danallen

I just got this 2008 road bike. Looking at the rear deraillier hanger, it seems ok .

The problem i am wondering about is that






I don't see any way to replace it if it gets damaged. Is it really unfixable if damaged?

dedhed

Anything is fixable The question is cost effectively

13ollocks

is it aluminum? Then I guess you might get one -two “bend backs” out of it. If it’s steel, then it’ll be fine - this was once how all dropouts looked. In any case, in the unlikely event that you do bend it, most things are repairable in the hands of a decent frame builder. Are you expecting to bend it? I’ve gone ~35 years since I last damaged an RD hanger - it’s a relatively rare occurrence if you look after your bike. Perceived repairability/nonrepairability wouldn’t be a factor if I was looking to buy a frame

mixteup

Even if it did break, all is not lost - There are numerous repair kits out there.

FBinNY 

As pointed out, it is repairable but won't be cheap or simple.

If the frame is still in production, a replacement a replacement dropout can be had and bonded in place, making a good as new repair.

Or, if there's enough left, it can be modified to accept a bolt on hanger.

Or, you could fabricate a hanger and a skilled welder could attach it.

Best bet is to try real.hard not to crack it.

Note, heating it will improve the chances of straightening without cracking. But aluminum is extremely conductive, so the question is whether the bonding adhesive can take the necessary heat.

Jeff Neese

I may be wrong, but it looks like forged steel to me. Highly unlikely to bend, and any crash that does bend it is probably going to crack the stays (or at least the joint) anyway.

FBinNY 

Both the color and fabrication scream aluminum. Though it's easy enough to check with a magnet or file.

Trakhak

Anything's possible, but I don't think Trek ever used steel dropouts/fork ends in their carbon or aluminum frames. The pictured dropouts are thicker than steel would be, or so it looks to me, and the finish is the uniform dullness of aluminum. FBinNY and several other experienced posters seem to have taken for granted that the dropouts are aluminum, as did I. If the OP wonders, a magnet test would answer the question immediately.

Kontact 

No one is going to be welding an inch away from an epoxy bond.

The world was absolutely full of non-replaceable aluminum derailleur hangers at one time, and it really wasn't a big issue. Dropouts like that are much tougher than the soft stuff replaceable hangers are made from, and can take quite a bit more impact before bending. I hate replaceable hanger - they might as well be made of lead.

It isn't worth worrying about.

JohnDThompson 

Looks like a Trek bonded aluminum frame and dropout to me. If the dropout breaks, the whole dropout would need to be replaced. It could be difficult sourcing a replacement, and also difficult cleanly removing the damaged dropout and bonding the replacement. If only the hanger breaks, a functional replacement could be cobbled up from claw-type hangers or a generic replacement hanger.

grumpus

If just the hanger or rear part of the dropout broke it could be TIG welded back together, being very careful to prevent heat build-up in the bonded areas (needs to be kept below about 60°C, which might be difficult when the weld is about 700°C and aluminium is a good conductor of heat). That's assuming that the aluminium is weldable at all, which depends on which specific alloy it is - 7075 is great for forging but will microcrack if you try to weld it. If it wasn't possible to weld in place you could remove the end by careful application of heat to the bonded areas; then weld repair the original, or find or make another end that fits, to glue in. Makes you glad to have replaceable hangers.

Kontact 

How are you going to prevent the heat going into the epoxy? A wet rag is not going to do it. You would never be able to trust those bonds after welding.

grumpus

It would be interesting, but you can cool with dry ice or liquid nitrogen, or those pipe freezers that plumbers use on water pipes - the challenge would be to maintain a steady heat gradient while welding, as you can't chill the weld pool. But I suspect it's not a weldable alloy anyway.
Indeed - whether steel or aluminium, good forged ends are remarkably tough. OTOH early bonded frames tended to be rather flexy and make worrying noises.

Kontact 

What is it about a Trek OCLV frame that is flexy and noisy?

oldbobcat

If this heat-treated alloy hanger gets hit hard enough to break, it's taking the rest of the frame with it. If it's slightly tweaked, it shouldn't take too much finesse to tweak it back. Put a wheel in the dropouts and don't get carried away.

