CYCLINGFORUM.COM - Where Cyclists Talk Tech --- Return To Home

 

    Register FAQ'sSearchProfileLog In / Log Out

 

****

cyclingforum.com ****

HOMECLUBS | SPONSORS | FEATURESPHOTO GALLERYTTF DONORS | SHOP FOR GEAR

Return to CyclingForum Home Page CYCLING TECH TALK FORUM
          View posts since last visit

The problems of internal gear cables
 Goto page 1, 2  Next

Author Thread Post new topic Reply to topic
Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

7/12/17 4:49 PM

The problems of internal gear cables

My wife was complaining that the front gear changing on one of her bikes was getting very stiff and difficult to wrestle up onto the big chainring. I tried it and agreed with her. It's a BH frame with internal cable routing.

I removed the cable, verified that both the shift lever and derailleur moved freely on their own, and then tried to fit another cable. However, when it came to pushing the cable up through where it exits behind the bottom bracket, it couldn't be done - turned out that the plastic sleeve that houses the cable inner where it exits behind the bottom bracket was completely jammed up inside with grunge that had come off the tyre when riding on wet roads.

I had another piece of clear plastic sleeve of the correct size to replace the existing one, and the cable could then be fitted no problem and ran freely. However, figuring that the problem was only going to happen again, I remembered that I had some heatshrink tubing, and used it to make a boot to keep the crap out. The lower part of the heatshrink slides freely over the plastic sleeve, and I heated the upper part with a match to shrink it around the cable inner. Had to add a bit of silicon sealer as well to make a complete seal around the inner:

<a href='https://photos.google.com/share/AF1QipPPRbUbRIirDdPtSf9BLGSMl7AJWmSNQi8u-bE77YeOEZMZRtXO5FRPGkaMaL-UYA?key=MlktR1BxZGF0UGZibk9zZVd1cHNzbmNjaW80Wmpn&source=ctrlq.org'><img src='https://lh3.googleusercontent.com/LN6H7lzdLQfP3wDltuohTWIdelxej2zA3B-5vjAQnvsdhqeOL2Nw_TfbmpJOFJvmP3pnGC8TobtFcFOVJZYIlMbN5FczieJ0uw-zO8-28Hu7CVp5ztXh1KJaDsV61nWeiqf_dU1CwQ' /></a>

 Reply to topic    

Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/12/17 5:04 PM

I have used both liner and heat shrink myself. Works well IMO and experience.

 Reply to topic     Send e-mail

daddy-o
Joined: 12 Apr 2004
Posts: 3307
Location: Springfield

7/12/17 7:47 PM

Interesting, the anchor passes the visible text as the argument and the reference holds the credentials. The publisher has some really neat tools.

 Reply to topic     Send e-mail

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/12/17 8:44 PM

Having bought one of the first marketing-success mtb full-susp bikes back in the 90's (Pro-Flex 856), I was disappointed that the serpentine, segmented rear shift cabling literally stopped working during the first ride. It was then that I did about the same thing as Nick, making "sliding umbrellas" from shrink tubing to protect the housings from dirt entry. I had to first add stationary extensions of the housing liner, pressed into the upward-pointing ends of the troublesome housings that I had carefully drilled a short portion of liner out of, before then shrinking the larger tubing onto the inner wire. This was my home-spun take on Gore's pricey sealed cabling kit, and worked so well that the modified cabling is still on that bike, now in my brother's possession after many, many races by both he and I.

Last edited by dddd on 7/12/17 8:45 PM; edited 1 time in total

 Reply to topic    

Nick Payne
Joined: 10 Jan 2004
Posts: 2625
Location: Canberra, Australia

7/12/17 8:45 PM

I use this web site to generate the image embedding link: https://ctrlq.org/google/photos/

You just paste in the goo.gl link that Google gives you when you want to share an image and it provides both the direct https link (which doesn't seem to work here) and the a href link (which does).

 Reply to topic    

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/12/17 9:12 PM

It occurs to me that Shimano also offers rubber-tube labyrinth shields which slide over the necked-down end of a special ferrule, and incorporate a contact seal at the other end of the tube to seal against the inner wire. The tube's length and diameter comprise air space around the inner wire that prevents transfer of contamination toward the end of the housing.

