ccinnz

Hi All


I had a little fall on my Guru Praemio, titanium frame, on the drivetrain side after which the Ultegra Di2 gears were out of synch by one gear, when shifting down ie I couldn't shift into the highest gear, and shifting into the lowest gear ended up with the chain jumping of the cassette and binding up between cassette and spokes. When riding the bike after the fall, the rear derailleur didn't look 100% straight.


I've, today, played around with adjusting the gears and while I can get them, at the micro adjustment limit, indexing ok, in the lowest gear the the rear derailleur pulley frame is touching the spokes.


At first I though I had maybe damaged the derailleur, but on closer inspection it looks ok, so I am now think I may have bent the drop out slightly. I have inspected the welds around the ends of the seat stays and chain stays and they all look ok.


I guess my questions are:


1) Is it possible to adjust the alignment of the lower pulley wheel? I can't see how it is!

2) Is it too much of a risk to try and force a slight `reverse' bend into the, removable, drop out? I don't feel comfortable doing this.

3) Anyone know of any good bike builders in Auckland NZ that could look at this, I know this is a long shot question. Am not sure whether I trust this to my LBS, or maybe I should!


Many thanks


Carlton

dabac

You say ”removeable dropout” - I can’t tell from here.
They do exist, but replaceable derailer hangers are far more common.
And yours is obviously bent.
What I’d do first in your situation is to try to get a new hanger. Or a new DO if that’s indeed how your bike is built.
I wouldn’t ride the bike as it is. Unless w/o making really certain that the derailer isn’t about to snag a spoke and make even further damage.
Bending derailer hangers is a so-so thing. Steel frames with fixed hangers would usually survive a few adjustments. Aluminium ones, particularly as badly bent as yours, may as well snap in the attempt. Or become weakened and fail later while JRA.
I have straightened a few as bent as yours and gotten good use of them. But then by taking them off the bike and heating them first.
And no, there is no way to adjust the alignment of the lower derailer pulley as such.
It’s expected to hit its spot by derailer hanger and derailer being true and straight.
I’ve occasionally made minor adjustments to the alignment of the DH. Sometimes they don’t snap/bend until after they’ve put a bend in the DO. Adding a few strips of shimming material between DO and DH is a safer option than trying to align the DO.

aggiegrads

Go into the bike shop with a new derailleur hangar in your pocket and it will guarantee that you will never need it.

I have several CX and mountain bikes with spare RD hangars that I purchased soon after buying the frames so that I would have one available if I needed one. I have never needed to use one, but the bike that did not have a spare broke and I had a heck of a time finding the correct replacement in stock anywhere.

I agree with dabac that your frame is probably fine and only the replaceable hangar needs to be aligned or replaced. There are tools for doing this, and any decent shop should have one.

edit: it looks like this bike takes the following hangar: https://wheelsmfg.com/derailleur-han...hanger-88.html. Although still technically a hangar, I wouldn’t disparage those who refer to it as a replaceable dropout.

dsbrantjr

When you find a suitable replacement hanger/dropout buy two. Then you will have a spare. Having a spare will ensure that you will not need to use it, kind of like carrying an umbrella to ensure it doesn't rain.

andrewclaus

Ditto this technique. If you have a sturdy bench vise with an anvil, you can blacksmith it back into rough shape then fine-tune it on the bike with the proper alignment tool.

rydabent

It replaceable hanger is used, or even a frame drop out, I would advise using a drop out alignment tool to make sure it is in alignment. Many shifting problems are due to misaligned drop outs.

trailangel

1) Not really
2)No... BEND IT BACK!!!
3)No... take it to local LBS......it's a 5 minute job with the rear DR off......

!!BEND THE DERAILLEUR HANGER BACK!!

cxwrench

ftfy.

joeruge

It is my understanding that derailleur hangers are designed to be aligned while on the frame with the wheel on the bike. Why else would Park sell a derailleur hanger alignment tool? Hangers are made with a softer alloy that can be bent, a few times. I don't use my alignment tool much, but have used it, as intended, a dozen times on different bikes with perfect results.

You have nothing to lose, really. If the hanger does break, (and there's only so many times you can bend it back before it does), you were already thinking of replacing it anyway. Oh and by the way, once you place on a new hanger, you need to check it with an alignment tool and adjust it as needed.

davidad

If you don't have a alignment tool you can substitute a spare rear wheel. Remove the der. and thread the rear wheel into the hanger (they both usually have 10mm threads). You can use the wheel to bend the hanger until the wheels are parallel. I have done this when the tool wasn't available. Buy a spare hanger or two to have as spares.

Ti Praemio - 2014 | Rear, Mech, & Gear Derailleur Hangers | DerailleurHanger.com

Amazon.com : Wheels Manufacturing Dropout-88 Derailleur Hanger : Bike Derailleurs : Sports & Outdoors

Barry2 

Bike fell over and bent my hanger.
Go to LBS for a straightening.
I get the speech, LBS.. "Your hanger might break. This hanger was only used on this bike for this year, so when it breaks... you'll be down for a while!"
Me "I've a spare hanger in my pocket"
LBS "Ignore everything I said, If you've got a spare, this one will never break"

Bhahahahahah
One of the worlds mysteries

Barry

OH and BTW even a new hanger should have it's alignment checked.

veganbikes

A good hanger alignment gauge will help out and might get it closer or back to running condition (or at least might be able to be straightened by other means) however like a lot of others have said get a replacement derailleur hanger (or replaceable dropout if you want to call it that) or two in case you need it. It is better to have them and not need them then to need them and not be able to get them anymore as can happen.

Also I have noticed a large number of people who lack the ability to search for hangers well, they will come to me at the shop and I do a simple google search or something on Wheels MFG's website and find it quick and they spent 10-30 minutes trying to find it. Not saying I have special powers or are better than anyone else it just baffles me they come to me and I find it quick without doing anything special at all or anything that difficult or requiring a lot of brain cells.

If you are looking for a good alignment gauge the Abbey HAG is one of the best: https://www.abbeybiketools.com/products/hag. It is a precision tool for a precision job and also looks nice. If not you can go to your local shop and they can help you out.

ccinnz

Thanks for all the responses. Bike is booked into a LBS who have said they can re-align it and I will order a spare hanger as well.
Many thanks
C