I have a 2020 Specialized Sirrus 4.0, and am considering a Domane SL5. I’m curious as to whether the Domane would be faster, and if so, how much so. Obviously, the motor determines the speed for the most part, and aero drag from the more upright position would be greater on the Sirrus. I’m typically averaging 14 to 15 mph over 20 miles (no wind or big hills) with the Sirrus on the MUP. Assuming the same motor (me) and same gearing, will the lower more aero driver position allow use of a higher gear at the same effort and result in a noticeable difference in speed? In other words, will the road bike and lower position get me there quicker for the same effort?

This may be a silly question, but I’d like to have an idea of what type of performance increase if any I would see in the more expensive bike.

+1mph

It's not a silly question. A more upright riding position will cause more wind resistance than bent over in the drops, but it may not be worth it to you. I gave up the drop bars years ago, in favor of butterfly trekking bars. I don't care if I'm a little slower.

That's a very complicated calculation. I can do it for you, but I will need the following information:
1) Your height and weight
2) Your hat size
3) Your astrological sign
4) Your spouse's name
5) Photos of your spouse
6) Names of children
7) Own or rent your home?
8) Name of your high school mascot
9) Your VISA or MC number (with expiration date and security code)
10) Chocolate or vanilla?

the answer is “4.”

I'm the opposite. I’m always looking for the next performance increment. I’m the one always micro adjusting the sheets and lines on our sailboat looking for the extra knot of speed.

I do know that improving strength and conditioning will yield better incremental gains in performance than changing equipment once you get to a certain level.

To me, faster is just funner.

15mph is fast enough on a MUP. If you aren't prepared to ride on a road, the bike you have is appropriate.

15 mph .... 17 mph on a MUP

I do ride roads, and my current bike works just fine there. And, the MUPs I ride are used mostly by cyclists.

just wondering if a “road” bike offers any performance gains other than a more aero position on the bike.

The following figure is figure 3 from this page:

https://www.sheldonbrown.com/rinard/aero/formulas.html

It will give a sense of the difference in power requirements as a function of speed for various positions. The difference from upright to drop bars is significant.

I actually am going the other way, back to upright position with touring bars in order to train at a decent power demand without excessive speed on the parts of my rides that are on MUPs and rail trails. it’s also a great configuration for standing to climb, which I do lots of since I ride SS.




Otto

Now we’re talkin. Thanks for that!

You have that backwards. After several years of serious training, there are greater opportunities for improvement through optimized equipment choice than through training. References available through Google.

Upgrade your tires and tubes and try bending your elbows more before you buy a new bike.

Already did/do that.

Yup, probably going to see very little improvement right out of the box, as far as average cruising speed goes.
It still takes a certain amount of power to go a distance at a given speed, and aero doesn’t play as big of a factor until you’re well above MUP speeds

Depending on how the gear spread lines up compared to the other bike, ie; tighter spacing, more speeds to choose from, you might be to dial in to a ‘better’ gear for a given stretch of road.

The differences in road bike geometry vs your hybrid generally make it quicker and more responsive to acceleration like sprints, starts and climbs. It’ll probably feel a whole lot faster.
Same goes for different rolling stock; stiffer, faster rolling wheels and tires contribute to a more lively ride feel, as well as making it faster to go down the road

On my commuting route I usually rode my 40+ lb (loaded) bike with upright bars. Occasionally I would ride my lighter 20+ steel vintage bike with drop bars. Average moving speed difference was less than 1 mph, i.e. insignificant. Of course, there are so many variables like having to slow for traffic signals, etc.

You only see significant speed changes if you change type of bike (i.e. MTB to road bike). an OK and fitting bike within the category will be very similar. You see some small advantage if you throw a lot of money at the problem. For example if you upgrade from old steel roadbike with cheap tires to all new carbon frame and wheel bike, but it will be a small increase in speed. the fact that the overall geoemtry between two road bikes is different, and your body creates different wind resistance on each bike probably contributes more to the differences. Geometry hurts (or helps twice: your body provides more power with better fit, and your body will be in the wind in a different shape/angle. So depending on your shape and fit, the old steel bike could actually be faster if the fancy carbon bike puts you in a weird position.

And yes, the motor determines speed. Many of the road bikes for just a fe thousand $ you can buy would be good enough for a TdF podium spot. You just need to find a better rider than yourself.

Just buy the bike. Its nice to have two bikes, or more.

It depends. How is your hybrid set up now? My 'fastest' hybrids have my hands at the same width, and my back at the same forward lean as when I ride the hoods on my drop bar road bike... Just like most cyclists mostly do. There's virtually no difference in aerodynamics or speed according to my ride times. Tires, gearing and bike weight can also be the same. But yeah, get a new road bike, it will definitely be fun!

Get something more aggressive. The Trek is too much like what you have.

Why spend cubic $ on an incremental improvement when you can improve the motor? Do some interval training on a regular basis and you will be able to improve your average speed one or two MPH. It’s not always about the equipment.

The obvious answer for people who want to throw money at the problem instead of working on it.... e-bike

ftfy

You already have a nice bike, just changed your bars, stem and tires.

Well, now two nice bikes.

Went to a LBS that we had not been to to get a pair of shoes. As we got in the car my wife asked, "Youre not planning to bring a bike home I hope." Said no, just shoes. Saw the 2020 Domane in Navy. Wife immediately said "Buy it - it looks like you." How do you say no to that.

Well N+1 does not always equal N+1 as she scoped out a Roubaix for herself.