Moisture

I'll start.

Original chain was very stretched out and worn out. Mix and match of several different (9 speed) chain types. Didn't feel too great. Friend replaced chain with an 8 speed. Was better, but never felt right. Ended up putting on a KMC 9 speed chain the other day; what a difference. the drivetrain feels brand new. Smooth, quiet, significantly better power transfer, much better shifting. It even goes around corners faster and smoother while pedaling. Very profound improvement.

Go!

shelbyfv

Is it an upgrade when you put on the correct part? Not surprised it works better than before.

veganbikes

The best way to improve a bike is with high quality cables, housing and brake pads and good stiff brake shoes. It is cheaper than say a new caliper or new levers or what have you but can make a world of performance difference. Of course as well replacing any worn items will be helpful so in your case new chain and cassette in the proper number will greatly improve shifting.

DorkDisk

Well-built wheels

msu2001la

New cables and bar tape are my favorite refresh.

ofajen

I could be contrary and suggest conversion to SS. 😊

But seriously, tires.

Putting fast rolling tires (Compass, now RH, RTP) on my 26er MTB was quite a revelation. It meant that I could ride big comfy tires on crushed stone trails and gravel and only concede an average of about 1/2mph (or less) to the lighter Schwinn running 700x32.

Not sure how many wanna go there, but perhaps in second place I’d put riding with Albatross-style touring bars. Maybe affected by riding SS since I spend so much time standing up on climbs and descents. But it is a surprisingly effective cockpit for a lot of riding, assuming you wrap and use the entire bar. No low crouch, but a lot of different sitting and standing postures with a bar that extends about 9 inches front to back and has a mildly curving forward section that can change height, width and angle for hand location. Worth considering if you ride straight bars and your hands hurt or if you have drops that never get touched.

Otto

tntyz

+1 for tires.
Recently replaced stock Bontrager R2 Hardcase Light with Continental GP 5000. Smoother ride, better handling - nice!

genejockey 

I recently refreshed the Battaglin MAX I built up in 2007 from an early 90s frame. New bar with shorter reach and drop (not getting any younger nor more flexible), new 12-30 cassette and medium cage rear derailleur (still not getting any younger), new chain, touched up all the chipped paint, new old Look pedals, new cables and housing, new tires, and of course new white bar tape. Had my LBS align the rear hanger. Took it out on Friday and I'm in love again! Scored numerous PRs on segments I've ridden over 100 times. Totally worth the time and expense.

bargo68 

cheap: tires
spendy: wheelset and tires

twowheeldesign

Another vote for tires and also an appropriate seat for your butt/riding style.

I rode my old seat which didn't agree with my rear end for far too long. Getting a good, correct size seat made the subsequent rides feel like an entirely different bike!

burnthesheep

Ignoring "as it should be" repairs of broken things, or non-functional things:

-saddle: it probably came with the bike because it was the most generic and affordable shape for that bike the company could stick on there. Get one that your bum likes.

-bar tape: same as for saddle.....usually it is something fairly generic, not colorful or matchy, maybe not most comfort or features. Customize a touch (or a lot). Get more comfy.

-tires: new or old bike....if you've been on slow/tired/puncture prone tires.......get the good stuff......better ride, maybe faster too

I consider that the "refresh" stuff. Wheels? Meh. That's "upgrade".

I'm getting some bar tape today. I have cable housing and cables sitting ready for the other bike.

This is a bit silly..........but I replaced the plain metal colored brake "noodles" on my road race bike with black ones. Dunno. I needed them when I ran new cables anyway and it was the same price. Why not.

Koyote

Bar tape. There's no cheaper way to make your bike look 23.8% better.

Rolla

I second veganbike's cable recommendation. Housing is about two dollars a foot and inner cables are four bucks each, so for less than $30, you get dramatically better shifting and braking. Invest in a good pair of housing cutters, and it will pay for itself.

And replace your chain a couple of times a year. I don't even check mine for wear; it's just a scheduled maintenance item.

Ironfish653

The “easy money” is on tires and brake pads. Both are easy to change, and you definitely notice.
Grips/Tape and saddle, too, although good saddles are not always inexpensive, and sometimes it takes a few tries to find the right one.

Changing the handlebars; wider, more sweep, flares, etc. can also make a huge difference, but it’s a bit more of an involved project.

SurferRosa

Love a new chain.

70sSanO

Since my bikes are older, and 3 of the 4 were frame up builds, and have been upgraded over the years there are a number of choices.

Probably the best was an overall drivetrain change in going from a double crankset to a triple on my road bike and installing mtb derailleurs with a wider range freewheel.

It basically gave me the same as the double and added a climbing inner ring. I have since swapped out the wheelset with a cassette, but the foundation was already there.

John

Pop N Wood

Personally I like going into my parts bin from time to time and randomly change parts on my bikes. Gives me quality time wrenching and lets me experience something new.

I need to start painting bikes next. Never been a big advocate of cosmetics, always focused more on how well things function. Keep thinking I should do a show build.

Thomas15

And yet we have a recent thread here somewhere on this forum where posters batted around the virtue of replacing only the inner brake and shifter cables, retaining the outer housing to save big bux.

Phil_gretz

The best upgrade that you can make for your bike is to give it to a stronger rider. The bike will experience immediate results.

Bill in VA

Tires are the quickest and easiest. The change from the OEM Vittoria Randonneur 28mm tires, an incredibly numbing, sluggish tire that initally made me doubt my decision to buy the bike, to a set of 28mm Continental GP4000SII was an incredible upgrade. Successive upgrades to Rene Herse (then Compass) 28mm and then 32mm tires were each an upgrade, but in a much smaller increment.

Then the other biggest change for me (but much harder) was losing 35 pounds of road-hugging weight by diet and riding.

Dirt Farmer

Wheelset and carbon bars, IMHO.

shelbyfv

^^I think they are investigatingMore reports may speed things up.

Germany_chris

Koolstops, leather tape/grips/saddles, supple tires

canklecat

Tires make the biggest difference on my bikes, in speed, handling and comfort. Usually the first thing I change on any new-to-me bike.

Tubes also. Latex tubes are more comfy on rough chipseal. Dunno if they're faster, I'm not fast.

Bar wrap. As I get older I need thicker, cushy bar wrap. Sometimes I'll double wrap, with an old inner tube as the base wrap, and a better looking "cork" or other cushioned wrap over the inner tube.

Saddle. I have a box of saddles that seemed comfortable 25 lbs ago, but after losing weight I switched to narrower, less padded saddles. Subject to change at whim and gain/loss of weight.

Can't say I've noticed any differences in chains, assuming they're the correct size and not worn out. I've dabbled with all kinds of lubes too and didn't notice any difference in speed. So I go for whatever makes the least mess.

The Chemist

My favourite upgrades that I've done:
1. Converted flat bar to drop bar, including brifters. More hand positions, more speed. Well worth the effort and cost.
2. Converted to a 1 x 9 (bike was originally a 3x9, then went to a 2x9, and finally decided I wanted to do away with the front derailleur entirely). Smoother and less mechanically complicated. Looks better too.
3. Specialized Armadillo tires. Very nearly puncture proof. Have had one flat tire in the 4+ years I've been running these tires.