Like many others I really want to try a suspension fork on my Pugsley. I have an older Marzocchi Z3 and a Z1 that I am going to use for this project. I plan to widen the fork to 135mm by making a new arch and crown for the fork.
I can post a few pics after I get to the minimum 10 posts
The donor forks for the fat bike fork projectThe blue fork has a 135mm spacer to simulate the final width of the fat fork. The green one has standard 100mm spacing. I made the spacer so that I could make a few rough measurements at the 135 mm width.
Both forks torn apart and ready to be modified. I removed the brake posts on the blue fork for practice. I hacksawed the posts off and then cleaned up the cuts on a lathe.
just make it good and people will ask You how much and if You can make one for them !!!
...and they will make You rich
i'm glad that "fat addicted" machinist finally got good idea and is ready to make it happen!
cheers
The final aluminum arch after lots of sanding and some polishing. The arch on the left side is an aluminum dust shadow. I still need to remove some excess material from the back of the arch to save weight.
Way to go. I've considered this myself as I have some older Z1 and Z2 forks around with the bolt-on brace. Just remember you're going to have to consider some limit to the full travel. The tires are so tall that they'll approach the bottom of the crown at compression.
This started out as the green Z1 fork. I found an old can of industrial strength paint stripper at work that removed the paint in about five minutes. The brake posts were also shaved off. The dropouts had been filed at some point in the forks life and they were crooked. I managed to set up the legs in a milling machine and take a skim cut to make them square again. The axle slots were also the old 9mm size and most rear hubs use a 10mm axle now. I cut them to 10mm while the fork was in the mill.
This is a prototype plastic crown so that I can figure out a few more measurements before I jump into a metal crown. I have a very special piece of metal that I have been saving for years, just waiting for the right project.
The grey coloured round bar on the back of the bench in the last pic is a 4 inch diameter 24 inch long piece of solid titanium. I just thought you guys might appreciate that info.
The new wider crown will be cut from a piece of solid titanium. It's not as light as an aluminum crown but I think it will be way cooler. I have sprayed a blue layout dye on the titanium and sketched a few rough measurements on it as I plan out the new crown.
This is definitely looking awesome. I know myself and one other that did a fat conversion on these forks keeping the 100mm spacing (there's a thread on here about it). I can't wait to see the finished 135mm version, should be awesome and not be so limited on tire/rim combos.
You're beating me to it. Ahhh... for lack of a DRO. I just don't trust that I could hit the marks without one. I also do not have the process for the super fine tolerance of the bore for the stanchions, let alone the steerer. Boring is such a difficult thing to master on any level, but nice clean high precision stuff is much tougher yet. At least for us garage hacks. If I could only hit 1.259 dead. Maybe I just have not experimented enough....
Interestingly, there is a real black art to the whole cryo fit thing. They use highly sophisticated equipment to create and then measure all of that stuff. "Tenths" are absolutely critical. And yet, a lot of that high tech knowledge does not necessarily transfer to clamp fitting. I had a pretty in depth discussion with a friend who does this stuff for a living (you ALL know the company), and he really had no idea of how or if the cryo knowledge was useful. The whole idea made him nervous.
Sit and study a modern cryo fit lightweight fork and you will see lots of subtlety in its design. There are some VERY important things going on there. None of it is by accident.
Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
- John Hajny, a.k.a. TrailMaker
FYI there have been issues with the forum displaying images of recent, might not be your fault.
So I'm not the only one with the issues? Seems none of my fellow mods know or heard anything about it, at least those that have gotten back to me on it...
As for the OP's work? SWEET! Beautiful work, making me jealous over here with all that tooling. Keep it up, you're gonna be so stoked
This is a Pugs not some carbon wannabee pretzel wagon!!
Regarding the cryo fit, I assume you mean for the steerer (if not simply press fit) and stanchions. Some of these older Marzocchi's have all three bolted in though, so I would assume the tolerance is not nearly as precise - am I wrong on that? I for one had a crown with all three bolted.
As an aside, I have also press fit steerers in and out of crowns to make the steerer tube longer, it isn't that difficult if you have a simple hydraulic press (I know, everyone has one of those, right?!). The one I used was just welded up with a simple bottle jack and heavy duty iron for the frame - it was originally for AMP forks but I used it on Marzocchi's back in the day as well. I know I wouldn't do it multiple times to the same crown for fear of fatigue, but I never got nervous about a one-time press out and replace with a longer steerer.
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Originally Posted by Drew Diller
