Build vent - Ugh!

[yeshoney]

Just sharing a little build story that I am sure happens to everyone once in awhile. So I am putting the final nuts and bolts in place on the Shelby Rat and except for the brake cable and lever to the rear brake and hand grips I figure it is done. Let me say that working on old bikes and being anal about things being straight, symetrical and look correct takes it toll. I had this thing put together and taken apart in various stages along the way as I experienced different issues that always crop up when you mix and match parts from different bikes and different eras. I can accept those as during mock up you never lock it all down and so there is always fine tuning. Here is where my issue comes in. I take the bike off the stand and sit on it and when I turn around to look att eh rear rim the whole bike feels flimsy, like something is loose. I think to myself thats weird, I just had the thing in the stand and ran it thru the gears (Nexus 7 Internal hub) and I must ahve had this thing up to 35 mph. So I put it back in the stand and start to retighten all the nuts and bolts. No issues. I then pressed down on the chain and it seems tight but has a lot of up and down stretch. I'm thinking that's weird. So i take a look at teh rear sprocket and I see the sprocket flexing back and forth as I press down on the chain. Almost 1/8th of an inch. Now I know that is way to much so i grab the whole wheels and wiggle it back and forth and the hub is loose. No wait maybe it is just the sprocket as I put it on in reverse to keep the front sprocket lined up correctly as I had to spread the rear dropouts to accomodate the hub. Now I am bummed. There is a nice list of things that need to go on in a particular order that now have to come off to get the wheel off to work on. All that wheel and fender alignment out the window, Ugh! OK, I take a break and accept it. Probably just reverse the sprocket and I will be fine or maybe I put the spacer on the wrong side when i put the sprocket on. OK, off it all comes. Break down the rear half and get to the wheel off. i start wiggling things and find out the whole hub is loose! This thing was brand new! OK, never had one of theese apart, but what the hey how hard can it be? I try the brake side first but that is together tight. I go to the gear side and start taking all the hub hardware off to get to the 4 lcok nut and washers that hold the hub in. Get them all loos and presumably tight again only to have it rtemain loose as I tighten it up. Truns out you need three cone wrenches to hold it all tight and 4 hands to make it all work! As you can tell I don't have 4 hands, Getting frustrated so I take a food break and come upstairs for some Pop Tarts! Yumm Strawberry frosted! Ok, in a better mood now. Somehow I overtighten the nuts and washers and then slowly loosen them individually until the guts are tight. I figure I am good now. Well, not exactly. You see Nexus Hubs require the axle to be fixed so that when you spin the hub and sprocket the wheel rotates. Well, the hub wasn't turning. OK, scratch head look at wheel, yell a few obscenities, take a deep breath, and start over. This time I get it done correctly and get it back together and put it all back on the bike. TOtal time 4.5 hours! What started out as a short trip down the basement to move the bike off the stand and start a new project turned into, well, ahh, umm a project in and of iteself. Now I am done venting/sharing/griping.

Pics to come~~

Joe

 

[B607]

Been there, done that. Not with a Nexus, but everything else! Now I always put my builds together while still in primer, tighten everything down and then RIDE. When I start painting, I know everything will click when I put it back together. You have more guts than me messing with that Nexus. I have my first Nexus and luckily it was okay from the get go. You're right. When you make a "parts bike", there's always some fitting issue to mess with. Good Luck on the rest of your build. Gary

 

[user 135]

I am scared of the Nexus hubs and have never taken one apart. But I know what you mean about something simple going wrong.

Don't worry it was time well spent and not irresposible. :mrgreen: :mrgreen:

 

[KOTA]

I would rather chop, section, stretch, or re-paint a frame 4 times then take a Nexus apart. Before I'd even attempt it, I'd have to get a CASE of Pop tarts.

