What is your opinion on a manufacturer decreasing a bike’s head angle by adding a longer travel fork? Are the benefits the same as a bike with a slack head angle to begin with? Does this change how well the rear suspension works?
Good question. Back in the early ’90s when front suspension first came out, people FREAKED OUT about this issue. Raise the front of your Bontrager an inch — MADNESS!!!
These days it isn’t such a big deal. When you lengthen the fork on a given frame, you slacken the head angle, raise the bottom bracket and slacken the seat angle. If you only raise the front end 10 or 20mm, no big deal. The effect on the rear suspension is negligible. If you raise your front end 100mm, then things get weird. The BB gets really high, and the bike starts to feel floppy. Also, the seat angle can get crazy-slack.
If the manufacturer is upgrading, say, from a 130mm to a 140mm FOX fork, it’s all good. Just resist the temptation to slap a DH fork on your trail bike. But a FOX 40 on a 1990 Bontrager … that would be SICK!
BTW: Slapping a longer-travel fork on your frame might void the frame warranty.