Gravel Tire Pressure on Pavement? (40+mm tires)
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Sure, a wider tire will still have cushion for paved riding but for me personally, I prefer even lower pressure for even more comfort on out terrible chip seal roads. I am not bothered by any rolling resistance penalties that may come with this decision. I suppose I have a preference for maximum comfort over speed. It's good to exercise preference and that we have this ability to.
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Tire Pressure
I thought I'd used this as a reference before, but perhaps not. I run 700x32 at around 45-50 pounds on pavement, 700x30 50psi, 700x28 55-60, and 700x 25 at 60-65. My 700x42 RH tires on gravel are typically 30-34 pounds. I rarely put them above that for pavement...maybe I should try, lol, but seldom ride a pavement only ride on that bike anymore. I weight in the 150 range.
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#29
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I just ran the silca tire pressure calculator.
It suggests 41rear 40front for my total weight on 43mm tires.
I run 45rear and 40front when on gravel/mixed surface, as mentioned earlier.
So pretty darn close.
But for pavement only? I am pretty surprised to see some of the low numbers mentioned in this thread since it's about gravel tire pressure for pavement. There is just no downside to bumping the pressure up a bit- a wider tire will still have plenty of cushion to deform over road imperfections and it'll roll faster than if it's at a low pressure.
I am not suggesting a 43mm tire be pumped to 90psi, to be clear.
It suggests 41rear 40front for my total weight on 43mm tires.
I run 45rear and 40front when on gravel/mixed surface, as mentioned earlier.
So pretty darn close.
But for pavement only? I am pretty surprised to see some of the low numbers mentioned in this thread since it's about gravel tire pressure for pavement. There is just no downside to bumping the pressure up a bit- a wider tire will still have plenty of cushion to deform over road imperfections and it'll roll faster than if it's at a low pressure.
I am not suggesting a 43mm tire be pumped to 90psi, to be clear.
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I'm 155# and running 42 mm Teravail Cannonballs on my gravel bike. The other day, I was riding on pavement but it was icy and I wanted the tires on the soft, grippy side, so I ran at 38 back/35 front, and that was good. Yesterday, dry roads and riding with a group where the others were on road bikes, so I wanted fast. I ran 46 back/42 front. That worked for fast, but also the road buzz was considerable. Based solely on comfort, 46/42 was too much.
That Silca calculator seems about right. It suggests about 42/39 for "fast group ride".
That Silca calculator seems about right. It suggests about 42/39 for "fast group ride".
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Also, it may be that the Silca calculator reproduces what some of you find is exactly right for your rig, no such calculator is going to be perfect. Tires, rims, road surfaces, and riders all introduce objective and subjective factors.
At times, what I wish I could calculate is the "plausible pinch flat" value. That would be the calculator that says, for a given setup and speed (say 20 mph), what's the minimum pressure to avoid one?=
(No smug comments about pinch flats and tubeless please. That's been done already.)
At times, what I wish I could calculate is the "plausible pinch flat" value. That would be the calculator that says, for a given setup and speed (say 20 mph), what's the minimum pressure to avoid one?=
(No smug comments about pinch flats and tubeless please. That's been done already.)
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That Silca calculator is very impressive, it comes up with numbers for me that are very close to what I have slowly evolved to with many experiments. It is the only calculator I have seen with so many road surface choices, I was winging that part.
I would say just punch in your numbers there, pump up, and go.
I would say just punch in your numbers there, pump up, and go.
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#33
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Man, that Silca calculator seems way off for me. The front pressure seems too high and the rear seems too low. It recommended 44F/46R for 100% road on 40mm tires, but for that I'm at ~40F/60R. I'll drop to 35F/50R if I'm on mostly gravel, and I'll adjust the pressures somewhere in between if I'm mixing it up.
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Man, that Silca calculator seems way off for me. The front pressure seems too high and the rear seems too low. It recommended 44F/46R for 100% road on 40mm tires, but for that I'm at ~40F/60R. I'll drop to 35F/50R if I'm on mostly gravel, and I'll adjust the pressures somewhere in between if I'm mixing it up.
