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Discussion Starter · #1 ·
I purchased my 1998 Trek 6000 off the showroom floor almost ten years ago. At the time I knew absolutely nothing about mountain bikes, having come from road racing for the past 8 years. However, I jumped in with both feet and have never looked back. I've purchased a few mountain bikes since and have learned much along the way.

However, wanting to keep the ol' '98 nimble, I decided to rebuild the front legs. Where I run into a dilemma is that I can't tell what model of Rock Shox are on my '98 Trek. There are no markings to indicate what model they are. Researching turned up the fact that the '98 Trek 6000 came stock with Rock Shox Indy S forks. The original owners manual was accompanied by a booklet on Rock Shox Quadra forks, which detail the Quadra 5 and the Quadra 21R.

So how do I tell which forks I ACTUALLY have on my bike?

Here's what I know about rebuilding the different models...

The Indy S can be rebuilt by simply replacing the 155mm long Type II Elastomer for the left leg. (Which I found on eBay. Sweet!) They also seem to have springs at the bottoms of both legs, but who knows if I should replace those.

The Quadra 5 has elastomers, but I don't know the details on these. Is there one in each leg? Is it one piece like the Indy S or multiple pieces like the Quadra 21R? Are the parts interchangeable with any other models? Could I use the Indy S parts in the Quadra 5?

The Quadra 21R has a series of elastomers called the MCU (microcellular) spring. You can combine any combination of elastomers to give you almost any spring rate you wanted.

So why not just tear the forks apart and look inside? I will. I just wanted to know if anyone knew so I could order the parts and not have the bike out of commission while I wait on those parts.

So why not just buy new forks? Because I'm on a tight budget and I'm not ready to drop $500 on a set of forks for a bike that originally cost $500.

Any help would be greatly appreciated.

Thanks,
Scout
 

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Well, the Quadra 21R was made in 1995 (Gary Fisher's only) and 1996 (bright yellow, seemed to come on everything) so its not likely that. The Quadra 5 was the very base fork and I believe its last year of production was 1997. Its easy to tell the difference between the the Quadra 5 and the Indy S. The Quadra will have 3 piece lowers (two seperate legs bolted together with the arch). The Indy series forks will be 1 piece lowers.
 

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Discussion Starter · #3 ·
That helps

Thanks, that helps.

I've looked for photographs online and noticed that just about every set of Rock Shox forks has a decal on them indicating whether they are Quadra, Indy, Dart, Judy... whatever. It sucks that mine don't. However, I also noticed that, just like mntbiker indicated, that so many Quadras were yellow. My forks are definitely solid black. Not that I would rely solely on that fact, but it does help.

I'm almost sure now that they are Indy S forks. I'm betting that the LBS just gave me the wrong booklet when I bought the bike.

Does anyone know what the technical differences are between the Indy S/C/XC/SL?
 

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Can't tell you everything, but the Indy SL had aluminum stanchions and steerer tube, the others were chromoly steel.
Also, I know I have seen 21R's stock, and aftermarket, on bikes that were not Fishers.
 

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A couple more things...the last Quadra 5's were solid black but with silver stanchion tubes.

The Indy forks had black stanchion tubes (upper tubes) on all but the SL

As I recall, the differences were this on the Indy's
S-base model, one sided spring
C-Dual springs(and MCU's)
XC-Dual springs, maybe an alloy steerer (not sure on that)
SL-Dual springs, alloy stanchion tubes, alloy steerer, yellow in 1997 (I owned one)
 

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Scout Sniper said:
I've looked for photographs online and noticed that just about every set of Rock Shox forks has a decal on them indicating whether they are Quadra, Indy, Dart, Judy...
I can tell you from experience with my Mag21s (similar vintage to the first quadras) that if you have fingernails and want those stickers removed you could. If you didn't want them removed, you'd probably be disappointed.
 

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noMAD man
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Damed antiques!

LOL!...I can't imagine wasting any time or money on one of those forks if I were actually going to ride it off road. I've had/have all of those forks at one time. Posting a couple of closeup pics would probably be fun...at least for a history lesson. If you're serious about keeping that fork, the Englund air catridges for those model forks is about as good as it gets, but even then I'd just buy another more modern fork with 30mm stanchions at least. Here's a pic of an Indy SL on a hybrid bike that I built. It's a super light fork with alloy stanchions and steerer. It has the Englund air carts in it and makes an awesome hybrid/commuter bike fork. Otherwise it has the rigidity of a rubber band on a 100 degree day.
 

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No Kidding

TNC said:
Here's a pic of an Indy SL on a hybrid bike that I built. It's a super light fork with alloy stanchions and steerer. It has the Englund air carts in it and makes an awesome hybrid/commuter bike fork. Otherwise it has the rigidity of a rubber band on a 100 degree day.
That's why it made it all of 3 months on my bike...My '96 Judy XC even felt stiff compared to that flex-o-matic.

:eekster: :eekster: :eekster:
 

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noMAD man
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Wow, '96 Judy XC.

mtnbiker72 said:
That's why it made it all of 3 months on my bike...My '96 Judy XC even felt stiff compared to that flex-o-matic.

