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I’m pretty light weight. My bike + me = 67kg. Will I benefit from using a 20mm width clincher tire instead of 23mm?

I ride mostly reasonably good tarmac road and social racing.
 

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I’m pretty light weight. My bike + me = 67kg. Will I benefit from using a 20mm width clincher tire instead of 23mm?

I ride mostly reasonably good tarmac road and social racing.
The benefit will be an even crappier ride and even less of a contact patch on the road. This will lead to fewer humans on the planet who think less is better.
 

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Comfort aside, as soon as your wheel starts bouncing due to tarmac conditions and tire pressure it robs away energy and thus speed.
A wider tire allows lower pressures to maintain the tire drop needed to optimize your tire's performance. In your case it would be about 20psi less (90 vs. 110psi for 23 vs. 20mm) and that is significant to drastically improve your comfort which will allow you to pedal faster and longer.
I have been recently posting the following article in several threads addressing the subject of your question: http://www.bikequarterly.com/images/TireDrop.pdf
You will do well if you read it
 

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the reduction in rolling resistance with larger tires is overstated - going from a 23 to 25 mm tire will save you on the order of .3 watts. Depending on rim width, the reduction in rolling resistance will be less than the increase in drag and also will have a weight penalty. Time trialing, for example, with a standard width rim will be faster with a narrower front tire.
 

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the reduction in rolling resistance with larger tires is overstated - going from a 23 to 25 mm tire will save you on the order of .3 watts. Depending on rim width, the reduction in rolling resistance will be less than the increase in drag and also will have a weight penalty. Time trialing, for example, with a standard width rim will be faster with a narrower front tire.
but the increase in traction and comfort is NOT overstated. a TT would be the ONLY time i'd even consider running a narrow front tire, and that would totally depend on the particular wheel being used.
 

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20 for TT, but a 22 Conti attack has lower rolling resistance than most wider tires (if I'm recalling rruff's crr data correctly) and has excellent grip. excellent fast front training tire.

but the increase in traction and comfort is NOT overstated. a TT would be the ONLY time i'd even consider running a narrow front tire, and that would totally depend on the particular wheel being used.
 

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...narrower is not necessarily worse.

This could be a bit counter intuitive to a lot of the current trend towards wider tires and wider rims, but I have used 20mm wide tires (old Michelin Hi-Lite bi-synergics) on my Mavic Ellipse fixed-gear bike with either dumb luck, or maybe a particularly good combination specific to that rim. I bought four of these tires cheap years ago, ride this bike around town and on training rides, and have yet to experience a flat tire, pinch flat or otherwise. I've used these 2005-06, when I was training on fixed extensively up to 200km rides, and again 2012-present (re-converted a hack bike last Summer).

It might be possible that the narrower profile will compress without pinching the inner tube or I've just been lucky. Although it's not the most comfortable riding combo out there.

I have a set of ridiculously narrow Nisi Laser clincher aero rims (used) from the late 80s I think, currently not built up, but with an external 18mm and internal 13mm rim profile, I am thinking a narrower tire like 20mm might actually work better on those as well.

Of course I could be wrong. Or maybe the hi-lite bi-synergics in 20mm were a particularly well-made skinny tire compared to others. But another benefit has been better clearance within fenders. So the low-down on skinny is not necessarily all bad.
 

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This could be a bit counter intuitive to a lot of the current trend towards wider tires and wider rims, but I have used 20mm wide tires (old Michelin Hi-Lite bi-synergics) on my Mavic Ellipse fixed-gear bike with either dumb luck, or maybe a particularly good combination specific to that rim. I bought four of these tires cheap years ago, ride this bike around town and on training rides, and have yet to experience a flat tire, pinch flat or otherwise. I've used these 2005-06, when I was training on fixed extensively up to 200km rides, and again 2012-present (re-converted a hack bike last Summer).

It might be possible that the narrower profile will compress without pinching the inner tube or I've just been lucky. Although it's not the most comfortable riding combo out there.

I have a set of ridiculously narrow Nisi Laser clincher aero rims (used) from the late 80s I think, currently not built up, but with an external 18mm and internal 13mm rim profile, I am thinking a narrower tire like 20mm might actually work better on those as well.

Of course I could be wrong. Or maybe the hi-lite bi-synergics in 20mm were a particularly well-made skinny tire compared to others. But another benefit has been better clearance within fenders. So the low-down on skinny is not necessarily all bad.
maybe if you included your weight this might make sense.
 

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My weight has yo yo'd over the years currently 185 lbs but in addition to that, I wear a messenger bag a lot of the time when I'm riding this hack in town. So I'm no lightweight (*used* to race at 145 lbs though), which makes me wonder if this combination of tire/wheel might be exceptionally robust for the 20c type.

Again, maybe dumb luck.
 

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20 for TT, but a 22 Conti attack has lower rolling resistance than most wider tires (if I'm recalling rruff's crr data correctly) and has excellent grip. excellent fast front training tire.
I believe this test was done on rollers. I dont doubt the results that rruff and Reinard (who did the same test earlier) had but they are no different than the wheel aero tests in a wind tunnel controlled environment. In other words, in real life applications there are additional variables that significantly affect the results and the ultimate goal of sustaining faster speeds at the least amount of rider energy. For the tire case, these variables are the changing road surface from smooth to rough over the course of an event, the suspension losses experienced by the rider and the comfort/discomfort of the rider affecting his sustained output.

When a tire is asked to perform under the actual riding conditions of the open road on tarmac ranging from semi-smooth to rough, the tire's casing construction affects the tire performance significantly more than width. IMO, I consider this to be the most prevalent factor for most riders and most probably all rec riders.
 

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I’m pretty light weight. My bike + me = 67kg. Will I benefit from using a 20mm width clincher tire instead of 23mm?

