Maxlee

I was wondering what's the difference between a hybrid and gravel bike if I were to put drop bars on a hybrid frame. Is the frame geometry similar? I'm a little curious because they seem somewhat similar in some aspects like having the capability of putting on a similar sized tire.

HTupolev

Framesets for flat-bar bikes are sometimes "longer" than for drop-bar bikes, since the handlebars themselves create less reach. Drop-bar conversions thus sometimes require high and short stems.

Another consideration is steering geometry, particularly trail. When using narrow handlebars, a high-trail geometry can feel floppy at low speeds and stiffen up too much at high speeds. Hybrids vary considerably in trail, but their numbers are usually higher than for road bikes. If you're using very wide flared bars, then you'll likely be okay; if you're aiming for a road-bike-like posture, your bike will likely have a livelier feel if you err toward lower trail.

Some other things to keep in mind:
1-You'll probably need new brake levers and shifters. Drop bars have a diameter of 23.8mm, while flat bars use 22.2mm, so you can't just move the components from the hybrid onto the drop bar. A few brands make special 22.2mm drop bars specifically to get around this (like the Pure Fix Drop Bar), but the ergonomics of straight-bar components on drop bars will still be a bit odd. (You could similarly "create" drop handlebars by just adding drop-shaped bar-ends to your straight bars.)
2-Pay attention to brake lever and shifter compatibility with the existing components. This includes brakes: if the hybrid has linear-pull brakes (full-size v-brakes or mountain mechanical discs), you'll need to either use a linear-pull brake lever (like an RL520 or Tektro Drop-V) or a pull adapter (like a Problem Solvers Travel Agent).
3-Also budget for cables, housing, bar tape, etc.

KraneXL

Gravel bike: A hybrid with drop bars. We've come full circle.

Buddha2499

Maxlee

KraneXL

Actually, there are some specific specifications that are common to basically all hybrids. Chief among them is a more relaxed geometry. After that, they may include spacing for larger wheels/tire, compact gearing, rack mounts, but may or may not include flat handlebars. In many of these specifications a gravel bike (or cross bike) could both fall well within the area and/or be considered hybrids.

Wilmingtech

I'll take a shot at this, but take my answers with a grain of salt as I have zero professional experience in bike building.

First off, while the term "Hybrid" can apply to many differrent facets of cycling, for simplicity I am going to assume you are comparing something like a Cannondale Quick, Trek FX or Giant Escape to an "All Road" type of bike such as Giants AllRoad or Cannondales Slate.

1. Top Tube length/reach -As mentioned above, the top tube for a flat bar hybrid is longer than a gravel drop bar bike. The reason for this (also as mentioned) is that your stem length on a flat bar bike is shorter. If you look into a road bike you are adding on avg 9-12cm of stem length to get to the handlebars an maybe 4-6cm to that to get you to the hoods where most riders spend their time. So while the top tube may be shorter, the overall reach for a rider on a road/gravel bike tends to be longer. Gravel bikes tend to have an even shorter top tube than their road brethren to give riders more stability in the front end to support additional weight when jumping on and off their bikes and control aroumd quick turns and short corners.

Adding drop bars to a hybrid will give you a nice long reach, great for riders with longer torso's and stable fast paced rides with stability in the front end when sweeping wide corners on descents.

2. Trail/Rake - Again as mentioned above the longer trail on a hybrid makes for a comfy, easy ride. You will find a longer trail on a hybrid than most road/gravel bikes and probably an even shorter trail on CX specific bikes. Remember above where the top tube is slightly longer but the overall reach may be shorter on a Hybrid? The longer trail allows a shorter reach to have more control at speed. Allowing the better handling and less twitch on fast descents.

3. Wheelbase - Have not seen this mentioned yet but the wheelbase on a hybrid is usually 4-5cm longer than on a road/gravel bike. This allows for a nice comfy ride, more suspension to the overall frame (longer length) and better tracking. The cross/gravel bike has a shorter wheelbase to assist getting around corners quicker, better response at the bottom bracket (Shorter frame length) and a more rigid controlled climb up short steep hills. Im going to also assume that it helps to keep the weight of the rider over the real wheel (shorter chainstays) for better traction.

Thats my no-clue best guess as to the difference between the 2 frame styles. I think depending on your build and riding style you could certainly convert. Although I dont think you would get the advantage from a hybrid that a gravel bike was designed for.

-Sean

Metieval

gravel is generic.

gravel bikes range from road race geo on a fatter tire 35/38 max, all the way to MTB geo with mtb tires that happens to have a drop bar.

Due the current customer base for hybrid bikes, and the demand for sit up relaxed style of riding. I reverted back to the 90's for my hybrid.

fietsbob

geometry, is angles and lengths data to compare..



here mostly it's opinions..

chas58

Exactly. so I'm looking at my wife's hybrid (Crosstrail) and comparing it to a Roker and a warbird

Hybrid has
+30mm top tube
+ 5-10mm wheelbase
about the same head tube angle (slacker than the Roker, same as the Warbird)
+50mm on the wheelbase
+40mm on stack
+25mm on reach (it has a super short stem and flat bar)

This make the bike feel more stable and easier to ride - a bit less nimble. Makes for a good gravel bike if I'm not in a hurry and don't need razor sharp handling.

KraneXL

Seems to me what makes a hybrid a hybrid would also work well for gravel? Maybe we should ask GCN to do a comparisons to see which fairs better on the gravel? Then again I suspect if has to do with distance, where the dedicated gravel bike would have the obvious advantage. Such as a 200 mile run across Kansas.

chas58

It does. But you are taking relaxed gravel geometry, and making it a even more relaxed. Its typically more upright too, although you can adjust that. That longer wheelbase makes it more stable in gravel or in long graceful turns, although its going to be harder to cut a tight turn if your are going slow, or turning hard on pavement. But yeah it would be good for 200 mile run.

80% of my rides are 90 minutes or less
20% of my rides are 3 hours or less
one ride per year would be across state.

Personally I target a bike for the majority of my riding, rather than the once a year thing. For something like that, even renting a bike from LBS is an option.