Mountain Biking - Possible to install disc brakes on old non-disc-ready fork?

Hi guys, I'm completely new here and need help. I have an old GT Aggressor from 1997 and have decided to install disc brakes on it. Based on the posts that I've searched and read, I don't think the fork has any mounts on it and the wheel/hubs don't look like they have the ability to mount rotors on them.

Can you take a look and tell me if that's true? And if it is, can I just buy adapters of some sort?

I'm looking at either the Avid BB7 mechanical brakes or Shimano XL America or something hydraulic brakes. Thanks!! :thumb:

You can't, sorry. You would need new wheels too by the way, by which point it would be cheaper and easier just to get a new bike.

So adapters for this sort of application don't exist? Why does the back wheel frame look like it has the ability to attach brakes? Is it just a mismatch of fork/frame, so the frame is capable but the fork is not?

This makes me very sad...

Correct, You are SOL. I have a new fork on my '99 Fat Chance that has disc brake mounts, but the frame has just V brake mounts. So I guess I can go Mullet if I want. V brakes work pretty well. It depends on what conditions you are going to ride in. I am thinking of sending mine out to have a disc mount welded on the frame. Not top of my list though.

Thanks for the help... but let's say i just wanted to put it in the back (which probably isn't that great of an idea since more braking power needed up front right?) that wouldn't be possible anyway? Is there such thing as a hub adapter?

I would use a couple of zip ties and some JB weld and make my own disk mounts. I would then make my own disk adaptors for the wheelset. I have done this in the past and it works great and I think I had about $14.62 in the whole rig.

I would use a couple of zip ties and some JB weld and make my own disk mounts. I would then make my own disk adaptors for the wheelset. I have done this in the past and it works great and I think I had about $14.62 in the whole rig.

since i'm new here, I can't tell if this is a joke or all seriousness. If serious, do you have a DIY of any sort or a list of parts that could be used for this purpose? I would most definitely consider this.

There is this

http://cgi.ebay.ca/A2Z-Rear-Disc-Brake-Mount-for-Tabless-Frame-DM-UNI_W0QQitemZ330316102947QQihZ014QQcategoryZ27949QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

But it would not work on your frame. Even if it did, your rear chain stays would probably not have enough clearance for the disc (the disc would rub, since these were never designed with discs in mind). Also if you did set something up your chain stays would probably fail with the extra load on them.
Look at a disc ready bike and see how much reinforcement is back there.

There is this

http://cgi.ebay.ca/A2Z-Rear-Disc-Brake-Mount-for-Tabless-Frame-DM-UNI_W0QQitemZ330316102947QQihZ014QQcategoryZ27949QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

But it would not work on your frame. Even if it did, your rear chain stays would probably not have enough clearance for the disc (the disc would rub, since these were never designed with discs in mind). Also if you did set something up your chain stays would probably fail with the extra load on them.
Look at a disc ready bike and see how much reinforcement is back there.

That's for the frame (as you know). That wouldn't help with the fork. Revert to 66's mod for the fork.

For the frame with the a2z...a 140mm may clear.


Possible to install disc brakes on old non-disc-ready fork?

You can't, sorry. You would need new wheels too by the way, by which point it would be cheaper and easier just to get a new bike.

or you can just replace the hubs with something disc-ready. six bolt or centerlock. reuse the old rims.
oh, the frame. A2Z will work. you should replace the fork as well.

There is this

http://cgi.ebay.ca/A2Z-Rear-Disc-Brake-Mount-for-Tabless-Frame-DM-UNI_W0QQitemZ330316102947QQihZ014QQcategoryZ27949QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

But it would not work on your frame. Even if it did, your rear chain stays would probably not have enough clearance for the disc (the disc would rub, since these were never designed with discs in mind). Also if you did set something up your chain stays would probably fail with the extra load on them.
Look at a disc ready bike and see how much reinforcement is back there.

Hi, thanks for the link.. doesn't my frame already have a mount (from the picture)? Or are those two holes used for something else?

That's for the frame (as you know). That wouldn't help with the fork. Revert to 66's mod for the fork.

For the frame with the a2z...a 140mm may clear.

Link to the 66's mod please? Is 66 a person?

If you have a 97 GT, ride it for what it is, a now vintage style MTN bike. It has a old style fork and I am guessing older components? Honestly, not trying to be mean or harsh at all, but even if you could upgrade to disc, its not worth it, on that bike. Save your cash and get a late 2000's model, and if you can afford it, keep the old GT for a second bike. I have a small collection of Fishers, and ill be honest, lately, I have been riding the two late 90's models with the spring forks and v brakes the most. They seem to give me a better workout.
I would love to have a older GT like that, those frames are the bomb!!!

