|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Shimano 333 hub problem
I built up a lovely kids bike with a Shimano 333 coaster brake 3 speed
hub. The young lad rode it on the ride we took today. There's been a consistent problem keeping gear #2 adjusted. It acts as if an internal spring responsible for pulling the hub into 2nd gear is somehow weak. That is, the little circle with the letter N doesn't settle down in its target hole. As a kludge, I used a bit of inner tube as a rubber band on the bellcrank to help pull the hub into 2nd, but that rubber decayed and I didn't have a spare. In any case, I've readjusted it several times in the past couple months. I'd suspect a dragging cable, except the hub shifts into the other gears just fine. 3rd gear requires the hub to retract the cable even more, and shows no problems. Of course, I lubricated the cable during installation. I even spent time grinding away part of the kickstand mount to give the straightest possible cable routing. Unfortunately, the bike is an hour away and I normally see it at most once per week; so some things are difficult to check, other things may be difficult to remember. But are these hubs extra sensitive to cable friction? Instead of the full housing, should I consider scrounging parts to run bare cable over pulleys, etc? But if anyone has tips, I'd be grateful. -- - Frank Krygowski |
Ads |
#2
|
|||
|
|||
Shimano 333 hub problem
On Sun, 06 Jan 2019 22:23:58 -0500, Frank Krygowski wrote:
I built up a lovely kids bike with a Shimano 333 coaster brake 3 speed hub. The young lad rode it on the ride we took today. There's been a consistent problem keeping gear #2 adjusted. It acts as if an internal spring responsible for pulling the hub into 2nd gear is somehow weak. That is, the little circle with the letter N doesn't settle down in its target hole. As a kludge, I used a bit of inner tube as a rubber band on the bellcrank to help pull the hub into 2nd, but that rubber decayed and I didn't have a spare. In any case, I've readjusted it several times in the past couple months. I'd suspect a dragging cable, except the hub shifts into the other gears just fine. 3rd gear requires the hub to retract the cable even more, and shows no problems. Of course, I lubricated the cable during installation. I even spent time grinding away part of the kickstand mount to give the straightest possible cable routing. Unfortunately, the bike is an hour away and I normally see it at most once per week; so some things are difficult to check, other things may be difficult to remember. But are these hubs extra sensitive to cable friction? Instead of the full housing, should I consider scrounging parts to run bare cable over pulleys, etc? But if anyone has tips, I'd be grateful. Its a few decades snce I rode with a Sturney Archer 3 spped hub and my understanding of how they worked was you set #2, which was direct drive and adjusted for #1/#3. As you mentioned, things like cable drag, etc can affect gears meshing. How old is it? I basically wore mine out. Well, dad purchased it second hand and it was the kids bike although it ended up being me who rode it, every where & everyday. Is the hand piece(?)/adjuster correct for the device? I vaguely remember one hand piece not being suitable, aka either twist grip or thumb shifter. They were "indexed". |
#3
|
|||
|
|||
Shimano 333 hub problem
On 1/6/2019 9:23 PM, Frank Krygowski wrote:
I built up a lovely kids bike with a Shimano 333 coaster brake 3 speed hub. The young lad rode it on the ride we took today. There's been a consistent problem keeping gear #2 adjusted. It acts as if an internal spring responsible for pulling the hub into 2nd gear is somehow weak. That is, the little circle with the letter N doesn't settle down in its target hole. As a kludge, I used a bit of inner tube as a rubber band on the bellcrank to help pull the hub into 2nd, but that rubber decayed and I didn't have a spare. In any case, I've readjusted it several times in the past couple months. I'd suspect a dragging cable, except the hub shifts into the other gears just fine. 3rd gear requires the hub to retract the cable even more, and shows no problems. Of course, I lubricated the cable during installation. I even spent time grinding away part of the kickstand mount to give the straightest possible cable routing. Unfortunately, the bike is an hour away and I normally see it at most once per week; so some things are difficult to check, other things may be difficult to remember. But are these hubs extra sensitive to cable friction? Instead of the full housing, should I consider scrounging parts to run bare cable over pulleys, etc? But if anyone has tips, I'd be grateful. Generally I'd suggest open, clean, lubricate but in the case of an F or FA gearbox, you need the Shimano ball cup tool to do that. Next time you're there, remove the bell crank and see if the pushrod moves easily with your thumb. If it does, you may merely have a sticky/smashed/worn bell crank and those are simple to reform. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#4
|
|||
|
|||
Shimano 333 hub problem
Following up on the problem three speed hub:
First, I see I mislabeled the hub. It's a Shimano 3CC coaster brake model, not a 333. I took the bike home and spent several evenings gazing at and pondering the hub's internals. The Shimano mechanism is much different than Sturmey-Archer's. Everything inside is pristine and now clean of grease and lubed with oil, except the ball bearings, which are greased. 2nd gear drive is via axial meshing of two members with 56 tiny crown teeth. I looked hard at that, since 2nd gear is where the irritating slipping occurs. But I see absolutely nothing wrong. With the guts assembled and the axle held in a vise, but with the shell (or wheel) removed, everything seemed fine, with one largely irrelevant detail mentioned below. Installing the shell plus wheel also seemed fine. For that work, I was holding the bellcrank in the various gear positions by means of a tapered wedge. But installed on the bike in a workstand, the hub first seemed fine, but then started the 2nd gear skip. Seems the cable tension adjustment had somehow shifted again; and it seems to me this hub is much less tolerant of misadjustment than the S-A hubs I'm more used to. Late last night, I re-adjusted yet again, and at 11 PM it seemed OK, but I remain worried. At this point, weather will prevent test rides for maybe a week. We'll see how things go after that. BTW, I thought the hub felt draggy. Applying a spring scale to a chain on the sprocket, it took about 1000 grams (2 pounds) to turn the sprocket even with no load, or even with the wheel overrunning. That seems to be built in to the design of this coaster brake version. There is a sort of steel band spring in the brake mech, wrapped about 330 degrees around a "spring guide", and normal pedaling rotates the guide inside that spring, with sliding contact. I thought "That can't be right," but on further thought and computation, it wastes only about 4 Watts. It's a little offensive to this guy used to perfectly free-running bearings, but it's mostly an aesthetic problem. And digging around the internet and printed sources, it seems Shimano tried and tried again with these hubs. There are several generations, some with bellcranks on the left, some on the right. The internals vary as well. I don't know where my hub is in the trial-and-error cycle. Overall, I like Sturmey-Archer better. - Frank Krygowski |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
shimano spd 540 problem | Mark Cleary[_2_] | Techniques | 3 | August 26th 09 11:06 PM |
Shimano 515 SPD Problem | Bailes | Techniques | 32 | May 17th 05 04:21 AM |
Shimano 515 SPD Problem | [email protected] | Mountain Biking | 28 | May 16th 05 05:15 PM |
Shimano 105 STI lever problem | Dan Daniel | Techniques | 13 | March 13th 05 02:53 PM |
Problem with Shimano R-535 wheelset | Mark Wolfe | Techniques | 7 | August 24th 03 01:20 PM |