I ride mostly reasonably good tarmac road and social racing.
I got 4 Conti 4000 20mm last year, put them on my carbon rims. The fastest tires I have even rode. BUT they wear off very quickly and I got 2 punctures over 1000km.

I just do not understand how anyone saying 25mm will have less rolling resistance than 20mm, total BS especially at my 180lb. I can feel they roll better.

Having said that, this season I got 8pc. 23mm Continentals 4000s on sale at wiggle.com I do not like punctures.
 

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I just do not understand how anyone saying 25mm will have less rolling resistance than 20mm, total BS especially at my 180lb. I can feel they roll better.
You do realize that there is a difference between "feeling" and what is actually measured with a stopwatch, right? An extensive tire rolldown test by Bicycle Quarterly demonstrated that even experienced riders cannot tell "by feel" which tires are faster.

The reason an identical 25mm tire might be faster than a 20 mm tire is that the narrow tire may need to be pumped very hard to prevent pinch flats. As a result the tire bounces off road surface irregularities rather than conforming to the roughness. That energy is transmitted to the rider and jiggles the body resulting in lost energy. Tests on very rough pavement surfaces have clearly shown wider, softer tires to be faster. It obviously depends on the tire pressure you chose but the tire needs to be compliant in order to be as fast as possible.

Add to all that the fact that higher pressure/narrower tires have poor traction, radpid wear, and are uncomfortable to ride and the argument for narrow tires is clear except for the lightest riders.
 

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The reason an identical 25mm tire might be faster than a 20 mm tire is that the narrow tire may need to be pumped very hard to prevent pinch flats. As a result the tire bounces off road surface irregularities rather than conforming to the roughness. That energy is transmitted to the rider and jiggles the body resulting in lost energy. Tests on very rough pavement surfaces have clearly shown wider, softer tires to be faster. It obviously depends on the tire pressure you chose but the tire needs to be compliant in order to be as fast as possible.

Add to all that the fact that higher pressure/narrower tires have poor traction, radpid wear, and are uncomfortable to ride and the argument for narrow tires is clear except for the lightest riders.
I'm talking about road cycling not Paris Rubiax, YES 20mm are only good for smooth roads, and they are faster than 23mm on SMOOTH roads. [email protected] roads get 23-25mm or 28 or whatever rocks your boat.

"As a result the tire bounces off road surface irregularities rather than conforming to the roughness." - you must be riding some really bad roads if your tire is bouncing.
Are we taking about road cycling or cross or some other cycling :)?

The less contact with road the less resistance at higher speeds.

Check those charts: http://www.industrializedcyclist.com/tiretest.pdf
not the golden standard but actually someone measured it.


In general terms, the total drag of a cyclist will consist of 80% tire rolling resistance and 20% wind resistance at 10 km/h or 6 mph. At 40 km/h or 25 mph the numbers will reverse, with total drag consisting of 80% wind resistance and 20% tire rolling resistance.
 

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I clearly do, but you are talking about totaly different environment. Discussion about rolling resistance without knowing, weight , speed, retraction force, rolling resistance force and few more factors is like beating dead meat. That is exactly what you do.
You're very very wrong.
 

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I'm talking about road cycling not Paris Rubiax, YES 20mm are only good for smooth roads, and they are faster than 23mm on SMOOTH roads. [email protected] roads get 23-25mm or 28 or whatever rocks your boat.

"As a result the tire bounces off road surface irregularities rather than conforming to the roughness." - you must be riding some really bad roads if your tire is bouncing.
Are we taking about road cycling or cross or some other cycling :)?

The less contact with road the less resistance at higher speeds.
And your last statement proves you are very confused on this topic. What determines contact patch size is total weight divided by tire pressure. Different tire widths change the shape of the contact patch but not the size.

The bouncing I am referring to, as I explicitly described, is the mechanical motion that is transmitted to the rider because the tire cannot properly conform to road surface roughness. It does not mean that the tire is literally leaving the road. That energy is lost in jiggling the body whereas the hysterisis losses in tire casing and tread deflection are much smaller. It is one thing to ask questions about something but another to make pronouncements from an incorrect understanding of what is going on.

Also you comment about 20% tire rolling resistance at 25 mph is incorrect. The number is about 17% and it is the sum of ALL frictional resistance in the bike: tires, chain, bearings.
 

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And your last statement proves you are very confused on this topic. What determines contact patch size is total weight divided by tire pressure. Different tire widths change the shape of the contact patch but not the size.

The bouncing I am referring to, as I explicitly described, is the mechanical motion that is transmitted to the rider because the tire cannot properly conform to road surface roughness. It does not mean that the tire is literally leaving the road. That energy is lost in jiggling the body whereas the hysterisis losses in tire casing and tread deflection are much smaller. It is one thing to ask questions about something but another to make pronouncements from an incorrect understanding of what is going on.

Also you comment about 20% tire rolling resistance at 25 mph is incorrect. The number is about 17% and it is the sum of ALL frictional resistance in the bike: tires, chain, bearings.
hey all good you can even pull the full spare from your car, it will be good workout.


If you are looking at this article:

Tech FAQ: Seriously, wider tires have lower rolling resistance than their narrower brethren

READ CAREFULLY:

While I have often pointed out that bigger tires roll faster at the same tire pressure than smaller tires that are otherwise identical, readers often don’t believe me.

Did you get the bold part?

at 130psi my 20mm have no deflection at all :) less than 23mm with 90-100psi.

Again discussions without details are pointless, If I have a time I will do 2 x1h sessions with powertap on rollers with 20mm and 23mm tires and send you data, it is very easy to see the difference. Rollers are not ideal for this test but, you will see the difference.
 
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