Why many gravel bikes have a more traditional geometry with little seatpost showing?

[cyan]

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the more traditional geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?

Is there a functional reason or just aesthetics?

[nmrt]

from what i gather, sloping TT only came about with the giant-spesh-trek wanted to minimize sizing and save cost. this way they could make fewer sizes with sloping TT and get the standover height.

when you are making a custom bike the above point does not matter. And hence, i feel, the sloping TT or horizontal TT, becomes a matter of aesthetic perspective for the builder and the buyer.

having said that, tom kellogg, had something to say about the functionality of sloping Vs horizontal TT on a compact versus traditional frame (taken from https://www.spectrum-cycles.com/geometry.php)

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the compact geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?

Is there a functional reason or just aesthetics?

[Ed-B]

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the compact geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?

Is there a functional reason or just aesthetics?

I can't say that my observations agree with yours, including the cyclocross bike part, where a frame with compact geometry is actually more difficult to shoulder due to lack of room in the main triangle.

But I would offer that a longer seat tube and larger open area in the main triangle makes more space for frame bags, especially a voluminous top tube bag.

[Hellgate]

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the compact geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?



Is there a functional reason or just aesthetics?Compact CX frames are a bad idea.

[FlashUNC]

Room for bags yo.

[wallymann]

Is there a functional reason or just aesthetics?

more room inside the main-triangle for bikepacking storage.

https://medias.apidura.com/2019/01/apidura-full-frame-pack.jpg

[9tubes]

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the compact geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?

Is there a functional reason or just aesthetics?

I would guess that at least part of the reason is that the modern concept of gravel bikes pretty much started with a few custom builders like Hampsten, and this was more than 15 years ago. Traditional level top tubes were more common back then and the early gravel riders were long-time experts (like Andy Hampsten) who thought of level top tubes as the default design. I can't say for sure but maybe one of the early builders can chime in.

[Jaybee]

Like many others said above, it’s room for bags. I kinda wish mine had a lower top tube. I bang my knees quite a bit when working the bike on single track.

[HTupolev]

It seems many gravel bikes (e.g. open up/upper, ibis hakka mx, cervelo aspero, and even custom builders like mosaic, baum, etc.) have a more traditional geometry with longer seat tube and little seatpost showing (unless you have longer-than-average legs)? For cross bikes, I understand the compact geometry makes carrying the bike on rider's shoulder easier, but gravel bikes?

Is there a functional reason or just aesthetics?
Never assume that there's a solid reason behind frame design choices.

But in this case...
1-Sometimes gravel bikes need to be carried, and sometimes gravel bikes get used as CX bikes.
2-Room for frame bags.

[hobbanero]

Most likely it is that gravel bikes derived from cx bikes. The frame bag argument makes sense, but a counter argument in favor of compact style is having more room for a dropper (those are a thing in gravel now) or at least more post showing to give you the option of softening up the ride with your choice of post.

On my gravel bike I have switched back and forth between a short dropper and a Canyon VCLS post. Both are big improvements...probably going to get the PNW post that is both suspension and dropper in one, which just has enough room to fit on my Diverge.

[Spdntrxi]

Most likely it is that gravel bikes derived from cx bikes. The frame bag argument makes sense, but a counter argument in favor of compact style is having more room for a dropper (those are a thing in gravel now) or at least more post showing to give you the option of softening up the ride with your choice of post.

On my gravel bike I have switched back and forth between a short dropper and a Canyon VCLS post. Both are big improvements...probably going to get the PNW post that is both suspension and dropper in one, which just has enough room to fit on my Diverge.


Ive had my dropper for about 6 months now.. maybe more. F"n game changer where I ride. No joke.

I will never buy a gravel bike again unless I have enough room for a dropper. And those things can be pretty tall. Easily 6+ inches coming out of the seat tube.

[Louis]

I know essentially nothing about gravel bikes, so help me out here.

What's the benefit of a dropper post on a gravel bike? I sort of get it for MTB's, when you're doing all sorts of gnarly stuff and want to move your CG all over the place. Same story on gravel? (around here gravel roads are just "normal" roads that aren't paved, not stuff that would IMO require as much moving about as an MTB course, but then again, I don't ride gravel, except for rails-to-trails stuff that's very flat and not technical)

[unterhausen]

In Central Pennsylvania, gravel roads often feature 20% slopes. And big rocks.

[cyan]

I can't say that my observations agree with yours, including the cyclocross bike part, where a frame with compact geometry is actually more difficult to shoulder due to lack of room in the main triangle.

But I would offer that a longer seat tube and larger open area in the main triangle makes more space for frame bags, especially a voluminous top tube bag.

Sorry, the cyclocross part was a typo. I meant to say the more traditional kind with horizontal top tube makes it easier for carry on shoulder. Corrected now

[cyan]

having said that, tom kellogg, had something to say about the functionality of sloping Vs horizontal TT on a compact versus traditional frame (taken from https://www.spectrum-cycles.com/geometry.php)

Good info! Thanks.

[cyan]

Frame bags is a good point. For those of us who rarely do bikepacking, I'd imagine having a bit more exposed seatpost with a more compact geometry should help with comfort on gravel trails with or without a dropper post. On the other hand, some may argue the bigger tires should mostly take care of that?

[Davist]

Mine has a longer top tube than my road bike, which I deliberately "sized up" (well kinda) in order to run a shorter stem, which moves me back a bit cg wise. I think it helps. This may result in looking slightly larger. I don't currently run a dropper but would consider and have the room.

[colker]

Frame bags is a good point. For those of us who rarely do bikepacking, I'd imagine having a bit more exposed seatpost with a more compact geometry should help with comfort on gravel trails with or without a dropper post. On the other hand, some may argue the bigger tires should mostly take care of that?

If you want more comfort change your saddle. Something wider, heavier like a Brooks which dissipates shock. Most of all: look for longer chainstays. One cm longer chainstays will give you significantly more comfort than 5 cm of exposed seatpost.

[Hilltopperny]

I went with a titanium setback post on my gravel bike in order to keep the post about 1cm shorter than my road bike. The bike is smooth whether running 28mm or 38mm in 700c or larger in 650b. All of my bikes have a Berthoud leather saddle which dissipates shock better than traditional saddles.

I can see the benefits of a more traditional geometry over compact on gravel if you want to do some bikepacking and also find it more aesthetically pleasing. Allowing more space to carry stuff can be important to some. I had mine built with the ability to put on a rear rack because a 54cm still doesn’t have a ton of room in the main triangle with two cages mounted, but will still fit a half frame bag.

Dropper posts are pretty great for when things get gnarly, descents get sketchy and for hard cornering off road. I really liked the one I had on my trail bike as well as my fat bike and can definitely see the benefit if you like to take your gravel bike out on single track or just to explore some rougher terrain. I personally would take out one of my mountain bikes if I felt the need for a dropper.


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[OtayBW]

I went with a titanium setback post on my gravel bike in order to keep the post about 1cm shorter than my road bike. By that, I assume you mean shorter leg extension as well, or do you compensate with a different crank arm length?

[cyan]

If you want more comfort change your saddle. Something wider, heavier like a Brooks which dissipates shock. Most of all: look for longer chainstays. One cm longer chainstays will give you significantly more comfort than 5 cm of exposed seatpost.

Interesting, why does longer chainstay improve comfort? Further away from the rear wheel/tire contact point?