Thinking about swapping out my 10 speed Shimano 105 cassette, 12/25 to a 11-34. Front is a compact 50/34.

Can I just purchase the long cage for my current derailleur? I'm wondering if I need anything else other then the long cage and a new chain??

Thanks,
Marty

Nope. You have it covered. Long cage and perhaps a longer chain.

Correct, as long as new cassette is still 10 speed. Realize the current generation of 105 (5800) is 11 speed.

If you don't cross chain you won't even need the longer chain and I'd try using what you have right now before getting a new derailleur. Cage length is more to do with derailleur capacity and longer cages really only are needed on triple setups. As long as you don't cross chain you won't need a new chain either. 50x28 uses more chain than 34x34 will.

Concerning the derailleur, I have two bikes with 11-32 cassettes with a quoted max cog size of 28. One of them didn't even need any b-screw adjustment right out of the box (maybe 1/4 of the way screwed in). The other needed pretty much max b-tension. Anyway, you should try what you have before buying a new derailleur.

You cannot use a long cage 10 speed 105 RD with an 11/34. You'll want a 9 speed shimano MTB RD

Great thanks a bunch guys!!!

It maybe a wrong question for this post but I don't understand the numbers on these cassettes so I'm wondering if they are correct for my group set. I have 105 5600 compact group set. Will both of them work and is there up and down's about them??

Any suggestions/links to either a 11/34 or 11/32 that's a good price for an old 2007 Cannondale compact 10 speed?? Good quality/price?? I don't need some supper lightweight over priced cassette.

https://www.amazon.com/Shimano-CS-M77...B003W9WS9W#Ask

https://www.amazon.com/dp/B003RLFVWQ?psc=1

Until he does cross chain on a ride and send his rear deraileur through his spokes. I would just do things the right way when upgrading not the cheap, easy, fast way

So are the links in the above post the right way???

Uh, why not? Because Shimano is ultra conservative in how they quote the limits of their equipment?

I have a short cage derailleur on two different bikes with quoted max of 28T and I'm running a 32 on both with no issues. One of them has TON of clearance and I bet I could run a 36T cog if I wanted.

Sorry its filthy, rode yesterday and haven't cleaned it yet, but here's a pic for proof. Quoted max of 28T, this is in the 32T. B tension not even halfway in.

up to 32 usually is fine, but like you noticed on your two bikes, some have clearance and some are maxed out. I had problems with my 5500 RD that has the same max with an 11-32 on my commuter and ended up have to swap to a deore RD after maxing out the b-screw.

I didn't say it WILL work. I said try it before spending money. How is that even debatable?

If he's buying a new RD, then he should just buy the one that works for sure. You simply won't have enough capacity with a short cage RD for a 50/34 11/34 combo, even if it clears the 34t, and sizing the chain for it to work forcing you to not use the 50/30-34 combo without exploding your drivetrain is simply not a good suggestion IMO.

I get the impression that most of this forum is cheap asses. If I suggest anything but Walmart level bikes, people jump down my throat because those parts "aren't necessary". I honestly thought I'd get a gold star next to my name or something for suggesting a way to possibly save money

It's really easy to try my suggestion in the work stand and order the other derailleur if it doesn't work. WORST CASE he ends up where he was going to start anyway. Best case he saves $50+

sure, but responses should be based on the assumed level of understanding of the OP. The person I would have suggested to try this to would have phrased their question very differently with a lot more detail and understanding. Time is money and if he's having a shop do it, he's going to waste more money to have them install everything twice and tune it. I simply wouldn't push a short cage RD with a 29T capacity to 39 for a normal type of rider that wants to be able to shift into all 20 gears without something bad happening. If you size the chain short to work in the 34x11/12/13, then the 50x30/34 won't work, and if you size it long then the 34x11/12/13 will go slack and possibly jump off chainrings and cause a crash. I probably shouldn't have said wouldn't work in my initial post, but added a caveat that my solution would work for sure.

Yes my knowledge level is not great but I’m planning on putting the new cassette on myself. (That’s why all the help is really appreciated)!

(I have two questions)
1. So what I’ve gathered here is you cannot (JUST) replace the plates cage parts, is that correct? (see pic).
2. Also can someone tell me if these will be ok/correct for a Shimano 105, 5600 group set? Or provide me correct cassette/link. - Here’s what I’m looking at but I don’t understand the numbers.
Amazon.com : Shimano XT CS-M771 Bicycle Cassette (10-Speed) : Bike Cassettes And Freewheels : Sports & Outdoors

OR

Amazon.com: Shimano HG81 10-Speed Cassette (11-34T)

Thanks a bunch guys!!

Just buy a long cage Shimano Deore derailleur. They will work with a road setup.

you also need one of these https://www.amazon.com/Shimano-RD-M59...ear+derailleur
and most likely a new chain

Bad advice. Cross chainging happens every once in a while.
Not worth the risk.

This is a 9 speed derailleur, am I not seeing the 10 speed option??

Do they make a 10 speed cassette in a 11-30 or 11-32 configuration that's a good quality and fair price like 105 components? If so please supply a link. That would help a ton! I'm trying to get a cost for a new cassette and derailleur.

https://www.sram.com/sram/road/produ...-1050-cassette

And....

Shimano 105 5701-GS 10-Speed Medium Cage Black Rear Derailleur

These work very well together and give you what you are after for the price you are after.

I personally run this setup and it is great.

Yes you can. Very easily I may add.

The "Shimano 105 5701-GS 10-Speed Medium Cage Black Rear Derailleur" is factory rated for "32t Max Low Gear when used with double crank 10-speed"


It easily puts a chain on a 34T cog with room to spare.


The last one I put together I set the chain so it cleared the front jockey wheel by about 5mm when slack (34T/11T) and I could have taken out 2-3 links and still would have easily had enough chain for the 50T/34T.

Tuning an FD to allow cross-chaining big/big and small/small with no rub noise is the hardest part.

He does NOT need a long cage. He needs a medium cage AT MOST.

Yes, It is a 9 speed derailleur, but 9 and 10 speed cassettes are the same width and the derailleur works with both.

The Sram 1050 cassette is a great piece at a great price.

I made a similar swap a month ago. I couldn't find a Shimano cassette in 11x36, so I went with the Sram cassette. I went with the Deore M591 long cage rear derailleur to make sure I could clear the 36T and take up all the excess chain that is generated in a 50x34 double with an 11x36 cassette. I've heard that short cage derailleurs can work with 32T cassettes and medium cage with 34T, but I didn't feel like taking the chance of damaging a derailleur, hanger, and spokes if it went really badly.