Crankycrank

Honestly, I wouldn't worry about it until you have a damaged hanger. As mentioned, minor bends can be re-aligned usually more than once. Just retired a 25-year-old alu frame that had its non-replaceable hanger re-aligned at least 5 times in its lifetime before the headtube developed cracks. Ride and enjoy until you actually need a replacement. It has already survived 15 years without damage.

danallen

A few years ago,someone on this site posted his opinion that minor bends to deraillier hanger is so common that having a spare on hand is important. I have never replaced one or thought one might be damaged. I just thought it is important to be able to replace one.

I thought the idea behind the hanger is it gives us a part that is relatively easy to replace, so we do not have to junk a frame due to a small flaw in the point where wheels attach.

Russ Roth

They can be straightened a few times if the hanger isn't bent badly but more than a few times and there's a good chance of it snapping. The issue of breaking leading to replacement hangers was largely around MTbs that are more prone to crashing through rough terrain and bending the hanger. Most of the issues I've had with bent hangers revolved around the kids knocking them over while leaning against the car waiting to be put on the rack. With anything that sees dirt or child use, replaceable is a good idea, otherwise I don't see it as a concern. If it did snap I'd go to the local shop and find a hanger that matched up enough that I could use a dremel and make it fit.

13ollocks

I believe the "RD hanger as a sacrificial component" concept came about with the advent of Al and CF frames. Prior to this, steel frames had fixed hangers that could be bent straight multiple times without breaking, and/or were built sufficiently stout that it would take a significant impact to incur any damage*. Al is less amenable to multiple rebends, and CF not at all - hence the replaceable hanger. However, hanger damage isn't "all or nothing" - most RD impacts aren't hanger-destroying events - an Al hanger could sustain sufficient bend to throw off the shifting and still be almost invisibly out of alignment. Such small bends are likely multiply straightenable without fatally compromising the hanger strength, and are also largely avoidable - absent crashes - by simply watching how you treat your bike - ensuring that it doesn't fall over, keeping the RD safe, and if you have to lie it down, placing it non-drive-side downward.
*the fixed hanger on my bike is 5/16" titanium plate - I suspect that the RD would be completely destroyed before the hanger or frame took any damage

Kontact 

Except that aluminum bikes with non-replaceable hangers were sold for 25 years. They aren't a bad thing, but aluminum dropouts clearly didn't "cause" replaceable hangers - which are now found on bikes with otherwise indestructible titanium dropouts.

If you have a replaceable hanger, you should have a spare, because replaceable hangers are made of very soft metal and have hardware that can be damaged. They are much less tough than aluminum one piece dropouts like you have.

It's a compromise - you can have a stiff, reliable hanger; or a replaceable one.



What's hilarious is that early on, Wheels Manufacturing offered steel hangers for those who were tired of flexible aluminum ones. Which is ironic because a steel hanger bolted to an aluminum dropout would definitely destroy the frame in the event of a crash. They discontinued those pretty quick.

Kai Winters

It can be 'realigned' if it is out of alignment. It is a one piece aluminum dropout/hanger. Unlikely to find a replacement due to age of frame.
If the hanger needs aligning take your time and use a proper alignment tool. If you just crank on it it is possible it will snap and then you are SOL.
If realigned many without a problem by taking my time and making small adjustments. I've never had to use heat. I have watched a coworker snap one because he just cranked on it...dead bike on a scrap pile.
That dropout is one of the reasons why replaceable hangers were invented...
Good luck and keep us informed.

grumpus

Probably nothing if it has properly sized tubes and well designed joints, compared to the early bonded frames I was referring to.

Iride01 

What Trek bike is that. Some seem to think it's a CF bike. But I was thinking it's a aluminum bike.

Didn't Trek make a aluminum bike with bonded aluminum tubes back in the previous Century?


Just curious. So no real help for your question other than I agree it'll come down to exactly how it gets ruined which will dictate how it needs to be fixed. Cost may well be more than it's worth to you.

Kontact 

Bonded, lugged frames shouldn't make any noise, either. The most wins of any single frameset ever was the first generation Vitus 979, and the second most is probably the TVT 992. Both are tubes glued to lugs. There are also several million Trek 2000 and 2500 type lugged frames out there making zero noise, along with nearly as many Raleigh Techniums. And then all the Miyatas, Colnagos, Alans, Looks, Giants, etc.

So I don't know what you are talking about.

grumpus

That's OK, it was long enough ago that I don't remember the details, could have been Vitus or Alan or some other, not a clue as to model or year (some time mid-1980s?) and I don't need to convince anyone of anything.