air to coil

good old fashioned hack thread alert:

does anyone know if its possible to swap out the air spring in a marzocchi fork for a coil, if the basic model is the same (i.e. a 44 or a 55)?

i have a 44 micro ti 29 and a 44 rc3 ti 26. i talked to alex last week about swapping the micro damper for the rc3, which will work. but now i'm wondering why not go all the way and swap in a sweet ti coil while i've got the forks apart

experience, insights and wild assertions welcome

By no means gospel, but I talked to Naz about doing this exact same swap when working in the shop a number of years ago and looking for an aggressive 29'er fork (pre-Fox 34/36 [HTML_REMOVED] Pike).

At the time, and not saying that is still the case, it would have required a custom spring plate to run the coil spring in the 29'er body (which would have been doable) and for some reason, I can't recall exactly, related to the lower damper assembly the RC3 damper could not work be retrofitted into the 29'er body.

If it had been possible at the time we had three or four folks, myself included, who were very interested in paying to make it happen.

It may be that changes in the years since have resulted in fittings that make it possible to retrofit now. Cool if that is case!

I switched my 55 from air to coil. It was all 26 though.

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At the time, and not saying that is still the case, it would have required a custom spring plate to run the coil spring in the 29'er body (which would have been doable) and for some reason, I can't recall exactly, related to the lower damper assembly the RC3 damper could not work be retrofitted into the 29'er body.

i've seen the damper swapped, and have the part that makes that retrofit possible

by spring plate, do you mean my man number 54 in the diagram below?

looks like its a guide for the main spring and keeps it and the negative spring separate. what would need to be different about it to run in the 29er chassis?

I switched my 55 from air to coil. It was all 26 though.

was it as simple as pulling out the air spring assembly and dropping the coil one in?

Cool; the damper retrofit part must have been a change after I inquired with Naz (it was years ago).

Yes, part #54. Sorry Omar, I don't know/recall what the difference would be. I haven't been intimate with the internals of a Marzocchi fork personally since I last owned one in ~2004, so it is just second hand information.

I just know, at the time, the stock part did not allow the coil to work in a 29'er fork.

Are the foot nuts/bolts (#88 / #37) different between the 26" and 29" forks that you have?

Yes, part #54. Sorry Omar, I don't know/recall what the difference would be… I just know, at the time, the stock part did not allow the coil to work in a 29'er fork.

no worries! at least now i know what to stare and curse at when i pull them apart

Are the foot nuts/bolts (#88 / #37) different between the 26" and 29" forks that you have?

yeah. a new foot nut is what makes the damper swap possible, apparently, and alex happened to have a few on hand; he's done the damper swap on his fork, is how i knew it was possible

yeah. a new foot nut is what makes the damper swap possible, apparently, and alex happened to have a few on hand; he's done the damper swap on his fork, is how i knew it was possible

Cool project. Weight aside (not my #1 either), the RC3 damper combined with a coil spring will make for a sweet fork.

Still a bit of a stiffness issue compared to the current standard (Fox 36/RS Pike), but the coil fork will sit into its travel more so you may notice an improvement over the air system there as well.

I do wish they had done a 29'er version of the 350. A few lemons aside its one of the best performance:price values out there.

I do wish they had done a 29'er version of the 350. A few lemons aside its one of the best performance:price values out there.

ahem

i guess boost isn't wholly evil

Youd think that theyd make all thd internals the same and just make a longer slider to accomodate a 29" wheel

Youd think that theyd make all thd internals the same and just make a longer slider to accomodate a 29" wheel

that's what i was hoping

I have exactly the same two forks, and was wondering if a transplant would be possible. This doesn't help you at all… but please update this with how it turns out! Sounds like that foot nut is something I'm going to need at least.

By strange coincidence, the TST damper in my 29er 55 distributed oil all over my brake and the forest floor on Saturday. I wanted to go for a ride today, so last night I shoved the RC3 damper from my 26" 55 in it.

Basically is went straight in with no hassles and using all the original parts. The only problem is that you can't hold the compression adjuster knob on, so if you want adjust it you have to carry the knob in you pocket or whatever. I didn't try the spring swap. The damper worked well and I rode up and down a mountain on it today. It looked like this (not a very helpful photo, I know):

i was all set to at least pull the forks apart tonight and figure out what needed to be figured out for the swap, but instead spent the better part of the evening pulling apart the bike room looking for my 1/2" driver, which has gone awol. oh well

nice to hear your conversion went well andrew. i think the footnut i have is meant to allow you to leave the compression knob in the fork rather than carry it around. of course, you have to carry around a pair of needle nose pliers to reach it, so not sure if it really puts me ahead any

biggles ran the spring swap idea by alex at marz who admitted he hadn't really looked into it, but couldn't think of any reason off the top of his head that it would necessarily result in an exploded fork and missing teeth. so that may be easier to manage that i'd thought. will try it this week and report back; here's hoping

Boom - I wish I had time to do the spring swap, but I was rushing. Let me know how it goes!