Play around with pressure, drop them a bit to improved speed and comfort.
If you're riding those 25mm at 100psi, then there's your problem.
I never ride them any higher than 80psi even on the road, I'll drop them a bit more though as I know the mud will definitely be greater than last time I rode it off-road.
Any suggestions on what I should get for the rear as I know 28 will fit?
well depend on whether you like skidding or not.
To increase comfort, a wider bar actually give a noticeable improvement.
26c gravel king front and 28c ribmo rear. Sorted.
@jesm started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Play around with pressure, drop them a bit to improved speed and comfort.
If you're riding those 25mm at 100psi, then there's your problem.