Going really fast on pavement, with off-road tires - yikes
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You do your thing, I'll do mine.
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Don't assume what others can/can't do.
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You could be. I have a section on my regular loop, short steep hill that I like to hammer and nail the right hand curve at the bottom. Usually hit the curve at 48-50mph, and have even done this on my 38mm Pathfinder Pro gravel tires.
Don't assume what others can/can't do.
Don't assume what others can/can't do.
Congrats.
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You could be. I have a section on my regular loop, short steep hill that I like to hammer and nail the right hand curve at the bottom. Usually hit the curve at 48-50mph, and have even done this on my 38mm Pathfinder Pro gravel tires.
Don't assume what others can/can't do.
Don't assume what others can/can't do.
Again, you are weird. You seem obsessed. Have you got a crush on me?
Last edited by Koyote; 12-07-20 at 10:35 AM.
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Keep Portland Weird!
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I don’t know why you are so obsessed with
me, but I’ll take it as a complement. And by the way: I’m flattered, and maybe a little bit curious, but not interested.
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For another data point: 38c front Pasela - 60 psi is sweet on the road. Soft and squishy for deep "gravel" of ~1 1-1/2" rocks used on pavement against a very hard wind at 15 mph - very unpleasant. 35c Pasela rear - 72 psi is sweet on pavement, The comment re" soft ad squishy upwind applies here too. I weigh 155 pounds.
For pavement go gravel rides I love having the old fashioned frame pump for the ride home. Don't use a gauge on the road but a finger squeeze before I deflate for the gravel makes returning to close enough easy.
For pavement go gravel rides I love having the old fashioned frame pump for the ride home. Don't use a gauge on the road but a finger squeeze before I deflate for the gravel makes returning to close enough easy.
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Thanks and ride safely!
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Anyone else experience this?
I had a huge tailwind on the second half of my ride today, and was hitting 35-40mp at times with some fast spinning (110-120rpm). I was running 33mm Donnely MXP tires at around 40psi (so pretty spongey) and wow... they were all over the place at those speeds. Downright terrifying. 40psi is good for off-road (these are tubed clinchers, so 35psi is about as low as I go with them) but maybe a little low for pavement I guess.
Even on a flat/straight road I felt like the rear was squirming back and forth with every pedal stroke any time I got north of 30mph. I was having fun spinning up and trying to hit top speeds, but a few times just stopped pedaling and coasted because I was worried I'd bite it.
These tires are great on gravel and hardpack dirt, and generally feel like they roll pretty fast on pavement (relative to other knobby tires), but today has me second guessing them for faster rides. I've been mostly riding Conti GP5000's lately so maybe I just am not used to the change and wasn't ready for it.
I had a huge tailwind on the second half of my ride today, and was hitting 35-40mp at times with some fast spinning (110-120rpm). I was running 33mm Donnely MXP tires at around 40psi (so pretty spongey) and wow... they were all over the place at those speeds. Downright terrifying. 40psi is good for off-road (these are tubed clinchers, so 35psi is about as low as I go with them) but maybe a little low for pavement I guess.
Even on a flat/straight road I felt like the rear was squirming back and forth with every pedal stroke any time I got north of 30mph. I was having fun spinning up and trying to hit top speeds, but a few times just stopped pedaling and coasted because I was worried I'd bite it.
These tires are great on gravel and hardpack dirt, and generally feel like they roll pretty fast on pavement (relative to other knobby tires), but today has me second guessing them for faster rides. I've been mostly riding Conti GP5000's lately so maybe I just am not used to the change and wasn't ready for it.
Been thinking about this, and I suspect this was just a combination of (slightly) low tire pressure and high cadence. Are you a decent spinner? If yes, I apologize for the following - you can disregard it. If not, then cadences of 110-120 rpm could've had you rocking side-to-side a bit on the saddle; combine that with slightly soft tires, and your bike could feel pretty squirmy.
The solutions could be slightly higher psi, taller gearing (so you can ride at 30-40 mph with lower cadences), and working on your pedal stroke - or some combo of all three. With a cadence feature on your computer, and some cadence drills, you can really smooth it out. When I was getting more serious about road racing many years ago, I worked on it, and was eventually able to go about 20 rpm higher with a nice smooth pedal stroke - which helps even at lower cadences.
