Scrib4lex

All things being equal - parts functioning as intended - which part of a groupset do people think would yield the biggest jump in performance/user experience if upgraded?

So, I’ve been toying around with the idea of upgrading some components on my kid’s bikes.
One is running a 2018 model year Sora 9sp - the other a 2017 model year Claris 8sp.

I just successfully resurrected the Dura Ace 7800 groupset on a bike I bought for myself. Went from misfiring around 50% of the time on the rear upshift, and 75% of the time on the front downshift (inside shifter paddle in both cases). And now that I’ve gotten past some initial trepidation about bricking my bike by working on it and have some baseline amateur mechanic confidence, I'm feeling ready to tackle some other projects. Long lead in, but here’s the meat of it.

1) - FRANKENSETS - How do people feel about mixed part groupsets? And what are the pitfalls of even considering this?
I have a baseline understanding that chain sizing, cranks, cassettes need a bit of coordination in order to run properly and even more to run optimally. I'm just starting to understand where you can “fudge” a bit - like a 3 position shifter can work on a 2 bite crank if you set it up properly. But I am still very green to the hobby and have a lot to learn.

With that in mind - what are peoples thoughts on this in general? I've seen some very cost effective components for sale online (FB marketplace/ebay) like 105 STI's, or Rear derailleurs - obv taking a bit of a gamble on condition - but feels like quite a bit can be gleaned by visual condition...

2) - If you were going to pick one part of the groupset that was most vital to shifting and feel - what would it be? The obvious answer seems to be the STI - the shifters themselves - but what about the rear derailleur? Does anyone think that swapping to an older but higher quality (in good condition of course) rear derailleur would be a noticeable upgrade in shifting performance? or is that really just a limit defined spring mechanism that has little to do with the overall feel of a groupset in action? I've yet to work on/replace a bottom bracket, but maybe thats a high value item in terms of performance... Maybe all of this is just plain silly to even be contemplating - back to question one about mixed part/series groupsets -

Real life scenario: First thing my “overactive wanna work on my bikes mind” is thinking - Take an old Dura ace 7400 8sp rear derailleur and drop it into my kid’s 8sp Claris groupset bike… I've seen a few of these on FB market locally in super looking condition for like 20-30 bucks...

Kai Winters

You can mix and match, to some degree, but you have to be aware of the rear derailleurs shift/movement arc...this has changed over the years as they evolved...but in general you can put a Sora derailleur on a Claris drivetrain and expect it to work pretty well if not just fine. You could do the same using the very nice Tiagra derailleur.
You can upgrade the 105 rear derailleur to an Ultegra without worry as long as they are both the same number of gears.
To me the most important part...other than the safety aspect of the brakes...is the rear derailleur. It performs its task perhaps dozens if not a hundred or so times per ride and sometimes under a lot of load and sometimes cross chained.
The current line of 105, Ultegra and Dura Ace...in the Di2 12 speed versions...are basically identical...they share the exact same electronic internals...the difference between them is finish and light weight...you pay lots more you get less weight lol.

You may encounter a problem 'dropping' an older model Dura Ace der on the Claris system...the shifting arcs may not be the same causing the rear der to not track the way the shifter is telling it to but it may...I don't know...
Good luck and keep us informed...

Scrib4lex

Kai Winters had not thought of the arc. And now come to think of it, i saw a video where a road biker who cut his teeth when the dura ace 7700 was the grail and was stull a die hard fan comped it to the current sora groupset to see if 20 uears of trickle down made the sora comparable. One thing i remember quite clearly, and can noticed on my 7800 groupset, is that the cassette has closer ratios to the steps. The sora cassette looks almost twice the size at the biggest gear.. i guess that prob translates to slightly different settings in the derailleur and the STI... Im gonna take a guess that the tigher ratios on the 7700/7800 also help with shifting smoothness since there is less travel or jump per shift. Could be why why my kids sora sounds so much harsher downshift when climbing as well..

From my personal experience the current Sora 9 speed isnt even close to feel and performance and experience of the dura ace 7800...

anyhoo, seems wise to try and keep the cassette, derailleur and sti in the same family or at least super close relatives...

Kontact 

I have found that even the cheapest rear derailleurs work fine. DA shifters with a Sora rear derailleur would not seem any different.

Cranks are big and heavy, so an upgrade of that part should contribute to both stiffness and weight savings more than most other components.

Shifters should be an upgrade, but I don't know how often they are, other than a small amount of weight.

Front derailleurs are definitely something money is well spent on.


