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Tire Pressure too low?


Xthrax

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My pressure pump says this is 45 PSI but I kind of doubt it. This is me standing on the wheel and for the record I am 175 lb. It feels solid with my hands but when I look at it on my phone I am a bit worried.

 

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That’s just how a round tire works. While the tire feels hard to your fingers, 175 lbs is a lot more weight to squeeze a round, flexible rubber tube filled with air. And that’s the reason it is used for this purpose. It’s supposed to compress under weight.

 How does it ride?

Edited by mrelwood
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5 minutes ago, Kurtosis said:

How many square inches are touching the ground? Should be equal to the weight of the wheel and rider divided by the pressure in the tire. 

Just me eyeing the inches, pretty close, but probably could use another 5 PSI. Thanks for the tip

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12 hours ago, Kurtosis said:

How many square inches are touching the ground? Should be equal to the weight of the wheel and rider divided by the pressure in the tire. 

Don't you love how logic and science work sometimes? ;-)

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Looks like a v1 Mcm5 

when I was using one I found it was best to put up with a stiffer tire rather than scraping the pedals more.

175 lbs, ran it anywhere from 45-50 psi.

I dunno what my tire looked like when I stood on it, but if it looks like that I’d be tempted to increase the pressure.

At 45-50 psi, when you squeeze the tire with your fingers it’s should have barely any give. On the spectrum of things, it’ll feel closer to solid rubber than pillowy or deformable much at all. 

And jumping on the wheel will have it deflect, but certainly not bottom out or hit the rim. Again I dunno what it looks like, just going off of feel. 

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Gozens 26-80psi TPMS Tire Pressure Monitor Valve Stem Cap Tyre Sensor Indicator (46 PSI) https://www.amazon.com/dp/B01HRIKK5C/ref=cm_sw_r_cp_api_glt_fabc_AYBS56W5TZQ1YJGEVWKT

these are the TPS caps that I’ve used, based off previous advice I’ve heard. Overall they work, but barely. When you see a sliver of yellow on the side, you know your pressure needs to be changed. And you want to get a pressure that’s rated for about 10% higher than what you intend to keep your wheel inflated at. See the chart on the product page; by design they’re not supposed to change color until you dip below a 20% air pressure loss threshold. A little too much pressure loss for EUCs I think, and on top of that the color change is hard to spot. 

also note that this adds about a cm on length to your valve stem. The angle and placement of your valve stem can make or break your ability to even put it on. I can get them on about 1 out of 3 wheels I own without any fiddling. 

Edited by Denny Paul
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In industries where calibrated and certified tooling is mandatory, “our” pressure gauges would be stickered FOR INDICATION ONLY (big red letters). Roughly translated: a higher reading probably means there is more air in there than there was when the reading was not that high. Maybe.

Edited by Tawpie
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i have used two different pumps and had them read a 10 psi difference lol... i dont care what any pump or tire says, i just go by feel.... pump it up until it feels rock hard to you (or you can just go by the max psi listed on the tire) and ride it, if you feel that the euc is wobbly and tries to immediately right itself aka fights you during turning, take a bit of air out and then try again.. just do this letting out a small amount of air each time until it stops fighting you and that is the ideal pressure for you... there is no magic formula, the size and thickness of the tire as well as your weight (including the euc,, they can vary by 50 lbs from one to another) and even the tire tread will have an effect so the only way to figure it out is by testing, then just measure the current pressure and write that down for next time... cheap pressure gauges and those on pumps can be extremely inaccurate, but it doesnt matter at all as long as youre using the same one each time :)

Edited by Rywokast
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  • 2 weeks later...
On 4/6/2021 at 3:02 PM, Kurtosis said:

What did you install?

This https://www.amazon.com/gp/product/B07Q21RNNB/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

On 4/7/2021 at 11:29 PM, Denny Paul said:

Gozens 26-80psi TPMS Tire Pressure Monitor Valve Stem Cap Tyre Sensor Indicator (46 PSI) https://www.amazon.com/dp/B01HRIKK5C/ref=cm_sw_r_cp_api_glt_fabc_AYBS56W5TZQ1YJGEVWKT

these are the TPS caps that I’ve used, based off previous advice I’ve heard. Overall they work, but barely. When you see a sliver of yellow on the side, you know your pressure needs to be changed. And you want to get a pressure that’s rated for about 10% higher than what you intend to keep your wheel inflated at. See the chart on the product page; by design they’re not supposed to change color until you dip below a 20% air pressure loss threshold. A little too much pressure loss for EUCs I think, and on top of that the color change is hard to spot. 

also note that this adds about a cm on length to your valve stem. The angle and placement of your valve stem can make or break your ability to even put it on. I can get them on about 1 out of 3 wheels I own without any fiddling. 

The ones I use actually give you a readout on the app and you can set alarms. More expansive tho, and kind of big. You can still them on your wheel but you better make sure its flush against the rim

 

On 4/13/2021 at 1:41 AM, Rywokast said:

i have used two different pumps and had them read a 10 psi difference lol... i dont care what any pump or tire says, i just go by feel.... pump it up until it feels rock hard to you (or you can just go by the max psi listed on the tire) and ride it, if you feel that the euc is wobbly and tries to immediately right itself aka fights you during turning, take a bit of air out and then try again.. just do this letting out a small amount of air each time until it stops fighting you and that is the ideal pressure for you... there is no magic formula, the size and thickness of the tire as well as your weight (including the euc,, they can vary by 50 lbs from one to another) and even the tire tread will have an effect so the only way to figure it out is by testing, then just measure the current pressure and write that down for next time... cheap pressure gauges and those on pumps can be extremely inaccurate, but it doesnt matter at all as long as youre using the same one each time :)

The main issue I had was the wheel lost pressure rapidly(full to nothing in 30 mins of riding) and I did not realize what was happening until it was too late and I had to step off and let the wheel crash. Now with the TPS my phone will make a audible warning before it get too low.

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