Loss of tire air pressure... raising blood pressure

[Tommycat]

Is it just me? Or does any one else have a problem with bike tires slowly losing air pressure? Seems like every time I want to go for a ride, the tires need to be pumped up? This happens on both my bikes. At tire pressures of 90 and 40 PSI. Can get frustrating. Verified Schrader valves tight and holding.(soap bubbles) New tubes. This isn't rocket science. Anybody using tire Slime or have a good fix? Thank you.

[AZguy]

Rubber is porous and tires/tubes slowly lose pressure... There's no way around it...

[max_volt]

Yes that is perfectly normal and is worse as the temp rises. You may have to top off the tires before riding. Car tires are the same and require a bit of maintenance.

[ncmired]

... what he said ... it's normal and the nature of rubber tubes / tires. You could ease the pain somewhat by using the CO2 inflators, a battery powered tire pump, or a "waiting to go" air compressor.

And, there are the Tannus tires: https://tannusamerica.com/

[Tommycat]

Noooooo fellas this is NOT what I wanted to hear! Well o.k. it's nice not being the only one. :-) hummmm solid tires... 0-0

To add insult to injury. Ten minutes after posting this, went out and found my back tire flat! What the.... Went to move it and found it hard to roll. Of course the first thing I think...Bad Mosfets. lol.

I definitely feel a change in the FORCE! ;-) Will post an autopsy. Rats only 28 miles on them and I just got my new rearview mirror mounted. sigh

[max_volt]

Yes indeed the force is strong and perhaps going in the wrong direction. I have a flat in my garage as we speak. I used to patch the tube but decided to just chuck it and start out from new.

[MoneyPit]

As has been stated, this is life on two wheels. However you can do a couple of things to make the problem more livable. All of the below assumes you are not running tubeless.

1. Use thornproof tubes.
Thicker rubber = a lower air loss rate over time.

2. Use oversized tubes
A tube that has not expanded so much is a tube that doesn't leak as fast. Or maybe even doesn't leak at all Noticeably, at least)

3. Do 1. and 2. Together. Using 2.3" tires and 3.0" thornproof tubes I basically had no air loss on one bike.

4. Use Slime or some other kind of tube sealant. I use Slime but have also used Berryman's. Both reduce air loss rate.

5. Do 2. and 4 together. No thornproof tubes for fat bikes. but my 4.0" tires and 4.9" tubes keep the tube from distending so much, and the slime does its part. I don't air back up for weeks. Usually only after checking it one too many times has finally decreased air pressure some.

[AZguy]

Thousands of miles in arizona thorns on fat tires with stans - zero flats with the same small loss of pressure. The stuff works. With the big tires and low pressures I only have to put a little air in every few weeks....

[AZguy]

Stans is great in tubes too. It's sold to seal tubeless tires but it's just fine in tubes. I'm running tubes in my fat tires. I just throw out the tubes when I replace the tires. It's a good idea to rinse out the tube talc before putting the stans in and I use 2-4x as much as they recommend. It's messy stuff but once you figure it out pretty easy. The valve cores will get a bit gummed up after a while and you need to clean them... not often enough to be a hassle and well worth zero flats.

[Tommycat]

Ahhhh, OK Stans is a sealer... like Slime is. Thanks for the clarification.

[AZguy]

It's pretty amazing stuff. I had a half dozen big thorns, 1/8" or so, in a tire. Funny just to pull them out hear the whoosh of air coming out of the hole and rotate the tire until some of the juice gets in and in a second it's completely sealed.

[Tommycat]

Yep, this is what happens when Instant Karma gets ya!





Found the problem... and patched.





Now here's the rub. It was on the rim side of the tube...? Didn't look to be right on a spoke nipple. Did I make a mistake when installing to use some baby powder to slick things up?
My tires are 44-584 (650B) 27.5 X 1.75. The tubes are 27.5 X 1.75/1.95. So what would be a proper over size to satisfy livable fix #2, when getting livable fix #1? Before adding stans… :-)


That said, even more ominous to me was this cracking/splitting starting to show around the middle of the tire. Thoughts?






Longer and a bit deeper in spots, right in the middle.

[MoneyPit]

Oversize: as much as you can stuff in. Its up to you not to create a pinch flat and this is part of where using thronproofs helps as you pretty much have to try to get a pinch flat. Insofar as the tire is concerned... Are those CST Cyclops? $14 tire if you bought smart. You can replace it or just run it into the ground. Your call.

