Mtb chainrings on road crankset

Hello, can I use mtb 28t or 30t directmount chainrings on road directmount crankset in 1x11 mode on a gravel bike if the types of the directmounts are the same? 

I have 50/34 Ultegra 6800 crankset and 11-28 cassette with ultegra 6800 short arm rear derailleur. I’ve got some problems with my knees a year ago and now I can pedal only light gears on a very high cadence. 34x28 now is too hard for my knees to pedal even on very small hills both on tarmac and on gravel. Need to get easier gears. I want to get rid of 2x because I can’t use 50t chainring even on long downhills. 50t is way too hard for my knees now. So I want to install 1x crankset at the front with road q-factor but with mtb 28t or 30t chainring. Thinking about directmount road cranks with directmount mtb chainring. I found easton ea90, praxis alba, sram rival, rotor vegast suitable for me for their price. Maybe there are other options. Will be happy for other brands advices. What do you think will it be Ok to use 28t or 30t chainrings on road cranks if the directmounts both of the cranks and the chainrings are the same?

edraven wrote:These have a Q-factor of 155mm: https://www.ethirteen.com/collections/all-cranks/products/xcx-race-gravel-carbon-cranks

Chainrings go down to 30T: https://www.ethirteen.com/collections/all-chainrings/products/ul-guidering

mtbnut87 wrote:If it was me (and it was) I would consider moving from Ultegra 2x to GRX600 2x.  46/30 gives you the gearing you want on the bottom and won't hold you back as badly as 30x11 on the top (you will run out of gear FAST!!).  The chainline is only 3mm different, which is nothing.  You can always go to a 11-32, 11-34, 11-36 or 11-42 in the back if this is not enough, although some of those combos might require a RD change and a Roadlink DM.  With 650b wheels, I have nearly the same bottom gear as my MTB with 30/51 and I have yet to complain.