GT Avalanche build


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This is my GT Avalanche


I put it together when I first got into mountain biking a few years ago. At the time I wasn't really sure whether I'd enjoy it enough to warrant the expense of something flash so it was built up with whatever I had lying around/could get for cheap. Even the frame was a gumtree special someone had saved from curb-side cleanup. As I fell in love with the sport I slowly upgraded the bits that were really bad, beginning with the Marzocchi shocks and better cantilever brakes. However, what I really needed next was a decent set of wheels, an upgrade from cantilever brakes and better shifters. After doing the sums and thinking it over I decided the best course of action would be to do all three at once. Easy I thought, the front fork already has disc mount and the rear dropouts are chunky enough to safely mount a rear disc adapter.

I set out tracking down parts. I sourced a set of XTR M965 callipers and shifters which also came bundled with a rear derailleur for a good price from the US.


Next were the wheels. A pair of Mavic Crossmax SLR's from a member of the forum


All semester everything waited patiently until I had the time to put it all together. With the last assignment in I got cracking stripping the frame down. Off came the decals, primarily because at some stage someone had incorrectly put Zaskar stickers on the frame and I live in constant fear of a backlash from the vintage GT community. They were falling off anyway so they had to go.


Next I got stuck in with the wet and dry sandpaper and metal polish. An hour or so of work and I had it to an almost mirror finish


The cranks got the same treatment. They were black Deore LX but the paint was rubbed in places and would look out of place on such a tidy frame so they were stripped and polished


Next up was a bracket for the rear calliper. I should have taken more care with the mounting holes because they came out more crooked than I would have liked. If I was doing it again I would drill the holes in the frame first than fit the bracket around that instead of the other way round. At the moment its also a little chunky but its secure and everything lines up properly. I'll get stuck in later with a file and hole saw to lighten it up a little.


The front I thought would be easy, I offered up the calliper, and quickly found the mounting holes too small. I made them bigger on the drill press but upon lining it up again I found the holes didn't quite match. Some weird Italian quirk? A bit of research and I found out the Bomber mounts were for 49mm 'Formula' callipers rather than the 51mm IS the XTR callipers are. The forums are awash with people who have done exactly the same thing. I didn't want to oval out the holes since they were dangerously thin as it is so an adapter would be required. Proper Magura ones existed once but I figured my chances of finding one was slim to non. At this stage I really began to wonder what the hell I was doing. Between new wheels, shifters, callipers, and time I'd spent cutting, grinding, drilling I could have bought a whole new bike. But I figured I'd come this far and the polished frame looked so damn good I had to keep going. I guess its because of this same sentimentality that I drive old Alfa Romeos and have a Lotus Europa in bits.
But I digress... Out again came the cardboard, alloy bar and hacksaw and I started the front adapter. It'll end up being a two piece affair similar to the rear.

This is where I am as of today.


More details to follow as work progresses.

Hopefully it's all worth it...


Likes Bikes and Dirt
Thats becasue those forks arn't desinged to take those sort of brakes, you'd need old Formula's or something from the 90's (as soon as you said xtr, i'm like that;s not going to work...)


Wheel size expert
It's good to see an old classic being kept alive. I would keep it as rim brake myself, it just keeps with the era and vintage of the bike and I haven't seen too many rim braked avalanches getting around either. I have converted a couple of unwanted steal GT frames to disk just to save them from the scrap heap. I use them as loan and fun bikes that just get knocked around by my mates and kids. You can buy A2Z rear brake adaptors that fit perfect and neat on GTs and they are made from a higher grade alloy.


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Hey guys, should of updated this the other week but got distracted working on various other projects.

Had the GT up and running for a couple of rides



I cannot believe, how much better it is, it accelerates quicker, cruises nicer, the brakes actually slow the bike down, the XTR integrated brake and shifter levers are a joy to use (I have no idea why the idea didnt catch on)

Obviously I'm happy with how it turned out. I'm still hunting for a m960/5 front derailleur to tidy up the front shifting though.

The front and rear disc adapters ended up kinda chunky, but they're solid and allow for fairly precise adjustments





So this was great for the two or three rides I got out of it before this happened...


I think a stick must have flicked up and twisted it off, fortunately the rear wheel escaped with minimal spoke damage and the derailleur looks ok. It was just a major bummer, and a long walk back to the car

New hanger has been ordered though, so hopefully be back out in a few days