Refreshing

I miss riding my road bike so much. I moved to the middle-of-nowhere South Dakota and am surrounded by gravel roads in all directions so my roadbike sits gathering dust. I have been riding a MTB frame with road drops and short stem but the feeling just isn't the same. When I stand and hammer the bike feels like it steers itself. I believe this is due to the high trail numbers but when I look at the trail of most gravel and cx bikes like Salsa Warbird or Specialized Crux they all have trail numbers in the 70's. On the other hand all of my favorite road bikes have trail numbers in the mid 50's.

Is there a reason for this? I am planning on buying a Surly Midnight Special (trail is ~55) with the hopes that it will feel like riding a roadbike (with fat tires) on gravel but perhaps there is a reason why no other bike manufacture is doing this?

Caliper

I think it's a combination of the longer rides that tend to occur on gravel, plus bumpier terrain and how many gravel riders use their gravel bike like a rigid, drop bar MTB.

I'm in a similar boat here in MI. My only pavement is 55mph with no shoulder and then miles of dirt. If you can find a Salsa dealer, give the Warbird a shot though. I got one this fall and love it. It does feel very good especially on dirt roads and will be much lighter than the Surly.

Marcus_Ti

They (generally*) have high trail numbers to slow steering response and make a bike more stable. Mr Asterisk makes his lovely appearance in the prior sentence as there is no standard in "gravel" geometry.

https://www.cyclingabout.com/underst...rame-geometry/

tyrion

+1 gravel bikes are designed to be more stable than road bikes. The Midnight Special isn't a conventional gravel bike, it's for those that want quicker road bike handling with "fat" tires.

Refreshing

Last year I was able to test ride a Warbird for almost an hour and I LOVED IT (kindof obsessed actually) But I can't afford the price tag :/

"more stable" Thank you for stating the difference so simply, haha. I THINK I want quicker road bike handling but I would be quite upset to buy and build up the Midnight Special frameset only to find out that I prefer the traditional gravel geometry.

Refreshing

That is an epic tutorial. Thank you for so much for sharing it!

Spoonrobot 

Refreshing

Hearing it put this way has me leaning towards the traditional style gravel/cx geometry instead the Midnight Special. I very much appreciate all the input guys. Thank you.

Metieval

unless you are planning to stick to the 650x47 thing. That will put the Midnight special back on the table as an option, because the road plus will numb handling back down again. Pneumatic trail

Spoonrobot 

Caliper

Any bike with positive trail will become more stable as speed increases. Lower trail just means that the stability increases less than higher trail. Only a negative trail would become less stable as speed increases.

Back to the OP, you know your local roads better than any of us. As I said, some people take a "gravel bike" to be a rigid drop bar MTB. If you aren't doing that and your roads are fairly smooth, then erring toward less trail than the typical commercial gravel bike may work for you. But, if you loved the Warbird then I expect you'll be happy with typical gravel geometry.
Another option at a lower price point than the Warbird may be an aluminum frame Trek Checkpoint.

bwilli88 

Why, ride it any way. Put the largest tires on it you can fit and ride it. Here is my Fuji Stratos, built for the Japanese market, that I have here in Cambodia, I put 32mm tires on it and I ride it every where.


DSC05631 by Bwilli88, on Flickr

in the mud

14290021_10154185349897562_4991815952762781302_o by Bwilli88, on Flickr

Down dirt and gravel roads

IMG_20160323_101607855_HDR by Bwilli88, on Flickr

Google youtube video "bike party"

Spoonrobot 

There's paper and there's practice. In the real world, the faster you go on a lower trail bike the faster the perception of steering required to track true as well as correct tracking becomes. Especially when small impacts from gravel are having an outsize effect on steering compared to higher trail. It doesn't matter if the math or theory says one thing, when you're heading down a 6% descent at 35 mph the difference becomes obvious, quickly. There's also an additional factor that trail changes as the relative angle of the bike (up or down) changes - it's why a high trail bike (70+) with a moderate front load becomes extremely difficult to ride uphill - it will wander and require significant correction as it wants to fall left/right. The relative trail has increased significantly and the high wheel flop is guiding the bike.

Remember, 1 degree = 1.75% slope.

Relative trail on a 10% grade will change as if the headtube angle was adjusted ~5.75 degrees. A low trail bike with measurements on flat of 73 degree headtube, 65mm fork rake and 42mm 650b tires will now have 1mm of trail going down our imaginary 10% grade. The head angle relative to flat has increased to 78.75 degrees. This is a huge part of the reason mountain bikes have such high trail. It's not uncommon to see very short slopes in excess of 30%+ and the extra trail is needed to maintain control during cornering. Bicycle Quarterly touched on this very briefly in issue 63 in their Caletti Monstercross review.

Don't take my word for it, try it yourself. I've spent the past year experimenting with bikes running low/med/hi trail so YMMV.