Direction of gravel bikes

[grwoolf]

I think the “aggressive/steep” vs. “long and slack” preference often comes down to a rider’s background and riding style. I spent years racing road/crits before I ever put a tire on dirt. As I got into XC Marathon and gravel stuff, I was naturally drawn to aggressive XC geometry for MTB and road-like geometry for gravel. I even “downsized” the frame on my first gravel bike to reduce stack like I often did with my road bikes. And I loved the racy “feel” of that bike on tame gravel. But it felt slow/sketchy on technical descents and single track, people were passing me constantly on that stuff. Maybe it’s just because I can’t handle a bike like Keegan, but the geometry wasn’t helping. And the “racy” feel of the bike didn’t make me go from A to B any faster, I just liked the feel. Then I bought a Checkpoint. It handles more like a boat (and is heavy), but I’m so much faster on technical sections. And on the smooth bits, it may feel slower, but it’s just that it’s smoother and more stable (which is typically faster and less fatiguing compared to rough and twitchy). There is nothing I enjoy more than laying out on that bike in the aero bars and just motoring during a race. It’s so stable that I’m in the bars even on the chunky stuff like at big sugar or sections of unbound. Basically, the slacker bike makes me more confident and faster on tech stuff and I see no downside on the smooth stuff.

When I first got into gravel racing, I thought I just wanted an aero Madone or Tarmac with more tire clearance and that would be the perfect gravel bike. Otherwise, why not just keep racing gravel with my XC bike (which wasn’t such a dumb question in hindsight). But after racing a good bit of gravel for the past 5+ years, doing a 5-10+ hour race on a gravelized tarmac/madone sounds slow and dumb to me based on my skill level and how I race. It’s all preference, but I like mine long and stable these days.

[OreoCookie]

@grwoolf

While I’ve raced gravel a good bit on my MTB with a 38 and I never felt like it held be back, I agree that the chainring size can be a big limitation if trying to use a MTB for gravel/road on flatter courses.

I have an 11-speed XTR/XT drivetrain. Getting chain rings for the crank is beginning to become a pain. I hope the 34-tooth Rotor chain ring will last at least another year. I have another almost unused XTR chain ring, but it has only 30 teeth.

I know I can get a third-party chain ring (e. g. from Wolftooth), but the picking is getting slim. Gearing-wise, 11 speeds are plenty. I’m just wearing out my components. Cassette and chain are less than a year old.

Since the frame is 10 years old, I want to replace it in 2–3 years. I can take some of the components with me. But it won’t be easy. I have great alloy wheels with XTR hubs. But I have quick release hubs in the rear, so I don’t think I will be able to reuse the wheels. The front has a thru axle, though.

@grwoolf

I think the “aggressive/steep” vs. “long and slack” preference often comes down to a rider’s background and riding style. I spent years racing road/crits before I ever put a tire on dirt. As I got into XC Marathon and gravel stuff, I was naturally drawn to aggressive XC geometry for MTB and road-like geometry for gravel.

C’est moi. When I got a great deal on an endurance road bike, I quickly found out the geometry is not for me. My racier aero road bike feels much better.

[Huegelreiter]

@eddiegrinwald

But what if my terrain isn’t getting more technical? Then why should I get a more capable bike? To make riding this same terrain easier and less engaging?

Exactly! Well except the last point.

As bikes don’t just get more capable. They get better optimized at other things and thus becoming worse at the former things. Bike design is always a compromise.

So my point is: Such “new” bikes or “progressive” geometry doesn’t make bikes more capable. It makes them worse at stuff they were optimized and well honed to beforehand.

It’s not just the weight or fit. It’s wheel flop in normal corners, it’s less pedaling efficiency, maybe it’s even harder to arrange your personal fit preference (e.g. can’t go much shorter with a stem if that thing is already only 25 mm to begin with).

This is a very tangible thing. I find I like steering angles of 69 to 70 ° on a 100 mm travel front suspension bike. You don’t find these on current carbon XC bikes anymore as everyone tries to “out slacken” the competition in search of the next best extreme XCO rock garden downhill tackling bike.

[OreoCookie]

@Huegelreiter

So my point is: Such “new” bikes or “progressive” geometry doesn’t make bikes more capable.

I beg to differ: most gravel bikes or down country bikes are inherently more versatile. You can do road rides on a gravel bike, especially once you put slick tires on it. A down country bike can handle XC racing, trails and MTB tours.

I think aero road bikes, scalpels with a very narrow purpose are less popular at the moment. I like that.

