Koyote

I was responding to the OP's question, as laid out in the first post. You seem intent on providing off-topic snark to the thread.

You do your thing, I'll do mine.

Rides4Beer

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.

Helldorado

I'll take that as a "no."
Thanks.

Helldorado

I assumed. And I was actually spot-on.
Congrats.

Koyote

You seem to have a lot invested in this. Weird.

Koyote

I’m not sure how you concluded that you were “spot on,” since I never responded to your questions.

Again, you are weird. You seem obsessed. Have you got a crush on me?

Helldorado

Spot-on in the sense that I predicted that you were riding down-hill to achieve speeds of 40 MPH, and making very wide turns. You never clarified that in your original post. But now you have.

Keep Portland Weird!

Koyote

That’s some reading comprehension you’ve got there!

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.

79pmooney

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.

Helldorado

Don't confuse other's correcting you (or clarifying your vague claims) with their being obsessed with you. That's just projection on your part, and probably not very healthy (and a little bit weird too...).

Thanks and ride safely!

Koyote

Let's try to get back on-topic...

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.

chas58

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.

Koyote

Agreed about carving turns at low psi on pavement, and agreed about the knobs. I threw in the cadence issue since the OP had reported that the problem was while pedaling at high speed and high cadence. And, given the way that gearing is headed on newer gravel bikes, his cadence might be really high at 30+mph.

msu2001la

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.

Koyote

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.

pipeliner

50 mph on 45mm TL Ramblers, 28/35psi. No problems.