# Bicycle tires vs automobile tires **URL:** \ **Category:** Factual Questions\ **Created:** [October 20, 2023, 9:39pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860 "2023-10-20T21:39:37Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [October 21, 2023, 12:42pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/21 "2023-10-21T12:42:00Z")
Also, I tighten the caps on my bike tires, which has to have some effect on slowing any leaks through the valve. So i assume permeating through the tire material is the main issue. Regardless, at 60psi I have to inflate about every 2 or 3 weeks, with weekly (weekend) use. My first BMW (2000) was great until the termperature took a major plunge that winter. My wife got a few blocks and one rim started spinning in the tire. The tire repair place said that maybe Germany doesn’t see the same temperatures, but apparently the tires had been put on without putting sticky goop on the rims to seal them to the tires despite cast rim expansion/contraction. He said this stuff was normal in North America. (I think they were aluminum rims with a larger expansion issue.) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 21, 2023, 2:13pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/22 "2023-10-21T14:13:51Z")
> [@chela](#): > > I’m amazed that your car and truck tires can go years without needing air. Are you checking them or just eyeballing the tire? Motorists are typically more tolerant of low pressure than bicyclists. Low pressure will decrease efficiency, but most motorists don’t care about that. On a bike, though, you feel the decreased efficiency. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [October 21, 2023, 2:34pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/23 "2023-10-21T14:34:06Z")
> [@Lucas\_Jackson](#): > > I can literally go years without needing to put air in my car and truck tires Are you sure air isn’t being added by someone else? When I take my truck in for regular service (usually twice a year), the mechanics will top off the air pressure without being asked to. It’s a little annoying actually, since they often add too much for my taste (but not enough to be dangerous) and I have to bleed a little off. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [October 21, 2023, 3:41pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/24 "2023-10-21T15:41:52Z")
Yeah, that doesn’t seem right. I’ve always had to check my car/truck tires and add air a few times a year at minimum. Seasonally for sure, but most of them do lose a _little_ air in between anyway. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [October 21, 2023, 3:46pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/25 "2023-10-21T15:46:20Z")
If you get your car serviced a time or two a year, wouldn’t they top off the tires as part of it? ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [October 22, 2023, 3:18pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/26 "2023-10-22T15:18:18Z")
> [@chela](#): > > I’m amazed that your car and truck tires can go years without needing air. Are you checking them or just eyeballing the tire? I generally trust the built-in air sensor on my vehicles. On the rare occasion that eyeballing seems to indicate that the tires are low. A check with my quality gauge confirms that they are correct or are with a pound of recommended pressure. I’ll add that I live on the mid California coast where it rarely gets cold of hot. ETA: I take vehicle maintenance seriously but if the tires don’t need air, they don’t. ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [October 25, 2023, 6:49pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/27 "2023-10-25T18:49:04Z")
I have little doubt that bike tires could be made as impervious to air loss as car tires, but no one would buy then because they would be heavy and lack traction. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [October 25, 2023, 8:56pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/28 "2023-10-25T20:56:42Z")
I just switched to winter tires, and over the summer one had lost about 10 psi. Another 5psi. The rest were fine. One was slightly over, still. It’s hard to be too accurate because the colder it gets, the less pressure in the tire. I may have to add air in a few weeks. The problem with low bike tires isn’t efficiency, it’s feeling the bumps in the road hit the rims, and the slide when you corner. ---
**Author:** ![gnarator](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gnarator/32/8266_2.png) [@gnarator](https://boards.straightdope.com/u/gnarator)\ **Post date:** [October 25, 2023, 9:16pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/29 "2023-10-25T21:16:56Z")
I bike commute, so I usually pump up bike tires every week or every couple of weeks. When I ride my bike with presta valves, it seems to hold pressure better than the ones with shrader valves, but they are different sizes and pressures, so that may account for it. I wish I got 5,000 miles out of my tires. Maybe the front tire, but the rear one wears down faster so I’m looking to replace them when the tread is worn down and the tire looks ‘flat’: > **[8 Indications That You Need To Replace Your Tires - BikeTiresDirect 21409](https://www.biketiresdirect.com/8-indications-that-you-need-to-replace-your-tires-article)** > > Signs your bicycle tires have worn out and should be replaced (see pic 4) Maybe 2,000-2,500 miles? I don’t really track mileage so it’s pure guesswork. ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [October 25, 2023, 9:30pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/30 "2023-10-25T21:30:01Z")
Back when I was road racing, the training tires were only replaced when they were down to the threads. One area where bike tires are similar to car tires these days is price. Ouch! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 25, 2023, 10:27pm UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/31 "2023-10-25T22:27:04Z")
> [@md-2000](#): > > The problem with low bike tires isn’t efficiency, it’s feeling the bumps in the road hit the rims, It’s more than just feeling the bumps. A bump like that can cause a pinch flat. ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [October 26, 2023, 1:11am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/32 "2023-10-26T01:11:56Z")
You can also damage the rim. My completely anecdotal, unstructured observation is that tubed and tubeless bike tires loose air at about the same rate. ---