[Huegelreiter]

Ok, fair enough - you can go in any direction with that notion of capabilities. And yes certainly - any gravel bike is inherently more versatile as a pure road bike or a pure mtb IF (and that is a big if) your riding encompasses road, super light and a bit of gnarly gravel. We can become lost in the weeds quick here because even pure (what is pure?) road bikes and mtbs are classified into many subcategories.

And also versatility is something different than capability and that one is also different from optimal. Whereas the latter like the former two also depend on the rider and his preferences and use cases.

But I don’t want to split hairs here.
When I say “Such “new” bikes or “progressive” geometry doesn’t make bikes more capable.” I’m talking about already good gravel bikes and even more about already good XC mountain bikes.

If you make especially the latter “more capable” you make them worse at the thing they are good now. It doesn’t help ME if you now can ride even gnarlier downhills a bit faster or with a bit more confidence if that isn’t what I want the bike to excel at and what it does the other 95% of riding time. Pedaling, climbing, cornering nicely on normal tarmac, fire road and forest trail roads all the way to single tracks. But not rock gardens.

[OreoCookie]

@Huegelreiter

And also versatility is something different than capability and that one is also different from optimal. Whereas the latter like the former two also depend on the rider and his preferences and use cases.

Versatile bikes cannot be optimized as well for any one task than a purpose-built bike focussing on a very narrow task. My aero road bike is amazing on tarmac, you can tell that it wants to go fast. But I moved to an area that has cobbles, and it is not great. I have to turn around when a road turns into a fire road with gravel.

@Huegelreiter

When I say “Such “new” bikes or “progressive” geometry doesn’t make bikes more capable.”

Geometry is the reason why modern bikes are more capable and versatile (in addition to advances in suspension tech for mountain bikes, although many of those are intimately tied to geometry). This is especially true for mountain bikes, because suspension tech for fully has evolved alongside with frame geometry and suspension tech.

@Huegelreiter

If you make especially the latter “more capable” you make them worse at the thing they are good now.

That is an assumption on your part. Full-suspension mountain bikes especially have become so good at e. g. minimizing pedal bob that they put older bikes to shame. My previous mountain bike was a 2012 fully, the last generation with 26” wheels. When I visited Chile in 2019 I got a rental, a Pivot trail bike with 130 mm travel. This thing ran circles around my bike, it was a better XC bike even though it wasn’t an XC bike. More progressive geometry, better suspension, 1x drivetrain, lighter, … My new-to-me hard tail has a top-end fork from 2018, and it is amazing how supple it is compared to my old Reba RL.

The changes in geometry for off road bikes (slacker head angle, more sophisticated suspension, especially in the rear, etc.) have made them better in most situations. When I switched to my 29” hard tail from my 26” fully, I felt as if I was wearing clown shoes for a day. Then it just felt normal.

With drop bar bikes you likewise have a plethora of designs, some hew closely to a road bike, others have a geometry comparable to hard tails from the late 1990s or 2000s.

@Huegelreiter

Pedaling, climbing, cornering nicely on normal tarmac, fire road and forest trail roads all the way to single tracks. But not rock gardens.

That reminds me of my old Lake Garda Moser bike tour guide where you see people will fully rigid bikes and V-brakes riding crazy things. Thanks to suspension tech, better geo and disc brakes more people can ride this terrain, you need less skills to be able to ride it. IMHO that’s a good thing. You don’t have to ride such terrain, but you have more options.

Plus, you could also do very technically easy MTB routes on a gravel bike if you are so inclined. You are just shifting the window of capability and can make easy trails more interesting by forgoing front and aft suspension and/or wider tires.

[Huegelreiter]

So would you say, that slacker and slacker head tube angles will make any bike always better and for every circumstance? So if 67° is good, will be 65° even better? And 60° in 2 more years?

Will make ever wider tires bikes more versatile, too? So is a fatbike the most versatile (and, going with “more versatile is more better” theme) also the better road and gravel and mountain bike?

Surely not. Bike design is always about compromises. Yes, on some we can work around better with cool ideas, designs and materials of components as in geometry and frames - but a bike always will be purpose build to some degree. Surely you don’t want to dismiss all the different bike types we have (from a foldable Brompton for commuting over a Track bike to Gravel and Mountain bikes).

Go too far into any direction and you will be less fitting for where you came from. That’s quite obvious, I hope.

[crandallGA]

Progressive gravel geometry has made the bikes less versatile IMO. Once trail gets close and above the 75mm+ range the handling with 30-35mm tires starts to suffer.

