SRAM Dual Drive Pushrod need?
 

We have had a couple of bikes show up that need a SRAM Dual Drive (DD) rear hub, one a Bike Friday and one a Schwinn. In both cases the hub pushrods were bent, This seems to be a weak point with this mechanism. It's almost impossible to find this part, now discontinued by SRAM. We am looking into having some 114mm DD pushrods made and think there may be a need here in the folder community for the rods. The rods need to be made on a very specialized machine known as a Swiss lathe so they are not cheap, even in quantity. So, here are two questions:

Would you be willing to pay $40 for a pushrod?
If not, what would you pay for one?

Thanks for your answers

Fred
https://cimg0.ibsrv.net/gimg/bikefor...b4f2305e67.jpg

$40 is extortion,...sheesh!

Pricey, but they are almost impossible to find. Because they are so long and thin they deflect if you try to make them on a simple lathe that feeds cutting tool into stock. The Swiss lathe machines that feed the stock into the tool are very expensive. Google "Swiss lathe" to see what they cost. To have a bona fide machine shop make one, you must pay for the machine, overhead, engineer's time, very skilled labor etc. Material cost is a very small part of the price.They would be cheaper if we were willing to order thousands as SRAM most likely did.

I see some on eBay and Google search, around $25. There is a Turkish website selling for $15. I remember buying one for $3.

There is a German CNC company that make small parts on their mini lathes for cheap prices. I could ask them for a price if someone is interested in ordering them.

Also, the pin seems to have 2 different part numbers.

From a more recent manual 11.3118.005.000 I see 2 for sale on eBay
From a 2010 manual 65 0328 002 004. This is what I bought a long time ago to replace the old one. I see 2 websites selling this. All around $25.

Also the originals are maybe rolled in bolt making machines instead of CNC.

Bike Friday has SRAM Pushrods
 

Bike Friday has about a hundred of the SRAM pushrods in stock (as of Mar 2, 2020). Price is $10 each plus shipping, which shouldn't be much because it's a small, light part. You can give them a call at 1-800-777-0258.

Kent (my workbench is 25 feet away from the inventory room) Peterson
Eugene, OR 97402

Maybe this is a dumb question, but has anybody tried to cut a threaded rod to length and use a nylock nut on one end? If a nylock nut is the wrong size for the clickbox to grab it, there might be other work arounds?

I am not interested in buying one at any price, I bought one when I heard that the Dual Drive was going to be taken out of production, thus I have a spare in case I mangle mine, thus I am good.

I suspect that there is a cheap home built way to make a substitute that functions. I am curious, I just ordered an M2 threaded rod on Ebay, shipping from China might take a few months given the current situation with the virus. If I get around to it and if it works, I will post something here.

Good idea. The thread on the end is metric coarse M2.5 x 0.45 I don’t know if there is a Nylock nut that tiny but you could always epoxy or permanent Loctite a nut on the end then grind or file it round, I’m not sure that the rod needs a slot on the end to tighten it. Finger tight seems to be fine.

Oops, my caliper said 2mm, that is what I ordered. So, when mine gets here, it won't work. Perhaps I forgot to calibrate caliper?

If it is a bit over 2mm, spoke thread is a hair over 2mm. So, I tried my spare shift rod on a spoke nipple, and it threaded in just fine.

In the photo below, the rod that has a shoulder is a new (unused) Sram shift rod, the other threaded rod is a spoke thread. You can see that they both have the same thread.

I do not have a really good metric caliper, so I tried my inch size caliper, the Sram rod was 0.082 inch diameter and the spoke was 0.086 inch. It sounds like if you got lucky and had a spoke that was slightly undersize, it might thread into the hub. In that case, maybe get out a long nose pliers and try to figure out how to make an end on the spoke that the click box would grip onto.

https://cimg1.ibsrv.net/gimg/bikefor...e9e1cc1694.jpg

The spoke that I measured, I am not sure where that spoke came from. I would not be surprised if spoke threads are not all manufactured to great precision.

Hmmmm, 0.082 mm converts to 2.08mm, so maybe I did order the right sized thread. The threaded rod option might work yet.

My folding bike and rear hub would not be easy to get at right now, it is packed up. Thus I did not try threading the spoke into the hub.

