Reverse mullet on cx/gravel bike a thing?
 

love my bike but it has limited tire clearance 35mm is rear max but front fork has a ton more clearance. Is there any advantage to using bigger tire out front...
https://cimg3.ibsrv.net/gimg/bikefor...754208f777.jpg
tires on now 25mm....fun fast comfy bike.

I think so.

More traction where you need it most. Makes the head tube angle effectively slightly more slack.


https://cimg4.ibsrv.net/gimg/bikefor...6112eccc1.jpeg

In this case it is 650b x 48mm in front, and 650b x 42mm in back (which is all that fits).

Running 700x50 front, 700x44 rear due to clearance

Advantages:

• Better steering and flotation in the soft stuff
• more shock absorption (a little like adding a small front shock)
• Noticeably more trail, making the bike more stable in the rough stuff.

For race day and race training, I like to run 50mm+ in the front, 38mm in the rear (as most of the power loss and rolling resistance comes from the rear). Besides, that is the biggest I can run.

thats a pretty significant size difference but it works for you?

running 700 x 42 front with smoother file tread , tubeless @ 32 psi , rear x 35 small block kenda w/ TPU tube @ 35 psi
smooth running, great feel and plenty of grip for my terrain. small amount I ride on road feels fine, not mushy. I like the combo.
I usually refer 'mullet' as a different wheel size - in mtb - usually larger front wheel and smaller rear wheel , like 29r front with 27.5 rear...
Ride On
Yuri

I run 50mm Front, 38mm rear. Any problems you expect?
Iike I said, it reduces the trail and makes the bike more stable, which is what I want when running big tires.
When running GP5000s, I want agile road bike handing. Works well for e.

a bit more trail actually helps in those areas where the front might get knocked around a bit more by chunks, erosion ditches and other irregularities...
I don't really feel any lose of 'quick handling', but I do feel the front 'rights' itself quicker and easier when the terrain causes deflection. I rely on that, rather than trying to strong arm every rough section. I keep a solid grip, but not stiff arm - I'm ok with the front bouncing around a bit, and then correcting on it's own... it's not like you're in the middle of a peleton, where any large deflection might have you overlapping wheels with a bike in front of you...
can't say for larger sizing much beyond low 40s, but there's a noticeable improvement of handling when going from 35 to 42...
haven't tried upping the rear yet so it's not clear what the max size might be. Looks as it might be limited by rear circumference, rather than width.
I do like the overall ride, grip of the Kenda small block 35s. I have a couple, so will stay with those for the rear, until they're done.
Ride On
Yuri

I would fit a cyclocross knobbier tyre (33/35) at the back and a similar tyre in 38/42 at the front. Ultimately, it is not much different than XC setup in 50 rear and 55/57 at the front. many XC race setup even go for something like continental race king at the back and cross king front.

I'd go
Rear: TERRA Speed ProTection 0101693 700 x 35C 35-622
Front:TERRA Trail 0150507 700 x 40 40-622

Both in Black Chili compound

Larger tire on the front can be run at lower pressure and provide more cushion, in addition to more cornering traction and float over loose sand. Almost all of my bikes have a larger tire on the front.

If I were to run different width tires for gravel, I would run the wider tire up front for sure. It will help reduce the chance of the front end digging in on loose surfaces and helps roll over large imperfections on the 'push' wheel versus the 'pull' wheel.

A wider front tire is pretty common on mountain bikes for all the reasons already covered in the previous replies (more grip for steering/control and lower psi means more grip AND comfort). The front tire on MTB setups also often has more aggressive tread for control, while the rear is less aggressive for better rolling resistance and a little less grip to make it easier to slide the rear end around. Pretty solid setup advice for bikes ridden in the dirt.

Actually, I do. but the larger tire up front reduces the trail and makes the bike more stable and less darty, which is good.
Even more so in a pelton, because I can't pick my line, but have to follow the wheel in front of me (especially with night racing, where its hard to see the terrain). Darting off to the side isn't an option when I'm elbow to elbow on both sides.

I like running a wider front tire on my custom gravel rig. The builder actually made a generously wide front fork. So I am currently running 2.2" on the front and 1.9" on the rear. This has been nice for the increased load with my handlebar bag and when I come up on water crossings to get more traction. I used to ride it with WTB Resolute 42's front and rear.

Back in my MTB days I ran a slightly wider tire on the front, narrower on the rear, for the same reasons stated above.

Running 650b x48 rear x56 front. All good.