Performance, Bike Geometry, and the "Placebo Effect."

[XXtwindad]

My Firefly has been nothing short of a revelation. At least I think so. But maybe it's in my head. A good cycling buddy thinks so.

This morning, on a flat (slightly downhill) section of street in Oakland, a cyclist passed me like I wasn't event there. I thought he actually had a motor. Long story short, I caught up with him, and we raced until the stoplight. I edged him out. Granted, my cycling fitness has improved significantly during the Pandemic. I'm on my exercise bike 5x per week with the resistance cranked up.

But I'm curious how much of progress is my own fitness and how much can be attributed to the bike. I absolutely love the way this bike rides. Tyler at Firefly said it was built to be a pure racing bike. It was built for someone like myself: longer torso and shorter legs in the six feet one(ish) range. The "trail" is 59. The chain stays are slightly longer (415cm). Those factors make descending an absolute pleasure. I can rail the descents, whereas before, I was a chicken****, especially on a rim brake bike. Once again, my buddy thinks this is mostly the placebo effect. I disagree, particularly when it comes to the descending element of the equation. I never knew what the expression "in the bike" meant until riding my Firefly.

I'm curious what others think. Can the bike itself actually make that much of a difference? Or is it like the famous Edison quote that genius is "one percent inspiration and 99 percent perspiration," with the bike being the "inspiration?"

P.S. I've attached the Firefly geo. I have a 110 stem on it. This seems like the ideal geo for a race bike built for me.

[tuscanyswe]

Does a person with short legs and long torso at 6´1" really sit at 81 cm? .)
Then i must be abnormally proportioned beyond salvation.

I think its a lot placebo to (but thats just as good as long as it works at least) unless u have been fitted very poorly on previous bikes perhaps then i can see how a now newly found balance makes u a lot more confident on decents.

[XXtwindad]

Originally Posted by tuscanyswe

Does a person with short legs and long torso at 6´1" really sit at 81 cm? .)
Then i must be abnormally proportioned beyond salvation.

I think its a lot placebo to (but thats just as good as long as it works at least) unless u have been fitted very poorly on previous bikes perhaps.

Well, I'm just guessing that was his build. That's my build and it fits me to a "tee." The ST is 550, TT is 580, and he used (I think) a 130 stem.

[Germany_chris]

I’m 6’1” with a short inseam and I’m at 73.5 cm

[unterhausen]

How careful are you to transfer your fit from one bike to the next? I know that stem height has a big difference for me. One time I decided my new bike would have the handlebars higher because I was doing mostly long distance. Once I took the spacers out, I felt so much more comfortable on that bike.

[tuscanyswe]

Originally Posted by XXtwindad

Well, I'm just guessing that was his build. That's my build and it fits me to a "tee." The ST is 550, TT is 580, and he used (I think) a 130 stem.

I cant really offer any good insights as to why u feel u are just at home on this bike but i have certainly had similar feelings for some bikes i have had. Sometimes a bike just feels right. I dont think i ever "performed" vastly better on one or the other in terms of speed but certainly confidence is everything when descening so it does not really sounds all that strange to me that one could be a lot faster on one bike than another on this type of riding.

[biker72]

I'm 6'2'' with a relatively short inseam at 73.8 cm.

[jtakeda]

assuming your contact points are the same on all bikes Im going to say its the placebo effect.

Wind, weather, energy, what you ate that morning/the night before, how hydrated you are, how sleepy you are, tire pressure, there are so many factors that can affect performance from one day to the next.

Adding in another factor of switching bikes will add even more confusion.

Originally Posted by biker72

I'm 6'2'' with a relatively short inseam at 73.8 cm.

I think this is a good example of shorter inseam. I'm 5'7'' and I ride at 75cm bb to top of saddle for reference

[XXtwindad]

Originally Posted by jtakeda

assuming your contact points are the same on all bikes Im going to say its the placebo effect.

Wind, weather, energy, what you ate that morning/the night before, how hydrated you are, how sleepy you are, tire pressure, there are so many factors that can affect performance from one day to the next.

Adding in another factor of switching bikes will add even more confusion.



I think this is a good example of shorter inseam. I'm 5'7'' and I ride at 75cm bb to top of saddle for reference

So, just to investigate this further, you and I (according to your posts) were/are both timid descenders. Yet your Potts evidently gives you another level of confidence. Is it the discs? The bike geo itself? Or spinach

[clyde the point]

I could ride that bike 6’2” 33” inseam I’d lower the seat a bit. A nicely made bike is just that. That’s what separates this bike from the mass produced TN models.

[benb]

There's so many things that can affect things and mislead...

I was thinking my bike was hurting my back.. a bit of overdoing it in the heat based on the disrupted year. I've been fiddling with my position a bit the past 6 weeks or so.

But it could just be sitting in a less than good chair trying to work at home. At work I was sitting in a $900 chair with an adjustable desk, at home I'm sitting in a piece of crap chair that doesn't necessarily adjust high enough for my fixed desk, and I'm sitting in it 10x more then I ever worked from home before.

Is my anecdote that relevant to you and your Firefly? Maybe not.. but just an example of how complicated it all can be. Stuff your doing off the bike can affect your perceptions of a bike.

In your case I suspect the following #s are way more relevant to your feeling great:

- The 810mm BB to saddle distance
- The 91mm setback
- The 610mm reach to the bars
- The 107mm drop
- Your cleat position

And these are less relevant:
- The STA
- The HTA
- The Chainstay length

IME you're going to feel like a monster when those first 4 #s are correct and the other 3 numbers don't matter as much unless it's an issue like descending or cornering.

My biking is going to hell again.. I had 6 weeks with my kid out of the house.. it meant I could get my work done and go for rides around lunch. Now he's home it's almost impossible to ride again, cause he's home and my wife is trying to work too. And he keeps us stupid busy from the time he wakes up till 8:30-9PM at night.

[charliedid]

Ride more think less...

[colker]

Everything makes a difference in cycling. The more you feel good about your bike the better you will do everything w/ it. It´s not placebo but it´s not that precise anyway. Geometry does make a difference on descending but good all around road bikes take care of everything you throw at them. A well adjusted rim brake too.
Otoh there are lines to be crossed that separate performance from non sense around upgrades, bling, titanium, weight, carbon, made in italy, custom, bearings... it´s a long list.

[jtakeda]

Originally Posted by XXtwindad

So, just to investigate this further, you and I (according to your posts) were/are both timid descenders. Yet your Potts evidently gives you another level of confidence. Is it the discs? The bike geo itself? Or spinach

Im a timid descender off road--put me on a road and its go time

But the discs add confidence for offroad because I know ill be able to stop. I rode mt Umunhum--the gravel route up the road back and I was terrified by the lack of braking power on the canti bike i was riding

[colker]

Originally Posted by jtakeda

Im a timid descender off road--put me on a road and its go time

But the discs add confidence for offroad because I know ill be able to stop. I rode mt Umunhum--the gravel route up the road back and I was terrified by the lack of braking power on the canti bike i was riding

A V brake has enough power on any dry course unless you are on a 8in travel downhill bike and it´s a technical trail w/ big jumps.