Marzocchi MX Comp bottoming out..

felix.london

Did the cable tie trick on my ride today and realised my 100mm forks were bottoming out before I'd even got to the good stuff!

I'm presuming if I increase the air pressure in the forks it will stiffen them up. But what forks would you guys recommend as an upgrade to the Marzocchi's?

I really want the most travel possible and Specialized recommend up to 10% increase over the original fork - so I guess that gives me up to 110mm (I don't know what the original fork was as bike was an eBay buy)

...maybe I could drop the bars (swap the stem) and go for a 120mm fork?

Anonymous

All forks will bottom out. If you're NOT bottoming out, then you're not using the entire travel - which makes it pointless extra weight.

felix.london

So there isn't any detrimental effect of constantly bottoming out the forks? And any obvious forks I should be looking at if I want to upgrade? - new or used. Something with a lock-out system would be nice

Anonymous

If you really are constantly bottoming out, on every single bump, then yes, eventually you'll cause problems. But forks are meant to bottom out a few times a ride.

felix.london

OK - I gettcha

No, it's only bottoming out on decent sized hits not little bumps and to be honest I think the forks are pretty stiff - if I stand with the bike in front of me and put my hands on the bars and jump up putting all my weight onto the forks I can compress them just over half of the total travel distance

Anonymous

What kind of sag are you getting? Should be roughly 20% on a fork that long.

felix.london

sag = the amount of compression of the fork when I'm sitting on the bike? :?

supersonic

When standing on the bike. Is it an air or coil fork?

felix.london

Air. OK - sag is 30mm

Also once the fork has been compressed the last 10mm doesn't rebound. You can pull it up and it will stay fully extended until the next time it compresses and that 10mm will stay down. Is that normal?

In two months of fairly intense riding most days I have done nothing to the fork in terms of maintenance - except give it a hose and wipe down - basically I treat the fork like the frame

supersonic

I'd strip, clean and replace the oil.

Set sag to 25mm.

felix.london

hmm, sounds like a major job. Easy enough?

supersonic

Pretty easy! Google for a service guide, used to be loads about.

felix.london

Yeah - cheers Supersonic. Found a Marzocchi manual online.

Phew..lots of bits in a suspension fork isn't there? It doesn't seem to say what oil to use.

And use "..the special screwdriver...the special spanner...and the special round-nose pliers..."


Are they're just trying to scare you into taking them back to Marzocchi for servicing?

Dirtydog11

felix.london wrote:

Yeah - cheers Supersonic. Found a Marzocchi manual online.

Phew..lots of bits in a suspension fork isn't there? It doesn't seem to say what oil to use.

And use "..the special screwdriver...the special spanner...and the special round-nose pliers..."


Are they're just trying to scare you into taking them back to Marzocchi for servicing?

It's 7.5 wt.

It could be oil levels are too low, if it's a problem that has developed over time then they probably just need an oil change.

felix.london

8) Cheers.

out of interest would these be a good upgrade?

http://www.merlincycles.co.uk/Bike+Shop ... T-2012.htm

bit more travel, lighter and with a lockout system which would be great for the steep climbs round these parts...

Anonymous

lockout won't help on steep climbs.
On steeper climbs, what you (ideally) want is a lower front end. Lockout keeps the fork extended, raising the front of the bike, and making it that bit harder to keep the front wheel down. It may also cause the front to wander on climbs.
This is made worse with a longer fork, although I'm not sure how the axle to crown lengths compares between those two.

felix.london

Yeah, makes sense. Thanks for the info.

After a quick look around looks like there's about 10mm difference in the axle to crown length.

felix.london

yeehaamcgee wrote:

All forks will bottom out. If you're NOT bottoming out, then you're not using the entire travel - which makes it pointless extra weight.

+1 Yeehaa - Just took an Enduro for a test ride and bottomed out the 160mm Fox Float.