I have a pair of 100mm bombers here that I am contemplating fitting to a bike that was never designed to run bouncy forks.

The bombers have an axle to crown measurement of 480mm the current forks 400mm.

The current steering is quite twitchy so a slacker head angle may be a good thing.

Has anyone done similar?

You might find it goes downhill nicely but uphill the steering may be very floppy and hard to keep in a straight line. A change in stem may help but probably not enough.

If it had 400mm rigid forks on I think 60mm forks would probably be the max you could use. Maybe 80mm at a push, could be worth a try.

Also the frame may not be designed for the extra stress a long fork will put on it so could fail in a worst case scenario.

Also the frame may not be designed for the extra stress a long fork will put on it so could fail in a worst case scenario.

Yes that had occurred to me, especially as the tubes are bonded rather than welded. 😯

Remember to deduct your sag (33mm?) from the equation. So now that’s just a 50mm increase. 😉