Mechanical help! 11-28 to 11-30

[Mitch54321]

This may be a fairly simple question so please excuse my lack of bike knowledge. Google hasn’t helped either.

I’ve got a new bike with Di2 and wheelset that runs a 11-28 cassette.

My road bike is indexed for an 11-30 cassette (which I prefer for hills).

If I just swap the wheels between the two bikes, will this be dangerous, or will I just not be able to access the 30t cog on the old bike?

If I swap the cassette on the wheels to a 11-30, will I just need to adjust the indexing on the new bike (which should be easy with Di2) or will I need to get a new chain?

Any help really appreciated. Ideally I want to use the wheels on both bikes.

[Cleanneon98]

The short cage derailleur will handle up to 30 or even 32, but you gotta check chain length. I don’t anticipate it having any issues actually shifting into that gear though

[Mitch54321]

It’s a medium case so will definitely handle it. I guess the best thing to do is change the new wheel cassette to 11:30 and reindex? A shame when the bike and cassette are brand new and perfectly indexed

[Cleanneon98]

You may not have to reindex at all, I don’t have to between my wheel and trainer and they’re def not exactly the same. My concern is how the derailleur will look when it’s in the fully extended big ring big cog position

[AdamJ]

As long as it’s the same amount of gears I.e 11 speed then the indexing shouldn’t matter. Only the issues regarding chain length and the derailleur but I’d put money on it being fine

[rkoswald]

Great video here for replacing a chain. The whole video is good, but skip ahead to 4:00 for sizing a new chain.

How to Size a Bicycle Chain

[huges84]

This is a hard question to answer due to the many variables involved, especially with swapping wheels between bikes.

First of all, I would think about what you’re trying to accomplish by swapping wheels around. Is it just the gearing or is there another reason? If it’s just the gears then you should just buy the cassette you want for the new bike.

Second, the gears in the back are only half the equation. If the gears in front are different, then the new bike might actually have an easier gear than the old bike.

Your best resource is the bike shop that you bought the new bike from. (If you bought used then pick a local bike shop). They can help you assess your best option. Make no assumptions about what you can do and just decide what your high level goals are and let them help you figure out the best way to accomplish that.

Some of the many reasons you might not want / be able to swap wheels between bikes:

• Incompatible hub widths or axle standards
• Disc vs rim brakes
• not enough Frame clearance for tire size
• mismatching number of cassette gears (“speeds”)
• mismatched drivetrain brands / models that are incompatible

[RecoveryRide]

I put an 11-30 cassette on my Madone (Ultegra Di2 short cage) to replace an 11-28 and didn’t need to change a thing: chain was fine, didn’t need to touch the indexing. YMMV.

[Cleanneon98]

Your taste in bikes seems

[RecoveryRide]

Hopefully new one arriving end of the month (addition, not a replacement)

[Cleanneon98]

I was gonna say I’ll take that Madone off your hands I just can’t have nice things