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-   -   comfortable inflation vs. manufacturers recommended range (https://www.bikeforums.net/showthread.php?t=1252076)

jackb 05-20-22 10:57 AM

comfortable inflation vs. manufacturers recommended range
 
Reading a lot about best inflation values for tires, I wonder how much the manufacturers range which is expressed on the tire itself should be adhered to. Do I disregard this range and just experiment around to find what's most comfortable? I'm well aware of the danger of pinch flats if I go to low.

DaveSSS 05-20-22 11:30 AM

Try the pressure calculator at zipp.com. It allows for tire width, internal rim width, tubed or tubeless, rider weight and type of road.

Iride01 05-20-22 12:38 PM

You want to be somewhere between the recommended max inflation pressure and the lowest PSI that does not result in pinch flats for the hazards you might encounter during most of your riding on that bike.

I let my legs, my comfort and my data collected by my bike computer tell me what that pressure is. Online calculators might be right. But they haven't been right for me.

They for certain might be a good starting point. Then after keeping your tires at their recommended pressure for 6 -12 rides, change it up or down a few PSI and see what you think after 6 - 12 more rides. Judge by both by perceived effort and by how well your bike computer tells you you did on rides of the same routes.

DonkeyShow 05-20-22 12:47 PM

+2 psi over the max to be on the safe side.

SoSmellyAir 05-20-22 12:56 PM


Originally Posted by DonkeyShow (Post 22513716)
+2 psi over the max to be on the safe side.

No problem if you only plan to hang your bike up on the wall as art.

ThermionicScott 05-20-22 01:11 PM

:popcorn

phrantic09 05-20-22 02:21 PM


Originally Posted by DaveSSS (Post 22513622)
Try the pressure calculator at zipp.com. It allows for tire width, internal rim width, tubed or tubeless, rider weight and type of road.

this

DonkeyShow 05-20-22 03:41 PM


Originally Posted by SoSmellyAir (Post 22513724)
No problem if you only plan to hang your bike up on the wall as art.

No problem riding soo far. Gotta admit I'm pretty scared going downhill at 35mph tho.

Sy Reene 05-20-22 04:09 PM

Everything I see on TV says inflation should be much less than it is.

SoSmellyAir 05-20-22 06:06 PM


Originally Posted by DonkeyShow (Post 22513891)
No problem riding soo far.

Past performance is not indicative of future results. Good luck


Originally Posted by DonkeyShow (Post 22513891)
Gotta admit I'm pretty scared going downhill at 35mph tho.

Why are you scared of going downhill at 35 mph with your tires apparently over-inflated by 2 PSI? And which "max" are even you referring to? The maximum pressure for your wheel, tire, or tube?

DonkeyShow 05-20-22 06:22 PM


Originally Posted by SoSmellyAir (Post 22514008)
Past performance is not indicative of future results. Good luck



Why are you scared of going downhill at 35 mph with your tires apparently over-inflated by 2 PSI? And which "max" are even you referring to? The maximum pressure for your wheel, tire, or tube?

relax, bro.

tomato coupe 05-20-22 06:40 PM

I thought everyone knew, inflation is on the rise.

LarrySellerz 05-20-22 08:14 PM

The "max" pressure rating on a bicycle tires about half of what it takes to actually fail. You wouldn't ever be close to that, play around as much as you want. Cubewheels was claiming that the rim could blow out at high pressures, but idk if he is to be trusted and thats not a failure of the tire anyways. Its like how ladders are normally rated to 250 lbs but routinely take loads of 400+. also tubes don't have a max pressure lol..

The current consensus seems to be that wider tires with less pressure are preferable, but that has changed over the years, back in the day people were trying to get narrower than 23s. Who knows what people will be doing in 20 years

Koyote 05-20-22 08:19 PM


Originally Posted by LarrySellerz (Post 22514092)
The "max" pressure rating on a bicycle tires about half of what it takes to actually fail. You wouldn't ever be close to that, play around as much as you want. Cubewheels was claiming that the rim could blow out at high pressures, but idk if he is to be trusted and thats not a failure of the tire anyways. Its like how ladders are normally rated to 250 lbs but routinely take loads of 400+. also tubes don't have a max pressure lol..

