sdodd

And, just so you don't think we are all just rote fans of Todd at Davinci:
1) he seems like a nice guy willing to engage with people. (which I believe would be a massive time sink personally, but I'm thankful he will do it)
2) His prices seem very reasonable with minimal markup over a good mail order site. I think he charged me $80 for the 'normal' white freewheel. At the time the best online price I could find was universal cycles for $74.95. I'm sure a LBS would have been well more than $80.

Completely understand that he is out of stock. Along with everybody else in the world.

simon

jethro00

Likewise, I am a fan of Todd. We met a long time friend of his one day when she saw our Grand Junction. She recognized the bike and told us she knew Todd when he was first getting started. I have bought parts and tools from Todd and he even once took parts off a bike he was building to send them to me because that was all he had on hand. All of that said, Todd, like it seems everyone else, is dealing with a long term parts shortage and there is no guarantee he will be around forever to service our tandems. S-o-o-o-o, we do need to figure out what parts will work on our tandems and where to find them if need be.

LV2TNDM

And be sure to remove any washer(s) under the crank bolt!!!! Otherwise your "crank extractor tool" becomes a "crank thread extractor tool!"

jccaclimber

Not just ACS freewheels, preferably the same model. I (fuzzy recollection) think my new one is a PAWS (22T) and is enough wider than the originals (Crossfire?) that it needed the spacer.
That's what we're trying to say. A normal freewheel tool cannot access the second ACS freewheel on the DFB. Your options are a punch and some luck (I wasn't convinced I could do this without damaging the DFB threads), permanent disassembly of the old freewheel, and removal with a pipe wrench, the special tool from Todd, or rigging something up like I did.

jethro00

I removed one of the front cranks (by the hardest). Park Tool has a good YouTube video that helped.
There is no noise upon rotating the spindle. Based on that, is there any point in removing the other crank?

A piece popped out of the eccentric mechanism. I see where it goes. But, I am not quite clear on which way that piece is supposed to fit in there. Can anyone clarify the proper orientation of that piece?

Pictures are below.

Many thanks.

jccaclimber

I didn't mean to remove the EBB from the frame, just the crank from the spindle. On the plus side, now you know how. If you look at the piece that fell out you'll notice that it has a wedge shape on one side. That should mate up with the triangular slot in the EBB. If it has an allen at each end it probably works either way. If only at one end, just make sure it's accessible.
Too late at this point, but just as an FYI, if you're careful you can remove and re-install the timing side crank arm without changing the EBB adjustment if you put the chain on the crank arm before putting the crank arm on the spindle. This is a tad trickier on the stoker's crank, but still doable. If you're one who is concerned about torque specs (I typically am, but I'm picky like that), the specs are all available on the DaVinci page.

jethro00

Thanks for the info. I got it back together without incident. The problem seems to be the freewheel. I'll contact Todd and see if he has anything available. If not, there are a few shops around the country that sell Grand Junctions who might possibly have parts.

jethro00

I spoke with Todd. Although he cannot say for sure that the captain's freewheel is causing the problem, that's about what is left to replace. So, freewheels and new bearings are in transit to me. I pulled the intermediate shaft and lock ring. I am ready when the parts arrive. Now that I know how to remove the intermediate shaft and have the right tools, I don't think it took 10 minutes.

jccaclimber

We’re you able to get a freewheel removal tool from him or did you buy a new DFB as well? If not, how do you plan to remove the inner freewheel? I still haven’t gotten to calling him to ask about the tool again. We simply did our trip without regearing.

jethro00

I am not sure what the "freewheel removal tool" is. I have the tool with the 4 prongs on one side and the tab on the other side for removing the intermediate shaft. That's a good tool and well worth the $25 or so it costs. I got a new DFB and 2 bearings. The next time I order something from Todd, I am going to send my DFB and old freewheels back to him so he can replace the freewheels and return it to me so I'll have a spare assembly. I may stockpile an extra set of parts that are hard to source elsewhere just in case Todd isn't around at some point.

jccaclimber

A common freewheel tool interferes with the DFB and won’t be able to remove the inner freewheel. This isn’t an issue if you are getting a new DFB or are having Todd do the swap.

jethro00

Well, now you've got me curious. What tool would be needed to remove the inner freewheel? I don't see any special tool for that on Todd's website.

jccaclimber

The tool is not listed on his web page, but he mentioned it in an email to me. Unfortunately that email thread went dark, so I ended up making a temporary tool. This was discussed around post # 48 of this thread.

jethro00

Got my new freewheels and tried to reinstall the intermediate shaft. After I tightened the assembly with the chain whip and the daVinci tool, it has some play side to side. By that I mean, if I hold the big ring and the freewheels and push horizontally, the intermediate shaft assembly will move horizontally a bit. Is this correct or is something not aligned or tightened properly?

jccaclimber

How much is “a bit”?

jethro00

I'll measure. I am wondering if I installed the lockring backwards. The lockring that goes on the right side of the BB has a tapered side. I put the tapered side toward the BB. I am now wondering iff the tapered side is supposed to be on the outside toward the 3 rings.