 

[Uncle Stretch]

Aw man yall are being scared of nothing . I pull the 3 speeds apart just for something to do. There is only one part that you have to worry about. Its the second thing that come off on the sprocket side. It has these two pins that hold these two little flapper parts with some little springs. When you turn it wrong the pins drop out and you may never see the little springs again. They really come apart as a unit and unless your going to clean them up and regrease them they go right back in as a unit. If you put one together the axels have flat spots on them and a small crecent will hold the axel while you lock the nuts on the other side. When you mess with one you will notice that when you turn the sprocket the axel turns the other way . If you tighten the nuts too tight on the brake arm side it wont turn and you will have to loosen it a little. Now take apart a Shimano 3cc or 333 and talk about a nightmare. the two brake shoes fall out before you ever get to see where they went. It will take you a while to figure out how they go back in....like two hours. :shock: :shock:

 

[JoeyMac]

That kind of stuff is why it's nice to have someone over to be an extra pair of hands. I know I would probably still be working on my Roadmaster if you hadn't come over to help. Let me know if I can help you out at all

 

[Larry]

Don't fret YH. It's why we do what we do.

I recently took in an orphaned World Traveler that was about spent. I must have about 40 hours of labor cleaning, regreasing and adjusting it back into shape. Now I can flip it for about 150$ :lol: On the bright side, that little bit of cash will go to the 24" wheel set for my Monark.

 

[Ace]

I would rather chop, section, stretch, or re-paint a frame 4 times then take a Nexus apart. Before I'd even attempt it, I'd have to get a CASE of Pop tarts.

I'ld rather settle for a case of spare parts :mrgreen:

After fidling with my backwheel to get it to work with the Xtracycleframe I had trouble putting it back on my Ghostrider. Just couldn't get it to freewheel anymore, so took it apart today. Here's the verdict:

Dangit. I was so sure I didn't use excessive force...but it's such a flimsy part, you wouldn't even notice it broke in two untill it is too late...sigh...that's my driver unit part #8 destroyed ! These Nexushubs are indeed trickier than I expected.

 

[JoKeR63]

I would rather chop, section, stretch, or re-paint a frame 4 times then take a Nexus apart. Before I'd even attempt it, I'd have to get a CASE of Pop tarts.

I'ld rather settle for a case of spare parts :mrgreen:

After fidling with my backwheel to get it to work with the Xtracycleframe I had trouble putting it back on my Ghostrider. Just couldn't get it to freewheel anymore, so took it apart today. Here's the verdict:

Dangit. I was so sure I didn't use excessive force...but it's such a flimsy part, you wouldn't even notice it broke in two untill it is too late...sigh...that's my driver unit part #8 destroyed ! These Nexushubs are indeed trickier than I expected.

Being that is a 22 tooth sprocket, I'd have to guess a high torque load. I do the same to Sturmies all the time and fear they'll explode. But I watched a Sturmie eqiupped British tandem (homemade) go up a 15-20% grade with a baby trailer! And that couple was pouring on the coal.
I had to walk my bike up this hill.

 

[rick74304]

Looks like an easy enough part to make a replacement for :wink: :lol:
We all feel your pain, my man. Just remember, if building cool toys was easy, everyone would have them!!
Yesterday, I went to the parts bin for some vintage pedals for my latest build. Every last pair I own were too large for the crank i'm running. :x So, all I could think of to do was swap out the old pedal axle shafts for the new ones. Well, the new shafts are shorter than the old, so theres no threads left for the retaining washer or lock-nut. Now what !?! Broke out the lock-tite for the threads, and a little dab of j.b. weld for just in case.
I still have to make some sort of handle bar stem to fit my new schwinn springer, because once again, nothing I have fits. :?
Time to call up the local oldies d.j, and have him play "making it work" by Doug and the slugs 8)
Dont remember the words, just the chourus;
Making it work, takes a little longer
Making it work, takes a little time
:roll: dont ask me to sing, really
Rick

 

[Ace]

Looks like an easy enough part to make a replacement for :wink: :lol:

If only :lol: but even if I were to manufacture the flimsy part myself, I would still have trouble placing it because the driver unit is factory closed, no screws or bolts to undo it...right, Uncle Stretch ? Or am I missing something here, besides experience ? :wink:

 

[Ace]

Being that is a 22 tooth sprocket, I'd have to guess a high torque load.

