spectastic

I got this carbon cross frame that was fitted with alfine 8. It uses a lock nut to secure the rear wheel. The nuts came loose when I pedaled, and the skewer popped out, causing damage to the non drive drop out, Shown in the picture. Is this a problem I need to worry about?

Andrew R Stewart 

I guess I'm stupid or unfamiliar with the Alfine 8 system. But how does a qr skewer and lock nuts combine? Out side of that the shot shows what would be on a metal frame pretty common QR skewer end cap embossing. Many millions of metal framed bikes have this indenting from the skewer caps and have lived many miles. Andy.

spectastic

sorry, there is no skewer. it's a locknut, with a washer that prevents the wheel from rotating. I'm more concerned about the crack/splinter than the grooves though

Homebrew01

How did it get so gouged with a washer ??

spectastic

I don't know what they're called.

the blue and green things

Andrew R Stewart 

The "blue and green washers" are anti reaction devices. meaning they keep the axle from rotating in the opposite direction of the gear's effect. If the axle nuts become loose then the axle tend to freely rotate within the amount that the washer's tab (fitting within the drop out slot) allows for. In time the tab can erode the slot and this free rotation will increase.

The key (bad pun) to internal geared hubs is to keep the nuts tight so no axle rock cab even start.

Sorry but I don't see a crack or splinter. What I do see is a deep grinding/gauging of the drop out's face from the axle washers' serrated inner faces. If this is too deep to allow the washers to seat and grip the drop out well then that is a real problem. Have you tried to reinstall the wheel, tighten the axle nuts well and see what happens yet? Andy.

spectastic

yes, it's on there as tight as I can get with my little wrench. I'm just worried about it getting worse. and as you said, the nuts dug pretty deep. Is there something I can do when I get back to repair it?

GamblerGORD53

Apparently this is just not a good idea for this kind of drop-out.
I think it needs to be firm in both directions of rotation.

Rowan

Go to the hardware shop, get the highest quality epoxy resin you can, and a stainless steel washer that allows you to put the hub axle through and fits in the drop-out area of the frame.

Hacksaw a slot into the washer, rough up the flat surface of the washer, then epoxy it in place, filling in with epoxy where the middle of the dropout is. File and sand back to ensure the axles fits neatly.

I don't know what effect this will have any of the dimensions involved in shifting the hub, but at least it will provide some level of security for the hub on that side until you get home and decide what you want to do with the frame.

While you are at it, you might as well do the other side as well.

spdracr39

Ride it and if it ain't broke don't fix it.

CliffordK

How many miles do you have on the frame/IGH combo?

There are torque limits for CF parts.

It looks like it is eroding deeper, and eventually will get to the point of failure. I like Rowan's idea of the washer, or perhaps eventually move to a standard gearing.

fietsbob

Anti rotation, internal torque transfer washers , with teeth that bit into the surface of the dropout

NB: Rohloff retrofit kit uses an arm along the left chainstay as a torque transfer..

You Are showing a toothed washer gripping into the Epoxy resin parts of the carbon composite ..

yes it is not unusual to have stainless steel faces on frames of made of other materials .

it's the sound bonding techniques that may elude the shade tree mechanic's capabilities ..

SquidPuppet

Serrated washers against CF seems like a really bad design to me. Really really bad.

Andrew R Stewart 

Agreed. Andy

spectastic

ok, I will try to find a suitable washer from the hardware store when I'm done with the tour.

a very wise mechanic suggested that I use jb weld to glue the washer on there. do you concur?

79pmooney

Andy and Rowan get it. Rowan has good advice. JB Weld is good stuff. Follow the instructions. Mix the stuff 1) accurately and 2) thoroughly. (Spend several minutes just mixing. Scrape the edges of the container and mix some more. And again. Epoxy is only as strong as the mix is close to the proportions it was designed for.)

