaller versions. They put more rubber on the road for better cornering traction. They require less psi to support the same load as a 19mm tire. 23mm tires are superior – now that we have the proper rim for them. With the C2 rim, tire width matches rim width, so the wheel is more aero. The tire sidewalls are part of the aero shape of the entire wheel, they don’t bulge over the brake track like they do on a 19mm rim. The same straightened sidewalls support the tire better in hard cornering and out of the saddle efforts, so the complete tire is more rigid and less squirmy. Stiffer is more efficient than squirmy, and more efficient is faster.

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The new wheel is more aero, it has lower rolling resistance, it corners and handles better, and it more comfortable – all increase speed, and all are a result of our C2 rim technology

 

And there I was thinking that it was the tire (and not the wheel) that determined the rolling resistance and cornering ability.

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And there I was thinking that it was the tire (and not the wheel) that determined the rolling resistance and cornering ability.

 

yes, lower down he does say that:

 

Jets are made for 23mm tires. Larger tires have lower rolling resistance than smaller versions. They put more rubber on the road for better cornering traction. They require less psi to support the same load as a 19mm tire. 23mm tires are superior – now that we have the proper rim for them.

 

This bit is key:

 

The tire sidewalls are part of the aero shape of the entire wheel, they don’t bulge over the brake track like they do on a 19mm rim.

 

It isn't really when the wind is straight on (0 deg yaw), more 5-15 deg yaw when that leading edge starts throwing air all over the place and destroying the effect of the aero rim.

 

In other words make sure the rim/tyre interface is really smooth with no bulges of tire out over the rim. On a 19mm race rim you can use Vittoria Cx or Veloflex Carbon 20's and they are gold.

 

23's do roll a little bit faster though when compared with a 19/20mm in the same rubber compound and casing. Less sidewall deformation and hysterisis.

 

Training, meh, use whatever works for you.

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And there I was thinking that it was the tire (and not the wheel) that determined the rolling resistance and cornering ability.

They do, but a 23mm rim changes the shape of the contact patch from "long and narrow" to "wide and short" meaning the tyre needs to deform less have an equal sized contact patch (which is determined by the total weight supported and the air pressure its pumped up to).

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Plenty of research floating around on the subject but when I last bothered to go into it in any depth (about 10 years ago) the theory was that 23's were no slower than 19/20/21's but more comfortable to ride on.

 

Given I'm 194cm and 93kg, Latmans theory of tire aerodynamics probably don't appy to me

 

Currently running 23's on both the road and track bike.

 

I was 183 and 91kg when i did my first few races and i got a fair bit faster when i used the narrow tyres on my tri-spoke/ disc

 

just speaking from experience,not a brochure of a wheel seller

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Wow, some amazing misinformation about silicone, casing compliance, etc.

 

The difference in RR of a super compound vs a standard carbon black makes a poofteenth seem big, so that dribble unless you're qualifying for the olympics.

 

Let's make it simple - the smaller the contact patch, the less rolling resistance.

Bigger rim = bigger contact patch.

Softer compound = bigger contact patch.

Weaker casing construction = bigger contact patch.

Lower pressures (generalisation) = bigger contact patch.

 

If your spine can handle 18s, and your rim profile is designed to hang on to them, then go with them.

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Weightweenies and slowtwitch forums have some good discussions and links on this.

 

If you are training by yourself, use the biggest that will fit between your stays. In my case its 25mm, but there are alot of frames that will fit 27/28mm. Race on something smaller (and train with them if you use a second bike, or in the lead up to a race), but otherwise you get increased comfort (= more power and miles) and increased resistance.

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19's at high pressure, 160+ are doable on the track, but on the road the ride is very harsh and susceptable to flats

 

Can make better aero saving by tweaking the position and attire aero helmet etc

 

Better to get some fast 23's that will get you to the finish line

 

Like Enzo said, In order to finish first, first you must finish!

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Larger tires have lower rolling resistance than smaller versions.

They put more rubber on the road for better cornering traction.

 

is it just me or is that a bit counter intuitive? surely the more rubber on the road, the more rolling resistance???

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Larger tires have lower rolling resistance than smaller versions.

They put more rubber on the road for better cornering traction.

 

is it just me or is that a bit counter intuitive? surely the more rubber on the road, the more rolling resistance???

 

wouldn't it depend on the road surface, think sandy beach skinny tyres vs a beefy set of desert duelers, the wide tyres have more grip but less resitance as they don't bog down.

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