GP5000 28mm pressures you run?
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The rider weight is important.. most of the tests are done with smaller riders. Also there is the financial aspect, the UCI has been compromised for decades and Big Gravel isn't much better. it's not like it will fail putting 40 extra psi of pressure in the tire... you could run 23s at 200 probably? The hard tire gives a harsher ride that feels faster even if it isn't which some people enjoy. A bike shop owner told me they overinflate tires for test rides for this reason, makes the bike feel fast.
Last edited by LarrySellerz; 05-14-22 at 07:58 PM.
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So, they aren't any faster, but they FEEL faster?
It's not just the harsher ride. They also handle worse. Instead of absorbing lumpy pavement in corners, they'll hop, and with all that centrifugal force, they'll hop sideways. You were asking about how to corner faster? That ain't how.
It's not just the harsher ride. They also handle worse. Instead of absorbing lumpy pavement in corners, they'll hop, and with all that centrifugal force, they'll hop sideways. You were asking about how to corner faster? That ain't how.
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For the OP, I run 70 to 80 psi @ 28 mm depending on the day and what I'll be riding on.
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Yeah I just like rear tire higher psi
I am gravitating to 85psi rear and 65 front
guess I just got used to it
guess I just got used to it
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So, they aren't any faster, but they FEEL faster?
It's not just the harsher ride. They also handle worse. Instead of absorbing lumpy pavement in corners, they'll hop, and with all that centrifugal force, they'll hop sideways. You were asking about how to corner faster? That ain't how.
It's not just the harsher ride. They also handle worse. Instead of absorbing lumpy pavement in corners, they'll hop, and with all that centrifugal force, they'll hop sideways. You were asking about how to corner faster? That ain't how.
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The rider weight is important.. most of the tests are done with smaller riders. Also there is the financial aspect, the UCI has been compromised for decades and Big Gravel isn't much better. it's not like it will fail putting 40 extra psi of pressure in the tire... you could run 23s at 200 probably? The hard tire gives a harsher ride that feels faster even if it isn't which some people enjoy. A bike shop owner told me they overinflate tires for test rides for this reason, makes the bike feel fast.
There are nuances to these of course but making these statements as fact is dangerous and could get people injured.
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I dunno if I'd go that far. If Larry and his bike together weigh about 285 lbs, plugging that into the 15% drop calculator gives 130 psi for 25mm tires. He's only a bit north of that.
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It wouldn't be my choice either, but I've seen bigger people use smaller tires.
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If he asked me, of course I would suggest 28 but even at his weight he would likely do well at 100-105F and 110-115R. 140 is way too high. And the 15% drop rule is arbitrary, I am not an expert but pretty sure there is no science to that versus 18% or 12%. It’s a round number.
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If he asked me, of course I would suggest 28 but even at his weight he would likely do well at 100-105F and 110-115R. 140 is way too high. And the 15% drop rule is arbitrary, I am not an expert but pretty sure there is no science to that versus 18% or 12%. It’s a round number.
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Maybe why Vittoria Corsas have 145psi max on their sidewalls.
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Larry ain't even on the chart. Hell, I ain't even on the chart and I weigh 60# less!
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Wow
Reduced pressure by 5psi per tire and was surprised how much more comfortable and less bouncy on rough roads it was for downhills.
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
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I am close to you (weight, bike model, tire model) and am at a similar spot on pressures as where you are at now. I run them a bit less in wet conditions.
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Reduced pressure by 5psi per tire and was surprised how much more comfortable and less bouncy on rough roads it was for downhills.
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
What is tangentially interesting is how most everyone might suggest that the LarryS scenario of 140psi in 25s is way too much, but this same chart also says that's correct. What would cause the Berto vs "Modern" models to incrementally diverge further apart from one another at higher rider+bike weights?
Last edited by Sy Reene; 05-17-22 at 05:01 AM.
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Reduced pressure by 5psi per tire and was surprised how much more comfortable and less bouncy on rough roads it was for downhills.
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
latest setting is 75 psi rear 60 psi front for 28mm GP5000
(at least on the rear tire) I felt 70 psi was too squishy and 80 bounced a bit on rough roads doing fast descents. Really surprised
It's interesting how many of the riders in this thread are using similar pressures, or scaled similarly to their different weights.
At 170 pounds, I was using 65 and 72-75 psi. Now, it's usually 70-72 and 78-80.
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I weigh 220 lbs, and am running my 28s (different brand) at 80/85 psi f/r
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I don't know if I find it humorous or what, but you're pretty much matching the Berto graph chart a couple posts up for a 45/55% F/R split on your total weight.
What is tangentially interesting is how most everyone might suggest that the LarryS scenario of 140psi in 25s is way too much, but this same chart also says that's correct. What would cause the Berto vs "Modern" models to incrementally diverge further apart from one another at higher rider+bike weights?
What is tangentially interesting is how most everyone might suggest that the LarryS scenario of 140psi in 25s is way too much, but this same chart also says that's correct. What would cause the Berto vs "Modern" models to incrementally diverge further apart from one another at higher rider+bike weights?
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I find the Silca calculator to be pretty spot on.