1989 Trek 7000 Mountain Bike/Gravel Bike

For my ongoing set of bike creation and rehab projects, I finally got around to repurposing a bike I've had for a long time. This is a 1989 Trek 7000 mountain bike that I was gifted for my college graduation. A fairly progressive ride for the time with a 'glued and screwed' aluminum frame complete with what were then considered 'oversized' tubes. It was used in true mountain bike mode for years before being supplanted by a full-suspension MTB years ago and being relegated to utility duty.

But it is now 2023 and gravel bikes are a thing. Hey, people even claim that gravel bikes are just 90's mountain bikes anyway. So let's test that out.

I decided to do a full renovation on the old 7000 and turn it into a gravel and adventure bike that perhaps I can use to lure the kids into joining me on trips.

Changes planned (all the best laid plans)

New tires. It needed them anyway since the old ones literally crumbled as I removed them. A pair of Schwalbe Billy Bonkers 26 x 2.1 tires look pretty cool. Wide by 1989 standards and even a bit by modern gravel standards. But this bike is stiff so some extra compliance doesn't hurt. They are mildly knobbed, decent rolling tires that should do fine on all sorts of surfaces

Drop bars. Because 'real gravel bikes' have drop bars, right? Also because I find that riding any distance on straight bars makes my wrists and hands hurt and I prefer curly bars for the hand positions. It was also an excuse to shorten up the reach as 80's mountain bikes had crazy long stems top tubes and thus reach. I was gifted a pair of flared alt bars with an extra loop for hand positions and/or mounts so that seemed a good place to start.

New stem: But, that requires a modern stem and this bike is an old-school quill stem into a threaded steerer tube which would need to change. The old steel bars and welded stem were definitely showing age with rusty spots etc. To continue using them safely would require a sand, inspect, paint effort. And the stem wouldn't hold modern bars anyway.

I lucked out and found someone selling a Ritchey stem along with a quill-to-threadless adapter. Perfect. Brings the bars back and up a bit from their original placement which is a good thing.

But, removing the stem brings another problem. The original integrated the housing stop for the front cantilever brakes. No stem, no anchor. Off to find an old-school 1" threaded steerer tube bracket that replaces a washer in the stack and anchors the housing instead.

New brifters (integrated brake/shift controls): Going to drop bars requires different brake and shift controls. I didn't want to replace the actual drivetrain, so it needed to control a 3 x 7 system. Hmmmm, vintage shopping time. Well, it turns out that's complicated. Even though vintage derailleurs are compatible between road and MTB, 3 x 7 wasn't really a thing in integrated 'brifters'. They didn't show up until the 8-speed configurations. But, it turns out that Shimano sells 3 x 7 groupsets today as low-end options. So, a new Tourney set of brifters meet the spec and are cheaper than vintage gear anyway. Funny thing is people complain about the Tourney groupset because the shifters use a thumb knob on the side for shifting to smaller gears. But that's how Campy does it anyway so that's fine by me. I did learn later that the Tourney brifters have a nasty habit of pinching the rider's hand when used. It's also worth noting that had I not done the drop bar conversion, I was going to have to find some replacement thumbies anyway because the old ones shattered while replacing the cables earlier.

Plans vs Reality, ugh

That was it for the intended changes. Miscellaneous cables and bar wrap were expected. But let's go down the rabbit hole of discovery when rehabbing an old bike:

Front hub: This bike hasn't been torn down in decades and it was ridden in mud over the years. The bearings surely can use an overhaul. So out comes the axle to find hardened, cruddy grease remnants. No biggie. The races are in decent shape (a few small pits) as are the bearings (so I thought). Clean it all up and reassemble it. Ugh. I haven't worked on cup and cone bearings in years. They require a fiddly game of getting the cone 'just right' and then backing it off 'a bit' to retighten with the locknut. Then turn and wiggle. Too tight and the bearings bind. Too loose and it wiggles. Either way, undo and try again. Many many times. Finally got it 'good enough' and moved on.

Rear hub: I'd actually had the cassette off to clean (and test the ultrasonic cleaner) earlier this year so I imagined this shiny end would be fine. But once I got it out, ugh. Rough turning. No problem, clean and restore like the front. But this time, it is obvious that while the races were still ok, half of the ball bearings were damaged and beyond reuse. So, order a bag of 100 (the small bag) and install them. Wow, how much easier that cup and cone adjustment is when pitted bearings aren't involved to bind the motion. I'll just use some more of these bearings to redo the front. Uh, no. For 'reasons' rear Shimano hubs use 1/4" balls but the front hubs use 3/16" balls (yes, SAE on Japanese parts). It's been that way forever. Sure, to a manufacturer it makes no difference and you might as well size to need and keep costs and weight down on the front. But to someone maintaining it, it is really annoying. ButI got the 3/16" balls too and redid the front again. Much easier with fresh bearing balls.