My 70°/43mm offset/32mm tired gravel bike was atrocious at road and crit riding in a way that my CX bike (72°/50mm offset/32mm tire) before it wasn’t - because of the front end geometry.

An additional 15mm+ of trail and perhaps 10mm of front center (from mid-trail) isn’t always going to help the versatility of a gravel bike because it’s entirely weighted in the direction of stability and the overall bike design isn’t capable of maximizing these changes off-road as much as on-road performance suffers - for most riders.

I’d also argue there’s a logical mis-step here. Increasing the versatility of a MTB would mean that the suspension tech and geometry changes would contribute to additional speed/comfort/control in situations outside of the normal riding design intent. Being able to handle more technical terrain is not versatility, it’s something the bikes were designed for originally and now they’re more capable at that same task.

In the late 1980s and early 1990s. MTBs became more versatile when the geometry moved to steeper HTA and relatively higher/better gearing, from the earlier generations. This increased their appeal to commuters, urban riders, and general fitness riders. Some riders using them for MTB riding disliked the changes and others welcomed them - depending on who was riding newer, flatter, perhaps larger and more sweeping corners - and who was riding old gnarly hiking trails with a lot of elevation and technical features.

A modern progressive MTB does not appeal the commuters, etc. because the features that have vastly improved it’s off-road capability have diminished it’s on-road performance. Those older design elements are now found in other types of bikes in greater variety.

[OreoCookie]

@Huegelreiter

So would you say, that slacker and slacker head tube angles will make any bike always better and for every circumstance? So if 67° is good, will be 65° even better? And 60° in 2 more years?

Not for every rider, terrain and circumstance. And making things slacker can’t and won’t continue forever. That wasn’t my point. Just that changes in geometry have made bikes more capable.

The simplistic focus on head angles forgets about how to implement the rear suspension, for example.

@Huegelreiter

So is a fatbike the most versatile (and, going with “more versatile is more better” theme) also the better road and gravel and mountain bike?

Simply put, the changes are a blend of bikes from neighboring categories. Hence, you make the bike more capable but potentially less optimized for one niche.

The MTB industry has tried wider tires, going up to 2.8“ at one point. The end result is a more moderate change from 2.25“ to 2.4“ tires. Something similar is happening in the gravel space atm.

@Huegelreiter

Surely you don’t want to dismiss all the different bike types we have (from a foldable Brompton for commuting over a Track bike to Gravel and Mountain bikes).

If I had infinite disposable income, sure, you might want to get a special bike dedicated to each purpose. But most of us don’t live in that world. My wife and I have decided my limit is two bikes. So having bikes that are more versatile is advantageous to most, I would say.

@crandallGA

Progressive gravel geometry has made the bikes less versatile IMO. Once trail gets close and above the 75mm+ range the handling with 30-35mm tires starts to suffer.

There is a huge spectrum of gravel bikes, it is not clear what progressive means, because you have different directions to move towards, racy road bike, endurance road bike, mountain bike, short wheelbase vs. long wheelbase. 3T moved away from an aggressive road bike that accepts MTB tires to bikes with a short wheelbase and more relaxed geo.

I have no idea which is best in what situation, but the fact that manufacturers are experimenting is something I really like.

@crandallG

A modern progressive MTB does not appeal the commuters, etc. because the features that have vastly improved it’s off-road capability have diminished it’s on-road performance.

Yes, which is why a lot of people have switched to gravel bikes as the do-it-all bike, displacing the Hardtail somewhat.

[GoLongThenGoHome]

That is essentially just a rigid mtn bike.

[Teddy_Focaccia]

On drop bar bikes, I think many of the geometry changes and “versatility” questions come down to changing tech and (importantly) perception of wheels and tires. We all appreciate that road bike wheel/tire tech has changed big time in the last 10-15 years, with the trend toward wider rims and tires and lower pressures. Disc brakes, tubeless tech, improved aerodynamics etc.

Importantly those changes have not been intuitive; lots of folks, including pros, resisted going wider/lower pressure because hard skinny tires “feel faster.” If you took a modern road bike with 30mm tubeless tires back in time 15 years, it’d be viewed as basically a cyclocross bike, and I bet a reviewer would say “great on cobbles or gravel, but heavy and feels slow and unresponsive on pavement unless you increase tire pressure to 130PSI.”

I think gravel is much earlier in this arc toward fully optimized tires. Right now we’re all still thinking that 50mm tires are a detriment on anything but very gnarly gravel or single track, and that narrower tires feel faster and more ‘versatile’. But I expect wheel/tire/frame tech, and just as importantly our perception of what’s appropriate and fast, to progress over the next 5 or so years, and for wider tires to be both better and more common in more applications.

