Listeners/readers are less likely to respond respond to qualified, well reasoned statements. This thread wouldn’t exist if he had said what is actually true: side knobs won’t help with cornering for 90% of rides purely on gravel roads.
For rides where I ride a bit of tarmac to gravel and then stay on gravel, I am very rarely leaning bike enough to need them. When I do lean enough, I would not crash due to lack of grip, but because the gravel is sliding beneath me (as was commented above).
However, one of my favorite routes is a gravel ride out to some single track and back. When it has been dry, the side knobs 100% help on the areas of single track that aren’t too sandy for knobs to go through.
I didn’t get the base data shared in my example (just the time saved for quick comparison) but everything I’ve seen from the WinTunnel and similar testing starts with CDa at the root, then extrapolates to the distance values commonly compared.
Having re-read the aritcle, I have additional thoughts re: the claims…
As you can see in the photo showing Inno traversing a technical section, this year’s Mid South course wasn’t just smooth gravel. Why didn’t the lack of side knobs put these racers at a disadvantage?
The problem with this statement is that he is taking a small section of the course and extrapolating it into the general conditions, which was not the case. From my understanding, Mid-South is a pretty fast course with packed dirt roads for the majority of the course. You generally make your tire choice based on the entire course, not just one (or a few areas). For Mid-South in dry conditions, a slick would be a great choice.
Again, “gravel” is not universal so using the conditions at Mid South to make a general claim re: gravel tires is flawed, at best.
In the photo above, you see me countersteering to catch a slide. I’m absolutely on the limit yet the lean angle doesn’t look that impressive—because it isn’t.
Again, he is taking a snapshot (literally and figuratively) and expanding it into a full-length motion picture. For those conditions pictured, a slick may have been a better choice…but just becuase he could not lean much on that turn doesn’t mean you can’t lean more in other turns. YOu also have to ask if leaning more in that picture was even necessary.
He also uses images of riders and bikes with mud splatters and says “See? They rode slicks and were just fine!” 2 things re: that logic - 1) You cn get mud splatters from one area of a course. Splatters don’t mean the entire course caused those splatters (see my comments re: Mid South this year above), and 2) these riders have greater skills than the layperson…they can use that to ride a faster tire which may not not be a good choice for riders of average ability. Pros / Experts are more comefortable with things like tire slide, loss of traction, etc. In short, they can compensate for the lack of control that a slick may bring, but could be challenging for other riders.
I’d strongly considered running the 32mm gp5000 at barry roubaix next month. I’m too scared of getting bogged down in deep sand on a 1 mile stretch though. Other than that one mile, i think it would be ideal honestly. ~40psi, with foam inserts just in case of an occasional larger rock or pothole.
Also another thing to consider with gravel racing…these are not crits, mtb, or cyclocross courses. Cornering is not really a thing…you’re going 5 miles down the road and then hanging a left onto the next 5 mile stretch. We can debate the value of side knobs from a physocs/theoretical perspective…but in all honesty IMO it doesnt even come into play in a significant way.
My mindset anyway, is if you have enough traction to get up the steepest climb, and enough volume to roll over the loosest/deepest section of a course, the only thing that matters is best rolling resistance; barring flats that is.
I’m doing my first gravel race next month. Bwr San Diego. I’ve borrowed a bike. Just need to put a fresh set of tyres on it. I’ve spent 30 hours researching and asking questions. This thread is a reflection of what’s been suggested. I still can’t decide. And to make matters worse. The wafer course- in the last week- has gone from 19 miles of gravel (25%) to 40 miles of gravel(50%).
Lol. Yea the problem with gravel, as others mentioned, is it can be basically anything. Asphalt, grass, big rocks, deep gravel you sink into, or a gravel road so smooth you’d be happy with a road bike and 25mm tires.
BWR SD is not particularly technical and I’ve done it on slicks, but you might find that a file tread with side knobs will give you more margin for error.
Lol, yes, I have ridden a bike off road. To be fair though I’ve only done a handful of gravel races, so it’s possible I shppose in other areas they’re set up like crits with corners everywhere. I suspect that would be a rare exception though…
I agree that this is more of the same N=1 answer, that serves little purpose in the broad world that exists here.
Sure, there are gravel routes and events that are pretty much straight shots for miles with a few 90* intersections to navigate the course. These may be taken at a pace that largely sidesteps real “cornering” considerations.
In my area, I have more than a few “winding” roads that also correspond with real pitches that mean you are at rally speed ripping around corners with enough pace to provide a pucker & white knuckles.
Add in the variation in “gravel” condition with our real “corners” and I am sticking with knobs in the middle and sides most of the time. There are times I have used minimal center tread with side knobs, and I don’t love them for my needs. But I know they are a great setup for some riders and areas.
Short and simple statements seem destined to fail in this discussion, IMO.
One thing that hasn’t been discussed much in this thread is the puncture resistance that knobs potentially offer against sharp rocks encountered in mtb and gravel. Maybe much of the benefit of knobs is increasing the distance between the outermost layer of the tire and the inner casing.
Yeah… it varies big time. By the sounds of it a lot of people would get absolutely rocked by many of the “Gravel” events happening in California! Always steep descents and corners. It’s really more what midwesterners would consider challenging singletrack, probably. Heck even the fire roads here are super gnarly.
Even though there are variations in “Road” & “MTB”, it’s arguable that “gravel” has a much wider range of what people consider as within each category.
I’ve been on tarmac that was rougher than some MTB trails (top of Empire Pass in the Tour of Utah Ulitimate challenge) and MTB trails more buffed out than a paved BMX track, so there are exceptions.
But when you talk about “gravel” I think there is far more chance we are not talking about the same thing. Stuff in my county is crappy really, with massive amounts river rock on top of bentonite clay as well as smooth stuff and a mix of loss gravel on top.
Then I can drive maybe 45 minutes to another county and have stuff that borders on dirt pavement with some kitty liter on top.
Then if I head to Sheridan WY I can hit hero gravel that is as fast as any pavement with minimal rock on top… where a prior Dead Swede winner took the top step riding a CX bike on 32mm Bontrager AW3 tubeless tires (that I loaned him ).
Gravel is far from a singular surface and tire selection is beyond personal to a point of being almost impossible to generalize.
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