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Good point Koyote. I'll do 30+mph at 120rpm, but I remember when I was first learning to do that I would be bouncing a lot in the saddle. I can see that being an issue at 40psi. I'm typically not on a heavy knobbed tire at those speeds, my issue usually comes with the steering response and ability to carve a tight turn at those speeds. I can do it safely, but it sure handles sloppy carving a turn with treaded tires compared to good slicks.
Wondering if the tire was new? Sometimes knobs are a bit squirrly new (and even worse when brand new and the mold release compound is still on them).
ID of wheel will make a difference too as discussed below. I'm using 22ID rims when I'm running 33mm knobby tires.
Wondering if the tire was new? Sometimes knobs are a bit squirrly new (and even worse when brand new and the mold release compound is still on them).
ID of wheel will make a difference too as discussed below. I'm using 22ID rims when I'm running 33mm knobby tires.
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Good point Koyote. I'll do 30+mph at 120rpm, but I remember when I was first learning to do that I would be bouncing a lot in the saddle. I can see that being an issue at 40psi. I'm typically not on a heavy knobbed tire at those speeds, my issue usually comes with the steering response and ability to carve a tight turn at those speeds. I can do it safely, but it sure handles sloppy carving a turn with treaded tires compared to good slicks.
Wondering if the tire was new? Sometimes knobs are a bit squirrly new (and even worse when brand new and the mold release compound is still on them).
ID of wheel will make a difference too as discussed below. I'm using 22ID rims when I'm running 33mm knobby tires.
Wondering if the tire was new? Sometimes knobs are a bit squirrly new (and even worse when brand new and the mold release compound is still on them).
ID of wheel will make a difference too as discussed below. I'm using 22ID rims when I'm running 33mm knobby tires.
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This thread is cracking me up. I'm now thinking about my pedal stroke and how smooth it may or may not have been on that day back in October. I've spent time on rollers and generally consider myself to have a pretty smooth pedal stroke as a result, but of course when you're out pedaling the crap out of your bike on a windy day, things aren't quite the same as they are on rollers in your basement.
So... I have this ride saved on Strava and looked it up now. Here is one of the segments, which covers about 90 seconds, where I was going hard and found things getting a little hairy. You can see the 0 cadence/0 power sections where I stopped pedaling and let it coast for a second or two to settle down, then started back up again. I was generally spinning around 115-120rpm, output between 300-500 watts. Speed around 35mph. When I think of sprinting, I think of constantly accelerating. In this case, I think I had already accelerated up to a speed where I ran out of gears, and was then trying to maintain that speed at a high cadence/output. I was on a 1x CX bike and definitely out of gears at this point.
I have no idea why I'm posting this, other than it seems to be relevant to the discussion. This is a flat section of road, with some small bumps that also may have contributed to me bouncing around. My takeway is still that my psi was too low for this situation.
So... I have this ride saved on Strava and looked it up now. Here is one of the segments, which covers about 90 seconds, where I was going hard and found things getting a little hairy. You can see the 0 cadence/0 power sections where I stopped pedaling and let it coast for a second or two to settle down, then started back up again. I was generally spinning around 115-120rpm, output between 300-500 watts. Speed around 35mph. When I think of sprinting, I think of constantly accelerating. In this case, I think I had already accelerated up to a speed where I ran out of gears, and was then trying to maintain that speed at a high cadence/output. I was on a 1x CX bike and definitely out of gears at this point.
I have no idea why I'm posting this, other than it seems to be relevant to the discussion. This is a flat section of road, with some small bumps that also may have contributed to me bouncing around. My takeway is still that my psi was too low for this situation.
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Max cadence was only 114, which is not too high. Average cadence is pretty much irrelevant, since you did some coasting - which brought down your avg.
Must be the psi, then, if you have a good pedal stroke. So I guess you just have to decide if this is a frequent occurrence, or whether you will just leave your psi alone because such a strong tail wind is pretty rare.
Must be the psi, then, if you have a good pedal stroke. So I guess you just have to decide if this is a frequent occurrence, or whether you will just leave your psi alone because such a strong tail wind is pretty rare.