# Shimano Nexus Inter 4 Shifter



## chuzz (Apr 16, 2019)

I'm not sure if this is where I need to post, but figure a mod can move it if needed. I was gifted an Esquire Nexus bicycle recently. Last week, I decided to put new tires on it as the ones on it were dry rotted. After getting the tires on it and the wheels back on, it wouldn't shift. I only have one gear and am not sure which one it is. This bike has a Shiman push button shifter with a lever under it. The hub is an SG-4R31. All I can figure is the lever under the shifter changes the hub gear and the push button shifter changes gears up. So, to upshift, you push the button and the gears get higher, to downshift, you hit the lever. I took the danged push button shifter apart and now I can't get it put back together correctly. Do any of you know of a site where I can find a schematic break down of how that shifter goes back together properly. I THOUGHT I had it right, but I still can't change gears on this bike. It's very nice bike and I love the way it rides, but I can't change gears and am peddling constantly to go anywhere. Please help me if you can. Thanks.


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## jimbo53 (Apr 16, 2019)

Most of the members here are of the single speed variety bike experts, but this link to Sheldon Brown's website might be helpful. 
https://sheldonbrown.com/nexus4.html
Good luck and welcome to the CABE!


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## chuzz (Apr 16, 2019)

Thanks for the welcome and the link, jimbo53. I have searched Sheldon Brown's information and he's got a TON of info on the SG-4R31 hub assembly, but not a word about the shifter anywhere. I guess I'm screwed unless I can figure it out on my own. I hate when things come apart and something unexpectedly drops out. I need to start recording stuff when I disassemble them, I guess. I used to be able to figure things out, but since having survived 2 brain surgeries 15 years ago, my comprehensive abilities have abandoned me almost 100%. I don't recommend brain surgery unless it's like me and a matter of life or death.


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## jimbo53 (Apr 16, 2019)

You might want to check out Rat Rod Bikes forum, too. Lots of folks over there are doing amazing custom work and use Nexus  multi-speed internal hubs. Maybe they can shed some light on your shifting issues


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## chuzz (Apr 17, 2019)

Thanks, man. I got rid of the 2 speed Schwinn. Tires were more than I wanted to spend on it. Dude that bought it didn't want the fenders or chain guard. Anyone want them? If I can't figure out this shifter after I look at Rat Rod Bikes, I may do some customizing of my own to it. I really like this Esquire and may just put a regular derailer and a different wheel on it along with new cables. I THINK I can figure out how to do that.


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## Duchess (Apr 17, 2019)

Don't know that shifter, but Shimano's integrated brake/shifters cannot be put back together to work properly without at least some mystery special tool (and maybe not at all). I had read that ahead of time, but figured the warning was for dummies. Turns out, I'm one, too. Figures, I _would_ be the last to know.


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## chuzz (Apr 17, 2019)

I dunno, I don't really see any need for any specialty tools. The hub could use some snap ring pliers, but if you're good with a couple of small flat blade screwdrivers, that'll take care of the snap ring. If the warning is for dummies, count me in. Apparently I'm a dummy too!


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## piercer_99 (Apr 17, 2019)

I don't know if I can help or not, I have the SG-4C35 on my 48 Roadmaster, I do not know how close it is to the  SG-4R31.  

I am pretty sure the hub cartridge is the same, yours has a roller brake, mine is a coaster brake.

Either way, when you set and adjust the shifter or replace the cable, on the hub are two red lines, they are alignment points, they should be lined up when the hub is in 4th gear, then everything is downhill from there.

I believe the shifter that you are describing is the Shimano Nexus ST-4S20 shifter, if so, they don't make it anymore and it is kind of a unicorn to find.  
http://www.bikevintageparts.com/index.php?route=product/product&product_id=75 

If you check that link out, and it is what you have, then, at least you have the technical name for it to start your hunt with.

I would think though, that you could replace said shifter with the standard Nexus grip shift, which is what I have and they are readily available and easy to find.

Also, if you are describing it having a brake lever on the shifter, this Nexus Revo should work also.

https://www.thebikeshopstore.com/ca...MI-8mQmPjX4QIV3rfACh15igpzEAQYCCABEgKSGPD_BwE 


Here is a couple photo's of the alignment points, in fourth gear.










This is the standard Nexus 4 speed grip shift, rather simple to find.





This is what my hub looks like, really other than the coaster brake, pretty much the same beast.






The bike it is on.








Hope it is somewhat of a help, let me know if I can be of any help.

Pierce


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## chuzz (Apr 18, 2019)

I tried Rat Rod Bikes, Jimbo, but can't get them to send me a confirmation email so I can join. I'm going to try again. And Pierce, thanks for the info, but my shifter isn't like those. I'm going to try to get my daughter to post some photos of what mine looks like later today. Neighbor has a moped with a loose wheel that he wants me to check out. I might make a couple of bucks off him, but suspect it's just a loose wheel bearing that needs adjusting. He just bought it and it sounds to me like it wasn't assembled correctly.