The current consensus seems to be that wider tires with less pressure are preferable, but that has changed over the years, back in the day people were trying to get narrower than 23s. Who knows what people will be doing in 20 years

Going higher than the rated psi will give you a slower and rougher ride with an increased chance of tire or rim failure. Aside from that, it's a great idea.

LarrySellerz 05-20-22 08:28 PM


Originally Posted by Koyote (Post 22514093)
Going higher than the rated psi will give you a slower and rougher ride with an increased chance of tire or rim failure. Aside from that, it's a great idea.

There are some benefits, for instance I have a commuter bike that mainly sees nice tarmac but has a 37 knobby up front. When I pump it up to 100 psi the knobs aren't in contact with the road when going in a straight line. sucks in corners but its great for rough terrain and potholes

Bike Gremlin 05-21-22 02:59 AM


Originally Posted by jackb (Post 22513590)
Reading a lot about best inflation values for tires, I wonder how much the manufacturers range which is expressed on the tire itself should be adhered to. Do I disregard this range and just experiment around to find what's most comfortable? I'm well aware of the danger of pinch flats if I go to low.

Opinions and experiences differ on this, but here's mine:

I don't exceed the max. recommended pressure - just to be on the safe side.
(having said that, I'm far from a super-heavy rider so I'm yet to see a tyre that squats much when I upload it to the max recommended pressure)

And I completely disregard the lowest recommended pressure.
(though, I'm usually heavy enough to not dare to go below that limit in order to avoid any pinch-flats)

I aim for about a 10 to 15 % drop in tyre height when I sit on the bike for the rear - and I use that same pressure for the front (explained with pics and in more detail here - optimal tyre pressure).

Chuck M 05-21-22 04:02 AM


Originally Posted by LarrySellerz (Post 22514092)
Cubewheels was claiming that the rim could blow out at high pressures, but idk if he is to be trusted and thats not a failure of the tire anyways.

I hope he can be trusted. I'm testing new cog spacers made from a composite of newspaper, toilet tissue and old lottery tickets this morning.

Koyote 05-21-22 05:59 AM


Originally Posted by Chuck M (Post 22514205)
I hope he can be trusted. I'm testing new cog spacers made from a composite of newspaper, toilet tissue and old lottery tickets this morning.

That only works if you strap an old truck battery to the back of your bike.

aliasfox 05-21-22 01:33 PM

As long as you have a cell phone and a friend or partner who’s willing to pick you up, go as low or as high as you want! I’ve just gone up or down 5psi at a time for a few rides to see how things feel, and eventually settled on a range that I’m comfortable with, which is about 78-85psi on my effectively 32mm front (28mm Conti Ultra Sport 2), and about 90psi on my effectively 28mm rear (25mm Conti GP4k - my last one). Both are higher than is ever recommended, but it’s what I like, and isn’t that what matters?

cxwrench 05-21-22 02:48 PM


Originally Posted by LarrySellerz (Post 22514100)
There are some benefits, for instance I have a commuter bike that mainly sees nice tarmac but has a 37 knobby up front. When I pump it up to 100 psi the knobs aren't in contact with the road when going in a straight line. sucks in corners but its great for rough terrain and potholes

You should really to refrain from offering 'advice' no matter how helpful you think you're being. Really...just stop. Limit yourself to reading and learning.

PeteHski 05-23-22 02:40 PM


Originally Posted by jackb (Post 22513590)
Reading a lot about best inflation values for tires, I wonder how much the manufacturers range which is expressed on the tire itself should be adhered to. Do I disregard this range and just experiment around to find what's most comfortable? I'm well aware of the danger of pinch flats if I go to low.

