GT Zaskar ('92/93?) Rebuild Complete

[bkpsu]

Wanted to share the build log of my GT Zaskar I picked up from a coworker of mine earlier this year (March). I decided to rebuild it back to its fully stock glory, mainly the Deore XT components. I'm very happy with how it turned out, and this has now become my main bike. It took me a while to get used to the bike's geometry, but I'm amazed with how well it rides now and it happens to be a perfect size for my 6'3" height.

Compete album: https://imgur.com/a/vlZeZ

I was never able to 100% figure out its age (no sign of a serial # on the rear chainstays), but from my best guess, it's a '92, mainly because:

-It came with the RS Mag 20s (which were replaced with the Mag 21s in 1993)
-It has a non-removable rear derailleur hanger, which was modified to a replaceable one in 1993 and on.
-It has a 68mm BB, which (I think) was changed to a 73mm in later years?

Any ideas on how to better date the bike would be welcome.

Thank you!

 

[legrandefromage]

Hello!

Nice and shiny

The 93 model year went with Aheadset leaving the threaded headsets behind. So yours will be 1991/92

But it could also be a Pantera which is identical until you have the frames side by side. Then you see the colour differences between 6061 and 7005. , 6061 is more silver with 7005 a lighter finish.

Don't know about the 68mm shell, not seen one myself so far. They've all been 73mm for me.

 

[Thias]

It has u-brakes. I think those are pre 91, right?

Edit: I did a bit of research and found out GT still had the u-brakes on Zaskar frames up until 92. So thats no help.

 

[Retro Spud]

Welcome to Retro Bike .... Great 1st post

 

[Factory Jackson]

Hello!
Don't know about the 68mm shell, not seen one myself so far. They've all been 73mm for me.

My 1991 Zaskar has a 68mm bb shell if that helps date it.

Lovely bike by the way.

 

[bkpsu]

Thank you all for responding and the hints! It's definitely interesting looking at the catalogs, because parts from my bike match different versions of the catalogs (92 or 93). I'm going to go with '92, based on my best guess and your inputs (shell size, threaded headset, etc...).

I visited a bike shop auction this past weekend, and came across a spare Mag20 fork in great shape! The steerer tube is way too short, but the legs are good (full motion and they hold air!). I ended up having to mod the original shocks (filled them fully with AT fluid and used a foam insulation insert to replace the worn out air valve to stop them from bottoming out), so they're stiff. I will replace them with these to see if the ride's any better...

In the long run, I'll keep looking for more original parts to replace (flip-flop riser, bars, GT seat post, pedals, etc...)

 

[Thias]

You can repair the mag air valves by making your own valves out of silicone. (The stuff that is used to seal bath tubs..)

Hey guys!

Inspired by this thread I tried to make my own replacement valves out of Silicone. My first try is a standard 1K silicone that I had left over from my bath renovation...

My mold is made out of aluminium tube, 8mm inner diameter. Cut it a bit longer than the original valve rubber. Closed the bottom with some tesa strips and pinned a few little holes to allow the air to escape.


I smeared a bit of oil on the insides so the silicone would slide out when hardened. Then filled the silicone in and left it alone for to days. Was not long enough thou..



As you can see, the right "plug" got damaged while sliding it out. They were not cured completely. So I had to wait another week before my attempt to make the hole for the ball needle.

Yesterday I did that eventually, using a thin needle. Then slid it into the Mags Valve cap, lubed the ball needle and filled some 250 psi.

....

Seems to hold the air. I tried to slide the ball needle in and out a few times. That went OK. So now I will wait a few days and see, whether it holds the pressure or not.

Wish me luck!

I had those silicone plugs in my mag for more that a year now and they hold up.

 

[Lhatch4]

Nice build!

 

[bkpsu]

Thias, thank you, that is excellent! I was looking for that info during the rebuild, but all I found was some people advertising their services to fix the valves, did not come across that post. I bought different strengths/thicknesses of rubber seal cord, but the thing that ended up working best was 1-inch "Frost King" round foam seal. When compressed inside the valve, it sealed up rather nicely and allowed me to pump the air in (though I had to be careful taking the needle out, as the hole wasn't closing fast enough). I will definitely have to try your method once I replace the fork and can play with the old ones...

Thanks again, everyone, this is a great community!