Then, of course, fit and geometry will need to catch up. 50+mm tires drastically change the steering feel, BB height, aerodynamics etc. of a bike. I’d argue we haven’t yet seen true race bikes designed around such rubber, and are only just starting to see race wheels that start to get close.

[crandallGA]

@Teddy_Focaccia

Right now we’re all still thinking that 50mm tires are a detriment on anything but very gnarly gravel or single track, and that narrower tires feel faster and more ‘versatile’.

I think this sentiment is more outdated than at first glance. Every (almost every?) major influencer in the gravel space has at least addressed if not confirmed the idea that wider tires, specifically XC tires right now, are as fast or faster than gravel tires.

Of course lots of people still believe that narrower (to a point) is faster, but I think the window has shifted far away from “we’re all still thinking”.

Another twist is that XC tires seem to be getting slower. The 2024 Race King and Thunder Burt are slower than their previous iterations. It’s likely that gravel tires have a much lower potential rolling resistance that has not been realized, while XC tires are closer to their lowest potential crr.

If the fastest 2.1-2.2 XC tires are testing around 18-20w and the average 40-42mm gravel tire is testing around 18-20w there is a big serving of free lunch.

However as construction improves and say the average 40-42mm gravel tire is now testing around 9-10w, well the conversation changes quickly.

There’s also an additional issue that Bicycle Rolling Resistance, the most common reference, understates the crr of XC tires and overstates the crr of gravel tires when viewed by non-paying users.

Most people using 2.2 Race Kings of 2.1 Thunder Burts are most likely not going to run them at 35psi. Just as most people using 42mm Pathfinder Pros or 44mm Thunderos aren’t going to run them at 35psi.

I think the only prognostication for gravel bikes is that specialization and development continue unabated.

It seems to follow that at times the fastest bike may be an aero gravel bike that only fits 45s because the aero losses by fitting 50mm+ cannot be offset by the decreased rolling resistance.

[Teddy_Focaccia]

@crandallGA

@Teddy_Focaccia

Right now we’re all still thinking that 50mm tires are a detriment on anything but very gnarly gravel or single track, and that narrower tires feel faster and more ‘versatile’.

I think this sentiment is more outdated than at first glance. Every (almost every?) major influencer in the gravel space has at least addressed if not confirmed the idea that wider tires, specifically XC tires right now, are as fast or faster than gravel tires.

Fair enough; “we’re all thinking” referred to what’s available and the design decisions that seem to underlie most gravel bikes right now. As noted above, “we” in the sense of this thread and gravel influencers/pros are more forward-looking than the industry as a whole or indeed the totality of gravel riders/racers.

I just listed to a Marginal Gains podcast where Josh Poertner said that to this day, when he’s doing neutral mechanical support for an event someone invariably shows up to ask him to put 100+ PSI into a >30mm tubeless tire. Just to say that old ideas die hard, and even very dedicated riders/racers often hold on to received wisdom long after it’s been disproved.

[Trix8806]

Getting proper clearance to fit a 2.2” race king takes a pretty dang wide fork (the Enve Gravel Adventure Fork with proper clearance looks HUGE compared to the Enve Gravel Fork with 50mm clearance).

I am all aboard the logic of the faster speeds on the 2.2” on many gravel terrains vs the traditional 40-45mm.

With that in mind, when you start properly designing for that clearance, the bikes quickly lose the ability to ride a road wheel set without looking completely absurd. If I had a bike that could run 2.2’s, it wouldn’t be my choice if I’m looking for both a road/gravel bike. I probably wouldn’t want to throw anything smaller than 45’s on there. If I had a separate dedicated road bike, it’d be easier to swallow.

I was at the MADE bike show in Portland and saw every type of (primarily titanium) road, gravel, and mountain bike imaginable. I’m in the process of building a Mosaic GT-1, and the 45mm clearance was a sticking point for quite a while. Baum had a beautiful gravel bike there with 2.2’s comfortably fit. I LOVE that for a gravel bike, but think it loses too much to also be a reasonably competent road bike, or for the milder gravel races, that so many of them are. It sure was beautiful and CRAZY light…

[grwoolf]

@Trix8806

With that in mind, when you start properly designing for that clearance, the bikes quickly lose the ability to ride a road wheel set without looking completely absurd.

Embrace the absurd. I relish the opportunity to show up to a road/group ride on a MTB running 38’s. I mean, we’re all wearing lycra and look ridiculous to begin with. If it works, roll it.

