Danger when Rear derailleur doesn't match sprocket/chainring tolerance?

Looking for advice from our mechanically competent users.

I recently got a new wheel set, and put a new chainring set [cassette] on them, a Shimano 11/32, with my 50/34 crank set. My rear derailleur is a Shimano Ultegra RD-6800 SS (short cage). And I didn’t think before purchasing about the tolerance of the derailleur. But the short-cage is only rated to handle up to a 28T Low sprocket Max, and a Total Capacity of 33T.

Like I said, my largest sprocket is 32T, which is in fact larger than 28, and the Total Capacity, or differential, between the sprockets and chainrings is (34-11)+(50-34) = 37, which is again larger than 33.

How problematic is this? There’s not an ideal amount of clearance between the pulleys and sprockets when it’s in the 32. But it seems to run smoothly. Also in the 50 up front and 32 in back i can shorten the chain with my hands slightly, so it’s not like the system is being pulled fully taught. And I’ve been scouring the internet for something conclusive, the main issue I’ve read about is your derailleur not being able to shift to the largest sprocket, but it shifts just fine. But my local mechanic warned about cross training in the 50 up front and 32 in the rear and possibly snapping my rear derailleur. How real of a concern is this? Obviously i’m not planning on ever cross training, but if i were to accidentally let it happen it would suck for my derailleur to snap mid ride or mid race.

I chose this setup because I’m a heavier rider at 180lbs and do 24 hour races and want to be able to spin up hills without going into threshold or above while keeping a decent cadence. I also do a lot of riding through the Appalachians which pose a similar problem on very steep 20+ minute climbs.

I am planning to get a mid-cage or long-cage in the future, but wondering how urgent this is.

The best option without getting a new RD might be this:

You can extend the position of the RD lower and still get away with the short-cage.

  • I added the DM version to my new Domane with the R8000 group and the stock RD with an upgraded 11-32 cassette.
  • I didn’t even need to lengthen the chain, but you should verify for you needs if you head for the RoadLink.
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“Need”? Probably not.

But I already had the DM RoadLink on hand, and preferred that option vs potentially over-stressing the “wrong” RD with my 11-32 that officially exceeds the rating.

Others are likely doing it and getting away with it (as I have seen the conservative ratings in the past as well), but I had the option handy and wanted to see how it worked.

The chain was sized for a 52 up front and a 28 in back. Me being a dumb dumb i replaced the chain right before putting the 50/34 up front and 32/11 in the rear. But it still shifts. keeps tension in the 34/11 and isn’t fully taught in the 50/32.

Sounds like to avoid a possible catastrophic failure ruining my wheel/frame i should re fit a new chain. and to increase shift quality get the road link.

thanks. That’s what i thought, but i really needed to hear it from someone else after images of my derailleur tearing off splattering me onto the road were in my head.

Just wanted to check in on how it was running? I am looking at changing my cassette from 25T to 28T, and based on calculations I am 1 chain link short. Wondering whether I need to change my chain if I wanted to use the 28T.

I never had any issues!