Dang, 32c tires are slow
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Gatorskins are a flat resistant tire that isn't too horrible riding.
GP4000/5000s are fast tires that are fairly long wearing and flat resistant.
The newly introduced 5000s come in 32mm wide, up from the 28mm maximum of the GP4000SII, up from the GP4000 25mm limit.
Last edited by Drew Eckhardt; 04-21-20 at 04:04 PM.
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#29
WALSTIB
Then The 33 is the place for you to be
#30
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#31
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No, they're faster because they have lower rolling resistance.
You are slow because you chose tires that have stiff carcasses with high rolling resistance, and/or you're out of shape.
Try the Continental GP5000. Unfortunately, there aren't a lot of low rolling resistance tires available in that width.
You are slow because you chose tires that have stiff carcasses with high rolling resistance, and/or you're out of shape.
Try the Continental GP5000. Unfortunately, there aren't a lot of low rolling resistance tires available in that width.
#32
WALSTIB
Ah, you mean fast, just not fast. Now that's clear
#33
Senior Member
Nothing to do with the degree of fast. The point is that the pursuit of performance doesn't imply that you're interested in the formal sport of bicycle racing. This is true even if you're interested in some sort of formal bicycle sport: randonneurs often care about tire performance, for example, but randonneuring is generally regarded as a different sport from racing.
Also, if someone wants to ride a bicycle as fast as possible, the sorts of bicycles used in the 33 are often very poor choices. If you're riding flat ground, for instance, a velomobile can dramatically outperform any road or TT/Tri bike. This is because bicycle racing is not about riding the fastest bicycles, it's about racing bicycles.
Also, if someone wants to ride a bicycle as fast as possible, the sorts of bicycles used in the 33 are often very poor choices. If you're riding flat ground, for instance, a velomobile can dramatically outperform any road or TT/Tri bike. This is because bicycle racing is not about riding the fastest bicycles, it's about racing bicycles.
Last edited by HTupolev; 04-21-20 at 07:21 PM.
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#34
WALSTIB
Nothing to do with the degree of fast. The point is that the pursuit of performance doesn't imply that you're interested in the formal sport of bicycle racing. This is true even if you're interested in some sort of formal bicycle sport: randonneurs often care about tire performance, for example, but randonneuring is generally regarded as a different sport from racing.
Also, if someone wants to ride a bicycle as fast as possible, the sorts of bicycles used in the 33 are often very poor choices. If you're riding flat ground, for instance, a velomobile can dramatically outperform any road or TT/Tri bike. This is because bicycle racing is not about riding the fastest bicycles, it's about racing bicycles.
Also, if someone wants to ride a bicycle as fast as possible, the sorts of bicycles used in the 33 are often very poor choices. If you're riding flat ground, for instance, a velomobile can dramatically outperform any road or TT/Tri bike. This is because bicycle racing is not about riding the fastest bicycles, it's about racing bicycles.
#35
Senior Member
Nothing that I said has much of any relevance to what bikes I ride. I'm not a velomobile person, for instance, I'm just pointing out that they exist and are not really within the scope of the 33.
All of my bikes would be legal to use in a road race in the USA, although only one wouldn't look at least a bit out of place.
All of my bikes would be legal to use in a road race in the USA, although only one wouldn't look at least a bit out of place.
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If a 32 is slow, it is not because it is a 32. It is because it is a crappy tire.
Anyone that thinks a 32 cannot be incredibly fast (lightweight, low rolling resistance) has not tried a Compass Stampede Pass.
Anyone that thinks a 32 cannot be incredibly fast (lightweight, low rolling resistance) has not tried a Compass Stampede Pass.
Last edited by Kapusta; 04-21-20 at 08:05 PM.
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It shows shows that at 116 psi, rolling resistance drops 20% from 0.49 (units not specified, could be kgf total at 50kg load per wheel) at 20mm to 0.39 at 28mm wide.
Conversely accepting rolling resistance of 0.45 you could ride a 28mm tire inflated to 85 psi, a 25mm at 94 psi, or a 23mm tire at 123 psi.
Or you could split the difference for some combination of lower rolling resistance and a softer ride.
3mm on a 700C tire moving from 25 to 28mm should cost 0.4 W from aerodynamic drag at 20 MPH assuming .5 Cd.
A Crr decrease from 0.0041 to 0.0039 moving from 25 to 28mm is 1.3 W for a 75 kg bike + rider at 20 MPH for a 0.9 W net savings.
Similar gains should be possible moving from 28 to 32mm at recreational speeds assuming you run the same tire which is the rub. Continental makes a supple 32mm GP5000, Compass makes low rolling resistance tires out to 40 or 50mm, but most manufacturers haven't caught up to clearance for that wide a tire coming standard on disc brake road bikes.
Last edited by Drew Eckhardt; 04-22-20 at 10:14 AM.
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#38
Interocitor Command
Dang, 32C tires are slow
#39
Senior Member
The graph has rolling resistance plots for the GP4000SII in 20, 23, 25, and 28mm widths.
It shows shows that at 116 psi, rolling resistance drops 20% from 0.49 (units not specified, could be kgf total at 50kg load per wheel) at 20mm to 0.39 at 28mm wide.
Conversely accepting rolling resistance of 0.45 you could ride a 28mm tire inflated to 85 psi, a 25mm at 94 psi, or a 23mm tire at 123 psi.
Or you could split the difference for some combination of lower rolling resistance and a softer ride.
3mm on a 700C tire moving from 25 to 28mm should cost 0.4 W from aerodynamic drag at 20 MPH assuming .5 Cd.
