Tips for rebuilding 80s Giant?

swelo · Apr 1, 2024

I love my riding 1989 Giant Sierra and use it as my go-anywhere ATB (mostly gravel and forest paths).

The paint is extremely chipped and scratched, and my touch ups haven’t helped much (looks better in the photo than in person), so I’m having it repainted. This creates an opportunity for braze-ons—specifically, I’m considering adding rear cantis to the seat stays and removing the chain stay-mounted U-break. Good idea? Bad?

A second area of consideration is the drivetrain. I really enjoy riding singlespeed, so that’s my initial idea. The drop-outs (although horizontal) are short, so I’m anticipating there’s at least a 50/50 chance I’ll need a tensioner. But it’s not a big leap from a tensioner to a rear derailleur, so I’m also wondering if a 1x7 would be a logical way to go for this particular bike. Any downsides to a 1x1 + tensioner and/or upsides to a 1x7 I should consider?

Thanks in advance for any input, suggestions, and cautionary tales!

Here’s the bike in its current form:

Uncle Grumpy · Apr 2, 2024

swelo said:
I love my riding 1989 Giant Sierra and use it as my go-anywhere ATB (mostly gravel and forest paths).

That helps to know. Seriously, knowing how a bike is going to be used helps us help you spend your money...

swelo said:
The paint is extremely chipped and scratched, and my touch ups haven’t helped much (looks better in the photo than in person), so I’m having it repainted. This creates an opportunity for braze-ons—specifically, I’m considering adding rear cantis to the seat stays and removing the chain stay-mounted U-break. Good idea? Bad?

Not a bad idea if you're getting the frame refinished. Also factor in brake ons for the cable stops. I was going to suggest brazing on a disc tab, but then you'd need a new wheel, assumed cold setting to new spacing to 135mm and then you'd want to add discs to the front as well - but now we're talking big investment for not a lot of gain.

Running a set of well set-up cantilevers will be fine. If you want to go with v-brakes then you'll need new levers with longer cable pull.

swelo said:
A second area of consideration is the drivetrain. My initial idea is to go singlespeed, but the drop-outs (although horizontal) are short. So I’m anticipating there’s at least a 50/50 chance I’ll need a tensioner. So that has me thinking about two rear cogs (manual change)…or just leaving the rear derailleur (Mountain LX) and making it a 1x7. Any advice on SS with a tensioner vs. 1x7 for this bike?

By all means play with single speed, but you'll need a tensioner (or maybe you'll get away with a half link or a half link BMX chain). Another option is a short cage derailleur such as that found on a road bike. Lock it into position with the set screws or a short length of cable.

1x7 is another option if your trails aren't super hilly.

swelo said:
Thanks in advance for any input, suggestions, and cautionary tales!

I wouldn't listen to me, I still run training wheels and I only come here for the tips on dog grooming.

Grumps.

looks easy from here · Apr 2, 2024

If you want to ss but skip the tensioner you could look up if there's a practical magic gear for your bike. You just need the precise cs length. https://eehouse.org/fixin/fixmeup

Re: geared vs ss, based on your flag I assume you have a hill or two in your vicinity?

Relics · Apr 2, 2024

I think you're crazy to get rid of that lovely Biopace triple... But then I have strange tastes 😅
If it were me I'd have another set of water bottle mounts added, canti brake bosses if you don't get along with the U brake, maybe a couple of braze ons on the fork legs for front pannier racks if it's appropriate for your use, and build it back up as it is.

My daily ride is the same year as yours and I just love the 21 speed groupset... I've never once wished I had less choice of gears while riding 😉

swelo · Apr 2, 2024

Thanks for the tips, all.

My other bike is a singlespeed running 73 gear inches, so I’m not afraid to mash up the hills around here!

But I’m increasingly leaning toward leaving it geared since I like this as a go-anywhere bike, and ideal trail gearing is spinny asphalt gearing. Plus, once a tensioner is involved, I get thinking about two rear cogs a couple teeth apart, and then it’s not much of a leap to a few more cogs and a lever on the handlebars to switch between them. 😆

swelo · Apr 3, 2024

looks easy from here said:
If you want to ss but skip the tensioner you could look up if there's a practical magic gear for your bike. You just need the precise cs length. https://eehouse.org/fixin/fixmeup

Re: geared vs ss, based on your flag I assume you have a hill or two in your vicinity?

Unfortunately, with the 460 mm chain stays, the magic gear calculator isn’t giving me a ~60 inch gear inside the blue field. How far outside the blue center can I go before a tensioner is needed?

Relics · Apr 3, 2024

I totally get the appeal of 1x, and also singlespeed. It looks clean and purposeful and saves some weight.
One other thing to consider if you go singlespeed is you'll need to find another chainring. That oval beauty won't let you run a constant chain tension, so then you're either having to find a round 48t ring (which is getting increasingly tricky in that bolt pattern) or keep a derailleur on there.

