Author Topic: What's the geometry of your dream gravel bike?  (Read 383 times)

german87

What's the geometry of your dream gravel bike?
« on: May 08, 2024, 12:32:37 PM »
When I was looking to buy a gravel bike, I was doing some research on reddit, here in chinertown, and other communities.

and it was interesting to see that everyone had a different geometry for their ideal gravel bike.

In my case

1. road geometry (although I don't mind a higher stack)
2. tire clearance with at least 29*2.2 tires
3. support 10-52t cassette and 42t or 40t 1by chainring.


If you could customize the geometry from a to z, what would be the geometry of your ideal gravel bike?



Pedaldancer

Re: What's the geometry of your dream gravel bike?
« Reply #1 on: May 08, 2024, 02:49:33 PM »
How does it help you if others tell you their sweet spot?
This can be very different due to different needs and wishes.
 ;D That's possibly the reason why so many different gravel bikes do exist.

german87

Re: What's the geometry of your dream gravel bike?
« Reply #2 on: May 08, 2024, 03:19:35 PM »
It doesn't do anything for me, I'm just curious what others think. ;)

Sakizashi

Re: What's the geometry of your dream gravel bike?
« Reply #3 on: May 08, 2024, 05:35:50 PM »
For racing with narrow bars on maintained gravel roads, something like a BMC Kaius is ideal IMO. I don't think there are any open molds with a comparable geometry.

If you do a lot of single track and fire roads with a lot of elevation the SC Stigmata is probably a great choice, assuming it fits you. That slack HTA works, but it can also be annoying unless you have wider bars. I think there are some new open molds that are more like this. I think the Carbonda 707 and the new elastomer suspension Light Carbon bike are more like this.

For an allrounder, I get while the Canyon Grail and Trek Checkpoint are popular options. I think a bike like the Carbonda 696 is also this kind of bike, though I have never owned one. I think most people are best off getting a bike that is this kind of geometry, sort of half way to a race bike but slightly relaxed and designed for a more upright position.

However, gravel bike geometry is pretty fraught with tradeoffs and compromises, so the question is really hard to generalize an answer for. Even if the frames can fit wider tires, unlike on the road, toe overlap can be a very consequential issue  when racing. With 165mm cranks, my max tire size is 700c x 42mm treaded tired with a FC <610mm. Realistically, I personally would be conservative and go with a 40mm tire to be safe. That means that for me, most racing or allrounder bikes are pretty much limited to relatively narrow tires unless they can take 650b / 27.5" tires at which point, I want something like a 2.1" tire so the handling doesn't feel too quick as a result of the overall tire / wheel being too small. Given that the 650b tire size is dying and the remaining 27.5" tires are XC tires that are quickly becoming only available in 2.2"-2.4" there are no allrounder options that meet my needs.

The ideal solution is to buy two bikes, which is what brands like Enve want me to do. One for racing on 40mm tires and the other an ultra / trail focused rig that clears 700x50mm. The other option, which i did, was to go custom geometry allowing me to just barely get what I want without having to make these specific compromises.

jfcb

Re: What's the geometry of your dream gravel bike?
« Reply #4 on: May 09, 2024, 10:52:54 AM »
For me it would be :
- Geometry close to road racing, but head tube angle of 72.5 is great.
- Slightly more stack (10mm)
- Fit for 45mm tires (that doesn't damage the frame in muddy conditions)
- Space for 48t single or 52t double chain ring
- Internal cable routing
- No mounts on the fork and bottom of the frame
- No compromise in stiffness (especially torsional) compared to a an endurance or climbing road bike.

mirphak

Re: What's the geometry of your dream gravel bike?
« Reply #5 on: May 10, 2024, 01:33:02 AM »
Geometry of a very tall endurance bike (stack of 600+mm for size 54). A bit but not much slooping, so that there is no need for a super long seat post, short top tube but longish reach, which translates into a very vertical (75 deg) seat tube for 71-71.5 deg steerer. And clearance for 50+mm tires. Wait, wasn't that what I built in titanium?
« Last Edit: May 10, 2024, 01:35:28 AM by mirphak »

Serge_K

Re: What's the geometry of your dream gravel bike?
« Reply #6 on: May 10, 2024, 05:53:36 AM »
I rode over 2k km on the VB GF002 last year, and because i didn't like the geometry as a "do it all" bike, i bought a new road bike. I did enjoy it a lot on actual gravel /off road though.
This year, i rode only c.200km on a clone of the latest Grevil (by Carbon Speed, Peter is on the forum), and i got along with the geometry much better, probably because it feels more like a road bike. On stupidly steep stuff, you have to put your weight on the bars otherwise the front wheel lifts off.
So while not exactly scientific since i didn't ride them side by side (at least i did use the same wheels & tyres), and i really didn't put much mileage on the Grevil clone, i guess i prefer the Grevil geometry, which is closer to a road bike (i use geometry bike geek website to compare angles & measurements). Almost all of my riding is road. I'm absolutely useless on a MTB, it's literally embarrassing. So that's a bias there.