The range printed on the sidewall of the tyre is often just a minimum and maximum pressure. Usually the box/instructions/website will provide you with an actual "recommended" starting pressure based on your weight, rim width and riding conditions. Some tyre manufacturers are better than others in regard to providing useful info.

I find the Zipp/SRAM online tyre pressure calculator below the most useful guide, in addition to what the manufacturer advises

https://axs.sram.com/guides/tire/pressure

PeteHski 05-23-22 02:45 PM


Originally Posted by aliasfox (Post 22514630)
As long as you have a cell phone and a friend or partner who’s willing to pick you up, go as low or as high as you want! I’ve just gone up or down 5psi at a time for a few rides to see how things feel, and eventually settled on a range that I’m comfortable with, which is about 78-85psi on my effectively 32mm front (28mm Conti Ultra Sport 2), and about 90psi on my effectively 28mm rear (25mm Conti GP4k - my last one). Both are higher than is ever recommended, but it’s what I like, and isn’t that what matters?

Well in addition to "what you like", there are also safety factors to consider. For example if you are using hookless rims and you exceed the maximum pressure then you could have a sudden blow-out. So at the very least you have to know what the safe limits are for your particular tyre/rim combo.

aliasfox 05-23-22 03:07 PM


Originally Posted by PeteHski (Post 22517037)
Well in addition to "what you like", there are also safety factors to consider. For example if you are using hookless rims and you exceed the maximum pressure then you could have a sudden blow-out. So at the very least you have to know what the safe limits are for your particular tyre/rim combo.

Fair enough, though I would hope people would stay within reason with regards to the min/max. I wasn't suggesting putting 200psi on a 32mm tire mounted to a hookless rim, but that within the min(rim, tire) and max(rim, tire) combo, you can experiment. And if you pinch flat while running tubed... well, that's what the cell phone's for.

PeteHski 05-23-22 03:33 PM


Originally Posted by aliasfox (Post 22517076)
Fair enough, though I would hope people would stay within reason with regards to the min/max. I wasn't suggesting putting 200psi on a 32mm tire mounted to a hookless rim, but that within the min(rim, tire) and max(rim, tire) combo, you can experiment. And if you pinch flat while running tubed... well, that's what the cell phone's for.

Yes, of course you can experiment within the stated min-max range for your tyre/rim combo. It was the bit where you stated that you prefer to run your pressures "higher than is ever recommended" that prompted my warning. But as long as you know what the safe upper pressure limit is then it's your call.

aliasfox 05-23-22 06:42 PM


Originally Posted by PeteHski (Post 22517130)
Yes, of course you can experiment within the stated min-max range for your tyre/rim combo. It was the bit where you stated that you prefer to run your pressures "higher than is ever recommended" that prompted my warning. But as long as you know what the safe upper pressure limit is then it's your call.

Oh - apologies for writing that in a confusing manner. I DO NOT recommend going beyond the recommended limits for the tire or the rim. What I meant to say is that I've put my numbers into tire pressure calculators, and they always seem ridiculously low to me. For example, with my (measured) 32mm front and 28mm rear, Silca suggests, for my 215lbs total system weight, that I should be riding 66psi in front, and 84psi in the rear. I can say for certain that I'm not a fan of how my front feels below 75psi, and I generally pump it up closer to 80psi. As for my rear, I can deal with 84psi, but I'm more comfortable at 90psi. That's what I meant by going higher than recommended.

Now, it may also be because the gauge on my Serfas pump isn't accurate, or maybe I'm just so used to riding on 23-25mm tires at 100-110psi for so long. But within reason (read: within the limits of what your tire/rim says), I say every rider should just go and experiment and see what makes the most sense to them - and different people will optimize to different criteria - personal comfort, perceived performance, time over a certain Strava segment, etc. After all, the calculators really are just recommendations.


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