I strongly suspect that the Alfine designers never dreamed their hubs would be used on anything besides a steel dropout. (I am also guessing this frame was not intended to see an internal hub.) Internally geared hubs work by using gearing to increase the torque from the low number of the chain tension times the cog diameter. The laws of physical reaction require that the difference in torque must be transmitted to a fixed object, in this case the bicycle. For the past 100 years, tightly nutted axles transmitted the torque to the bicycle. But those hubs only altered the torque around 33% at max. The is a relatively small torque difference that the nutted axle on a steel dropout handled easily. Now with hubs with far more torque difference, the challenge is considerably greater. The Alfine comes with a washer that is far more positive in transmitting that torque that a simple nut.

Rowan's advice is sound. However, you must approach this job like it matters. Read the instructions. Plan your work. Get everything in order and lined up in advance. Clean all parts to be epoxies with epoxy thinner and rough up the metal parts with clean sandpaper . (Do this in good ventilation - the solvent is bad.) Set out the epoxy, pre-measured but not yet mixed. Then take a break, go sit somewhere quiet and visualize the whole job. When you are ready, go back, mix the epoxy, stir as above and go to work. You want a good, clean professional job, no voids, no excess where you don't want it. As soon as you finish your work, place any remaining epoxy in the freezer. Clean up and go do something else.

Edit: See the next paragraph in reference to the epoxy flowing. Part of the set up of this job is having ready a means of securing that washer where if belongs. This securing must be positive. If the washer is just sitting on the epoxy, it will move, maybe an impressive distance while the epoxy is in that unworkable state. (Imagine warm chewed bubble gum only worse, the consistency of cold molasses.) I would consider a means of securing the washer like masking tape over the dry clean outer surface of the washer to the dry clean surfaces of the dropout to locate the washer properly at the axle, then clamping it in place with a C-clamp. Again, visualizing the whole job is very important. YOu are going to have to do this work keeping those surfase dry to get that tape to work. Tape will lift off the finished epoxy nicely as long as it is not trapped by any of it.

When the epoxy is set up but not quite rock hard, you can trim it with very sharp tools. (Don't touch it until then - you will make a royal mess of things!) Epoxy flows after you have left the room while it is in that unworkable state. Hence the need to trim. And you may find that there are now some voids. Pull that epoxy out of the freezer, warm it up to room temp and do any repairs necessary.

Let it cure the full time on the instructions being careful to keep the temperature at least that warm.

With care, you will have a dropout that is far better able to handle the use and abuse it will see with an internal hub, probably for many years. Good luck!

Ben, a former boatbuilder who has done a lot with that stuff

Rowan

You really need to look at this sooner rather than after the tour, if you intend to keep riding. Otherwise, you won't have any worthwhile foundation attached to the frame to do any sort of repair.

79pmooney is an expert, and his method is what you need to follow to get this right. As far as positive clamping, I was thinking a stiff clothes pin, but you can also pick up small clamps from model shops that might do well, too. Take that advice to mask the clamp so it doesn't end up being a permanent part of the repair.

The funny part about this is that the repair itself is likely to take not much more than an hour, but it's the time you put into the preparation, like everything else, that will determine the outcome.

CliffordK

As far as clamping, make sure you have a method to keep the surfaces parallel.

One option would be to get a piece of threaded rod & 4 nuts.

Put 2 "backing nuts" spaced at 130mm.
Then add 2 nuts to hold the washers in place.

If you have access to a dremel and file, it may be easiest to do the final finishing of the slot once everything is glued in place, with the full 24 hr curing (being careful not to damage your frame).

========

Some of the longer torsion bars are for coaster brake bikes, but I'd certainly consider adding one when you have a chance.

Rowan

This is the ideal solution, and is cheap to do, and effective if properly masked to avoid the epoxy sticking it in place.

I did think of it last night because I used the same method to hold in place the piece of a broken dropout while I brazed in back together on my old Fuji Touring... but it was bedtime for me.

Bike Gremlin