BLD25

Hello, I found a giant Propel Advanced that had an ultegra crankset crack and take out the detailer hanger. I was thinking o could pick it up cheap for less than a couple hundred bucks and run it as 1x and repair it myself maybe. Any thoughts?

BLD25

Is this the wrong place to ask this question?

Trsnrtr

I can transfer it to the Bicycle Mechanic's Forum for you. Probably a better place to ask.

DanBell

Unless you're planning on repairing it yourself, you're probably best off sending pictures of the damage to a reputable carbon frame repair shop and have them give you a ballpark figure on the repair. That combined with the price you can buy it for will tell you if it's worth it.

BLD25

Thanks!

Brocephus

Not enough info here, but if you can get an Ultegra-equipped bike, that has a busted carbon frame, for a couple hunnerd bucks, that sounds like it MAY be a great deal, just for the parts.
Then hunt down a deal on another frame, and transfer the parts to it. But, how well do you know the seller, and trust his word on how the bike was ridden ? The bike could be rode hard and put up wet, a dozen different ways, and the whole project could quickly become a money pit.

WizardOfBoz

The Propel Advanced was (I think you have a 2014 frame) a pretty pricey bike and the market value of the frame may justify a fix. If you got the complete bike for a couple hundred bucks I'd say you got a deal, even if you have to buy a new frame.

New frames on eBay seem to go for in the neighborhood of $500-750. If you can get this fixed for less than that it may be of interest to do so and reassemble the the bike. If the cost is close to that or higher I'd be prejudiced to toss the frame and buy a used one.

IF the only damage is the FD hanger pulling out, the cost shouldn't be that high. But as suggested by others, send pics to a reputable repair shop to get quotes.

Given the nature of your question, I'm assuming that you don't have a lot of experience in fixing high-modulus fiber composite structures. If this is the case, I suspect that "fixing it yourself" will be unsatisfactory.

sch

Where I would be willing to tackle a pure CF repair ding, one in the FD mount area such as pixed is more involved, and may
need a new FD mount placed, or not, but likely removed and replaced. At any rate a google on CF bicycle frame repair
listed three shops that offer such services: Appleman, Ruckus Composites and Calfee. Calfee has had good reviews.
Typical costs run in the $150-300 range, this repair likely more rather than less. Repaint not included. If bike priced
right this is a good deal.

CliffordK

I thought I had replied.

Anyway, the easiest repair would be a simple wrap, but low tire clearance could be an issue. Necessitating a better, but more involved repair of grinding away and feathering edges around the damage and making a patch/plug.

Carbon Fiber work is somewhat different than fiberglass, and tends to squeeze out as much resin as possible, but still should be doable.

Dropping to 1X should make it easier, as you don't have to put the hanger back on (and avoid the cause of the problem in the first place.

You may not suffer a catastrophic failure at that location, but it does get a fair amount of stress from right/left pedaling forces. So, whatever is done, it will need to be strong.

BLD25

Thank you to those that have replied. To make things more clear, it is not a complete bike, but rather the frame. The guy threw that number out, but I might be able to get it cheaper.

I am considering repairing it myself. I have not repaired carbon, but I have looked into it. I had not built wheels, or installed a groupset either until I tried it for the first time.

To reiterate, my thoughts were if I could get it cheap enough and remove the derailleur hanger and repair the carbon, I could have a sweet 1X frame for peanuts. I guess I was hoping someone had done something similar, or could say with more authority that this particular location on a frame was more/less of a deal. Anyway, thanks for any help!

Mad Honk 

BLD,
I work with CF almost daily and once the fibers are broken they cannot be repaired. The frame is toast for all the correct reasons. If you want a CF frame look on the appraisals page here. One of the co-ops had four of them for sale in the last month. I think that if anything sounds too good to be true it likely isn't. FWIW. HTH, MH

mrt2you

i have never repaired CF but i did attend a couple of classes about doing them on corvettes.
it requires really specialized equipment and isn't something for a DIY repair.
a quick overview of the repair goes somewhat like this.
first you must grind out all of the damaged fibers, then feather them back. once feathered you count how many layers of CF there are and what direction the fibers face.
you next use pre-saturated CF matt and lay them in the proper direction and the same amount of layers as the original part. you also have to cut the matt at the ends of where you tapered the original area ended. after laying each layer you roll out as many air bubbles as you can. after rolling you seal it in a bag and remove the air. once the air is removed you use a heated pad to cure it. once cured you lightly sand the edges to lay back to the original area. i am sure with a hollow bike tube being repaired there is something that gets inflated to support the back side.
one very important part is don't breath the fibers. they are hazardous to your hands, lungs and skin so wear appropriate protection. also vacuum all fiber dust away. don't blow them off the part. once airborne they can stay that way for a long time and again are hazardous to your health.

2old

I've heard nothing but good reports about Craig Calafee's carbon repair. Look at his website and maybe send a picture for a quote in order to assess the amount of work necessary.

zacster

Stay away. I have an older cracked carbon frame that I didn't consider sending for repair. I just bought a used frame instead for what it would cost to repair, if that is even possible, and then you never know when it will fail again. It just isn't worth it.

Kimmo

I have a bike with a crack above the FD, and it's okay, but this doesn't look it. I'd be interested in repairing it if it was free, but I wouldn't pay for it.

sch

If a possible starting point for a 1x bike, then removal of the FD mount, stripping paint/coatings off and
pushing back the bulged out CF with feathering would allow an over wrap of CF using one of the
inexpensive kits. As long as you bulked it up reasonably I think it could be done. That is a high stress
area on the bike but a fracture of the tube is more likely under high torque pedaling scenarios than bombing
down hill. It would not be a bike I would want to use in the local "Worlds" sessions.

BLD25

Okay, thanks everyone