Sram also made two versions of a rubber-bellows cable shield, the longer version (called a Bass Worm) also provided some tension assist to the derailer's return spring, while the small one was yellow and gripped the narrow extended nose of the ferrule.

In the distant past, front derailers had housing running up to a housing stop on the derailer, and the housing quickly packed with water and/or dirt.
Simplex replied with a dwntube housing stop that left the lower end of the housing horizontal, to allow water drainage (as below), while others relied on stainless-wound housing with no vinyl covering to allow water to escape.
This of curse before derailers ditched their housing stops and open guides replaced any housing stops.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/13/17 7:26 AM

Gore "Grub Seals"

While we're on the topic of sealing cables, does anyone know of a source for these?



Gore called them "grub seals" and they seem to be rarer than hen's teeth. They're great for sealed or semi-sealed shift cable systems, but I've only seen them with Gore and SRAM cables. They're much smaller than the "inchworms" that are used on V-brakes, which are easy to find. If I can find a source, I'd like to buy a bunch of them.

dddd, my Proflex 856 came with Gore cables and the original cables are still on it. It seems like the old yellow Gore cables were more durable than the later Gore and SRAM cables.

 Reply to topic    

KerryIrons
Joined: 12 Jan 2004
Posts: 3234
Location: Midland, MI

7/13/17 9:41 AM


quote:
I've only seen them with Gore and SRAM cables


My Chorus group came with one for the rear cable (purchased fall of 2014). I assumed they were part of the Campy group but maybe the supplier (Merlin) added them into the box. I have two Campy cable sets in my "stock" cabinet and neither set has one in it.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/13/17 9:48 AM

I've never seen them with Campy cables...

...so you're probably right about Merlin adding it. Actually, they make no sense with Campy cables, since they don't have a protruding liner or ferrules with an extended nose.

 Reply to topic    

Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/13/17 9:55 AM

What is up with this rim? Is this knurling?


 Reply to topic     Send e-mail

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/13/17 11:24 AM

That was pretty common on bikes in the '70's

Notice that this is a chromed-steel rim and they were notorious for poor braking, especially when wet. The knurling helped to keep the pads from glazing and hopefully provided better braking, though that may be debatable.

 Reply to topic    

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/13/17 2:04 PM

The braking in the rain with these knurled-steel rims is dismal, just not as bad as with smooth-sided chromed-steel rims. I recall once riding across a grass field after evening dew had settled on it, then going down a steep hill that curved blindly around the hillside. When I first applied the brakes to the old Schwinn's smooth steel rims, the sensation was exactly as if the bike accelerated in response to braking, literally "nobody home" in the braking department. Luckily no traffic at that hour, and oddly, years later, my home is along the same part of the same road where that occurred.

My Pro-Flex 856 was nearly a pre-production model, the only one to have yet arrived at I. Martin Imports in July 1995. As such, I was soon notified of a recall for the suspension units (no top-out cushions inside the shocks had been installed, presumably to achieve greater advertised travel figures), and the subsequent bikes included full Gore cabling to address the problem of immediate dirt entry into the housings. I also later received an updated, reinforced swingarm to replace the original that broke at the drive-side dropout area.
The durability of Gore cable housing liners seemed to be much more a function of how the cable was routed than of the quality of the liner. Often a sharp bend or step feature near the bottom bracket was where the liner wore through early on, allowing the cable's travel path to become contaminated.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/13/17 2:31 PM

The 856 is definitley a piece of work

The Girvin Vector fork was a nightmare; I had to realign it after virtually every ride. Ultimately, I replaced it with a Marzocchi Bomber, then later, an Atom Bomb, which is what's on it now. The rear shock elastomers weren't terribly effective, nor was the oil damper. After replacing the elastomers with a Speed Spring and playing with the oil viscosity, I gave up and replaced it with an actual shock (not the overpriced, under-performing Noleen that Proflex sold). The Stratashock air shock seized after a short period of not being used (a common problem) but the Risse Racing Astro-5 that's on it now works reasonably well. I replaced the horrible cantilevers with V-brakes, so I could actually stop reliably. The rear derailleur was upgraded to a SRAM 9.0.

