adding suspension forks to non sus frame.

[Gotte]

I'be got a pre 98 saracen which came with heavy, ugly maxpower chromo fork. I was going to swap them out for ions P2's (going to use the bike as a yourse), but then someone pointed out I'd be altering the geometries, as the p2's are a couple of inches longer. Wheel flop was mentioned. Not ideal as I'd have front panniers as well.
I got to thinking, there must be folks here who add suspension forks to non-suspension designed frames (or is that heresy?).
If you've done this do you find wheel flop an issue, or a non-issue?
Back in the ole days, I added suspension forks to non sus frames and can't really remember noticing any real difference. I was young then, though, and probably didn't notice a lot of things.
My other option was to add a really old pair of marzocci air sus forks I have hanging around. They are lighter than the original forks, though about 500 g heavier than the p2's. There's not that much travel on them, but that means they bring the bike closer to its original geometry. I'm looking to use the bike for more remote touring, so the suspension might actually be useful.
I'm just not sure how reliable, long term, air forks are. These must be twelve, thirteen years old now.
Any advice on any of this is much appreciated.

 

[orange71]

You should be ok as long as the axle to crown is about the same as the rigid forks (?395mm). A lot of the <65mm suspension forks will be like this.

 

[JohnH]

I got to thinking, there must be folks here who add suspension forks to non-suspension designed frames (or is that heresy?).

Hi there Phil. Firstly, the Sahara that you've got isn't quite a non-sus frame -- it's just that the forks that it was designed for are very short-travel. But I know what you're going thru...

Even though I had these Bomber Z2s available, I was worried that with 50 or 60mm of travel, they would be too long for the Sahara (axle-to-crown distance was an extra 10 or 20mm compared with the forks fitted by Saracen). So I bought a pair of RS Quadra 21s from another RetroBike member. The threaded steerer was exactly the same length as that on the original Saracen forks so it was an easy swap. And because they were very short travel, they suited the geometry of the bike perfectly....

(Excuse the strange routing of the rear-brake cable, that was my first attempt at connecting V-brakes to a frame that was designed for cantilevers. I eventually sorted it out, as seen on another thread.)

However, tearing along stony trails with only 15 or 20mm of travel in your front forks soon takes its toll on your wrists. And so I ditched the Quadras, had an Aheadset fitted to the bike and popped the Bomber Z2s on.

What a difference in ride quality! The look of the bike is affected by the longer forks -- but you really don't care because the Marzocchis are SO much better than any shorter travel forks that you could fit.

So, that's my experience. Hope that helps!

 

[Gotte]

Thanks for that.

The Marzochis I've got haven't got a name on, so I can't tell you exactly which they are.
THere's a pic here off Google of some similar:

'cept mine have about 2" of travel - much shorter than these. The fork's are the same though, in that the chamber only goes half way and then tapers to the end. Oh, and mine are red, if that means anything. They have two little dials on the front to adjust the dampening. The only thing that makes me wary of them is whether they are dependable. Don't suppose you know how they work. I'm guessing chambers with air seals.
Are those seals likely to perish with age?

I quite like the idea of using them, as I'll just be touring, so not bombing it anywhere, but they should give some relief from rougher terrain.

I have also got some RST 381 DS's that I could put on. And a pair of okay looking chrome rigids like this:

http://cgi.ebay.co.uk/CHROME-MOUNTAIN-B ... 557wt_1139

Suppose there only one way to tell.

On a side note - I didn't realise the Sahara forks were even suspension. There seems no travel in mine whatsoever, and no obvious room for travel. Are they the barest minimum elastomer? I can't move mine even standing on them.

 

[orange71]

DH3?


http://tinyurl.com/4jszg65

 

[silverclaws]

If it is one of these forks, that is what is inside, so if yours does not move, I guess either the elastomers have turned to glue and glued the thing up, or someone has replaced the elastomers with a metal tube, after probably finding out that sourcing replacement springs is a p.i.t.a.

 

[Gotte]

Thanks for that. I had a look at the originals, hit the crown on the underside with a hammer, and out they slowly came. Looks like you were right - the elastomers must have perished. It's strange because the rest of the bike looks in okay condition - chain, chainrings, blocks and rear block all look pretty unworn. Maybe the elastomers went with age, rather than wear.

Anyway, it's lucky I did wallop them, becasue after they were out, they are pretty much the same length as my P2's, which is a stroke of luck.

Might still add the Marzochi's just to see what they are like.

here's some photos, front and back:

Looks like a lot less travel to me than those DH3's[/img]

 

[silverclaws]

The early elastomers did perish, age was one thing, contaminaton with oils was another, later MCU's came out which were more resistant, but have heard about MCU's liquifying with heat and there dripping out the bottom. My fors I am still experimenting with, and have managed to pull the rebound elastomers out of an old HiTen fork, which used steel springs and elastomers. If this current idea doesn't work out, I will have a go at casting my own out of a two part polyurethane casting kit which gives a durometer shore rating of A50, which I understand, is ok for shock forks ;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220678508854&ssPageName=STRK:MEWAX:IT

I don't need forks for big hits, not my style, just the bog standard off road cycling I have always done, touring and singletrack. It was either forks or flexstem, but didn't like the idea of wear in a flex stem.

 

[Gotte]

Thanks for that.

Any idea what my Marzochi's are, and how reliable they are?