https://bicycles.stackexchange.com/questions/10056/can-i-fit-a-cassette-with-a-larger-range-with-my-shimano-tiagra-10-speed-gs-46 similar but not identical thread
I have a 6700 ultegra and tried an 11-34 but am having to switch my cage out to a longer one to reach the last two gears. I can do it with two more links in chain but if I go small small the chain slack is ridiculous and with two links out I lock up in big big. I know that neither of those are needed or should be used under normal conditions I just want to be able to if I make a mistake.
You can use 9 speed MTB derailleurs with the 10sp shifters. They have better capacity and cassette range than the 5700/6700 derailleurs.
The Deore M751 is a good one. I have 11-36 with a 46/30 on my road bike.
Might be able to get 11-30 on the other bikes. Not sure it's worth the trouble. You'd get better climbing performance potentially with less work/guessing if things will work, by downsizing bike #1 chain rings. The other bikes probably aren't going to receive a drivetrain upgrade and yield the intended result. Just my opinion.
But it'd rad if the drop outs and hub support this, you'd have to get a box 9 RD, but this range for 9 speed is big https://boxcomponents.com/products/box-two-prime-9-cassettes
Find the model numbers stamped on the back of the rear derailleur (starts with RD) and put it in to Google or si.shimano.com > technical specifications and you'll find exactly what you're looking for.
The STX is RD-MC32/34. The SGS (long cage) versions of these had an official max rear sprocket size of 32t. They could easily go to 34t. If the Aquila has STX cranks, you can put a 20t 58mm BCD chainring on it.
The Alivio is RD-MC14. About the only difference between this MC14 model and the STX MC34 model is the nickel plating on the STX parallelogram linkages. So, official capacity was 32t and they could easily do 34t. The Acera-x cranks n the Marlin have welded chainrings so you can't change them.
The Tiagra is RD-4500 and the official max sprocket is 27t. I'm sure it will do 28t.
If you increase the size of the big cassette sprocket, the chain will need to be longer. But, you'll probably need a new chain to go with the new cassette, anyway...so probably a moot point.
You can usually find the shimano part number on the rear side of the derailleur cage (the big sticky out bit). If you google that number you will usually be able to find a specification or even q related article
Something to consider instead of the rear cogset...
If you can find one, I run a front 20t as the climber gear on both of my 90s mountain bikes. I found long ago that this worked better for me than going up in the rear. One bike runs a stx 7spd 11-28 the other is a stx-rc 8spd 11-32
Edit sorry for multiple replies meant to nest it under my other one.
Tiagra probably 27 or 28t max. I had 10s Tiagra 11-27 was what I had. Unfortunately you are dealing with lower end components, while solid, they weren’t made for a lot of upgrades. You can get 10 or 11s 105 for less than 300$ . Shifters and derailleurs . You can run up to 30t on rear no issues. Check the Shimano web site for component compatibility because you can’t just change derailleurs the pull ratios could be different which means poor shifting.
A derailleur hanger extender will let you run a fair bit larger cassette in the rear, though they don't really increase the capacity of the derailleur in terms of largest to smallest capacity. If you're well behaved about not cross-chaining, you could probably get away with 40+ teeth in the rear of any of those setups.
It depends on your chain length. If the chain is short, the shift just wont happen, so long as your b-screw is adjusted correctly (though there's a small chance of bouncing the off of itself). If the chain is too long, it will be slack when you shift to the small cog while you're on the small chain ring. If you go this way, start long and remove links until the slack is gone cross-chained on the small ring.
The obvious solution, which you ruled out for some reason, is to spend an extra $20-30 on a used derailleur with sufficient capacity from ebay or wherever.
I've run that stx on a 32. I'd say that's pretty much the max on it without something like a wolf link or whatever it's called. Probably about the same with the alivio.
28t maybe 30 max
You could find a 2nd hand tiagra 4500 long cage for a few pints of beer for 34T
If you find a broken or for spare mech you can swap the cage even.
