noglider 

What kinesthetic illusions have you observed? What kinesthetic illusions might exist?

Examples:

Your bike goes faster after you clean it.

An aluminum fork (of typical steel fork dimensions) makes a harsh ride.

A fixed gear requires less pedaling effort than a freewheel.

Hudson308 

Pedaling effort is lowest on the middle freewheel cog.

Red bikes are faster.

masi61

Sloping top tubes can make visualizing how bunched up (or stretched out) a person is, confusing.

Roamer2

Hill increase in length/steepness in direct proportion to how close to the top you are.

thumpism 

The older I get the faster I was.

JohnDThompson 

I ride faster on warm, sunny days.

RobbieTunes

I can relate.

RobbieTunes

It's easier to ride some routes backwards.

RobbieTunes

Pulling is easier than pushing.

52telecaster

my 4 cross wheels are more comfortable..... it may be true but i am sure i cant tell.

squirtdad

some how the slight uphill on the way out is still a slight uphill on the way back

Chombi1 

Staring at your bike computer while riding makes you get in the miles faster.
Thinner tires are faster.
Your first leather saddle will break in before your butt does....
You can always drop a guy who's riding an MTB...
Those cute and pretty podium girls just can't wait to hug and kiss the winners in a race!
The badger must be always mad at everybody.....
How can an all American guy like Lance Armstrong ever lie to the world??.....

tkamd73 

There is always a headwind!

Lascauxcaveman 

If you ride as fast as I do, sure.

Drillium Dude 

A 56cm frame is the basis for a perfectly-proportioned bike. And as everybody knows, perfectly-proportioned bikes are fastest.

DD

stardognine

LOL, maybe that's my problem, too? 😁

It's always faster going down the other side.

obrentharris 

-Tandems are slow up hills.
-A properly designed bike will act like a giant spring, storing up energy on the downstroke and releasing that energy on the "dead" part of the pedal stroke as forward motion.
-Red bikes are faster.
-A slammed stem will always make you go faster.
-Deep section rims will help a 'cross bike steer a straight line through mud.
-(Fill in any name from the pro peloton here) can't climb.
-(Fill in any name from the pro peloton here) has a weak sprint.
-The toast will always fall on the floor butter side down.
Brent

Chombi1 

Sex is a bad thing to do, the evening before a race.....
Women love guys who shave their legs.....really!
Nobody puts weird stuff in bottles in feeding stations....
Yeah, buy those mesh cycling shoes a half size too small, they eventually will conform to your foot perfectly!
Splatter bar tape is cool as they look like sophisticated abstract paintings...
They never will put disc brakes on road race bikes.....
Campagnolo always knows the best way!
Euro made C&V bikes are the fastest!
All bonded framed bikes eventually asplode to smithereenees and their frame tubes will spear you dead before you hit the tarmac with your face!
Tubs are not worth the trouble....

gugie 

Not an illusion! Vector analysis of the vast majority of wind conditions proves this to be correct.

stardognine

And I bet it's especially pronounced, on yellow bikes (really the fastest). 😁

Hudson308 

Leather saddles are more comfortable.

Lugged frames are stronger (see avatar).

Only steel is real.

Reynolds 

20 tires are too hard, 25s are slow. 23 are perfect.
Campagnolo has a better feel to it than Shimano.

canklecat

Those may not be illusions.

My '89 Centurion Ironman has significantly more drivetrain drag than my hybrids with long cage rear derailleurs.*

I didn't notice this for awhile, until I was doing chain maintenance on all three bikes one day. I noticed when spinning the cranks backward to run the chains through a shop rag there was a lot more resistance in the Ironman's drivetrain. Particularly in the two largest rear cogs.

It's due to the excessive spring tension in the cage pivot of the Suntour GPX rear derailleur. Unlike some derailleurs, it's not adjustable as-is. I'd need to drill a hole to accommodate a lower tension setting for the retention finger of the cage pivot spring.

If I press just lightly on the cage to artificially reduce the tension, the drivetrain spins almost as freely as my other bikes.

So it's possible the effects you or other cyclists think they felt with fixies and single speeds might very well be real, at least with certain rear derailleurs. In the case of my Ironman with Suntour GPX, I'd guesstimate it's costing me the equivalent of a few watts. Roughly enough to offset any gains from better tires.

*(I've described this at length in other threads so I'll just summarize: Yep, I've checked every possible cause. Everything. Whatever you can think of, I've checked it, including stuff other BF members suggested back in the autumn when I posted about it. It's the rear derailleur cage pivot spring tension. I have an older Shimano 105 RD to try out, after I clean it up.)

ThermionicScott 

Not specifically a "kinesthetic" illusion, but after looking at C&V bikes for years on this forum, the cogs on my bikes loom large in my mind. A 26T looks like a 28T, a 13-21T still looks wimpier than it does when it's on someone else's bike, and it bugs me. Cog size dysmorphia?

noglider 

When I say "illusion" I mean falsehoods that we experience. And I don't mean axioms or expressions of Murphy's Law.

There was recently a discussion somewhere on BF about whether going downhill on a fixed gear could require less effort than coasting with a freewheel. Some people it does. That's absurd.

Four-cross wheels do not feel different from three-cross wheels. There is a lot of folklore, as Jobst Brand put it, about how wheels work. If there is a difference in radial stiffness between 4x and 3x -- and there isn't -- the difference would be overshadowed by any springiness in the tires.

We convince ourselves that these things exist because we have reason to.

And some things are hard to determine because they are hard or impossible to measure. It is certainly hard to do a blind comparison between various bikes.