Cost effective groupset upgrade for trainer only-bike

[ediryppah]

So I bought a mostly broken down bike for extremely cheap to put on the trainer. I cleaned it up, fixed the drivetrain as much as possible, stripped it of breaks and such and it works... fine, not great. It's complete Tiagra 4600 and apart from everything being pretty worn I hate the ergonomics of the 4600 shifters.

I'm looking at a cost effective way of upgrading the drivetrain. Mostly doing Zwift (with virtual shifting) or workouts in ERG-mode, or turning off ERG-mode for VO2 and threshold efforts. Thus, I don't find the need for 2 chainrings, I'm never in small. As it's indoor only, weight is not a concern at all. Shifting quality really isn't either, as I rarely will shift.

Looking for:

• Bottom bracket
• Crankset (or just a new chainring for the Tiagra crankset I guess)
• Rear derailleur
• Cassette
• Shifters

Anyone done anything similar, or have some good ideas?

[SillyMochi]

If you're only using it on Zwift and even with virtual shifting, why not forget about the cassette and shifters entirely and just use the Zwift cog instead?

[TidyDinosaur]

Or get some cheap second hand 105 R7000 or ultegra R8000 11 speed shifters. I also have the sensah mechanical shifters and they are a lot smaller and less comfortable than the Shimano ones.

And yes ,if you use it like me only in ERG mode, even a full cassette is overkill. You could just set it up single speed

[ediryppah]

If you're only using it on Zwift and even with virtual shifting, why not forget about the cassette and shifters entirely and just use the Zwift cog instead?

If you're only using it on Zwift and even with virtual shifting, why not forget about the cassette and shifters entirely and just use the Zwift cog instead?

I do Zwift for just riding around or racing, but when doing workouts I do them on a phone app or on my Garmin and always turn off ERG-mode for efforts >threshold (because that's what you're supposed to do, or so I've heard).

using the small ring is less noisy than the big one, at least on my machines. It assumes ERG mode / virtual incline though, otherwise obviously you spin out.

on alix,
BB is 10-12 eur.
crankset can be had for <40 eur w rings, i think, if you buy the cheapest, heaviest ones. Fairly good one costs 45 (crank & rings) (I recently specced that on 2 bikes for friends, perfectly legit stuff).
sensah mechanical w mechanical brakes, i've used, it works. A friend is very happy with the ltwoo R9 mechanical, hydro, i suspect they do the same, cheaper, mechanical / mechanical. If you go 10 speed or less, it gets really, really cheap, but idk if it's as good as the 11s stuff i'm talking about, i simply do not know.
11s cassette is 20-25 eur.
All shipped to Europe as of a few weeks ago.

Sensah is an option for sure. Was looking for 10 speed stuff but reviews and stuff are few and far between.

[acedeuce802]

Does virtual shifting not work for Zwift workouts in resistance mode?  I've never tried it, so not doubting, genuine question.  I know that in ERG mode, shifting will change the target power, and in free-ride mode, it'll act as a gear change, but not sure about resistance mode in a workout.  Zwift cog or single speed with a tensioner would be really reliable and simple, if it works for your setup.

I use Sensah 11 speed on my trainer.  It's been working for several years and a few thousand Zwift miles.  I routed the cables externally with really big bends to minimize cable wear and friction.

[ediryppah]

Does virtual shifting not work for Zwift workouts in resistance mode?  I've never tried it, so not doubting, genuine question.  I know that in ERG mode, shifting will change the target power, and in free-ride mode, it'll act as a gear change, but not sure about resistance mode in a workout.  Zwift cog or single speed with a tensioner would be really reliable and simple, if it works for your setup.

I use Sensah 11 speed on my trainer.  It's been working for several years and a few thousand Zwift miles.  I routed the cables externally with really big bends to minimize cable wear and friction.

Yeah it would work. You can just turn off ERG and virtual shift. Virtual shifting is amazing on the trainer, but Zwift is kind of expensive to use year round and if I'm just doing a workout I usually watch bike racing or something on the screen.

[Tilmanstoa5ty]

Okay i just finished my indoor setup and faced the same challenge so hear me out:

- Get a single speed conversion kit from aliexpress (most you can find are for mtb hubs which means you need an additional 1.85 mm spacer to fit it on a road hub)

- get a chain tensioner to keep tension on the chain (this way you don’t need a rear derailleur)

- get something to virtually shift, here you have two options:
Option 1: you want to spend money —> get the zwift play. Gives you virtual shifting and all the other fancy stuff
Option 2: you don’t want to spend money —> get the qzfitness app (you can also use this app to use your zwift play with mywoosh for example but that’s another topic)

- all steps done? You have a working indoor setup without the need to spend a ton of money on zwift cog. The single speed cog is a lot sturdier than the zwift cog. I did the calculations and single speed conversion kit, chain tensioner AND zwift play came out cheaper than zwift cog

If you have any questions feel free to ask me

P.S. You can use the app i mentioned for all sorts of stuff and controls on your trainer. You are NOT limited to zwift using it. I haven’t really used it a lot as i just got the zwift play but definitely check it out as an option.