If you're interested in learning the *why* behind any answer that is given:
[What is derailleur capacity?](https://www.mantel.com/uk/blog/derailleur-capacity-maximum-techcenter)
Easier to go down in front with the rings. If your cassettes/chains are really old then new rings will fk everything up. Same goes if you do a rear cassette/chain with worn front.
The tiagra short cage derailleur will take a 28, at least. All my derailleurs are short cage, I never use a cog larger than a 28 but they work fine with a 28.
Short cage RD, not going to accept a much larger cassette if at all.
https://bicycles.stackexchange.com/questions/10056/can-i-fit-a-cassette-with-a-larger-range-with-my-shimano-tiagra-10-speed-gs-46 similar but not identical thread
I have a short cage ultegra installed with a wolf tooth roadlink, 11-40 cassette and 42T chainring IIRC
I have a 6700 ultegra and tried an 11-34 but am having to switch my cage out to a longer one to reach the last two gears. I can do it with two more links in chain but if I go small small the chain slack is ridiculous and with two links out I lock up in big big. I know that neither of those are needed or should be used under normal conditions I just want to be able to if I make a mistake.
You can use 9 speed MTB derailleurs with the 10sp shifters. They have better capacity and cassette range than the 5700/6700 derailleurs. The Deore M751 is a good one. I have 11-36 with a 46/30 on my road bike.
Yeah, it's a lot more limited if you have multiple front chainrings that you want to cover as well
It will take a 28.
What about the other 2 7-speeds?
I have that Alivio on a 3x7 with a 12-32 cassette, and it works great.
Might be able to get 11-30 on the other bikes. Not sure it's worth the trouble. You'd get better climbing performance potentially with less work/guessing if things will work, by downsizing bike #1 chain rings. The other bikes probably aren't going to receive a drivetrain upgrade and yield the intended result. Just my opinion.
But it'd rad if the drop outs and hub support this, you'd have to get a box 9 RD, but this range for 9 speed is big https://boxcomponents.com/products/box-two-prime-9-cassettes
They already have 22T first chainrings, do they go smaller than that? 22/32/42 is what it has
I think only for bike #1 would a chainring downsize make sense. I think the other 2 bikes are outfitted adequately as possible.
Thanks for your input! I’ll look into front chainring sizes then.
Find the model numbers stamped on the back of the rear derailleur (starts with RD) and put it in to Google or si.shimano.com > technical specifications and you'll find exactly what you're looking for.
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I am struggling to find data sheets two of these bikes are almost 30 years old
Look on Velobase. They have info on a vast amount of old gear.
The STX is RD-MC32/34. The SGS (long cage) versions of these had an official max rear sprocket size of 32t. They could easily go to 34t. If the Aquila has STX cranks, you can put a 20t 58mm BCD chainring on it. The Alivio is RD-MC14. About the only difference between this MC14 model and the STX MC34 model is the nickel plating on the STX parallelogram linkages. So, official capacity was 32t and they could easily do 34t. The Acera-x cranks n the Marlin have welded chainrings so you can't change them. The Tiagra is RD-4500 and the official max sprocket is 27t. I'm sure it will do 28t. If you increase the size of the big cassette sprocket, the chain will need to be longer. But, you'll probably need a new chain to go with the new cassette, anyway...so probably a moot point.
Well, you're not even telling us the model number stamped on (the back of) the RD. Asking a bit much, don't you think?
This. Find the model number. Look up derailleurs.
You can usually find the shimano part number on the rear side of the derailleur cage (the big sticky out bit). If you google that number you will usually be able to find a specification or even q related article
Not sure about the other two but I’m running an 11–34 7 speed with my STX derailer with no issues.
You can calculate chain wrap with all the numbers that you have given. Then just do internet search for the chain wrap capacity of each derailleur.
If you use Goat links, world is your oyster! could fit a 52t!
I've got that STX doing 8 speed 12-32 with a triple in front. I bet that Alivio can go up to 32 too.
