Giant Cadex 980c Build - Ultra Budget and Lightweight

[QuangVuong]

GIANT CADEX980C

Giant's stable boasts an economical Shimano 105 SC- equipped carbon fiber road bike and the market's only carbon fiber hybrid (even though it's not called one) . The $799 980C road bike has 8 carbon fiber tubes (including the monostay rear triangle) bonded to polished aluminum lugs, a one-piece head tube/lug assembly, and stainless steel dropouts . The fork is polished aluminum . While not revolutionary, the 980C breaks ground by of-fering high-performance composite technology to the masses .

http://www.giant-bicycles.com/en-au/abo ... .masses/3/" onclick="window.open(this.href);return false;

Looks like it was first introduced in 1987, but my model would possibly be from 91, from the serial number on the BB(GC101241 and 9J30). When it was first realeased, it had red writing with a white 3D shadow. From 1990, the shadow changed to blue like on mine. And in 92, the writing changed to silver with a red shadow + additional colourful shapes. So its from the same year as my Peugeot, and 2 years older than the Centurion.

Parts List(Prices do not include postage price and ones for $0 came with frame.)
Giant Cadex 980c Frame - $100 - 1723g
Giant Composite Fork - $0 - ????g
Shimano 600 Headset - $0 - 108g
Rolls Titanio Saddle - $0 - 309g
Sakae seatpost - $0 - ????g
Sakae Stem - $10 - ????g
Carbon Drops - $20 - 290g
Bar Tape - $2 - 45g
105 Groupset(Mix of 105SC and 5500) - $65 - ????g
KMC Titanium Chain - $35 - ????g
Fulcrum 5 Wheelset - $50 - 1755g
Rubinos - $30 - 500g
Cables + Housing - $15 -????g

Total Cost so far: $327
Weight as of now: ????g

Anyway, got the frame this morning








Bottom bracket with weird looking corrosion.


This fork, Im pretty sure would be from the CFR1. The original fork would look exactly like the one on the Centurion. So got to work on the forks first of all. It had the label composite on it, and I was hoping that it would be a carbon fork. After sanding down the paint, it turns out that it is, but theres an issue. Theres water on the forks so I could take clear pics otherwise itll be kinda foggy.


Right side fork is all good 3k weave.


But left side is unidirectional.


Well, thats all I got done today. But there is a question. What should I do about the lugs? Polish(however, I dont ewally wanna go through hours of polishing again), brushed(something unique, but in which direction?), or black painted(easiest method, but kinda boring)?

[wqlava1]

The frame looks good but the forks look like they have a crack along the outer right side and scratches across the inner face of the left side, from your photos. Am I not seeing it in the right light? Not wanting you to do a face plant whilst out riding it.... I've got a CFR3 of my own and a CFR1 that one of my sons rides - both with what looks like the same frame. I keep watching for any damage on the frames. Both had aluminium forks from new, different from your model.

[QuangVuong]

That fork was 100% fine with the paint on. Once I sanded it off, it looks crap. I am sure there are no cracks, and whatever else. Those arent scratches. Thats just the unidirectional CF weave, compared to the 3k weave on the right side. Im prob gonna paint it in gunmetal/black to hide the crappy CF weaves.

I believe all the Cadex(CF ones) frames were the same. Hopefully the frame will hold up.

Anyway, I have stripped the clear coat, and will begin polishing the lugs. Giant had decided to clear coat the lugs as well, making everything a little harder to do.

[Dan]

At the risk of repeating myself (in a thread which is pretty much a repeat of that in which I originally posted something to this effect) - I'll leave you to test ride a 20+ year old set of carbon forks.

Make sure you take a video.

[QuangVuong]

Dan, no worries Ill test it out, both frames as well as this fork. Will be testing out something else as well(better check down below)

The clear coat on this frame was in too good condition which meant it took a while to strip it. Gonna go for a brushed finish on the lugs, so gotta sand down the lugs a bit first.

Got the tubes painted though




You guys may call me crazy, but still. Yes, these are two holes I drilled into the top tube for internal cable routing.
Underside near the headtube


Topside near the seat post.


Brushed finish is a little too rough for my liking, so I Will continue sanding, before brushing it.


As for the forks, painted them gunmetal. Decided that the odd CF weaves look weird. Prob looks better this way.

[hitchhiker]

Hmmm, now I happily ride a lugged carbon frame daily and realise they aren't the death traps some make them out to be, but I'm not so sure about drilling holes in one!

[QuangVuong]

Road or the MTB?

Holes shouldnt be too bad. Look at the braze on tab and the bidon holes, as well as the small holes on the end of the seatstays and the mono stay. There are 2 holes under the cable mounts anyway, so I just enlarged them. If it break, it breaks. Hopefully not when Im riding at speed.

[ldrcycles]

I'd be very suspicious of the forks (looking at the pics, obviously things can look different in the flesh, as you said they don't have any cracks) but the holes for the brake cables should be fine. I'd want to put something around them to seal them and prevent any cracking occurring.