BUT, there is always the "Ultegra effect", where the pro group is actually not necessarily as light or functional as the group one or two levels below. In the '80s Ultegra had nicer shifting and was lighter than Dura Ace, just as Chorus over C-Record. Force had a better front derailleur than Red. DA hydro levers were easy to crack, etc.

choddo

Shifters, no doubt. Maybe cables with those teflon coated ones. Rear mech - then cranks for aesthetics

The rough climbing shifts from your son could well be inexperience/ just not timing & easing off enough to allow the chain a little give. I always shift just before 12/6 o’clock when climbing, and only one gear at a time.

aliasfox

I think shifters and cables would provide the best performance benefit, especially if you're on older, non teflon coated cables or not on compressionless housing.

Crank/BB would provide the biggest benefit in weight, especially if going from an old cartridge BB (square taper, Octalink) to one of the newer two piece, hollow spindle designs. Depending on the rings, you may get a good improvement in shift performance, as well.

If the cassette’s not worn out, then any upgrade there would mean lighter weight or different ratios more suited to your terrain, but unless you're going from something that has no ramps to something that does, actual performance differences aren't likely to be huge.

There’s a difference in derailleurs, but unless you’re under heavy loads or going very high mileage, the performance differences aren’t going to be huge (some argue that 105 and Dura Ace mechanical derailleurs of the same generation are nearly imperceptiblly different), and you’d get more significant weight gains elsewhere.

Always make sure that whatever gear you're putting on has the same cable pull ratio as everything else you're planning on using it with. I don't know if 30yr old Dura Ace 8-speed will have the same cable pull ratio as Claris, for example. Also, 30 yr old Dura Ace may very well be worn out, so even if it does work, don't be surprised if it seems tired.

ScottCommutes

I don't know your kids or their bikes, but I suspect that letting them select fun colored cables would mean more to their enjoyment of their bikes than slightly different mechanical parts.

HTupolev

This is incorrect.

The amount that a derailleur moves laterally for a given amount of cable pull is often referred to as "actuation ratio." All Shimano derailleurs that are 9-speed and below (except for some very old Dura Ace stuff) share the same actuation ratio, so they can be swapped out without breaking indexing. So, you can change out Sora and Claris parts.
However, this isn't true for current-gen Tiagra. Shimano's 10-speed road components used to use the same actuation ratio as the lower-speeds stuff, but when they launched Tiagra 4700, they changed it to match the 11-speed road stuff. So you can use an older-generation 4600-series Tiagra rear derailleur with Sora or Claris, but if you try to use a modern RD-4700, it won't index correctly. (The same is true of GRX400: the rear derailleur matches the actuation of Shimano's 11-speed road components.)

bblair

Mid range new stuff works better than old top end stuff. Especially if it is old. I have a few 40-50 yo Campy Record der and they shift like crap compared to new Ultegra. But, they were great in their day.

Best bang for buck: new shift cables and chain. Definitely chain.

PeteHski

This^ and a new cassette if worn. Also a new BB if the old one is rough or creaking. Drivetrain condition is more important than the spec.

seypat

How old are the kids? If/when they hit a growth spurt the bikes will no longer fit them. Maybe put some new cables, housing and brake pads on. Don't mess with anything else unless it's not working.

Jughed

Assuming everything is in working order - chains, BB...

I've got a mix of everything - older bike with 9 speed Ultegra, new 105, franken bike with 105, Ultegra and Dura Ace, and a bottom tier Sram 1x on my cross bike. They all shift and perform well - the bottom tier Sram is bullet proof, it just works.

-Brake hoods top the list for me. The ergonomics of the contact point trumps everything. They all shift, with the 9 speed Ultegra having the best shifting of the lot - but the brake hoods suck.
-Then gear ratios.

eduskator

I dislike mix & match in general, for everything in life, so my opinion about this goes without saying.

I like to have as less brand on my bicycle as possible. I remember there was a thread here a few months ago about how many brands did everyone have on their bikes. results were interesting.

aliasfox

Ah, but the logos on my 9-speed Ultegra 6500 crank have been worn away by my heels, and the logoed plastic caps on my 9-speed Ultegra brake hoods are a fingernail's snap away from being lost on the side of the road - so aside from the rear derailleur, I could be riding a bike with a logo-less groupset!

Yan 

For mechanical groupset, the shifter by far.

SoSmellyAir

You already got the most important part, i.e., by referring to a "groupset" rather than a "gruppo". Bravo!

easyupbug 

Shifters for me.

wheelreason

Right rear brake pad...

Fredo76

Obviously, the bottle opener, and the corkscrew!

Shadco 

The pedals, without them you aren’t going anywhere.

PeteHski

Doesn't that apply to nearly all groupset parts?

Maelochs

Pretty much, no. Chain, maybe. BB. You have not drunk from the well of Fixed Gear, and are thinking like a sane person ........

eduskator

Cables? What is this prehistoric word?

eduskator

PeteHski

Ah, but the OP was clearly asking about shift quality and reliability. Pedals are definitely not very important for that.

I would assume the OP was not looking to delete any functional parts of the groupset!