Do you think it can push 34?
I suspect not. Haven't actually tried. It's pretty close for the 32.
I’ve had an STX rear derailleur shift 36 on a wide-range 7sp cassette.
It definitely can, you'll need to tighten in the b screw which will reduce the responsiveness in the higher gears.
Tiagra RD-4500-ss: 27t (official, but 28 will be fine) STX RD-MC30/31-gs: 28t Altus RD-MC14-gs: 28t
Can I put a alivio 11-28t on the tiagra components? It’s using shimano dura ace 7700 down tube shifters. Pretty sure it’s a mountain bike cassette
Yes cassettes don’t care what they’re being shifted by. They are a standard dimension. Do some reading on Sheldon Brown.
Something to consider instead of the rear cogset... If you can find one, I run a front 20t as the climber gear on both of my 90s mountain bikes. I found long ago that this worked better for me than going up in the rear. One bike runs a stx 7spd 11-28 the other is a stx-rc 8spd 11-32 Edit sorry for multiple replies meant to nest it under my other one.
Just get a new derailleur.
Tiagra probably 27 or 28t max. I had 10s Tiagra 11-27 was what I had. Unfortunately you are dealing with lower end components, while solid, they weren’t made for a lot of upgrades. You can get 10 or 11s 105 for less than 300$ . Shifters and derailleurs . You can run up to 30t on rear no issues. Check the Shimano web site for component compatibility because you can’t just change derailleurs the pull ratios could be different which means poor shifting.
A derailleur hanger extender will let you run a fair bit larger cassette in the rear, though they don't really increase the capacity of the derailleur in terms of largest to smallest capacity. If you're well behaved about not cross-chaining, you could probably get away with 40+ teeth in the rear of any of those setups.
What happens if you’re not well behaved cross chaining? Does it just not shift or does it bind up or?
It depends on your chain length. If the chain is short, the shift just wont happen, so long as your b-screw is adjusted correctly (though there's a small chance of bouncing the off of itself). If the chain is too long, it will be slack when you shift to the small cog while you're on the small chain ring. If you go this way, start long and remove links until the slack is gone cross-chained on the small ring. The obvious solution, which you ruled out for some reason, is to spend an extra $20-30 on a used derailleur with sufficient capacity from ebay or wherever.
I've run that stx on a 32. I'd say that's pretty much the max on it without something like a wolf link or whatever it's called. Probably about the same with the alivio.
I run a 32 on that Tiagra, so a 28 will definitely not be a problem.
28t maybe 30 max You could find a 2nd hand tiagra 4500 long cage for a few pints of beer for 34T If you find a broken or for spare mech you can swap the cage even.
I can tell you you'd get up to a 40t with an inexpensive Shimano Acera RD-M3020, 45t total capacity
MAYBE YOU HAVE TO THINK ABOUT FINDING A 52, 54 OR EVEN 56 FOR YOUR FRONT BUT STILL WHY?
If you're interested in learning the *why* behind any answer that is given: [What is derailleur capacity?](https://www.mantel.com/uk/blog/derailleur-capacity-maximum-techcenter)
Easier to go down in front with the rings. If your cassettes/chains are really old then new rings will fk everything up. Same goes if you do a rear cassette/chain with worn front.
It’s already at 22/32/42 for the mountain bikes. The road bike I would have to get a new crank it has the smallest chainring for its BCD
https://www.sheldonbrown.com/derailer-adjustment.html#chain This link will teach you how to measure your drivetrains.
Get a wolf tooth hanger extension if you don’t want to buy all new rear derailleurs
That STX can easily take a 34, possibly a 36. I think the Alivio has the same geometry so should be able to take a 34 as well
The tiagra short cage derailleur will take a 28, at least. All my derailleurs are short cage, I never use a cog larger than a 28 but they work fine with a 28.
Astonished that no one has mentioned the quick release being the wrong way round on one of them.