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I just wanted to get an idea of what you all run when it comes to tire pressure with larger gravel tires in the 40-50+mm size for primarily pavement. I’ve been testing tire pressures with the Fleecer Ridge tires which are 55mm but roll nice on pavement. I’ve gone as low as 25-30psi and up to 40-45psi which is high but I’m also ~250lbs. Honestly I didn’t think I felt that much of a difference, but I think the bigger test would be doing longer rides than my short 15 min. test rides 😅
Still, I was curious to see what others ran, and the reasoning behind why you settled with that tire pressure.
Still, I was curious to see what others ran, and the reasoning behind why you settled with that tire pressure.
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Why do the charts all seemingly advocate for less % drop on the front tire? There is probably an explanation but I never got a clear one. One reason I heard is when standing your weight is more forward so it is not good to make the pressures too different. I don't really buy that, and I put a slightly bigger difference front vs rear than the charts say to.. a ~5 psi front vs rear difference for gravel tires. The Silca chart is for a 47/53 weight distribution on gravel, and gives only 2psi pressure difference for me.
Last edited by scottfsmith; 11-18-21 at 09:20 PM.
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For riding where I'm typically seated for most of the ride, ie road and gravel, I'm typically inflating the rear tire 20% more than the front, primarily for hand comfort.
For riding where I'm typically standing for most of the ride, ie mtb, I'm typically inflating the rear to 10% more than the front, as the bike feels more stable in the turns.
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Man, that Silca calculator seems way off for me. The front pressure seems too high and the rear seems too low. It recommended 44F/46R for 100% road on 40mm tires, but for that I'm at ~40F/60R. I'll drop to 35F/50R if I'm on mostly gravel, and I'll adjust the pressures somewhere in between if I'm mixing it up.
#39
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As already stated, that is a significant difference R to F. If you've been riding this way for a while, it might feel "normal" because you are adjusted to it. Have you considered giving the slice pressures a chance, and seeing how they feel/ride? It's just air and a 2 minutes of your time to adjust the pressures. Or, look up "15% drop" and find a chart.
I've tried dropping the rear, but below 50 or so it feels squishy and bouncy when standing to climb. My method of establishing tire pressures is basically to drop them until they feel squishy, then raise them back up a smidge until they stop feeling sloppy. For some reason, there's less of an issue with the front wheel being sloppy at lower pressures than the rear.
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I thought I'd used this as a reference before, but perhaps not. I run 700x32 at around 45-50 pounds on pavement, 700x30 50psi, 700x28 55-60, and 700x 25 at 60-65. My 700x42 RH tires on gravel are typically 30-34 pounds. I rarely put them above that for pavement...maybe I should try, lol, but seldom ride a pavement only ride on that bike anymore. I weight in the 150 range.
They used 50F/65R with 30mm tires (for what is it worth)
Man, that Silca calculator seems way off for me. The front pressure seems too high and the rear seems too low. It recommended 44F/46R for 100% road on 40mm tires, but for that I'm at ~40F/60R. I'll drop to 35F/50R if I'm on mostly gravel, and I'll adjust the pressures somewhere in between if I'm mixing it up.
I wonder if most people realize this?
often, when I ride through a damp spot (or anything that leaves a mark on the tire), I make sure the damp spot on my tire is the same width on the front tire as it is the back tire. Realistically, the front tire needs a LOT less pressure than the rear to get the same tire drop (or width of the tread in contact with the pavement).
your numbers look right on.
#41
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So first time hearing about the Silca calculator so I plugged my weight & tires in: at 260 loaded weight the 42mm 700c tires I can run 41/44 F/R and slightly less for rougher roads or slightly higher for smoother roads. For 55mm tires I can do 25/27. That…… is honestly close to what I was noticing when I would hop on my bikes w/o checking pressure. Obviously the 42mm UD tires were way more sensitive to pressure changes, but I was riding the 55mm RH and not immediately realizing how low the pressures were. I guess when you’re so used to running high pressures due to weight and running tubes it feels different when you can finally dial down to lower pressures, but I digress.
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I’m 143lbs and I run 28/26 road/mix and 25/22 gravel on Donnelly strada uhs wc tires. My average speed on the road drops at higher pressure. I also run 70/65 on my 25mm tubed tires on my road bike, higher pressure than this is slower and more painful for me. Though I rarely ride the road bike anymore, even on all road rides, the gravel bike just feels better.
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