Not too long after all of that, I bought a Jamis Dakar Pro with disk brakes and suspension that wasn't a pain to maintain. The Proflex has been gathering dust ever since. The most positive things I can say about it are that it got me into mountain biking and it's relatively light. That said, I've been tempted to take it for a ride just for laughs (hopefully).

 Reply to topic    

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/14/17 12:56 AM

My 856 rear ODS shock seized early on, I had to rebuild it and relieve the piston ring gap that had become tight enough to cause seizure when the shock got hot.

My brother later bought the bike and added Speed Springs, then later on had the front damper blow out it's oil during a race. This was very weird in that the liquid oil, upon escaping from the damper, attached itself to the shock spring like a piece of gum and actually had hardened by the race's end. I concluded that the rubber top-out bumper that had been retro-fitted inside of the shock per the early recall melted that day and combined with the hot oil to produce something akin to hot-melt glue.
He then bought Risse air shocks for it and was extremely pleased.
I've got a K2 3000(?) model from 1998 or so that I bought used, very cheaply after the '08 markets crash. I've used it as a loaner and done quite a few rides on it myself. It's like the 856 but with a longer carbon swingarm pivoted ahead of the seat tube, it has the Vector linkage fork and has front and rear Noleen shocks that still work to this day.
After sellng the 856 to my brother, I put a used Vector Carbon fork on a box-store Pacific hardtail frame, which worked superbly in combination with my chosen componentry. I've always used this bike for the local duathlon where I ride down to the river and leave my bike and shoes there, then hitch a ride back up to town to the start. I've been dead-last to the bike transition more than once, but never arrived to find that last-remaining bike stolen!

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/14/17 6:34 AM

I'm surprised that the forks lasted for you

Granted, the 856 was my first MTB, so it had to endure my "first year crash fest" while I developed a semblance of off-road skills. Still, even a minor "get off" would result in the fork being twisted out of alignment, necessitating disassembly and reassembly every time. It didn't take long before I got tired of that nonsense.

Were the carbon Vector forks any better?

 Reply to topic    

Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/14/17 11:01 AM

"chromed-steel rim "

Fun to keep tires on. I used to run and hide when working at the LBS in 2012 when the old Schwinn bike came in for tires. Chrome steel rims. Carbon rim stop much better, even old tech carbon rims... ;)

1/2 of Schwinn Chrome rim bikes that left the shop with new tires in the summer came back. Folks would have the bikes in hot car long enough to pop tires and tubes. A few while driving, POW!

 Reply to topic     Send e-mail

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/14/17 3:00 PM

I crashed the Pro-Flex on a couple of slow, tricky descents, but can't remember ever having to re-align the forks like I had to do on my old dirt bikes in the 70's.
It was my 3-1/2th mtb, since one of those was a hybrid.

The Schwinn steel rims to this day are difficult to get a tire's beads seated all the way around. Usually takes a couple of tries, deflating before each try and using something as a bead lubricant.
The upside was that these rims, even without bead "hooks", could handle tandem air pressures.
Those explosions must have resulted from cheap tires reaching bursting pressure, I can't imagine a properly-seated bead lifting off. Perhaps these tires never got fully seated, or as when an unused bike sits too long the beads settled back into the rim channel when the bike was rolled with tires flat(?).
To this day I often encounter bikes with tires not properly installed, not fully seated, or with the tube interfering with the bead's contact with the rim.

 Reply to topic    

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/14/17 4:59 PM

Vector Carbon

I found this fork at a swap meet in 1998 for $150, said to be stiffer than the alloy Vector. I found that it had too short of a steer tube to fit on my used-buy GT LTS frameset, so it went on the Pacific frame and off came the Judy fork I had been using. The Pacific handles so well that I don't think I have ever crashed it.
Same for the GT, which ended up with the longer Judy Hydra-Coil fork, except I did crash the GT a few times due mostly to riding in unfamiliar trail conditions.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/15/17 5:01 PM

Schwinn had special sized 27" tires...