german87

Re: What's the geometry of your dream gravel bike?
« Reply #7 on: May 10, 2024, 05:21:18 PM »
It's sounds good and yeah I agree about that gravel bike geometry is pretty fraught with tradeoffs and compromises, so the question is really hard to generalize an answer for. That's why im interested Gravel Bike  8)

For racing with narrow bars on maintained gravel roads, something like a BMC Kaius is ideal IMO. I don't think there are any open molds with a comparable geometry.

If you do a lot of single track and fire roads with a lot of elevation the SC Stigmata is probably a great choice, assuming it fits you. That slack HTA works, but it can also be annoying unless you have wider bars. I think there are some new open molds that are more like this. I think the Carbonda 707 and the new elastomer suspension Light Carbon bike are more like this.

For an allrounder, I get while the Canyon Grail and Trek Checkpoint are popular options. I think a bike like the Carbonda 696 is also this kind of bike, though I have never owned one. I think most people are best off getting a bike that is this kind of geometry, sort of half way to a race bike but slightly relaxed and designed for a more upright position.

However, gravel bike geometry is pretty fraught with tradeoffs and compromises, so the question is really hard to generalize an answer for. Even if the frames can fit wider tires, unlike on the road, toe overlap can be a very consequential issue  when racing. With 165mm cranks, my max tire size is 700c x 42mm treaded tired with a FC <610mm. Realistically, I personally would be conservative and go with a 40mm tire to be safe. That means that for me, most racing or allrounder bikes are pretty much limited to relatively narrow tires unless they can take 650b / 27.5" tires at which point, I want something like a 2.1" tire so the handling doesn't feel too quick as a result of the overall tire / wheel being too small. Given that the 650b tire size is dying and the remaining 27.5" tires are XC tires that are quickly becoming only available in 2.2"-2.4" there are no allrounder options that meet my needs.

The ideal solution is to buy two bikes, which is what brands like Enve want me to do. One for racing on 40mm tires and the other an ultra / trail focused rig that clears 700x50mm. The other option, which i did, was to go custom geometry allowing me to just barely get what I want without having to make these specific compromises.

german87

Re: What's the geometry of your dream gravel bike?
« Reply #8 on: May 10, 2024, 05:22:42 PM »
Could I ask you why you want 72.5 head tube angel?

For me it would be :
- Geometry close to road racing, but head tube angle of 72.5 is great.
- Slightly more stack (10mm)
- Fit for 45mm tires (that doesn't damage the frame in muddy conditions)
- Space for 48t single or 52t double chain ring
- Internal cable routing
- No mounts on the fork and bottom of the frame
- No compromise in stiffness (especially torsional) compared to a an endurance or climbing road bike.

german87

Re: What's the geometry of your dream gravel bike?
« Reply #9 on: May 10, 2024, 05:28:11 PM »
it is not 1000000% embarrassing.
I really think your riding style is cool too, because there is no right or wrong way to ride a bike, it all depends on how you ride it!

I rode over 2k km on the VB GF002 last year, and because i didn't like the geometry as a "do it all" bike, i bought a new road bike. I did enjoy it a lot on actual gravel /off road though.
This year, i rode only c.200km on a clone of the latest Grevil (by Carbon Speed, Peter is on the forum), and i got along with the geometry much better, probably because it feels more like a road bike. On stupidly steep stuff, you have to put your weight on the bars otherwise the front wheel lifts off.
So while not exactly scientific since i didn't ride them side by side (at least i did use the same wheels & tyres), and i really didn't put much mileage on the Grevil clone, i guess i prefer the Grevil geometry, which is closer to a road bike (i use geometry bike geek website to compare angles & measurements). Almost all of my riding is road. I'm absolutely useless on a MTB, it's literally embarrassing. So that's a bias there.

RDY

Re: What's the geometry of your dream gravel bike?
« Reply #10 on: May 10, 2024, 05:51:12 PM »
69degree head angle.  75.5-76 degree seat angle.  longish FC and 1100 WB.  around 610 stack and 425 reach in a 58.  78-80mm BB drop. sloping top tube.  DEEP headtube. downtube flared to shroud the bottle.   aggressively dropped seatsays. BB386Evo.  Clearance at the rear for 54x700 in 2x with a road 50/34 chainset. clearance at the front - as much as possible.  preferably downtube storage.  seat tube cage very low mounted. 27.2mm seatpost with vibration damping insert.
« Last Edit: May 10, 2024, 06:27:03 PM by RDY »