**Author:** ![wguy123](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wguy123/32/3161_2.png) [@wguy123](https://boards.straightdope.com/u/wguy123)\ **Post date:** [October 26, 2023, 1:34am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/33 "2023-10-26T01:34:10Z")
I bike a lot and have a variety of bike tire/tube sizes. My road bikes with 25mm tires and 100 PSI need frequent pumping. My commuter bike with 2.4" (60mm tires) and much lower pressure can go months without needing air. My mtn bikes also have bigger tires, but they run such low pressures that I always make sure they are up enough. Two more data points: I don’t have any tubeless and I use tube sealant on all my big tubed tires but not on the two small tire bikes. I think it’s a combo of small air space + high pressure and lack of sealant. > [@outlierrn](#): > > My completely anecdotal, unstructured observation is that tubed and tubeless bike tires loose air at about the same rate. Interesting! I will be converting my mtn bike (or buying a new one over my partner’s protests) to tubeless and will have to gather some data. ---
**Author:** ![snowthx](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snowthx/32/10660_2.png) [@snowthx](https://boards.straightdope.com/u/snowthx)\ **Post date:** [October 26, 2023, 2:35am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/34 "2023-10-26T02:35:43Z")
The sealant in tubeless works when the tire is spinning, spreading over the inner surfaces. When idle, the sealant pools at the lowest spot, so I suspect air loss on tubeless tires would be about the same as tubed, assuming similar rubber. ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [October 26, 2023, 4:15am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/35 "2023-10-26T04:15:40Z")
Yeah, once the tubeless tire is set up, it isn’t much different than a tubed tire with regard to air loss. Some tires have thinner and more porous sidewalls, and it may take some time for the sealant to make them airtight, but once that is done it’s good. > [@wguy123](#): > > I will be converting my mtn bike (or buying a new one over my partner’s protests) to tubeless and will have to gather some data. The learning curve for installing tubeless tires isn’t particularly hard, but it can be incredibly frustrating, depending on the setup. But it is completely worth it. Do it yourself, don’t have a bike shop for it for you. Installing/troubleshooting tubeless tires is a skill you’ll need to know, sooner or later. ---
**Author:** ![Smapti](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smapti/32/17938_2.png) [@Smapti](https://boards.straightdope.com/u/Smapti)\ **Post date:** [October 26, 2023, 4:28am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/36 "2023-10-26T04:28:50Z")
Maybe this is a good place to ask my own question about bike tires. I ride an electric mountain bike for my commute to and from work, about 6 miles each way. (Mostly from - I ride from my house to the downtown bus station, load it onto the city bus for the rest of the trip to work, and then ride it home at night after the buses have stopped running.) My ride is entirely over paved roads, but I went with a mountain bike because I figured it’d be more durable than a road bike, and because I’m a heavyset fellow and figured the heavier bike would support my weight better than a lighter frame. **What the hell am I supposed to inflate my tires to?** I’ve gone through a few tires since I bought it a year and a half ago, mainly because of driving over nails or screws or such things, and the information printed on the tire is pretty broad - the pair I’ve got currently say the acceptable range is 35-65 PSI, which is a huge range. My attempts at Googling it haven’t given me anything more comprehensive than “sometimes lower pressure is good and sometimes higher pressure is good, and sometimes they’re bad, and you’ll figure it out”. All I’ve figured out so far is that I’ll get a pinch flat on the rear tire unless it’s got about 10 PSI more than the front tire. Is there maybe some mathematical formula where I can plug in my weight and the weight of the bike to figure out what the optimal pressure should be for each tire? ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [October 26, 2023, 4:49am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/37 "2023-10-26T04:49:42Z")
> [@Smapti](#): > > maybe some mathematical formula Definitely no formula. Higher pressures are more efficient, lower pressures are grippier. Higher pressure limits are as much about the wheel the tire is likely to be mounted on than the rubber itself, lower pressure limits are unlikely to pinch under most riders most of the time. And, as always, both are probably more lawyer driven than science. For your described riding I’d suggest higher pressure unless it feels harsh or you start losing traction. ---
**Author:** ![The\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_librarian/32/402_2.png) [@The\_Librarian](https://boards.straightdope.com/u/The_Librarian)\ **Post date:** [October 26, 2023, 5:10am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/38 "2023-10-26T05:10:03Z")
> **[SILCA Professional Tire Pressure Calculator](https://silca.cc/pages/sppc-form)** > > Dial in your tire pressure to get the most comfort, speed, and efficiency out of your ride. If you are looking for the best free marginal gain, click here Not a formula: online calculator. ---
**Author:** ![MonkeysBrother](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@MonkeysBrother](https://boards.straightdope.com/u/MonkeysBrother)\ **Post date:** [October 26, 2023, 5:26am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/39 "2023-10-26T05:26:59Z")
Silca, a manufacturer of bicycle tire pumps\* and accessories, has a calculator. I use it and the recommended pressures are comfortable, though they seem a little lower than what used to be recommended when I was younger. I have a road bike with 700 x 25c tires and a hybrid that I commute to work on that has 700 x 32c tires. [https://silca.cc/pages/sppc-form](https://silca.cc/pages/sppc-form) (you don’t have to give them your email for the calculator to work) \*As an aside, I’ve had my Silca floor pump since the late '70s. It’s a little beat up and has gone through a few gaskets over the years, but it still works just fine. No, I’ve not been paid for this endorsement. 🕶 And on review… ninja’d. ---
**Author:** ![The\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_librarian/32/402_2.png) [@The\_Librarian](https://boards.straightdope.com/u/The_Librarian)\ **Post date:** [October 26, 2023, 6:50am UTC](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860/40 "2023-10-26T06:50:05Z")
A (very) rough rule of thumb: When standing next to your bike, leaning with max force on your saddle you should just see the rear tire compress. Or: when you try to push your thumb into the tire you should just feel a little bit of give. (Assuming a “normal” grip strength vs. Body weight) The results of the calculator are superior, but do require a pressure gauge. [Previous page](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860.md?page=1) [Next page](https://boards.straightdope.com/t/bicycle-tires-vs-automobile-tires/991860.md?page=3)