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More Data From Silca - Tire Pressure & Comfort ( & New Link to part 3B)
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Another fascinating read about the impact tire pressure has on ride qualities.


https://silca.cc/...pressure-and-comfort

Thank you to all of the people who have been contributing data to these discussions.

Update: More data from Silica......

Via copy and paste.
Part 3B: FAQ and Putting it Together So Far
We've decided to push Part 4 back a week and do an FAQ about the first 3 segments of our series as we have had so many questions and comments regarding the series so far. For a quick recap:
Part1: History of tires getting wider and the effect of rim width on actual tire width
Part2: Measuring Tire Stiffness in the Lab
Part3: How Tire Stiffness effects ride comfort for the entire bicycle

https://silca.cc/...g-it-together-so-far
Last edited by: TRIing2Run: Jul 1, 16 9:52
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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Its really so cool that Silica is posting all this data, thank you silica!

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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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tmm;dr

(Too much math; didn't read)

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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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Quote:
More interestingly from a SILCA standpoint, is that the difference [in vertical stiffness] between 4 of the 5 frames is less than the gauge error of a standard bicycle pump (+/-5%),

So to some up, we all should be getting more accurate pressure gauges instead of freaking out about frame stiffness - says a pump manufacturer ;-) But they do seem to back it up with real data.
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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Good information. But the conclusion ends with, "Triathletes, some of whom are now racing at pressures 2Bar (30psi) lower than before, are telling us that they are running better off the bike as they are less fatigued from vibration, and better still, they aren't riding any slower! "

And, to my knowledge, there isn't any evidence that "vibration" causes the type of physiological fatigue that would affect run performance.

It might. It's plausible. But I don't think we know.
Last edited by: trail: Jun 24, 16 7:39
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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I keep trying to explain springs in series to people with regards to comfort. You can clearly deflect a tire with your thumb, but how much can your thumb deflect a frame, that should tell you that tires clearly dominate vertical compliance.
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Re: More Data From Silca - Tire Pressure & Comfort [trail] [ In reply to ]
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Vibration alone may not be fatiguing, but tensing up is. That is my normal reaction when the roads turn into washboards. I had been running 95 psi / 23mm front and 105 psi / 25mm back. With all of the data coming out from Flo, Silca, and Tom, I did a few test workouts at 90 f / 95 r and like the change in the level of vibration on my normal training routs. It also resulted in slightly faster avg. speeds. I used those pressures for my last race and finished the highest overall and highest bike leg place of any of my races to date.

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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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TRIing2Run wrote:

Vibration alone may not be fatiguing, but tensing up is. That is my normal reaction when the roads turn into washboards. I had been running 95 psi / 23mm front and 105 psi / 25mm back. With all of the data coming out from Flo, Silca, and Tom, I did a few test workouts at 90 f / 95 r and like the change in the level of vibration on my normal training routs. It also resulted in slightly faster avg. speeds. I used those pressures for my last race and finished the highest overall and highest bike leg place of any of my races to date.

Happy to hear that. Science works :)


Chris Thornham
FLO Cycling
FLO Blog | Facebook | Instagram | Twitter
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Re: More Data From Silca - Tire Pressure & Comfort [Canadian] [ In reply to ]
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Yes it does. Thanks for all you have shared. My wife love s the 30 we picked up for her road bike. I hope to add a new front 90 to the collection shortly. 😎
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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TRIing2Run wrote:

Vibration alone may not be fatiguing, but tensing up is. That is my normal reaction when the roads turn into washboards. I had been running 95 psi / 23mm front and 105 psi / 25mm back. With all of the data coming out from Flo, Silca, and Tom, I did a few test workouts at 90 f / 95 r and like the change in the level of vibration on my normal training routs. It also resulted in slightly faster avg. speeds. I used those pressures for my last race and finished the highest overall and highest bike leg place of any of my races to date.

May I ask how much you weigh? I know I've seen a chart with weight and tire pressures somewhere before but am interested in how things correlate.

I also wonder how my TitanFlex frame would effect this.

Formerly DrD
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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The best tire gauge for bikes in case anyone was wondering...

http://www.kappiuscomponents.com/...gital-pressure-gauge
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Re: More Data From Silca - Tire Pressure & Comfort [Broken Leg Guy] [ In reply to ]
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My weight 167lb.
The system is just a series of springs. The system would have more flex with the more flexible frame. Should not be too different, tires would be a slightly lower % of total. Would still get better road grip for cornering.
Last edited by: TRIing2Run: Jun 25, 16 9:09
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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I'm curious how much weight plays a roll here. I am 235lbs and totally buy into the lower PSI science, as I've always ridden at max as a result of my weight. Being a heavier guy, I'm curious if there is any info out there suggesting what someone of my size should ride at? The normal charts will all say max.
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Re: More Data From Silca - Tire Pressure & Comfort [Silvercivic27] [ In reply to ]
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Thanks for the heads up on that. I've been looking for a better gauge.