Edit: On further review, looking at the intermediate shaft diagram on the daVinci web site, it looks like I installed the lockring in the correct orientation

jethro00

There is about 1/8" play from side to side. I can't recall whether there was any gap when I removed the assembly. Is this normal or is something not assembled correctly?

sdodd

There should be no play on the intermediate shaft. To be honest, if I had 1/8" movement it would be interference with everything. I have about 1mm clearance between my left side freewheel and the left stoker crank. And I have about 1mm clearance from my lockring of the 3 cog drive side to the intermediate shaft 'bottom bracket'. I will look at my bike. I think maybe you have the intermediate shaft bearings pressed in too far into the shell.
simon

sdodd

Be sure to reference the manuals on the DaVinci site.
https://www.davincitandems.com/owner...mediate-shaft/
https://www.davincitandems.com/owner...haft-bearings/

I do recall assembling once and having some slop. There was something wrong with my cartridge bearing and bearing spacer assembly. The bearing spacer should prevent the bearings from being pressed 'in' too far, otherwise the shaft can have slop. Then make sure that your lockring and bottom bracket body are assembled correctly.

sdodd

In my setup the intermediate shaft lockring is silver and the 'chainring' lockring is black so you can see the gap between the two.


This is my setup. Not even sure I could have slop - spacing is very tight.

jethro00

Tonight, I am going to compare the new freewheel assembly to the old one. I wonder if the new one is a tad less thick. That could cause a gap.

Edit: I checked and they are the same thickness. I wonder if I tightened the lockring too much and it compressed the assembly.

<<I do recall assembling once and having some slop. There was something wrong with my cartridge bearing and bearing spacer assembly. The bearing spacer should prevent the bearings from being pressed 'in' too far, otherwise the shaft can have slop. >>

I got 2 new bearings from Todd, but chickened out on removing the old ones for now. The directions for removing the bearings refer to bad things that can happen if that does not go well . So, the cartridge bearing and bearing spacer assembly have not been altered.

jccaclimber

Pictures in a bit, but I’ll bet your DFB just isn’t fully threaded in. Assuming the bearings are still flush with the outside of the shell (highly likely since you didn’t take them out and there’s a spacer between them), you just need to tighten it down.

Shift into the largest front sprocket, smallest rear sprocket, hold the rear brake, and stand on the captain’s pedal for a moment. The torque from the chain on the freewheel will thread it on the rest of the way.

jccaclimber

Ok, a few more pictures. You got me curious, so I quickly pulled min apart and reassembled it. If you want the part most relevant to you, skip to the text by the last picture.
1. Mainly a note for my future self, here is the innermost sprocket orientation. While you wouldn't be able to shift to the smallest gear with this sprocket on backwards (and might have issues in #2), it still wouldn't prevent reassembly as the sprocket is ~0.15 mm shy of where the inside shoulder mates to the bearing inner race. This also tells you that it should be *very* close to the shell.

Here's the bearing it seats against. It is pretty much flush with the outside of the shell. I have not taken this portion apart since getting the bike.

With the shaft installed, this is what it looks like sticking out the right side of the bike (bearing also near flush). I'm using this photo to point out that the threads (at least on my older bike) do extend past the bearing. This is ok because there's a relief for them in the DFB (next image).

Here's the DFB. I'm using non-standard freewheels because 1. I want a much lower ratio than standard to get my wife and I up the hills around here. 2. They were available at my LBS. I mention this because these freewheels DO NOT FIT PROPERLY. They are just a bit too wide, so I ended up making a thin spacer to sit between them and the right side bearing inner race. Without doing that they would have rubbed the shell. These are just a bit wider than the ACS freeewheels that came off, which I think were Crossfire models, although don't quote me on that last part. That said, you can see the clearance diameter on the ID that the unthreaded portion goes in.

Finally the relevant part! I spun on the DFB on by hand until it stopped moving smoothly and as you can see there is still a gap. It's a bit of an odd thread profile to begin with, but for whatever reason it gets a bit stiff (at least ours) before being fully installed. As a result it gives that "getting stuck" sort of feeling at about this point. While I didn't look especially hard, it didn't have obvious contamination. It's possible with the sharp thread profile and being a used bike that there's a ding somewhere on the thread, but I didn't inspect it for that point. I'm not normally a fan of pushing harder when something doesn't go, but since it was stiff coming apart in that area, and freshly cleaned/regreased I went ahead and gave it a bit more shove. In my case this was done by holding the rear brake and standing on a pedal to tighten it down. It felt smooth as I did this, so I went with it (then pulled it apart and did it a couple more times to make sure the feel wasn't changing). Once I'd done that the gap closed right up.

jethro00

jccaclimber, thanks for all the info and pics.
<<Shift into the largest front sprocket, smallest rear sprocket, hold the rear brake, and stand on the captain’s pedal for a moment. The torque from the chain on the freewheel will thread it on the rest of the way.>>
I will do that tomorrow and report back. That's an easy fix if you're right.

<<You got me curious, so I quickly pulled min apart and reassembled it.>>
You did that "quickly"???
If you can do that quickly, you need to video that process and post it on Youtube and the daVinci web site.

jccaclimber

I can't tell if you're kidding or not, but if you're serious I'll put a quick video together, it really doesn't take long. As for the measurements taken, well, no CMM, but I'm unusually well equipped to do linear measurements under about 600 mm.