4 ms·

Well, there are tubeless tires (no pinch flats) and wider tires (lower tire pressures). 28C at 60 psi vs 21C at 90 psi.

ehnto 6y ago
Yeah but you'd have to get out there with a pump to change pressure, I think that's the real benefit with this technology. I ride on the road to get to my trail head, and ride at about 20-25psi on 2.8" tubeless tires once on the trail. They're a real drag on the road at that pressure, so I have to stop and pump them up or just deal with the drag. If I could hit a switch and have them inflate themselves back up to 40-50psi for the trip home that would be so awesome. Even on the trail it would be good, downhill at low pressure then put some pressure back in for the climb. Or maybe a bit more pressure for the jump trail and so on.
- Toutouxc 6y ago
  I don't have a source for that, but I've always thought that low tire pressure doesn't really contribute that much compared to aerodynamic drag, even on the joyride home at 20 km/h on a heavier freeride rig.
  - wtallis 6y ago
    I take a scout group on a week-long bike trek on the C&O Canal towpath most summers. That's a flat but unpaved trail, and most of the kids have hardtail mountain bikes because we also do trips for singletrack mountain biking. Over the course of the week, all the kids doing the trip for the first time get faster from day to day. When they start out and don't take my advice about tire pressure seriously, their sustainable cruising speed tends to be in the 8-9mph range. High tire pressure (and careful attention to ensure the brakes aren't rubbing) gets everyone up to at least 11-12mph depending on how hot the weather is. Drafting gets the group up to 14-15mph. So basically, in my experience on longer rides a low tire pressure will prevent you from getting up to the speed where aerodynamic drag is a big concern. And on hilly terrain you spend a lot more time either climbing at speeds far too slow for aerodynamics to matter, or on descents where you have no trouble at all overcoming drag to reach unsafe speeds.
  - ehnto 6y ago
    If you're never going over 20kmph and you have big heavy DH tires on, you will still be experiencing a lot of rolling resistance for the majority of your ride. Considering my ride home is done at like 10-20kmph on a set of Maxxis Minions, rolling resistance should be making up ~50% of my total resistance. At 50psi I find I'm mostly on the centre of the tire, so not even rolling on the full 2.8" width like I would be at 20psi, which I can feel a difference in. CyclingAbout has a great video about aero and bikepacking which is a good intersection of what we're talking about here, though he's using fast rolling tires: > By the time you’re cycling at 30KPH, as much as 90% of the resistive force experienced comes from aerodynamic drag. And it’s not until you get down to 12KPH when rolling and air resistance are equal. https://www.cyclingabout.com/fascinating-aerodynamics-bikepacking-bicycle-touring/ https://www.cyclingabout.com/fascinating-aerodynamics-bikepa...

Yeah but you'd have to get out there with a pump to change pressure, I think that's the real benefit with this technology. I ride on the road to get to my trail head, and ride at about 20-25psi on 2.8" tubeless tires once on the trail. They're a real drag on the road at that pressure, so I have to stop and pump them up or just deal with the drag. If I could hit a switch and have them inflate themselves back up to 40-50psi for the trip home that would be so awesome. Even on the trail it would be good, downhill at low pressure then put some pressure back in for the climb. Or maybe a bit more pressure for the jump trail and so on.

Toutouxc 6y ago
I don't have a source for that, but I've always thought that low tire pressure doesn't really contribute that much compared to aerodynamic drag, even on the joyride home at 20 km/h on a heavier freeride rig.
- wtallis 6y ago
  I take a scout group on a week-long bike trek on the C&O Canal towpath most summers. That's a flat but unpaved trail, and most of the kids have hardtail mountain bikes because we also do trips for singletrack mountain biking. Over the course of the week, all the kids doing the trip for the first time get faster from day to day. When they start out and don't take my advice about tire pressure seriously, their sustainable cruising speed tends to be in the 8-9mph range. High tire pressure (and careful attention to ensure the brakes aren't rubbing) gets everyone up to at least 11-12mph depending on how hot the weather is. Drafting gets the group up to 14-15mph. So basically, in my experience on longer rides a low tire pressure will prevent you from getting up to the speed where aerodynamic drag is a big concern. And on hilly terrain you spend a lot more time either climbing at speeds far too slow for aerodynamics to matter, or on descents where you have no trouble at all overcoming drag to reach unsafe speeds.
- ehnto 6y ago
  If you're never going over 20kmph and you have big heavy DH tires on, you will still be experiencing a lot of rolling resistance for the majority of your ride. Considering my ride home is done at like 10-20kmph on a set of Maxxis Minions, rolling resistance should be making up ~50% of my total resistance. At 50psi I find I'm mostly on the centre of the tire, so not even rolling on the full 2.8" width like I would be at 20psi, which I can feel a difference in. CyclingAbout has a great video about aero and bikepacking which is a good intersection of what we're talking about here, though he's using fast rolling tires: > By the time you’re cycling at 30KPH, as much as 90% of the resistive force experienced comes from aerodynamic drag. And it’s not until you get down to 12KPH when rolling and air resistance are equal. https://www.cyclingabout.com/fascinating-aerodynamics-bikepacking-bicycle-touring/ https://www.cyclingabout.com/fascinating-aerodynamics-bikepa...