[QuangVuong]

Yep, and heres a longer explanationation of my thoughts. Look at the seat tube. There are 4 holes(bidon cage and braze on tab). This tube is also in compression(as weight is applied on the saddle and hen downwards, and the reaction force will be upwards), so its unlikely that the downtube will break. If it does, then that would most likely be due to too much bending stress. Now th top tube is also placed into compression(forks reaction is towards the back of the bike, and reaction from seat stays is towards th fronts to break if the tube is pushed from either the top or bottom if the force surpasses the CF tubes ultimate tensile strength. Sideways movement will be minimal as well. So I believe that even drilling holes won't make it any worse. Bu you are right about it being a possible source if stress concentration. But then again, when I removed the cable guides, each had 2 holes for mounting. I just enlarged the pair near the seat, and drilled one opposite the pair nearest to the head tube. If it breaks then it won't be too catastrophic as the tube will push other, and it'll be unlikely the rest of the frame will fail too. It may crack but not fully break.

I will try to find suitable internal cable mounts, but if I can't, the polyurethane has already sealed up the weaves. Plus, the brake cable will be there anyway, so it won't be exposed.

I will try to find suitable internal cable mounts, but if I can't, the polyurethane has already sealed up the weaves. Plus, the brake cable will be there anyway, so it won't be exposed.


Oh and this frame is actually heavier than the Centurion. Most likely due to the larger diameter tubes, and maybe even thicker tubes. Which is ok with me. I'd prefer a stronger frame incase anything happens.

[munga]

what could go wrong?

[ldrcycles]

when I removed the cable guides, each had 2 holes for mounting.

My bad, i had missed that before. In that case i think it'd be pretty unlikely there would be any problem.

[Dan]

Not an engineer, but wouldn't inwards force from either end of the seat tube put it under compression, not tension?

[QuangVuong]

Ah right. Dunno how I managed to write tension twice.

[QuangVuong]

The build begins!


But first, need to polish up the stem and post


Someone must have painted this stem black, as well as cut it! Little short for my liking. Im fine with a cut stem, but who cuts it right at the max height insertion point?


Anyway, sanding began with 180 grit paper to remove the paint and larger scratches


Then continued with 240 grit for the leftover paint, and smoothing out the scratches


Then 600 grit paper.


Polishing begins for me at this stage. Sure I can continue through to 2000 grit paper, but thats only if Im really bothered. I use Autosol, and some random cloth, and the process is below in the video. I really should buy a buffing wheel for the bench grinder. Thatll get me to mirror finishes in no time with no effort.


Click to play


End result. Still need to do a little more around the clamp area.


Well, got everything together, and only need to do the final adjustments tomorrow! Dont mind the BMX pedals. Need to get used to the Dura Ace toe clips first, or find a pair of road pedals.


My lovely hollow gold chain!

[ldrcycles]

That chain looks sick, the whole thing is great, brilliant job .

[QuangVuong]

Thanks. All my bikes will run gold chains. This is the only one with a hollow one though.

FInally bought a foot pump. Bloody massive thing. Blackburn TP-5


And more shots!












More gold chain goodness






The shiny Nitto


Rolls Titanio

[hitchhiker]

That has come up very nicely! Well done

[rheicel]

Nice work!

Sent from my Nexus 7 using Tapatalk 2

[HappyHumber]

Looks the goods....

Now ride it HARD and LONG and prove the carbon-doubters wrong.

[sunho]

great job mate.
some aggressive bar position there!

[QuangVuong]

Thanks guys!

HappyHumber, will do! Ill take it easy for the first couple rides, then once I feel what it can take, Ill go back to my curb jumping and aggressive riding style. Today I did go for a longer ride, and hit 60km/h. The forks and frame all hold up fine, so its looking good so far.

sunho, I just copied the same bar position as my Peugeot(which was set by the previous owner). I found it comfy, and so stuck with it. Did adjust the hoods to my liking though. Anyway, youll be seeing this frame on the Sat retro ride!

[sled]

sweet maybe i should keep that cadex nice work

[LugNut]

That came up quite nicely. I sold a similar frame for $50 buy it now on eBay, it was listed for about 40 minutes - I didn't realise there was actually a market for these things. I guess I see why now.

Personally though, I'm with this guy.

[Joe H]

QuangVuong,

Having seen this bike in action today I went back and re-read the thread. That was a seriously good job with the frame and build. It looks great and was obviously well set up. It's a cool thread and I'm sure I'm not the only one who will be interested to see how it holds up as the miles go by. I have a friend who just noticed cracks in the frame in his $3000 carbon fiber Merckx after about 3 years. You hear stories about how fragile carbon is and then you see how really old carbon is still out there. I have too many bikes and all but two mountain bikes are steel (those two are aluminum), but I'm intrigued by how this (or your other CF bike) go. Twenty years ago I was really interested in the Kestrel 500 SCI (CF, no seat tube, 650 wheels) but wondered how it would hold up. Never did get one but I may have to check around... Well done on both and thanks for posting.

Joe

[QuangVuong]

Hopefully this will be able to hold up for the next decades as well! Did you jump the speed humps on the downhill from the golf club? I did on this. Was wary about it snapping, but looks like it can hold up. The Centurion will last forever as I wont be riding as much due to rarity. And you do hear about these newer frames being quite fragile, most likely cause they are 1-2mm thick! The holes I drilled were through ~3.7mm thick tubes(crazily over engineered), and so I wouldnt be too worrysome about that, and more about the lugged joints.

And about Kestrels, I am addicted to the looks of the 4000! Got someone to look out for one in white for me over in the US. Thats most likely my next bike project at the end of the year when Im done with school, and able to make some money.