Another option might be what the young and hip call 'Dinglespeed': Single chainring up front, two cogs on the rear, a derailleur and no shifter. The idea being you can switch between the two rear cogs simply by adjusting the cable adjuster barrel on the derailleur to suit your terrain or physical condition part way through a ride.

Not really sure how I feel about that, but it's another option to consider!

shreddagorge · Apr 4, 2024

I just rebuilt a friend's similar (but newer) Giant replacing a 2x8 with 2x11 and the chainline works. Square taper BB replaced with FSA/splined, and bottom-pull FD replaced with clamp-on Shimano 3x10 that was lying around - interfered with the bottle cage a little (which standoffs resolved). If you're having problems with those caliper brakes, I think "Problem Solvers" has some alternative hanger and pull ratio solutions. Good luck and please keep us updated!

shreddagorge · Apr 4, 2024

Relics said:
I think you're crazy to get rid of that lovely Biopace triple...

Ooh... good eye! 🧐

I once got into an argument with a Shimano rep who was railing on triples and saying their end is nigh. "Good lord, think of the tandem riders!", I pleaded...

swelo · Apr 12, 2024

An update on this project:

Years ago, we were house-hunting and looking at quite a few from the 50s and 60s. And unfortunately, many of them had been “remodeled” to the point of vandalism, where it seemed like the owner didn’t actually want to live in that house and was trying to make it something it wasn’t. You see where I’m going...

I have decided to embrace what this bike is and wants to be: a classic geared mountain bike. So here’s my revised menu:

- 1989 DX brake levers to replace the plasticized Exage levers with unsightly unused shift-mount pieces (because the thumbies were switched out along the way)

- Chain and cassette (the old ones are toast)

- Bars with a bit of backsweep (plus grips and plugs)

- Saddle (trying out a Brooks B67 I already have)

- Panaracer Gravel Kings 26 x 2.1

- Repaint (maybe, probably…the current paint has many dozens of chips and scrapes and unlovely touch-ups)

One thing I’m still wondering—with the new 11-28 7-speed cassette, I have plenty of gear range across the 28 and 38 chain rings. Could I swap the outer 48 with a chain protector (really, the chain is safe, it’s my pants that need protecting!), or would relying on the 38 for the whole cassette range compromise the chain line?

TampaDave · Apr 13, 2024

Are you thinking about painting it yourself? Super fun. Check out the Squid Bikes website for some ideas of what you can do with a rattlecan. As for professional painting, I got a quote for $3000 "at a minimum" from a pro. He was like "Dude, get it powdercoated, it'll last longer anyway." WAY less expensive, even for fancy effects. If you want effects eg fades, you'll have to find somebody who knows what they are doing, expect to pay $500-600. For a single color, really any shop can do that, just make sure they know what to mask off, should be ~$200, maybe less? including blasting, which after you've sanded down a couple of frames you'll be willing to pay any price, believe me. Plus $40 per extra coat (eg clear). Also if you have any small parts that just need to be black, bring em down, they won't charge a fortune to throw em in the pile, they usually assembly-line small parts one day a week. Prismatic Powders' website is a lot of fun if you want to do something unique.

I think you're right about 3x7, it really gives you a good range. 1x7 is fine on the street. For off road, even with a wide range cassette, you'll want a smaller chainring up front and that usually means new cranks. Most (not all) Shimano hubs will take an 8-9-10spd freehub transplant, which is actually pretty easy, there's a little fiddling involved but if you're rebuilding your hubs anyway, it doesn't add any time. Might have to redish your wheel but that's easy enough as long as you pay attention (or get the shop to do it, they won't charge ya much). That's what you want to do if you're interested in 1x off-road, opens up a lot of options. Re bash guard, I'm with you I literally never use the big ring. See if you can find a Girvin Rock Ring on ebay, it's more of a 90's thing than an 80's thing but it would look awesome on that bike

Relics · Apr 13, 2024

I really like this new plan. Pretty much exactly what I did with my '89 rig and it's always my go-to bike. A comfortable, reliable trecking machine:

I can recommend the Brooks Conquest saddle. It was specifically made for mountain bikes in the mid-to-late 80s. A little trickier to track down but I believe they've re-issued them so maybe available new too.

The Rock Ring is a good shout. That was going to be my suggestion too. All the rage in the early 90s!

Are you still planning to oust the u-brake and add some braze-ons here and there?

swelo · Apr 16, 2024

Thanks for the additional tips. For painting, I have a shop that can strip and wet paint for a reasonable price. But I’m not planning on moving the rear brake/adding braze-ons anymore—I’m thinking of the project as just a refresh. The U-brake works fine and is the piece that proclaims this as a bike from 1989.

Tips for rebuilding 80s Giant?

swelo

Uncle Grumpy

looks easy from here

Relics

swelo

swelo

Relics

shreddagorge

shreddagorge

swelo

TampaDave

Relics

swelo

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