A few questions about mountain bike suspension?

Question

i want to upgrade from a 150mm fork to a 170mm double crown fork, but i heard that you cant increase the suspension amount b/c it messes with the balance of the bike, but is 20mm really that much?

and if i do get that fork i have to get a hub for the through axle so wich kind of hub should i get?

last is any one willing to sell a Marzocchi dropp off triple?

Answer 1

I have some forks in a drawer in my kitchen.

Answer 2

Well, some frames can take a double crown, some can't.  It's not just the travel in mm that matters, rather the distance between the axle and the crown.  Different forks with the same travel might have different a2c length.  

Regarding geometry, roughly, 1 inch difference between fork 1 and fork 2 is one degree change in the head tube.  Also, it might put more stress on the bike.  It probably wont matter on the short or mid run, but over time it might cause the headtube to ovalize.  

You also raise the bottom bracket, which if you're riding on rocks might be a good thing, but if you like cornering it raises your center of gravity and not that good for cornering.  

How much will it be and will it be noticeable?  I don't know, but I just think it's better to keep withing the designed parameters.