[SillyMochi]

I'll jump on that "ghetto virtual shifting" train once somebody figured out how to remap Chinese brifters like an ER9 to work with it. One day ... maybe ...

[bichler.bua]

My setup is three years old and while I still use it, I prefer to ride outdoor - meaning I do not spend a lot of effort optimizing my indoor setup.
I am running Rouvy on an Elite Direto XR, bought an used aluminum frame for cheap and installed a Sensah groupset.

[Tilmanstoa5ty]

Please say more!
I am very interested in the following:
using mywhoosh or other free software (I'm allergic to subscriptions, especially when the service/soft sucks), getting virtual shifting using ideally physical buttons, or at worst, digital ones. I would consider using the zwift buttons if it's clear they aren't keeping my hostage on zwift. I'd much rather use something platform agnostic though.
The stuff needs to "just work" though. I tried using gta bike mod a few times, it drove me crazy. It's essential that you can just on the bike and start riding without having to do 100 steps.

Benefits: using the small ring is more silent than the big ring, while not spinning out, which means i'm not limited to ERG mode. And presumably, i could set up a huge range of virtual gears, like 60-11 down to 34-36, for eg.
Opens up the idea of having an indoor bike with no groupset, which appeals to me aesthetically.

The developer made some tutorials and is pretty active on reddit, since my first year of zwift is still running i haven’t tried out a lot of this stuff myself. But you can find most of the information online and if you have further questions the developer invites you to message him. This is a pretty small project and not some huge company you can’t get in touch with fortunately.

Here are some ressources:

https://www.qzfitness.com/

https://youtu.be/mJl2zkQ2SuA?si=vFtCT3j2ZEffkGYu

https://youtu.be/X3Q2WjbqMJo?si=IkINOUI7Q9_20Gl3


I think once you set it up as you need it will „just work“. I will probably switch to mywoosh once my zwift subscription ran out and then i will try all that stuff out myself. But the features already look promising. And it’s still actively developed and will probably only get better. Oh and it’s 6€ so my „you don’t wanna spend money“ was actually wrong but i think 6€ one time is pretty fair compared to any subscription.

[SillyMochi]

Looks solid. Thank you for sharing! I'll bookmark it if I ever build a dedicated trainer setup.

On a sidenote: that dashboard gives me anxiety 
(I know it's just to showcase what metrics you can display and probably nobody will ride it like that)

[Tilmanstoa5ty]

Looks solid. Thank you for sharing! I'll bookmark it if I ever build a dedicated trainer setup.

On a sidenote: that dashboard gives me anxiety 
(I know it's just to showcase what metrics you can display and probably nobody will ride it like that)

It's fully customizable so i'd probably delete everything apart from the virtual shifting. UI wise it's certainly not the nicest app but as long as it gets the job done i don't mind.

[Crash217]

or SRAM blips! Or better yet, open source blips, the hardware should cost 3 bucks and the signal that goes click click can't possibly be rocket science.

I'm honestly shocked no one has yet sorted out how to hack sram or shimano groupsets and started showing tutorials on unlocking blips or creating your own for every thing.  I mean, people didn't waste any time jail breaking phones, firesticks, automotive/powersports ecu systems etc etc etc.  I think it just proves how niche the bicycle industry is that someone hasn't figured out how to backdoor into the electronic groupsets to make them play however the end user wants them to.

Maybe with slightly smaller, less proprietary companies like  WheelTop, LTWoo or Sensah it'll be more feasible? 

[SillyMochi]

Well, actually ... Shimano DI2 has already been hacked: https://www.cyclingnews.com/news/shimano-di2-wireless-hacking/
Full paper if you interested in the details: https://www.usenix.org/system/files/woot24-motallebighomi.pdf

And honestly, I'm not surprised. Just look at the DI2 app's look and functionality. That thing reeks of shoddy coding. So, I don't think it should be too hard to "jailbreak" - but like you said, the user group is just much smaller. Or maybe more honest - errr yeah, forget about the last part 

[srf0638]

Necro'ing, but I wonder if any of the Chiners have a ~Zwift Ride competitor (belt drive? bearclaw/adjustable cranks?) in the works....