These would work but I'd prefer thornproof if it were me.

https://www.amazon.com/PACK-2-10-2-35-Schrader-Replacement-Mountain/dp/B01348DKGU/ref=sr_1_fkmr1_4?ie=UTF8&qid=1527353028&sr=8-4-fkmr1&keywords=27.5"+thornproof+tube

or here... best of both worlds. Oversized and thorn resistant. For an ebike where you don't GAF about weight I would consider these perfect. I used this size in 26" and presta for my Cyclone bike that ran Cyclops 2.4" tires.

https://www.amazon.com/Sunlite-Thorn-Resistant-Schrader-Valve/dp/B00MR8NEPG/ref=sr_1_3?ie=UTF8&qid=1527353267&sr=8-3&keywords=sunlite%2Bthorn%2Bresistant&dpID=41lvCO0XbXL&preST=_SY300_QL70_&dpSrc=srch&th=1&psc=1

[Tommycat]

Hi MoneyPit,
Thanks for your replies.

Are those CST Cyclops? $14 tire if you bought smart. You can replace it or just run it into the ground. Your call.

OEM Huffy Parkside...errrrr inexpensive. XCEs?

Oversized and thorn resistant. For an ebike where you don't GAF about weight I would consider these perfect. I used this size in 26" and presta for my Cyclone bike that ran Cyclops 2.4" tires.

https://www.amazon.com/Sunlite-Thorn-Resistant-Schrader-Valve/dp/B00MR8NEPG/ref=sr_1_3?ie=UTF8&qid=1527353267&sr=8-3&keywords=sunlite%2Bthorn%2Bresistant&dpID=41lvCO0XbXL&preST=_SY300_QL70_&dpSrc=srch&th=1&psc=1

LOL Weight concern with a Magic Pie V5? Never a thought. :-) Got the above tubes on my wish list. Thank you for your research! But speaking of weight, and considering a tire/tube upgrade. Would a wider tire hold up any better? And better ride. Or just go for better quality or more tread?
If I read things right can I go up to a 2.35...but would I want too???

[MoneyPit]

On my Specialized Stumpjumper I went to wider Alexrims DM24 rims, which took the same tire and gave it a wider base, which in turn eliminated tire squirm over uneven surfaces. Those wider rims also let me add wider tires, at which point my width was determined by what would fit in the frame and forks. I went from a bike taking 26x1.95 tires to 26x2.4 and I loved it. More stability overall. Slightly taller so the bike had a slightly higher top speed. I think I gained 2 mph. But get this... Being that my Cyuclone was a mini-Cyclone, the taller tire meant slower acceleration Which on a mini Cyclone means more heat and those motors like to overheat. So I ended up going back to stock 26x1.95 tires with those bigass tubes - which still fit great. It was only a small difference but heat is such a big problem with those little motors I was after every edge I could get. In your case, that likely won't be an issue. As a rule I like bigger tires. Your mileage may vary.

[Tommycat]

Will stay OEM size for now.

Looking at it closer, the puncture may have been over a spoke nipple. May just be a one off. Will get it back on the road and order the thornproof and some Stans for the back tire for the air leakage testing. :-) Thanks again for the inputs!

[AZguy]

I use way more stans than they recommend. In my fat tires I use no less than 250cc per tire and have used as much as 500cc per vs. the 60cc they say... Like I mentioned some tubes have an enormous amount of tube talc that bind up with the stans so it's a good idea to rinse the talc out before the stans (a little leftover water won't hurt anything)...

[Tommycat]

OK AZguy will do! Flush out the insides of the tubes with water first.

[Tommycat]

Rats, it's definitely official! I am a failure at tube patch repair... 3 tries, three failures. :-( Did it as a kid...no problems. Seen the videos, read the instructions, just no luck. Waiting on new oversized tube and Stans.

[MoneyPit]

Rema Tip Top patch kit. The old standby for a reason. almost impossible to fail.

[Tommycat]

Roger that! I'll throw this Walmart kit in the trash. Slime brand BTW :-) EDIT: Ordered it's on the way!

[Tommycat]

Time to get back on the road!





Comparison shot...





The new tube is defiantly more substantial in thickness and heft! I like it! Put some tread on it and who needs a tire? :-)


Internal wash...





White creamy looking water came out, well worth the effort to get some talc out.


WHAT!!! It goes in WHERE???





Ahhhh, no worries. Fit like a glove. So at this time I'm not going to put the Stans in. Want to get some data points for the air leakage as is. Front verses back, although the weight distribution is certainly not equal.

May just have stumbled on the potential cause of the premature tube failure. When I purposely over inflated the tube to 45 psi wanting to set the bead and accurately bleed off to the recommended 40 psi.
Found a 5 psi difference between my automatic pressure gage, and the digital one I use for accuracy. So it looks like I've always been running the tire pressures 5 psi low. hummmmmm. Will calibrate and update new pressure loss information in time...