I've decided to get a brooks b17, and I want to get fenders to keep it protected,. Question is, what kind of fenders are best for a bike with disc brakes. I have 700 28c tires and I've been seeing reviews are best for the Cascadias but would I go with 35mm or 45mm?

Id prefer they were as small as possible as I don't want huge fenders on fairly slim tires.
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Another question, could I just do fine with one of those seat post fenders made typically for mountain biking?

Is that unheard of to use on a commuter bike just for rain?

Anyone with a bad boy, or even just did brakes who has success with fenders let me know.

I heard you can use spacers and a longer set of screws to fit them better, please let me know people

Thanks

Disc or rim brakes, doesn't make any difference for fenders. I'd try 35mm fenders instead of 45mm, for 28mm tires.

Protecting your B17 is going to be more about covering the top against rain, than about fitting fenders. Use a saddle cover or a random plastic bag. Scrunch another plastic bag under the seat if you're worried about spray hitting the underside.

Oh I know about that, I just want fenders to protect the bottom

Which Bad Boy? If you've got one of the Solo fork models,then attaching the front is going to be an issue.

For the rear,or the front on a standard fork model,the 35's(Road) will just clear some 32mm tires;28's won't be a prob. If you get the Cascadias,they come with longer bolts and spacers to get around the disc calipers on the left side. If you get another model fender,just get longer bolts and spacers from the hardware store.

Yeah - a full fender on a 'lefty' front fork is pretty much a custom installation. The 'fatty' front end is no issue.

Full fenders protect the front derailleur, bb and your lower legs and would be a better choice for commuting in rain. Axiom makes some nice polycarbonate / ss ones.

Detachable mtb style fenders will mostly keep your back and face reasonably clean. They're OK for driving on wet roads AFTER a rain or in very light rain. Otherwise be prepared to have to wash down the bike often and do laundry after every ride.