5

Going on two years ago, I had an, err, unfortunate kinematic incident. I crossed three lanes to make a left turn during a huge break in traffic, and only had a few inches left of the lanes in which I tried and failed to stabilize. This sent me across roughly two foot landscaping rocks (so effectively no breaks on the edges), and accidentally hitting a couple of bushes before it flashed through my mind that hitting them dead on could slow me a bit. A couple of bushes later, I lost the last bit of control, and just about face-planted into a large rock. A golfball size dent in the helmet at hairline, three front teeth killed (my dentist capped the fourth to match), and something like mild arthritis in one knuckle of my ring finger (which apparently took a lot of weight).

Anyway, the bicycle fared marginally better :). It's a Fugi (no, auto destruct, not "Fungi"!) Absolute 1.7 if that matters.

As it clearly had friction, I took it to the nearest bike shop (I'd bought it from a place half an hour away during covid), told them what happened, and paid about $80 iirc for a tuneup.

It initially seemed ok, but when I started pedaling hard, issues showed up.

In low front hub and high rear gears, there is definitely a clicking and rubbing (it's 2x9, btw). From this photo, it looks like there is no gap between the chain and the side of the derailleur:

closeup of derailer

(it ends up a bit more centered when not at the extreme gear settings).

The derailleur looks a bit bent to my inexperienced eye:

derailleur rear view 1

derailleur rear view 2

It also engaged in the dreaded gear-hopping under load. To my surprise, I was able to duplicate this--I think it was going between the 7th and 8th. Unfortunately, I shifted before I took a video, and couldn't get it to do it again. (I'll keep trying). (for that matter, is there a way to upload a video here? I don't see any permitted types).

I was watching for bent teeth as it spun, but couldn't see any variation. Any hints on checking would be helpful.

The front derailleur guide seems to rub as I reach hi-front and low-rear combos. Can I simply adjust the screws for that?

Here it is in hi/7, which is the highest gear can shift to: front derailleur rub

I'd prefer to do any repairs myself rather than elsewhere (I'm like this with cars, too--and I don't even need to crawl under the bicycle!).

thanks in advance.

EDIT more pictures, referred to in contents

derailleur removed view 1

derailleur removed view 2

mounting plate view 1

mounting plate view 2

4
  • 1
    This kind of assessment is best done in person.
    – Paul H
    Commented Jul 6 at 1:03
  • 2
    Your 2nd photo indicates that the derailleur hanger is bent which is OK as it’s a sacrificial part. Ask your LBS to check and replace if that’s the case. Commented Jul 6 at 7:29
  • There is no preferred video upload - instead post to youtube and edit the link into your question.
    – Criggie
    Commented Jul 6 at 10:43
  • Upvoted for the use of "kinematic incident".
    – MaplePanda
    Commented Jul 6 at 21:38

2 Answers 2

2

Your rear derailleur looks damaged. The left side plate shouldn't be that far away from the right side plate. Also, if the derailleur is damaged, chances are your derailleur hanger might also be. Although one comment mentions the derailleur hanger, I wouldn't be so certain about that based on the pictures alone, since the damage to hanger (if it's there) seems to be minor. To see if the hanger is damaged, you need to take a picture right from the rear, not slightly from the side.

Derailleur hangers on aluminum bikes may not be repairable, so a new one is the best option, although very minor damage could possibly be bent back. On steel bikes there likely wouldn't be a separate hanger, and the repair would be just bending it back.

2

Pic1: Is the chain even on the jockey wheel's teeth? It seems to be off completely and riding beside the jockey wheel (idler wheel)

Pic2: The hanger appears to have an S bend in it - the black thing with 0052 written in white. Although this could also be the camera combined with the slight angle.

I would suspect you will save a lot of effort and frustration by replacing the rear derailleur with a new 9 speed item. Once some part is bent by impact, they never work the same again. The old one can go in your spare parts/donor bin.

Once you fit a new derailleur that is definitely not-bent, you'll be able to spot if the hanger is bent in relation to the rim. If the hanger is aluminium it has a high risk of cracking if you try to un-bend it (straighten it) or will definitely be weaker. However if the hanger survived straight, then it should be fine to reuse.

Also take the chain off the bike and examine it closely - lay it out flat on a flat concrete floor and see if it has any obvious kinks or bends while lying on the side plates and stretched out straight. Then twist it 90 degrees so the side plates are vertical and re-examine. If there's any specific problem spots you might graft in a spare link, but that's generally a short term solution and a new chain is the best fix.
A new chain probably will skip on an old cassette too, so replace the cassette as well.

Your inner cable is frayed - just fit a new one for a few dollars rather than struggle to save that one.


The front derailleur will be a separate problem, and I suspect it has been yanked out of position more than damaged. Try and focus on getting the rear end working right first. Fortunately they're unrelated systems.

Do carefully check your rims for trueness - they can take a beating in any accident. Also check your brake's function, and presumably you have a new helmet already.

3
  • 1
    1) the chain was on the jockey wheel, but there's a good gap between the wheel and the frame at this point.
    – hawk
    Commented Jul 6 at 21:45
  • 1
    2) I added two pictures each of the dismounted derailleur and the plate. I assumed that gap on the plate isn't good. 3) Do I remove the crank (?) to get off the chain until if find my chain tool? 4) I was surprised at how little the derailleur costs ($35 on amazon. a lot less on aliexpress, but .. . .), as well as cassettes! And at the plate costing as much as the derailleur? thanks
    – hawk
    Commented Jul 6 at 22:01
  • 1
    as for the helmet, I found the Virginia Tech crash tests, and got the top-rated one! (this makes three I've broken: the first to a hit and run, the second to ice)
    – hawk
    Commented Jul 6 at 22:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.