I like your idea of trying a spoke. From the Park Tool site, 2.2mm x 56 tpi is common 2mm spoke threading.Here's an interesting discussion:

https://www.bikeforums.net/bicycle-m...cle-spoke.html

Spoke thread does mix metric and SAE. We measured the threaded end of the SRAM shaft at 2.5 x 0.45 which is a standard metric thread. From this link

https://www.engineeringtoolbox.com/u...nf-d_1809.html

#2 - 56 has a metric pitch of 0.453. For a short run this will possibly work. I'll grab a spoke tomorrow and try it. I do have a piece with the internal thread to check the fit. The piece came from Aaron at Aaron's Bicycle Repair, an internal gear specialist and a helpful guy. Aaron's Bicycle Repair, Inc..

I must eat my words. Remeasured the existing DD rods that I have by setting a Mitutoyo metric micrometer to 2.5mm and the threaded end has a LOT of slop. Passes right through. Set it to 2.20mm and the threads just squeak through. 2.00mm, it doesn't pass. I measure pitch with a magnifying loop with a scale. The length to measure I so short that I can't tell the difference between 56tpi and 0.45mm pitch. I will grab a spoke Saturday (shop was hectic yesterday). Until then, the true thread spec is up in the air, at least from me.

I mentioned above that i would order an M2 threaded rod to try an experiment, I did and that rod thread is NOT compatible.

So, the only viable possibility I see at this time is a spoke thread. (Or quick buy one from Bike Friday before they run out.) My folder has not been ridden in almost two years, is in storage, I am not going to dig it out to try a spoke. If someone else tries one, please let us know how it worked. From the photo I posted above, it appears that the spoke would need to thread into the hub with about seven threads (rotate the spoke seven times) to get as much thread engagement as the commercialy available pull rods.

Good luck with your endeavors, and stay safe out there.

Too tight?

Use a wire wheel on a bench grinder and "polish" the threads a little at a time. You might want to use a pretty fine wire wheel. Brush the threads lightly at first until you get a feel for it, roll the rod opposite the rotation of the wheel and by all means use the tool rest/table!

Test fit the rod every so often as you don't want to take off too much material.

If its too loose you're hosed.

Thread pitch did not appear to be right.

Weather looks good for a bike ride tomorrow, and I have not had my folder out for a couple of years. So, pulled it out of storage to get it ready for a ride.

And, while I had it out, pulled the shift rod out of the hub to check some options. I mentioned above that the M2 threaded rod appeared to have the wrong thread pitch, confirmed that, it only threaded in a few threads so that won't work. Tried the spoke, and it threaded into the Dual Drive hub just fine.

So, there is the answer, if you can figure out how to put some form of knob on the other end of a spoke that will fit into the click box and that the prongs in the click box can grip onto, you are set.

I am guessing that if someone had access to a spoke thread cutter, that you might be able to put some threads on the other end, and try to cut a nipple to go on the end. The reason I said cut the nipple is that it would have to be pretty short for the rod to pull out far enough to go into high gear. Or, maybe come up with some other idea.

So, good luck with your shift rod fabrication experiments, I did all I could.

I'll pay $40. Has anyone tried using the pull chains used on the SRAM hubs that go on Bromptons? I wonder if the threading is the same. The push rods are used to pull something inside of the hub towards the outside, not push something in as the name would suggest. Maybe a chain would work?

Seems like most people missed the above post made earlier?

Yes, somehow, I missed your post. We did get some quotes to have these made on a Swiss lathe which is necessary for such a thin rod. Amazing machines. Google them. . The quotes were pretty steep, not to mention that we were not certain of he thread. I am going to order a couple from Bike Friday for my personal New World Tourist. I think it would be difficult to make a chain work.

Did anyone buy extras??
 

seems like a bit late to the party. Just checked the Bike Friday website and can’t find anything for scram fuel drive.

have searched eBay and the lot. Hoping that someone on here will be able to help. Had a guy ‘fix’ my bike. Only to find that he just ripped off the click box and push rod. I feel sick just speaking about.

hoping for a miracle...

DO NOT search the Bike Friday site for these. Instead call them and ask for one. Roger

Hopefully if part of the rod is still inside, you can remove it. They are threaded in, right hand thread. I hope no damage has been done.

Would be glad to pay $40 or $50 for the pushrod!

Bike Friday still have some in stock, I ordered one this week from them.

I can't find the part on their website. Could you please provide a link?
Many thanks.

Call Bike Friday on the 800 number and talk to a real person and do your order. Roger