"Faster" frames?
 

Given the same tires/wheels, does a longer/slacker geometry like you'd see in a gravel bike any slower than a classic road geo? I mean, clearly, there's an aero component, if one bike has you sitting closer to straight up, but aside from that, unless you're running a crit or something where tights turns are a huge part of your game, is there any reason a roadie should be faster than a gravel bike, over, say, the course of a century?

Personally, I have short femurs and a long gorilla torso, so my weight winds up pretty far forward on most bikes, and a gravelly long front-center and slack front end lets me descend faster without feeling like I'm gonna endo, but I just wonder if there's an objective tradeoff I'm missing.

Thanks!

Geometry affects handling more than speed.

Let's hope that tiktak doesn't notice this thread.

It's more important that the bike fit you. So if the gravel bike feels better, then just put what ever tires on it you feel appropriate for the road and be done with it. Once you've ridden it several thousand miles, If you then think you should be doing better than you are at that time maybe it can be figured out what your next bike should be.

Guessing and imagining that we do here will leave you never being able to decide what bike to get.

While the gravel bikes seat tube is a tad slacker on various models, it's not that much slacker.

Well, I bought a gravel bike this year and I am enjoying the heck out of it. The ability to ride many mountain bike trails along with decent speed on the road is wonderful. However, there is a fly in the ointment. There is a short off-road Strava segment nearby that I had been trying to get a top rating on. On my gravel bike, I managed 7th place, not bad for a 72 year old, but I thought maybe I can do better. So, I took out my trusty Look 595 and did that section with it, guess what? Second place. To be honest this is a pretty smooth gravel path, slightly uphill at first. I am also an experienced mountain biker with little fear of unpaved surfaces. If the trail were less smooth my gravel bike would rule, but on smooth gravel my Look 595 road bike is way faster

If you ignore aerodynamics, weight, handling, and gearing, are only comparing two bikes that otherwise have identical fit in a straight line on a flat road with identical tires, they're all the same.

:twitchy:

In the last two years I have owned systemsix ( aero road bike ), alloy topstone ( gravel bike ), giant revolt adv 2 ( gravel bike ) & now Ibix MX gravel bike.

When I put on the same carbon wheels with the gp5000 tires the SystemSix is a tad faster if I am trying real hard to go fast. I have a 37 mile loop that once in a while I try to avg 20 mph. At my lower power lever and speed seems like the aero bike was good for about 0.5 mph maybe 1mph that would be stretch. 1 mph is a lot if you are trying to go fast on bikes. A more powerful rider at higher speeds would notice a bigger difference in speeds.

If you like to ride in an aero position at 95% of the time at 95% of your power on your bike rides get the faster aero bike. You will enjoy it, they are fast!!! The person riding the bike is the biggest aero draw back. So if you not in an aero position your aero bike is not doing much for you.
Since 99% of the time I am not in an aero position I found the comfort and versatility of a gravel bike with multiply wheel sets suites me better.

The rest of time ( group rides, fitness rides, stop lights etc... ) there is zero difference in speed.

Same wheels, tires and gearing, same rider aboard; for outright speed, it’s the aero, provided you’re riding fast enough. For sustained speed over a century, it’s the one that fits you best.

I have similar physiology to the OP, and I like something a little bit taller and longer, like a Synapse compared to a CAAD13, so that I don’t have as much weight on my hands
I’m also partial to wider bars and longish stems with steeper head tube angles, but steering/handling feel is very subjective and rider-dependent

...I've never tried to figure it out, but I have a lot of different 70's and 80's bikes I ride here from time to time, in rotation. Certainly you're correct that the biggest single difference is in the rotating weight of wheels and tires. That's obvious when you upgrade them.

But I'm not sure there's not some effect from where your center of body mass sits in relation to the crank spindle. So with a shorter top tube, tighter geometry bicycle, I end up putting it together with a different (longer) stem. And the steeper angles of the frame usually set the seat tube more upright. All of this serves to move my overall center of body mass farther forward on the bicycle. Thus you end up more over the spindle axis. Most people find this a better position for spinning higher cadences. But I admit I don't have any real science to back this up. And the overall effect might be more one of perception than actual performance.

I don't ride with a speedometer, it's too distracting.

With everything else being equal, if you can do a 100 mile descent without turns and steep enough that you might endo, slacker geometry is better. For everything else it doesn’t matter.

John

That makes sense. I absolutely put out more speed on my track bike, though how much of that is the straighter chainline and how much is the geo, I dunno. Also, it's probably that I just spend less time coasting and more time pushing pedals, so I'm putting out more watts.

As long as you can get "aero", there is no big speed difference between bicycle types running close to the same tire pressures, even when running different tire types and sizes. What makes any bike fast is the strength of the rider and aerodynamics, everything else is very minor. I tested my time over a 12+ mile route with no steep grades on three different road bikes and a classic MTB with 2.1" wide knobby tires, and I have finished the same route within 20 seconds on all of the bikes in the last year. The only change on the MTB setup between riding it offroad and on pavement is running either 40psi or 80psi in it's tires. So as long as the bike is sized to let you get horizontal, there is no advantage in speed in any other bike. It IS more comfortable to ride the road-bikes in a horizontal position though, but that is because of the drop bars of course. Here are two of my road bikes and what my MTB currently looks like;


https://cimg6.ibsrv.net/gimg/bikefor...3634a22fde.jpg
https://cimg0.ibsrv.net/gimg/bikefor...385a9384a5.jpg

I never thought a mountain bike could look completely uncomfortable. Until today.

False. Just the rolling resistance difference between tires is significant.

Also false. Rolling resistance and weight are two non-minor factors. Especially at lower speeds, where air resistance is less significant.

You rode four non-aero, antique bikes with crummy tires over a course at around the same speed. <slow clap>

There's another aspect to "fast" frames' Frames that feel "fast" or "race" inspire greater effort. More effort, faster times.

I just picked up a Pro Miyata frame from a forumite and set it up with roughly period race hardware. Chorus crank, Cyclone derailleurs and brakes, my usual Delta standard pedals, etc. First ride - this is a slightly less radical but just as pure race as my old Fuji Professional that I raced and loved, only now with late '80s better tubing and a couple of other nice touches. Like my Fuji, it just wants to go fast. And is a pure joy to ride fast. So it happens, Regularly. Always faster than I would on another bike. Just like you would drive a windy road faster in a Ferrari than a Volvo, even if you weren't in a hurry.

Maybe his non-pictured 3rd road bike was a Pinarello Dogma F12, lol.

This is it;

https://cimg7.ibsrv.net/gimg/bikefor...bb727217cc.jpg

:twitchy: Are any of them your size?