Originally Posted by Iride01

I'd only give it a go after checking the specs for your rear DR. Not all Di2 rear DR's will handle that much front difference.

If you don't know where to find the spec's or how to interpret them then just give us the model numbers and someone might check for you. If you tell us the min and max cog on your cassette, then the total chain capacity can also be checked out.

Spec's of current products can be found for that item on Shimano's product site.... https://bike.shimano.com/en-US/home.html might need to change the country up in the top right of the page.

You can also find specs for all product here.... https://productinfo.shimano.com/#/ but for older products you might need to go into the archives which also is a link on that page.