mdcoram

For me it's all the cables dangling out of the hoods

SamSpade1941 

Aero levers fix that problem . I’ve had both in enough quantity now to know I’m not ok with non aero levers save for a rare collectible bike that should be left in a period correct configuration

ryansu

really narrow handlebars I find that on most of my keeper builds I upgrade the cockpit to Nitto or VO bars of 44cm or wider bars along with a technomic stem, I find that makes the ride very comfy. I don't mind non aero bars for cable routing but I do like the chunkier feel of Tektro brake levers- more comfortable for my hands.


upgrade to stem bars and levers

clubman 

....their tendency to breed like rabbits in my basement.

base2 

...Except for center-pull brakes. Especially the long reach ones. Compressionless Kevlar® reinforced brake cable housing such as Jagwire KEB SL does help a lot though.

Center-pull pads on steel rims just plain suck. Period.

Unca_Sam

Rust...

BFisher

...vintage grease.

KonAaron Snake 

single pivot brakes and weaker rims.

79pmooney

I raced in the '70s and did many long solo rides. Spent hours dreaming up ways to get my hands over the brake hoods. (Surgery to open up the "V" between index and middle finger? But that had its drawbacks. Loss of hand function. Getting to the brakes fast would be a challenge.) Didn't take this fantasy to re-working the levers themselves. But in the '80s, when I first saw an aero lever it was "I wanted these 10 years ago!"

Keeping the exposed cables to be "retro" or "vintage" or "correct". Not me. My bikes are to be ridden. If I could have gotten aero levers in 1977, I wouldn't have thought twice about it (outside of thinking of it as an unfair racing advantage that might get banned). Later, when Shimano went with the cables coming off the inside top of the levers for the shift housings, my thought was "why? Hidden is SO MUCH nicer." And patenting that setup so Campagnolo had to run the cables hidden? Thank you.

There is the one small advantage of the old housings sticking up in the wind that on one ever talks about. The health benefit. They saved riders from (usually bad) crashes. All of us back in the day al least once hit something we didn't see and jammed the crotch of our thumb hard against that housing. And as unpleasant as that was, it was not the classic launch over the handlebars. Just a dented rim and a sore hand.

Ben

nlerner

the people who post incessantly online about them.

mgopack42 

A$$ hatchet vintage saddles. I think my body requires a cut out , or it will squawk!

jadocs

….all the ones that I want in my size are owned by other people.

cb400bill

Cottered cranks. I hate working on them so much I gave my tool to the LBS. I won't buy a bike that has them. Nope.

Unca_Sam

I've thought, "why fight the Raleigh BB threading, just keep the BB and find a suitable crankset that's cottered." Then I remember that they're typically steel, and carry a weight penalty.

OldsCOOL

When anybody thinks they have a real gem of a find when digging out a schwinn varsity or huffy, asking obscene prices on Craigs.

Heavy wheelsets, stem shifters, dork disks, turkey levers, and the disk on the outside of the big chainring.

Andy_K 

Toe clips, single pivot or centerpull brakes, non-aero brake levers, friction shifting, 53-42 cranksets, freewheels...

That is, I love vintage frames.

riva

I do mups so bad brakes. Already steam rolled an erratic youth with one of my old tandems..

tyrion

Gearing not low enough.

Reynolds 

Steel rims.

gugie 

The original "cut out seat to protect my er#$*@$" was first made in 1890

USAZorro

Having to put good tires on a bunch of bikes can add up. Finding suitable brake blocks that don't cost more than the bike did can be kinda rough too.

canklecat

Hey, those protruding brake cables are a safety feature. They keep the bike attached to you when you go over the bars.

masi61

1) Narrow quill pedals with tabs at the end of the cage to neatly hold a toe strap.

I wanted to have my feet be snug as a bug in a rug with these - but I always got jammed on the outer part of my (D-width, not really what I consider wide) feet.

2) uncomfortable cycling shoes. I had the old Puma shoes where the stiff leather and shallow toe box just killed my feet.

3) Aluminum rims that would go out of true all the time.

4) Handlebar stems with no removable faceplate.

thinktubes 

One set of water bottle mounts.

Hajo

... except stuck seatposts. I have had to deal with two of them the past year and I will never ever buy another bike with a stuck seatposts.