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## chuzz (Apr 18, 2019)

This link shows exactly how my hub looks. I'm guessing that I line up the two red marks on it along with 4 on the shifter to have it properly adjusted. Can anyone confirm this?
http://m.bicycles.net.au/forums/viewtopic.php?t=97880


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## piercer_99 (Apr 18, 2019)

chuzz said:


> This link shows exactly how my hub looks. I'm guessing that I line up the two red marks on it along with 4 on the shifter to have it properly adjusted. Can anyone confirm this?
> http://m.bicycles.net.au/forums/viewtopic.php?t=97880





yes, that is the proper alignment.

Also, unless you just don't like the grip shifter, there should be no problem with using it for this hub.

good luck.


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## 49autocycledeluxe (Apr 18, 2019)

Rat Rod Bikes appears to be dead. they would not let me sign up either.


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## chuzz (Apr 18, 2019)

Okay fellas, I now have a functioning 4 speed Esquire bike. Thank you very much, piercer_99. Since you told me there should be no problem using a grip shifter, I pulled the one off an old Raleigh that a neighbor donated to me a couple of years ago. I stripped the cable housing off the Esquire as it runs full length and used it on the cable off the Raleigh. I lubed the cable and housing with WD-40 and 3 in One oil and slid the old cable through it with no problem! Re-assembled everything and rode off. Much to my amazement, all of the gears work flawlessly now. You guys probably won't think this bike is much to look at, but I just love riding it. I think maybe it's the seat and handle bar positioning for me. Here's some pictures of the cursed shifter and the internal parts. I won't go into detail about how many time I put it back together and took it apart, because I lost count! I tried several different variations, and NONE of them worked once I put it back into place and aligned the red marks on the hub while keeping it in 4th gear. So, you can now see my Esquire with the grip shifter on it. Now I gotta find something else to keep me occupied and frustrated. Neighbor never brought the moped over. I may try to frankenstein a bike just for the heck of it. I'll let you know. Thanks again to everyone who offered help and opinions.


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## piercer_99 (Apr 18, 2019)

49autocycledeluxe said:


> Rat Rod Bikes appears to be dead. they would not let me sign up either.



I will let the head rat know you guys are trying to sign up, he is a friend of mine.

I just spoke with him.


Your email provider is blocking the emails from rrb,  just send him an email directly at

   steve@ratrodbikes dot com  except take out the dot and drop a . and no spaces.

or pm me and I will get you the info.


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## piercer_99 (Apr 18, 2019)

chuzz said:


> Okay fellas, I now have a functioning 4 speed Esquire bike. Thank you very much, piercer_99. Since you told me there should be no problem using a grip shifter, I pulled the one off an old Raleigh that a neighbor donated to me a couple of years ago. I stripped the cable housing off the Esquire as it runs full length and used it on the cable off the Raleigh. I lubed the cable and housing with WD-40 and 3 in One oil and slid the old cable through it with no problem! Re-assembled everything and rode off. Much to my amazement, all of the gears work flawlessly now. You guys probably won't think this bike is much to look at, but I just love riding it. I think maybe it's the seat and handle bar positioning for me. Here's some pictures of the cursed shifter and the internal parts. I won't go into detail about how many time I put it back together and took it apart, because I lost count! I tried several different variations, and NONE of them worked once I put it back into place and aligned the red marks on the hub while keeping it in 4th gear. So, you can now see my Esquire with the grip shifter on it. Now I gotta find something else to keep me occupied and frustrated. Neighbor never brought the moped over. I may try to frankenstein a bike just for the heck of it. I'll let you know. Thanks again to everyone who offered help and opinions.
> 
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Great news,   that is awesome that your bike is working well.

Glad I could offer some assistance.    Enjoy the ride.

Pierce


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## chuzz (Apr 19, 2019)

Hey Pierce, I sent Steve an email and will let you know if I get signed up. I like a LOT of the custom bikes that they have there. Very creative people!


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## chuzz (Apr 20, 2019)

I took it for a short ride yesterday and had to do a LOT of peddling on the way home in 2nd gear because of the 25mph headwind. Riding out was easy and fast, but not coming home. I won't be doing that again anytime soon. LOL


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## Archie Sturmer (Apr 20, 2019)

Shimano has a website with a literature search feature.
They have illustrated parts breakdown (exploded view) diagrams, as well as installation procedures.
https://si.shimano.com/#/

https://si.shimano.com/#/en/search/Keyword?name=4S

As I recall the 4-speed was an up-gear shifter, requiring large rear sprocket, and relatively small chain ring in front.


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## chuzz (Apr 20, 2019)

Thanks for the links, Archie, but it's a moot point now. I actually prefer the grip shifter I put on it. I tossed that cursed shifter in the recycle bin this morning. Adios to that!


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