A Crr decrease from 0.0041 to 0.0039 moving from 25 to 28mm is 1.3 W at 20 MPH for a 0.9 W net savings.
Similar gains should be possible moving from 28 to 32mm at recreational speeds assuming you run the same tire which is the rub. Continental makes a supple 32mm GP5000, Compass makes low rolling resistance tires out to 40 or 50mm, but most manufacturers haven't caught up to clearance for that wide a tire coming standard on disc brake road bikes.
It shows shows that at 116 psi, rolling resistance drops 20% from 0.49 (units not specified, could be kgf total at 50kg load per wheel) at 20mm to 0.39 at 28mm wide.
Conversely accepting rolling resistance of 0.45 you could ride a 28mm tire inflated to 85 psi, a 25mm at 94 psi, or a 23mm tire at 123 psi.
Or you could split the difference for some combination of lower rolling resistance and a softer ride.
3mm on a 700C tire moving from 25 to 28mm should cost 0.4 W from aerodynamic drag at 20 MPH assuming .5 Cd.
A Crr decrease from 0.0041 to 0.0039 moving from 25 to 28mm is 1.3 W at 20 MPH for a 0.9 W net savings.
Similar gains should be possible moving from 28 to 32mm at recreational speeds assuming you run the same tire which is the rub. Continental makes a supple 32mm GP5000, Compass makes low rolling resistance tires out to 40 or 50mm, but most manufacturers haven't caught up to clearance for that wide a tire coming standard on disc brake road bikes.
Furthermore, the graph assumes a STEADY STATE rolling resistance, which is usually not the case unless it is a TT indoor.
If you do many multiple hard out-of-the-saddle accelerations, or in a steep (7%+) climb, where torque on the tire is not constant, then you also have to consider hysteresis loss of the tire on lower pressure vs that on higher pressure.
You can't just simply say "wider tires" roll better and ignore everything else, because road surface and rider's style should also be considered in tire preference.
Another problem with 32mm or wider tires is that most are usually not made with "speed" as the main performance factor, most are made with durability as a factor too. I would be very surprised if any 32mm+ tire would actually outperform a 25mm one on a typical road, even roads with many cracks on them.
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did he ever say what kind of tires he used? I have had some tires that felt like my brakes were on. Now I use 32c Gravel Kind slicks and they roll pretty well
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Right, that's what i said, tire pressures play a role.
Furthermore, the graph assumes a STEADY STATE rolling resistance, which is usually not the case unless it is a TT indoor.
If you do many multiple hard out-of-the-saddle accelerations, or in a steep (7%+) climb, where torque on the tire is not constant, then you also have to consider hysteresis loss of the tire on lower pressure vs that on higher pressure.
You can't just simply say "wider tires" roll better and ignore everything else, because road surface and rider's style should also be considered in tire preference.
Another problem with 32mm or wider tires is that most are usually not made with "speed" as the main performance factor, most are made with durability as a factor too. I would be very surprised if any 32mm+ tire would actually outperform a 25mm one on a typical road, even roads with many cracks on them.
Furthermore, the graph assumes a STEADY STATE rolling resistance, which is usually not the case unless it is a TT indoor.
If you do many multiple hard out-of-the-saddle accelerations, or in a steep (7%+) climb, where torque on the tire is not constant, then you also have to consider hysteresis loss of the tire on lower pressure vs that on higher pressure.
You can't just simply say "wider tires" roll better and ignore everything else, because road surface and rider's style should also be considered in tire preference.
Another problem with 32mm or wider tires is that most are usually not made with "speed" as the main performance factor, most are made with durability as a factor too. I would be very surprised if any 32mm+ tire would actually outperform a 25mm one on a typical road, even roads with many cracks on them.
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Link to source of charts:
https://www.bicyclerollingresistance...000-comparison
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#47
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No.. not mine. Sorry thought they might be recognizable -- these are from bicyclerollingresistance website. I believe they use a textured roller of some sort.
Link to source of charts:
https://www.bicyclerollingresistance...000-comparison
Link to source of charts:
https://www.bicyclerollingresistance...000-comparison
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#49
WALSTIB
My comment on don't worry about speed is for someone who puts 32 tires on then not happy about the speed.
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I haven't read all the replies, so this may have already been said, but 32mm wide tires are not necessarily slower than narrower tires. What will be slower is if you switch from lightweight racing tires with a thin tread and supple casing to a thicker and heavier tire with some flat preventative strip under the tread.
On a tour two years ago I was using Panaracer Pasela 70x35c tires... Paselas are known to be the most budget friendly lightweight supple tires you can buy. But I was getting lots of flats, so I replaced my rear tire with a Specialized Nimbus with 'Black Belt' flat protection.
I instantly went from coasting away from my group on downhills to having to pedal on downhills to keep up. Same size of tire, but vastly different construction mad a huge difference.
Epilogue: That slow-as-spit tire is also very long wearing, and I have a personal rule that I don't replace tires until they are worn or damaged, and these tires are tanks and unlikely to suffer any damage, so I am stuck with that tire for at least a couple thousand more kms.
On a tour two years ago I was using Panaracer Pasela 70x35c tires... Paselas are known to be the most budget friendly lightweight supple tires you can buy. But I was getting lots of flats, so I replaced my rear tire with a Specialized Nimbus with 'Black Belt' flat protection.
I instantly went from coasting away from my group on downhills to having to pedal on downhills to keep up. Same size of tire, but vastly different construction mad a huge difference.
Epilogue: That slow-as-spit tire is also very long wearing, and I have a personal rule that I don't replace tires until they are worn or damaged, and these tires are tanks and unlikely to suffer any damage, so I am stuck with that tire for at least a couple thousand more kms.