PeteHski

Your outside effort equates to around 140-185 W at 17-19 mph riding on the hoods. So your gym bike appears to be reporting incorrect Watts for your effort. At the stage you are currently at, a genuine 235W for 2 hours would not be an easy spin. It would be a major effort. To put it another way, it would equate to around 21 mph on the flat.

Redshift96

No offense, but this is awful advice to offer to someone who is 6'3" riding a 52cm frame.

Sure, wait to plunk down stupid money on your ideal bike until you're sure you actually enjoy riding hard, but it's going to be difficult to gauge how comfortable/fun cycling will be for you when you're riding a bike that is WAY too small for you. Bad yardstick = bad measurement.

Redshift96

If you're anywhere near the SF Bay or Sacramento area, you have an embarrassment of local resources to draw upon, whether for moral support, group rides, racing, tracks, TT's, and/or professional support services. If you need specific suggestions, PM me.

IMHO, the Pro's Closet is consistently overpriced by a healthy (for their bottom line) margin. And their offerings often appear overly worn given their asking price for anything other than urgent replacement type situations. And to boot, their sales staff have been appallingly uneducated about what they're selling, IME. Sad but true. If you're going to charge a premium for something, the least you can do is be prepared to speak intelligently about it.

LOTS of reasonable bikes to be had locally through CL, or on eBay or various bike forum classifieds. Although the pickings will definitely be slimmer for frames over 58cm. You're outside the bulk of the bell curve, but I've seen some very nice 60cm/62cm go by over the last year or two. Have a knowledgeable friend help you set up some alerts on CL and eBay and review any likely candidates with you.

Yes: You're not Brandon McNulty. Lol.

But take heart, almost no one else on the planet is either. Also, I'm not Steph Curry. I know, it's a painful reality.

Sorry, it had to be said.

But seriously, while there are way too many variables to offer any concrete answers, there could be all kinds of reasons he went much faster while putting out similar power numbers. Primarily weight, but then: drafting, winds, aerodynamics, efficient equipment (helmet/kit/wheels/tires/drivetrain/etc., and not least: PROPER FIT/BODY POSITION on the bike. I'm sure there are other factors I'm blanking on at the moment, those are just the glaringly obvious points off the top of my head. Then there's the issue that he can do it for 6 hours, but that's a different tangent.

In some ways, cycling can get a lot more complicated than running. You have all the same biomechanical training/adaptation considerations, with a whole new slew of mechanical and man/machine interface aspects to deal with, But look... anyone who can run a sub 5min mile is, at the very least, a very competent athlete. Beyond that, you'll need to take the advice offered elsewhere throughout this thread and just get yourself on a properly fitted bike, and put in some time to find out how the sport suits you, both in terms of aptitude/potential, but more importantly, how much appeal the actual experience of riding/racing holds for you. and how well your motivation holds up over time.

Try it, see if you like it. Everything ends up boiling down to that.

Hope this helps.

TL: DR: Buy or borrow a bike that fits. Go biking. If you don't like it, sell/return the bike and take up trail running.

smashndash

Right but a long ass stem (perhaps with 20deg rise) is going to give a better approximation of what it's like to ride than making no changes. A $30 stem is much cheaper than, say, a $1000 "entry level" bike. If your 3 contact points are the same, the handling of the bike really doesn't matter all that much in a straight line.

rm -rf

Here's McNulty on Sept 26. 26.6 mph, 112 miles, 4140 feet, 268w average (and weighted average power 312w, a more useful number)
https://www.strava.com/activities/6067737721/analysis

It's a race. There's 70 riders on strava that day, and likely many more that aren't. He's taking full advantage of the draft as much as possible. A peloton taking the width of the road and many riders deep is a huge power saving for the riders sitting in the pack. Drafting even one other rider is a significant help, but a large group is another level.

You can drag a section of the time line to see it zoomed in for more detail. Check out the flat section between mile 20 and 30. Most of it is in the low 200 watts or even much lower, yet the speeds are in the upper 20s. Then switch the chart to Time instead of Distance and check out the climbs, and how long are the big power efforts.

Click the Power Curve too. Slide the cursor along the curve and see where that best effort occurred.

Redshift96

Your point about cost is well taken. But even a 140mm stem and a setback seatpost isn't going to make a bike that is 4 to 5 sizes too small feel like anything close to an appropriately sized/fitted bike. Not to mention the short crankarms, short headtube/steerer, narrow bars, short wheelbase, etc. It's going to be pretty hard to figure out whether cycling really appeals to you or not when you're riding an ill fitting bike as the test. Let alone a bike that is WAY too small for you. He's SIX THREE !! On a FIFTY TWO cm frame !! That's... clown car territory..

Not to mention that there's a lot more to evaluating a bike than riding in a straight line.

Every rider has to wrestle with this initial dilemma. "How much cash do I want to splash out just to figure out if I want to do this sport? But if you want to ride, you'll figure it out. Hopefully with a minimum of missteps (wrong bike purchases).

Extremely, It is literally step one for every new cyclist. (If you count a helmet as step zero.) How long you wait to take this step depends almost entirely on your pain tolerance. And maybe your finances as a distant second. But whatever you end up spending on a truly well fitted bike, it will feel like a bargain. I promise.

NOT minimal. To say the least. Just the opposite, the difference will likely feel massive. And the difference in comfort and your ability to ride further will be a whole different dimension.

Best advice I might offer is to go on a lot of test rides at local bike shops, talk to other bikers who might be able to locate a loaner or two or three in the appropriate size, and do a lot of online bargain hunting with a few go-to friends who can "sanity-check" any promising candidates and hopefully go with you to test ride them before buying.

Oh, and go through the online bike fit routine at Competitive Cyclist dot com to get an approximation of what the ideal frame size really is for your body geometry. It's NOT just about inseam length.

Again, hope this helps.

smashndash

Lots of factors.

- drafting a pack makes a HUGE difference. A ride that's around 20mph for me solo would be closer to 25mph in a pack at the same power, I think.
- races don't stop. At all. Every time you brake on your outdoor rides, your average speed tanks
- position makes a huge difference. If you have 25lbs to lose, I can guarantee you that your position isn't as optimized as McNulty's. I have maybe 8lbs to lose and my legs hit my belly.
- equipment makes a much bigger difference than most people realize. Especially at 25mph+. Wheels, tires, bike, speedsuit, helmet etc all adds up. At 30mph you're probably looking at 100W+ between a bad setup and a good one. Dan Bigham just beat Wiggins's 2015 Hour record while doing ~60W less. And that's comparing one top tier pro setup to another.