Tires don't hold pressure long!

W

Widegide

Member
Region
Canada
Is it normal for these Schwalbe tires to lose close to 10psi, in a week?
New bike with only 110 km. Both tires dropping equally, so kinda rules out bad tube or tire.
 
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What size tires and what's your normal pressure? Also, were they originally filled with air or with CO2? CO2 permeates through rubber and is a known problem. If you don't know what was in the tires, you might want to purge them and fill with air. (I use mostly CO2 and don't seem to have the problem, maybe because I use a lot of Slime, I don't know. But, yeah, you could easily be within normal parameters, regardless.

You could check that your valve cores are snug too.

TT
 
What tubes are you using? The standard tubes in my Schwalbe tires were quite thin and a 10 lb loss in a week was common for me as well. I switched to Schwalbe Downhill tubes, which are twice as thick, and the air loss is now minimal. The thicker rubber walls of the Downhill's offer a bit more flat protection as well.
 
6zfshdb said:
What tubes are you using? The standard tubes in my Schwalbe tires were quite thin and a 10 lb loss in a week was common for me as well. I switched to Schwalbe Downhill tubes, which are twice as thick, and the air loss is now minimal. The thicker rubber walls of the Downhill's offer a bit more flat protection as well.
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I agree it's probably thin inexpensive tubes. Since switching to Continental tubes my air pressure has been much more stable and only needs to be topped off about once a month or more.
 
THE SCIENCE BEHIND TIRES LOSING AIR

Rubber is comprised of long elastic strands of polymers. An inherent characteristic of those elastic polymer strands is micro pathways through which gasses are able to pass. The air in your tube eventually escapes through these micro pathways. Voila - lost air pressure in your tires.​


This process is called diffusion. The higher the pressure and lower the volume, the more quickly the tire will lose pressure. Even with the same amount of air passing through the rubber, the effect is more significant because of the lower volume. On average, tires will lose 1-2 psi per day. For low volume, high pressure tires, you will most likely need to top off your tires every 4-7 days to keep it within the recommended range.​

handsomecycles.com

Why do bicycle tires lose air over time?

handsomecycles.com handsomecycles.com
 
Add Slime. Weekly checks required now will turn into every month or 2. No other changes required. It really is that simple.

This issue made me nuts for years going way back before getting into e-bikes. Tried different tubes as suggested by my LBS without any change. Then I went against their advice regarding Slime, and WALLAH! No more tire leaks or need for frequent checking. Have been a major advocate for it since (several years now). -Al
 
Outside temperature changes, especially warm to cold, can be a cause. I’ve had to add some with almost every bike tire after a week or two.
 
Tars Tarkas said:
What size tires and what's your normal pressure? Also, were they originally filled with air or with CO2? CO2 permeates through rubber and is a known problem. If you don't know what was in the tires, you might want to purge them and fill with air. (I use mostly CO2 and don't seem to have the problem, maybe because I use a lot of Slime, I don't know. But, yeah, you could easily be within normal parameters, regardless.

You could check that your valve cores are snug too.

TT
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This may be the issue. The tires were about 20psi when I got it. I've topped the tires up a couple of times now, and the loss of pressure is slowing a lot!
 
When you get tired of messing with it, try the Slime. It's cheap, it's easy, and it works.....
 
Tubolito tubes weight 40% less than standard butyl rubber tubes and are more flat resistant. I find they hold pressure for at least a month or more. They do cost more.
 
my acoustic with skinny tyres requires topping up weekly or so...I run them around 100psi.

My e-bike has 45mm gravel tyres, and since purchase (1 Feb) I've not pumped them up...but the LBS pumped them up to 65 psi at the 1st service last weekend...I reckon I'll get another month until they need air.

The fatter/bigger tyres on the e-bike are way less sensitive to tyre pressure than skinny road tyres, and running lower pressure means they leak less...so a double whammy .

mike
 
Alaskan said:
Tubolito tubes weight 40% less than standard butyl rubber tubes and are more flat resistant. I find they hold pressure for at least a month or more. They do cost more.
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How many people with ebikes care about tubes that are lighter? If they are more flat resistant, that's s something to pay attention to, but my experience is the same as AHicks regarding Slime. Flats and pressure drops are largely eliminated with Slime. It probably adds 40% more weight to the tubes, but the electric motor on my bike way more than makes up for that.

TT
 
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Tars Tarkas said:
How many people with ebikes care about tubes that are lighter? If they are more flat resistant, that's s something to pay attention to, but my experience is the same as AHicks regarding Slime. Flats and pressure drops are largely eliminated with Slime. It probably adds 40% more weight to the tubes, but the electric motor on my bike way more then makes up for that.

TT
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Many ebike riders thinking that their motors and batteries insulate them from the impacts of weight are not thinking things through. Yes the motor helps reduce the impact of weight on the rider effort. However the amount of weight of tires, rims and tubes does has real impact combined human/motor effort, bike speed, battery consumption, etc.

Once you look at, think about and understand the physics of weight, its distribution and stop lugging around unneeded gear, pay attention to aerodynamics and wind drag on bags, cluttered cockpit, and yes amount of weight at near the rims, you accelerate faster, you go further on a charge can sustain higher speed...things most ebike riders care about.
 
I enjoy myself while biking, but I am NOT a biking purist. Never have been, never will be. At 300lbs, I look terrible in spandex for starters.

From where I sit, there's a convenience stand point, and a safety standpoint that are BOTH enhanced when running Slime. I don't have to mess with weekly checks, no matter what pressure I'm running (100psi or 15psi). I set it, and it stays put for months. As if that's not a good enough reason by itself, there is FAR less likelihood of having a problem when out on a ride - or possibly having an issue because I'm running my tires dangerously low unnoticed.

So you be the judge. Should any downside to having 6oz or so of liquid (Slime) rolling around in your tires be enough reason to ignore the advantages of running it? Electric bike or not, for me, the advantages of Slime or a similar product far out weight any downside.
 
Alaskan said:
Many ebike riders thinking that their motors and batteries insulate them from the impacts of weight are not thinking things through. Yes the motor helps reduce the impact of weight on the rider effort. However the amount of weight of tires, rims and tubes does has real impact combined human/motor effort, bike speed, battery consumption, etc.

Once you look at, think about and understand the physics of weight, its distribution and stop lugging around unneeded gear, pay attention to aerodynamics and wind drag on bags, cluttered cockpit, and yes amount of weight at near the rims, you accelerate faster, you go further on a charge can sustain higher speed...things most ebike riders care about.
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There are absolute laws of physics, I get that. Yes, your battery, motor, tires, and everything else, will last longer and take you farther if you cut down on the weight you haul around. But there are real-world compromises we all make and accept. I ride a Rad Rover with 4" Slimed tires. If I was bound by the immutable laws of physics, (I am, of course, but I can "cheat" on them with my ebike) I guess I'd have to ride a 14 pound carbon frame racer (with no motor or battery). I don't have to, and I'm not going to. I'm quite content with the idea that my battery may only take me 41.7 miles down the road instead of the 41.76 miles I might get without the Slime. Sometimes I even pack a lunch for my ride... how much weight is that? I don't care. (Depending on where I'm biking, sometimes I even carry a 15 pound Kryptonite 5ft. Fahgettaboudit Chain! And an Abus folding lock!!!)

That's one of the reasons I have and like an ebike. I'm not trying to argue, I'm just saying we all make choices and we're generally happy with them. For me, lighter tubes, sans Slime, are easy to forego.

TT
 
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