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Tyre pressure for bicycle
in Public transport & cycling
24 replies 3.4K views
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Most of the track pumps now have a head which takes both types of valves. I'm not sure that a 12v compressor would like to go to the pressures needed for a road bike, although they would be fine for wider tyres. They are designed for high volume, lower pressure,where bike pumps are the other way round.
For the op, I'd go for around 60. I always blow the rear up slightly more than the front, as it carries more weight.
I use the compressor to put my car tyres to 32 psi up front which on the gauge is around 1/3rd capacity if i remember correctly (the compressor is at my mothers - it's hers really, not mine).
With the max capacity on this bike being 40-80psi or whatever it says on the tyre (it's somewhere in that region) i'd say the compressor should be more than capable of reaching the required psi.
To be honest i'm only really mentioning it because we already have it, plus an adapter is like £1.20 off eBay. Compare this to going the track pump route which would be like a £20 outlay. Even one at half price if such a one exists - it's still dearer than a £1.20 adapter. If i had a track pump already then i wouldn't even be asking about 12v compressors.
In fact, i've found the exact compressor that my mother has: https://www.halfords.com/workshop-tools/garage-equipment/tyre-inflators-pressure-gauges/essentials-analogue-tyre-inflator
I think that would be fine for occasional use. I pump up my roadbike every time it is out, about 2-3 times a week and my workbike once a week - on Monday morning.
I referred to road bikes, and I see it has a 100psi maximum. On my roadbike with 23mm tyres I run it at 120 rear / 110 front. Wider tyres are more in vogue now, so I've gone to 25mm tyres with 110 rear and 100 front. Some people racing will go to 140psi or possibly even more.
My pump is an Edinburgh Bike coop own brand one, which was half price at about £11 in their sale.
I've had really bad experiences with 12v pumps, 2-3 uses and they break. I haven't tried for some time now though. I use a twin-barrel foot pump for car tyres. So I think my bias might be shining through about pumps!
Tyre pressure should be higher at the rear than at the front unless you're using a narrower tyre than on the front (unlikely). Using the chart given in an earlier post is okay but doesn't consider that the weight on a bike is unevenly distributed. So for a racer type you're more like to be 45/55 front rear, someone more upright might have a bit more of the weight on the back, then you have to take into account actual bike weight and any load you carry.
Someone about 175 + bike of say 30lbs would be looking at with a 37mm tyre on a hybrid around 35psi on the front and 55psi at the back. If you're going off road you might want to reduce that a bit.
Re getting air in, as above, track pump for home, on the road I use a Specialized Airtool MTB, another good one but for the specialist/enthusiast is the Lezyne Micro Floor Drive HV Mini Pump. Costly but will most definitely get your tyre to whatever pressure you want.
CRC have a track pump for £15 delivered, there's probably cheaper out there though:
Also it is doable to inflate a car tyre from flat with the track pump which I find easier than the foot pumps. I had a fun time last December when my rubbish Japanese alloys were leaking air which I was keeping topped up using a 12V air compressor until one snowy night it wouldn't screw onto the thread. The clamp on the track pump worked fine though so I topped up all four tyres using the track pump!
The reason I cited the table from the Schwalbe technical data above, and not the Berto graph is that most people don't have any idea how their weight is distributed. With the bike unladen, my weight distribution is 60/40, and fully laden for touring 67/33, both much more uneven than the article citing Berto assumes. Either way, the 15% compression of the tyre that the Berto data is based on is an arbitrary figure to start with.
Simply repeating bad advice to put same pressures in tyres is BAD advice.
Berto may have made a unilateral decision on the 15% based on his personal experience but for road riding as per the article he was actually pretty much bang on.
"On smooth roads, tire pressure is a matter of personal preference (at least with supple tires). High and low pressures offer the same performance."
"See what feels best to you. That is the optimum tire pressure for you. Don’t worry about tire pressure any further!"