WTB: TriRig Omega SV (not x). PM me if you have one :)
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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I'm about 10 lbs heavier than you. I typically ride at 95/100. Combined with the TitanFlex it's a very smooth ride.

Formerly DrD
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Re: More Data From Silca - Tire Pressure & Comfort [GreenPlease] [ In reply to ]
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GreenPlease wrote:
Thanks for the heads up on that. I've been looking for a better gauge.

Although that gage claims it can be used for "bleed down", based on the design of the connection (a Silca "crack pipe") and the button location, I want to point out that it appears the only thing it will bleed air from is the small volume between the gage and the valve.

Once the pressure in that section drops below the pressure inside the tire, a presta valve automatically closes.



http://bikeblather.blogspot.com/
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Re: More Data From Silca - Tire Pressure & Comfort [Tom A.] [ In reply to ]
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Tom A. wrote:
GreenPlease wrote:
Thanks for the heads up on that. I've been looking for a better gauge.


Although that gage claims it can be used for "bleed down", based on the design of the connection (a Silca "crack pipe") and the button location, I want to point out that it appears the only thing it will bleed air from is the small volume between the gage and the valve.

Once the pressure in that section drops below the pressure inside the tire, a presta valve automatically closes.

I would not have thought of that. I wish there was something like my Topeak handheld air pressure gauge (which is great for bleeding and fits disc wheels) that I knew was accurate :/

WTB: TriRig Omega SV (not x). PM me if you have one :)
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Re: More Data From Silca - Tire Pressure & Comfort [GreenPlease] [ In reply to ]
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I will be using a manometer from now on at all races because I do not trust gauges. Physical properties of a liquid cannot lie!

XTERRA South American Adventure | @idking90 | Strava | IG: idking90
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Re: More Data From Silca - Tire Pressure & Comfort [Tom A.] [ In reply to ]
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That depends. To get the pressure in the first place to measure the tire pressure, the gauge has to depress the valve stem. If that depression is maintained, it could bleed pressure off of the tire.
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Re: More Data From Silca - Tire Pressure & Comfort [iank] [ In reply to ]
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For bike tire pressures, it will need to be quite tall. The other option would be to go really old school and get one filled with mercury.
Last edited by: TRIing2Run: Jun 26, 16 3:12
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Re: More Data From Silca - Tire Pressure & Comfort [Tom A.] [ In reply to ]
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Tom A. wrote:
Although that gage claims it can be used for "bleed down", based on the design of the connection (a Silca "crack pipe") and the button location, I want to point out that it appears the only thing it will bleed air from is the small volume between the gage and the valve.

Once the pressure in that section drops below the pressure inside the tire, a presta valve automatically closes.

Tom, I think it has to press down the presta valve as it screws on, how else would it ever even read the pressure?
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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TRIing2Run wrote:
That depends. To get the pressure in the first place to measure the tire pressure, the gauge has to depress the valve stem. If that depression is maintained, it could bleed pressure off of the tire.


From what I understand about how the Silca adapter operates, I don't think it physically depresses the presta valve...so, I guess I'm not sure then how that Kappius gage actually functions...hmmm.

Yeah, if the connection physically depresses the valve, the bleed should work...but then, I guess I'd be concerned about how much pressureis lost when the gage is removed.

I guess I still prefer a "known accuracy" gage attached to the pump, since you can then "sneak up" to the desired pressure ;-)



http://bikeblather.blogspot.com/
Last edited by: Tom A.: Jun 25, 16 19:33
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Re: More Data From Silca - Tire Pressure & Comfort [TRIing2Run] [ In reply to ]
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TRIing2Run wrote:
For bike tire pressures, it will need to be quite tall. The other option would be to go really old school and get one filled with mercury.
Valid point. You'd need something close to 200 ft tall.
But if we're already going to the lengths of filling tires with nitrogen, may as well do a mercury manometer. The mechanics already huff plenty of tubie glue; how much worse can Hg be? You'd want it to be about 25 ft tall (25 ft = 7620 mmHg = 147 psi. Because you never want to max out your gauge, of course). That could totally fit on a pro team's bus. But then you'd need an accurate thermometer to modify your calculations for the density of the mercury.

XTERRA South American Adventure | @idking90 | Strava | IG: idking90
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Re: More Data From Silca - Tire Pressure & Comfort [iank] [ In reply to ]
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The latest part of the series is live and even has a Slowtitch mention!

Part3B: FAQ and Questions Answered

Josh
http://www.SILCA.cc
The 3 Keys to Super Easy, Super Fast Tire/Tube Installation (even with latex):
https://www.youtube.com/watch?v=9W85RCHoukI
How much speed and comfort is your tire pressure costing you? More than you think! https://silca.cc/blogs/journal
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Re: More Data From Silca - Tire Pressure & Comfort [joshatsilca] [ In reply to ]
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Thanks for the information you are publishing.
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