Opinions wanted. I'm thinking of swaping out my suspension fork for a ridged one. Mostly I ride on pavement but do ride some gravel paths and fire roads(90/20). Also I would get a pair of 26 x 1.25 tires. Price wise it looks like it can be done for about $90.00 plus the time to swap every thing.

Thanks

You're going to have difficulty finding the right tire for that 90/20 split.

Universal Cycles -- Dimension Rigid Non Disc Fork
Universal Cycles -- Schwalbe Marathon Greenguard Tire

Legs and arms make good suspension , but you may have to get off the saddle ahead of hitting the rough patches.

Sounds like a reasonable plan. If I were you I might consider slightly wider tires with largely smooth tread--maybe 1.5-1.75. The bigger tires will weigh a little more, but won't roll slower and will do better on say fire roads. i think not having suspension is great whenever you really don't need it.

I've heard of rigid bikes going to suspension forks having issues due to geometry, but would the opposite also come into play? Would he have to find a fork that didn't screw with the geometry too much?

Thanks for the replies. Here's the fork and tires I was thinking of.

Nashbar Rigid Mountain Bike Fork

Geax Street Runner City Tire

The fork is suspension adjusted. Those Schwalbe Marathon look good and may be the better choice.

I did something like that to my commuter. As long as the rigid fork has a crown axle dimension close to your suspension fork, handling should stay about the same. One gotcha is that a lot of steel forks are set up to replace an 80mm travel fork so if you have a 100mm travel fork you need to find a longer fork like the Salsa Cro-Moto. Also try and get a replacement headset crown race for the new fork since that is easier than trying to pull the old one and reuse it.
For tires with a more dirt friendly tread, try the Vittoria Randonneur Cross or Trail.

I was debating the same thing as I am older fatter than before and the thought of taking a header on the trails = doom. My fork is a beast and must weigh 6-7 lbs all day. I was even debating going to a 27 IN WHEEL with rigid fork?