Hi, thanks for the link.. doesn't my frame already have a mount (from the picture)? Or are those two holes used for something else?

sry but those holes are for mounting a rack and/or fenders, disc mounts are diff, and you are sol

I would use a couple of zip ties and some JB weld and make my own disk mounts. I would then make my own disk adaptors for the wheelset. I have done this in the past and it works great and I think I had about $14.62 in the whole rig.Nice little block o' 6061 from the scrap yard and eight hose clamps will do it too :D.

If you have a 97 GT, ride it for what it is, a now vintage style MTN bike. It has a old style fork and I am guessing older components? Honestly, not trying to be mean or harsh at all, but even if you could upgrade to disc, its not worth it, on that bike. Save your cash and get a late 2000's model, and if you can afford it, keep the old GT for a second bike. I have a small collection of Fishers, and ill be honest, lately, I have been riding the two late 90's models with the spring forks and v brakes the most. They seem to give me a better workout.
I would love to have a older GT like that, those frames are the bomb!!!

want to buy it? =)

thanks for all the help and info guys, I guess it's going to be more money and time than it's worth. i'm in grad school so it's hard to justify buying another bike (regardless of how cheap) if i already have a working one..

There is nothing wrong with decent v brakes...

My 2001 Rocky Mountain Blizzard has no disc mount on the frame which is a little sad since it is about as good a hardtail ever made but the newer front fork does... I run a Shimano mech disc up front and an xtr v brake inb the rear and my braking could not be any better as the front brake does all the work anyways.

Perhaps one day I will get disc tabs brazed to the frame... and in this case they would be well worth it.

Link to the 66's mod please?

Yeah man...sorry. Here's (http://www.bikeforums.net/showthread.php?t=522937)the thread with his mod. Just scroll down and you'll find it.


Is 66 a person?
Used to be a fable until someone didn't take him seriously one night when they were sleeping. Now he's fading into an urban legend.

I'd say that if you really wanted to put disc brakes on a non disc fork that it could be done, but it's not worth doing on the old GT Aggressor unless you've got money to burn.

These don't look like your standard brake mounts and they look like they might be the sort of thing to solve the "old fork without disc tabs problem":

http://p1.pinkbike.com/photo/2547/pbpic2547100.jpg

If you just want hydraulic brakes look at some Magura HS33 rim brakes. I have them on one of my mountain bikes and I think they are probably superior to discs in many ways. I think they are "THE" brakes in trials competition where power/modulation and reliability are high priorities.

Link to the 66's mod please? Is 66 a person?

Is '66 a person???? Oh no, he is much more than a person or an urban legend. He is the shredder of the gnar in Pisgah National Forest. He is the reason that hikers shiver and weep in fear when they hear the sound of knobbies in dirt. He is the reason freeride bikes were built, he is mountainbiking.............now you know this.:innocent:

Is '66 a person???? Oh no, he is much more than a person or an urban legend. He is the shredder of the gnar in Pisgah National Forest. He is the reason sheep tremble and back into a circle when they hear the sound of knobbies in dirt . . . .Fixed.

Fixed.

:notamused:

Fixed.

:roflmao2:


I wondered what the heck that was all about.
http://img.dailymail.co.uk/i/pix/2008/01_04/sheepcircle_800x601.jpg

^^ Word got out one year that 66 was considering racing in The Iceman Cometh. The Local populace braced for it . . .

http://cache.eb.com/eb/image?id=62574&rendTypeId=4

Once again.......:notamused:

The jealousy will eat you guys alive...let it go.

http://1.bp.blogspot.com/_SqhhJb_P3Kk/SayQYXRdw3I/AAAAAAAAFhM/_h49gHKW75k/s400/mountain+goat.jpg

"If we pretend we're rocks, maybe he won't see us."

^hahahahhhaaha

I'd say that if you really wanted to put disc brakes on a non disc fork that it could be done, but it's not worth doing on the old GT Aggressor unless you've got money to burn.

These don't look like your standard brake mounts and they look like they might be the sort of thing to solve the "old fork without disc tabs problem":

http://p1.pinkbike.com/photo/2547/pbpic2547100.jpg

What's the name of this brake system? Link?

What's the name of this brake system? Link?

It's called 'Over Kill"