Thanks for shining your light on this, that actually sounds very plausable. I am sure I was very carefull while tinkering with my Xtracycle, and can't remember something breaking, or giving it a reason to break. My guess now is it was in 2 parts already but held in place by the other hubparts, and simply fell out when I took it all apart to have a look...same result though, I'm still left with a broken driver unit, just not by messing it up with stupidity :mrgreen:

 

[yeshoney]

Well, I can't speak for the 3 speed version except to say they are are two very different beasts the 3 and the 7 speed. Most of the external pieces as far as lock washers/nuts etc look similar, but the area under the internal shift joint and the cable router are unique to the 4, 7 and 8 speed. I am not sure why the counter rotation is necessary, but then I am not well versed in the whole planetary gear setup inside. What i do know is that I have had to make the cut axles fit into many a drop out and then use one of the many counter rotation washers they offer or in one cicumstance grind the catch off and just lay the flat of the axle against the bottom of the drop out and tighten it so it would not spin (risky, but worked!) I wish i had the throw away money to open one of these up and take it apart and try to put it together so I could have a hands on to what makes them work.

Joe

 

[rick74304]

Looks like an easy enough part to make a replacement for :wink: :lol:

If only :lol: but even if I were to manufacture the flimsy part myself, I would still have trouble placing it because the driver unit is factory closed, no screws or bolts to undo it...right, Uncle Stretch ? Or am I missing something here, besides experience ? :wink:

Well, seeing as my only experience is with refurbing sturmeys, i'm declaring myself as unqualified to give any further advice on shimanos! I will say though i'm rethinking my plans to use a 7 or 8 speed hub in future builds if they all share that same inherent design flaw. There's just no way that little pawel/teeter-totter looking thing will handle the torque load that my big butt would put on it climbing hills :roll:
Anyone know if 3 speeds and their larger 7 and 8 speed cousins share that same design?
Rick

 

[Quanah]

Perseverance and Pop Tarts always pay off! Time well spent is how I would look at it, now you know your bike even better.

 

[JoKeR63]

Looks like an easy enough part to make a replacement for :wink: :lol:

If only :lol: but even if I were to manufacture the flimsy part myself, I would still have trouble placing it because the driver unit is factory closed, no screws or bolts to undo it...right, Uncle Stretch ? Or am I missing something here, besides experience ? :wink:

Well, seeing as my only experience is with refurbing sturmeys, i'm declaring myself as unqualified to give any further advice on shimanos! I will say though i'm rethinking my plans to use a 7 or 8 speed hub in future builds if they all share that same inherent design flaw. There's just no way that little pawel/teeter-totter looking thing will handle the torque load that my big butt would put on it climbing hills :roll:
Anyone know if 3 speeds and their larger 7 and 8 speed cousins share that same design?
Rick

Well, one thing I've found is that coaster brake models of both Sturmie and Shimano hubs use thinner planitaries than their no-brake cousins. I've had both coaster versions and they both had a skipping planitary gear or two. So I'm sticking with caliper brakes on my hub gear bikes for now.
It's possible that these pawls are undersize too, just 'cause they're trying to cram more stuff in the same space.

 

[Markm]

hey Ace, could you scan that nexus exploded diagram for me????? :mrgreen:

 

[Ace]

Shimano has every single hub online at http://techdocs.shimano.com/techdocs/index.jsp 8)

The nexus 3 speed coaster diagram is at
http://techdocs.shimano.com/media/techd ... 609174.pdf
Most common at
http://techdocs.shimano.com/techdocs/bl ... 6480752414

Enjoy :mrgreen:

 

[Markm]

Right On!!1 Thanks!