I have a spare full-time indoor bike just for the trainer.
Looking for 2 sets of advice - whether I should abandon my current setup and go for a cheap new bike, or whether I should just go for full/partial new groupset on the current frame.
If the latter, the bigger question is how creative I can get with the drivetrain.
Current setup is a 2nd hand Specialized Allez on a Kickr Core.
Tiagra shifters, crankset (50/34), rear derailleur. Claris front derailleur. I think either 105 or Ultegra cassette (11-34) - whatever I could get at the time.
The ride is not great, not smooth, and it is prone to dropping the chain when I’ve been on the small ring and moving back up. Its ok, but has never felt smooth on the trainer as much as it does if I try another of my bikes (hence, not a problem with the trainer). I use the appropriate spacer for 10sp on the trainer hub.
The Allez if I put back on its original wheels, feels fine on the road. Hence I’d thought it was a matter of indexing the gears, but I took the whole kit to a store for that, who spent an hour on it and told me it was fine - I’d just some chain rub on front which I knew about (either very top or very bottom gear rubs on the front derailleur chain guide a touch, regardless of screw adjustment).
Also no matter how much I cleaned the bike when purchased, and put on new cassette & chain, it still has dirt and residue on the drivetrain meaning its black and minging - which in theory ought to be avoidable with a purely indoor bike.
So I find myself considering a new bike, for fresh drivetrain, for clean drivetrain, and hopefully start fresh and get a smooth ride from it.
I can get a Specialized Allez for £650 just now with Claris, or £989 for the Allez Sport with Sora.
Trek Domane same specs for about £700 / £1,000.
Decathlon options, at £850 for a Triban RC520 with 105 seems great, but my size hasn’t been seen for a while (6 months+).
50/34 and 11-32 gearing sees me lose a bit off the climbing gears - currently I have 34:34 for when I face the Alpe du Zwift.
I’ve also never had less than Tiagra on a bike in years. I borrowed a bike with Sora on holiday a few yr ago and it was rough shifting, but the bike wasn’t well looked after so had a few issues.
Should I just get the new cheap bike and accept only 8 or 9sp gearing and less gear ratio? Will I notice significant drop in shifting quality?
So then I wondered - the frame, stem etc is fine. Possibly even the shifters are salvageable (though they’re old and scuffed) and I don’t care about wheels or brakes. A new drivetrain or even partial drivetrain is probably the cheaper option.
But then I further considered I could get creative with gearing. I’ve always felt on Zwift I could power a higher gear. I struggle more with leg speed but I’m a big guy (102kg) and for years on the road I used to ride what I think was referred to as the “pro’s compact” - a 52/36. AND I ride 170mm cranks on my current road bike so changing to get close to my current main outdoor setup makes sense I think.
So I was then trying to figure out, if I bought a Tiagra or 105 52/36 crankset… could I then buy the Medium/Long cage rear derailleur and put an 11-34 cassette on the back?
Giving me 52:11 4.73 to 36:34 1.06 gear ratios, new/clean drivetrain and 10 speed?
I’ve been to 2 bike shops about this. One said yes, one said no.
The guy who said No, said it was due to 52/36 and wide cassette exceeding the Tiagra rear mech maximum tooth count (though I’d never have reason to ride in that gear, and he specified Tiagra, it occurs to me maybe a 105 mech has wider range?)
So ultimately its new bike or new groupset… and if the latter, whats the best gear ratio setup I can get without paying silly money?
Bottom bracket has “BC1 27x34” printed on it which I think means its a BB-RS500 cartridge unit, I’m guessing that would need to be replaced.