Cassopher

I’m running a 105 groupset on an Allez Sprint and was given an Ultegra cassette and they are both 11 speed. Is there anything that I need to do to the derailleur or cables, or is it completely interchangeable? Can the new cassette just be slapped on? TIA

Bob the Mech

What 105 cassette was it (11-28, 11-30 or 11-32 teeth)? And are you replacing it with the Ultegra with the same spread or smaller?

tyrion

You might have to adjust the B screw:

Cassopher

The 105 cassette is an 11-28 and the Ultegra is an 11-32.

Kapusta

You may need a longer chain.

Bob the Mech

If you have a short cage rear derailleur and you fit the 11-32 things will get rather tight in the chain department. Short cages will accommodate 11-28 to 11-30. If you have a medium cage derailleur there will be a little more wiggle room chain wise. Medium cages accommodate 11-32 to 11-34. These accommodations rely on the rigth chain lengths in all cases to give the appropriate 'chain wrap capacity', as well as the adjustment to the 'B' tension screw. Worse case scenario with short cage mech and 11-32: While in the big ring shifting the chain up the cassette to the larger sprockets (lower gears), the jockey wheel cage rotates forward to it's maxiumum postion before the chain can step up to the next sprocket, jamming the chain under load...snapping the chain, twisting the cage...or breaking the rear derailleur hanger on the frame. Or it might just work with no drama. The choice is yours

Safe soloution: Long cage mech and new chain fitted to size. Why? Because I've demolished a rear mech in the scenario above, thinking I could work with the shorter chain issue, until one day I kind of forgot about the set up and pushed my luck a little too far...

Cassopher

So I went ahead and put it on and went for a short ride around my neighborhood and you were correct about jamming the chain. It struggled to move up to the next gear while under load. You know your stuff!

Maelochs

Just hammer away at the old cassette until it shatters, coat the hub liberally with Liquid Nails, and hammer on the new cassette. Completely interchangeable. I have mixed Ultegra and 105 enough to know .... it is all in how hard you hammer, and using enough glue.

Bob the Mech

I learned the hard way many moons ago my friend and I've pick a few things up along the way when wrenching on bikes for the past 30 odd years

MikeWMass

You can use a short cage derailleur with a wider gear spread, as long as it is able to reach the large cog (if not you can use one of those hanger extenders); just size the chain for the big-big. It may be too loose on the small-small, but nothing bad (or at least not bad enough to end your ride), unlike if the chain is too short and you try to shift into big-big.
I ran a short cage 5600 rear derailleur with a 50-39-30 crankset and a 12-30 cassette with no problems.

Kapusta

Length of the cage and wrap capacity mean nothing if the chain is too short.

tomtomtomtomtom

My rear cassette is an SHIMANO 600 mf 6208 Freewheel 13-30 6 speeds, and its look like, maybe, it's time to change it. I would like to know, if I want to update it, is shimano brand new MF-TZ500 6-speed Multiple Freewheel 14-28 cassette is better or worth than my oldschool high level range cassette ?.

in two words, the old high level range is the new middle range level ?