...to fit those rims. They weren't the same as standard 27 rubber.

 Reply to topic    

Sparky
Joined: 08 Dec 2003
Posts: 19068
Location: PDX

7/15/17 6:47 PM

I guess that source the tires originated from is the only experience i can speak to. I do not remember the source or brand to add anything else i am afraid.

 Reply to topic     Send e-mail

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/16/17 12:39 AM

There was no Schwinn-specific tire size for any 27" rims, all are/were 630mm BSD.
I've bought very old Varsities and Continental with very old Schwinn Puff tires in the 27x1-1/4" size, and those could be just as difficult to fully seat as modern 27" tires on the steel Schwinn rims!
The Schwinn shops back in the day used tire-mounting pliers that gripped the inflated tire and had long handles for leverage to lift beads up onto the bead-seating ledges at the base of the rim sidewalls, one side at a time. Something that I have had to do with bare hands, with difficulty, on many occasions with tires on other rims, but I'm not strong enough to do this with tires on Schwinn rims.
Many other standard sizes of tires did have slightly-different-sized Schwinn equivalents, which led to many millions of erroneous tire purchases over the years.
I bought a Hybrid at Goodwill last month for example, which had a 622mm 700c tire mounted onto a 630mm 27" rim. The rim had deep enough of a channel to allow easy mounting, but no way would the beads come up enough to rest on the bead-seating ledges, so the tire was very uneven in height around the wheel. I had to tune up a discarded 700c touring wheel in order to get the bike sold.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/16/17 5:08 AM

All I can tell you...

...is that Schwinn tires fit their rims better than anything else and they often did not fit well on other brands of rims.

 Reply to topic    

Brian Nystrom
Joined: 26 Jan 2004
Posts: 5096
Location: Nashua, NH

7/16/17 5:10 AM

All I can tell you...

...is that Schwinn tires fit their rims better than anything else and they often did not fit well on other brands of rims. Local Schwinn dealers told people that their tires were a special size, though it's possible that they were being loose with the truth, as that was pretty common, too.

 Reply to topic    

dddd
Joined: 11 Jan 2004
Posts: 3345
Location: NorCal

7/16/17 5:55 PM

There was surely some truth to that from time to time, and from batch to batch of Japanese tires in those days nearly 50years ago, and that it might become gospel to those selling Schwinn tires. I've bought semi-recent Conti 27" wire-bead tires that were virtually impossible to get seated on a Schwinn 27" rim, but were nearly as bad trying to get seated on the Kinlin alloy 27" rims on a late-80's Costco/Motive ten speed (I could never get them mounted straight after fixing a flat while out on the road).

I remember buying some really old NOS, US-made, 27x1-1-8" Schwinn "280" clincher tires that had sidewalls that looked like woven canvas. I think these were made for 1960's Paramounts and that the "280" referred to their weight, as with certain tubulars.
I mounted these on my Bridgestone 400 almost 20 years ago, and despite their modest rolling performance they still punctured easily and lasted not very long. If only I knew then how much they might be worth today on Ebay!

 Reply to topic    

daddy-o
Joined: 12 Apr 2004
Posts: 3307
Location: Springfield

7/16/17 6:07 PM

My Schwinn typhoon came with 20x1.375" rims. 20x1 3/8" tires did not fit. And the ones from the other store didn't fit either. Very frustrating for someone who just learned fractions.

Does anyone have a story about switching from steel rim 27x1 1/4 to tubulars? Whatta dream.

 Reply to topic     Send e-mail


Return to CyclingForum Home Page CYCLING TECH TALK FORUM
           View New Threads Since My Last Visit VIEW THREADS SINCE MY LAST VISIT
           Start a New Thread

 Display posts from previous:   


Goto page 1, 2  Next  
Last Thread | Next Thread  >  

  
  

 


If you enjoy this site, please consider pledging your support

cyclingforum.com - where cyclists talk tech
Cycling TTF Rides Throughout The World

Cyclingforum is powered by SYNCRONICITY.NET in Denver, Colorado -

Powered by phpBB: Copyright 2006 phpBB Group | Custom phpCF Template by Syncronicity