:eekster: :eekster: :eekster:
I had one of those on a Specialized Ground Control...first full suspension for me. I got a set of those White Bros. high tech cartridges that gave my XC 3" of travel. Man, 3" of fork travel in '96 was DH territory...LOL! How times have changed...thank goodness.:D
 

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Discussion Starter · #10 ·
Now what?

So I tore them apart last night. Turns out there was a purple MCU elastomer in each leg, but no springs in the bottom from what I could tell. So does that narrow down what model my forks are?

I completely understand what you guys are saying about how these forks are absolute junk by today's standards, and probably not so good by decade old standards either. But married with kids, one of which I just bought a brand new Trek 4500, I'm not in any position to spend even a $100 on new forks for my bike. I have to do whatever I can to make these forks even marginally better than rigid forks.

That being said, I can tear down these forks and put new, softer rate MCU's in there for like $15. The information is what is priceless to me. So thanks for you input. Now for an additional question: Even with the MCU's removed, the fork was still very hard to compress and I had to pull up pretty hard to get them to rebound back to top dead center. Seemed sticky, so I used a cable spray to clean the sliders and then lubed them up with a chain lube. It's a little better, but still not as smooth as I would expect it to be. What next?

Thanks again,
Scout
 

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mmmmm - quadra 21r, good like candy
was my deflowering suspension experience and I've been corrupted ever since...
 

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noMAD man
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Scout, you realize that the fork might even be seized up with some bushing damage? Most oweners of these forks never serviced them with fresh grease. If you can't get the sliders to move smoothly, the fork won't be worth trying to repair. Just spraying "stuff" in there won't get the job done. You need an 8mm (I believe) allen wrench on a long extension with a ratchet wrench to remove the sliders so that you can clean the lowers and regrease the fork bushings and MCUs. These forks don't use oil, they use a grease like Judy Butter or Slick Honey...not automotive grease. If you can't disassemble and regrease the fork properly or have a shop do it, you might as well throw the fork away. For better identification of that fork, post us a pic and maybe we can be more specific, but I think all the possible candidates you mention here are constructed pretty much the same. One other thing you need to know for the right MCUs or other parts is the stroke length of that fork. Some were 50mm, some 65, some 75, etc. We won't be able to tell you that over the internet. You'll have to get the fork moving freely and measure the free stroke of that fork. Those forks are easy to disasemble with the allen socket and extension, and there are no high tech damping cartridges or other more complicated devices in those forks.
 

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The Quadras have a bolt on fork brace. The earliest Quadra 21R's used the bolt on crown of the Mag 21, later on used the cryofit crown.

The Indy forks are a one piece casting - no bolts anywhere.
 

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TNC said:
LOL!...I can't imagine wasting any time or money on one of those forks if I were actually going to ride it off road. I've had/have all of those forks at one time. Posting a couple of closeup pics would probably be fun...at least for a history lesson. If you're serious about keeping that fork, the Englund air catridges for those model forks is about as good as it gets, but even then I'd just buy another more modern fork with 30mm stanchions at least. Here's a pic of an Indy SL on a hybrid bike that I built. It's a super light fork with alloy stanchions and steerer. It has the Englund air carts in it and makes an awesome hybrid/commuter bike fork. Otherwise it has the rigidity of a rubber band on a 100 degree day.
(it's not the same without the pic, but .....)

BUWHWHWHAHAHAHAHAHAHHAHAHAHAHAAAA!!!!!!

Oh, damn, that'sHAHAHAHHAHAHAHHAHAHAHAAAAAAAA!!!!!!

Oh wait, more AHHAHAHHAHAHAHAHAHHAHAAA!!!!!

WOw, okay, i'm dohahahahahhahAHAHAHHAHAHA!!!!

PHEW! Okay, deep breaths! Yo, T, give the moose back his antlers, eh?!?!?!?! :p :D
 

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That's like asking what crapy pogo stick do you want? I had a quadra 21 on my 96 Trek 7000 and upgraded to a Judy XC which at the time was a sweet fork but not very durable. Those elastomer forks are giant pogo sticks!!!

If you are low on cash comb the internet and look for a 80mm Marz MX comp. Thats what I put on my old Trek 7000 which is now in its second life as a single speed. Retails for $285, but I got it for $215 at price point. Great shock for the money. Granted its not a Fox, but it does not have the Fox price either.
 

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Scout Sniper said:
So I tore them apart last night. Turns out there was a purple MCU elastomer in each leg, but no springs in the bottom from what I could tell. So does that narrow down what model my forks are?

What next?

Thanks again,
Scout
Sounds like an Indy S to me. The "S" was the OEM only version of the "C".

You'll need a long 5mm hex (allen) wrench to loosen a bolt in the bottom of each fork leg. The top caps and elastomers must be removed first, loosen the bolts and pull the lower leg assembly from the steerer/crown/stanchion assembly. Clean and inspect everything. The bushings in each leg should look grey in color - a copper or gold color indicates they're worn out. Reassemble with a good quality bearing grease, -use Judy Butter if you can find some.
 
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