I’m not a fan of cycling’s obsession with image and tradition over function, so I take any opportunity I have to fly in the face of it.

[Teddy_Focaccia]

For sure; track bikes look like this, talk about excessive fork/seatstay clearance! And they tend to be pretty fast…

I’ve also been running 34mm tires on 3T Discus rims (HOOKED 29mm internal/40mm external, aka the Poertner Special) on my gravel bike in “road mode”. These tires blow up to ~38mm on the wide rims, look less absurd, are quite aero per Josh Poertner, and are VERY comfy over rough pavement and light gravel. Recommend.

[Jolyzara]

@grwoolf

@Trix8806

With that in mind, when you start properly designing for that clearance, the bikes quickly lose the ability to ride a road wheel set without looking completely absurd.

Embrace the absurd. I relish the opportunity to show up to a road/group ride on a MTB running 38’s. I mean, we’re all wearing lycra and look ridiculous to begin with. If it works, roll it.

I’m not a fan of cycling’s obsession with image and tradition over function, so I take any opportunity I have to fly in the face of it.

You wear Lycra mountain biking?

[Power13]

@crandallGA

I think this sentiment is more outdated than at first glance. Every (almost every?) major influencer in the gravel space has at least addressed if not confirmed the idea that wider tires, specifically XC tires right now, are as fast or faster than gravel tires.

I’m not certain this is accurate…yes, it is certainly the product trend. but I think we are far from saying that XC tires are proven faster.

I have seen precious little actual testing…and even then, I think there are some big gaps in logic. Take for example Dylan Johnson’s testing - he’ll ride certain sections of a course / route on different tires. Those sections tend to be the rougher / chunkier sections, so it makes sense that bigger tires test faster. What is not done, however, is to test tires across an entire course, where you have a range of surfaces / levels of gravel. Even Dylan noted that his 2.2 tires were probably the wrong choice at BWR NC, because he got dropped on a road section.

[Teddy_Focaccia]

Definitely depends what you optimize for, and that might be personal. I do a granfondo series where each course is ~50/50 pavement and gravel, some of it quite gnarly. Obviously no gear choice will be perfect for everything, so up to the individual whether they prefer more weight/drag on the pavement or a rougher ride and lost watts on the rough. I usually optimize for the rougher stuff, as you’re normally in a pack on the roads and I can live with some lost watts there.

OTOH it seems Paris-Roubaix is now generally raced on pretty standard road setups. Apparently this is because most of the course is road, and the racing is now so fast from the gun that you’re best off optimizing for that and just suffering on the cobbles.

Obviously 2.2s are not faster on asphalt, and I’m not sure at what “level” of gravel they become preferable. But that point sure seems to exist, so my next gravel race bike will 100% have the option of fatter rubber even if I may not run it on all courses.

[crandallGA]

@Power13

Even Dylan noted that his 2.2 tires were probably the wrong choice at BWR NC, because he got dropped on a road section.

Sure, but he was back to trumpeting Thunder Burts and Race Kings in the next episode or the one after. And anyway, prior to his adoption of MTB tires he repeatedly said he’d never run anything smaller than 47mm pathfinder pros on any course including BWR. So if the ideal tire ends up between 47-56mm it wouldn’t be surprising. As much stake as we want to put into DJ’s opinion after one race where he didn’t quite have the result he wanted.

Regardless, I find the amount of testing showing (specific) XC tires to be as fast or faster than most gravel tires to be as compelling as the testing showing 28-32mm tires are as faster or faster than 23-25mm tires. There’s not a huge body of results for either one but there’s enough to be influencing large numbers of pro and amateur racers.

One could also take the stance that we are seeing significant real life iterating and testing by racers this year, at events. There were a lot of XC tires in the top 25 at Unbound this year, for example.

@Teddy_Focaccia

Obviously 2.2s are not faster on asphalt,

Except it’s not obvious, in the same way that 5-10-15 years ago it was “obviously 30mm tires are not faster on asphalt” - and then suddenly they were. The model which allows wider tires in one range to be faster, would necessarily not change in another range.

It seems clear meta-analyzing the BRR results that the ideal tire construction follows a sort of power law with respect to width and construction so that 2.2 Race Kings will be significantly faster, on asphalt, than many or most gravel tires just by the nature of how they are made and the thickness of the tread. I’d wager a Race King with the knobs completely shaved off into a slick would probably have 2/3rd the crr; 11-12w. Whereas most gravel tires would probably have almost the same crr as the casing is relatively thicker and stiffer with or without knobs.