Bottom bracket: Well, after that discovery in the rear, there was no way I wasn't going to pull out the bottom bracket now even though it felt basically ok at the pedals. Pull the cranks, grab the spindle... ewwwww. That's a nasty grind in there. Pull it apart to find damaged balls AND races this time. It's a goner.

No problem. Square taper, 68mm English threaded BBs are a dime a dozen and readily available, right? Uhhhh. Sure. Unless you happen to have a 1989 Trek 7000. For some reason, it used a very long 136mm spindle. Something that appears to not have been made in well over a decade. I could find used ones on eBay but they didn't look much better than mine. After asking advice from other mechanics I learned this is a real oddball size. Most had never seen it and the few who had didn't know where to get one.

So, given that the other dimensions on the bike are normal (rear spacing, BB width etc.) I took a gamble and ordered a common Shimano BB in the longest still made - 127.5mm - and hoped it would be long enough. It's only 4.25mm on each side. Amazingly enough, it did. Several mm clearance still on the chainrings and crankarms and a chainline that looks and works fine. So I really don't understand why the original was 136mm. That would make the chainline further out and make a really wide Q factor. Hmmm

After this, it was pretty much straightforward rehab work.

Cleaning. Years of grime to get off of white paint and out of crevices. But other than where damaged over the years, it is in great shape. I think it was automotive Imron paint back in the day. Being aluminum, there was no rust to deal with. Surprisingly the inside was clean too. Head tube clean and BB not bad considering the damage there.

Replacing cables and housings (some were ok, others rusted). I even found the cool (not common in the 80s) internal routing of the rear brake was done well with internal guides and the replacement compressionless housing slipped right in after threading out the old one. (yes I kept a fishline on it but didn't need to, it turned out).

Cargo: While I was doing this project, I figured I'd finally make the rack actually be sturdy. When it was installed eons ago, the only fit kit the shop had was some chintzy sheet metal and bolts that kinda worked. But put any real load on the rack and it would slowly bend.

Not great. It's tricky because there are no seatstay mounting points, it has to be the brake bridge hole. But being cantilever brakes, that means the struts have to split around it. But I found a sturdy bracket from Old Man Mountain that it meant for mounting lights but super overbuilt. Then regular struts reach out and do the job.

I also had some fenders lying around, and it's Winter, so let's do it right.

Miscellaneous: For some reason, 34 yr old rubber blocks were a bit hard so new pads. Bar tape (hey, it's an 80's bike with teal accents, why not go colorful). Put on some flat pedals so others can ride it.

Results and later

All in all, it came together really well. Snazzy new look. Better fit than before with the raised bars with shorter reach. I did end up getting a chance to test some Reshift Top Shelf handlebars which raised the bars another 50mm which made it perfect. Shifters work fine (if somewhat hazardously) and it actually passes as a good gravel bike.

I also found some very bling Avid Shorty Ultimate cantilever brakes. Easy upgrade, right? Nope. Installation got complicated because it turned out the rear mounting studs were mildly misformed. Or so I thought. They worked with the original brakes and the front but these new brakes just bound up every time I tightened the anchor bolts. After a bit of trying to figure it out including trying a variety of nylon washers as slip spacers etc, I left the original cantilevers on to revisit some other day. Or perhaps year. Eventually, I got tired of seeing the rear cantilever sitting there and revisited the problem. I had misunderstood the issue. The front brake bosses were attached to the steel fork. They were very normal. The rears were bonded (glued and screwed in this case) to the aluminum steatstay and appear to have been custom kit. The base or the boss (the widest part where the spring hole usually is) was not set deeply enough. The main shaft and thicker base were fine. But when the brakes were bolted down, the back rubbed against that base and locked up. Apparently the old Shimano LX cantilevers were a fraction of a mm less deep. So, with a little experimentation with sandpaper, a dremel and file, I was able to remove a fraction of a mm of the aluminum base and provide clearance. Ta da! Now the rear brake works. Much nicer looking. (And probably a bit better functionally, but I didn't do side by side testing)