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 Post subject: Kona Dog Collar
PostPosted: Tue Oct 12, 2010 4:53 pm 
Dirt Disciple
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Joined: Thu Oct 07, 2010 10:34 am
Posts: 34
Location: South Coast
Hi there,

First post from an experienced cyclist but a newbie here:

A while ago on here there was a discussion about the Dog Collar used to guide the rear canti brake cable around the seat tube. I seem to remember that some people stated that they did not wear.

I am just finishing a rebuild of a 96 Kona Lava Dome, some parts of the bike show remarkably little wear but the Dog Collar has been damaged by the brake cable sawing down and outward by about 2.5mm.

I am thinking of boring it out and fitting a harder material tube insert; has anyone had this problem, tried this solution or have a better solution?

I look forward to any responses.

flyingfinn


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 Post subject:
PostPosted: Tue Oct 12, 2010 6:11 pm 
retrobike rider
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Joined: Sun Sep 23, 2007 11:22 pm
Posts: 7321
Location: Hove
They are only guides, so they don't have to do a lot if you are using canti brakes. I haven't got anything like 2.5mm of wear on any of mine, but they're only aluminium and they've had a steel cable rubbing against them for 14 years, so maybe a bit of wear isn't unexpected.

It seems to be a c4mm hole, so I wonder whether you could drill it to a little less than 5mm and jam a bit of cable outer in there?


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 Post subject:
PostPosted: Tue Oct 12, 2010 6:17 pm 
Old School Hero
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Joined: Tue Oct 12, 2010 6:06 pm
Posts: 186
Location: Arundel
i might have a spare if thats what your after??


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 Post subject: Kona Dog Collar
PostPosted: Tue Oct 12, 2010 6:44 pm 
Dirt Disciple
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Joined: Thu Oct 07, 2010 10:34 am
Posts: 34
Location: South Coast
Beaver,

A spare would be a good option as then I can run one on the bike whilst I engineer a solution on my damaged one. we are pretty close for location can you pm me with a price and whether it would suit you if I could manage a collection this weekend - otherwise paypal and post would do.

Anthony,

Actually having looked at the device over the past few months it is a good principal but the function of changing the line of pull from side of tube towards the centre does result in a side load. the older method of having a braised on tube is more reliable but I quite like the look of the dog collar.

I think with the wear I have I will need to bore out to about 6mm and I was going to machine a tube that inserts into this and as a protrusion that takes the lead further towards the centreline in a slight curve.

flyingfinn


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 Post subject:
PostPosted: Tue Oct 12, 2010 6:47 pm 
Old School Hero
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Joined: Tue Oct 12, 2010 6:06 pm
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Location: Arundel
ok mate ill have a look through my spares boxes and see if i can find one was it specifically the dog collar you were after or will the older version do aswell?


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 Post subject: Kona Dog Collar
PostPosted: Tue Oct 12, 2010 6:53 pm 
Dirt Disciple
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Joined: Thu Oct 07, 2010 10:34 am
Posts: 34
Location: South Coast
Beaver,

Dog Collar preferred as I might be able to defer the actual repair/improvement process, but the older type will do if that is all you can find.

Just had a quick view of your A'Ha too, with a tidy up that will still make a good cruiser.

flyingfinn


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 Post subject: Re: Kona Dog Collar
PostPosted: Tue Oct 12, 2010 8:21 pm 
retrobike rider
retrobike rider

Joined: Sun Sep 23, 2007 11:22 pm
Posts: 7321
Location: Hove
flyingfinn wrote:
Actually having looked at the device over the past few months it is a good principal but the function of changing the line of pull from side of tube towards the centre does result in a side load. the older method of having a braised on tube is more reliable but I quite like the look of the dog collar.

I take your point, but nevertheless I have three here and only one shows any sign of wear at all, so perhaps yours has led a particularly hard life up to now.

flyingfinn wrote:
I think with the wear I have I will need to bore out to about 6mm and I was going to machine a tube that inserts into this and as a protrusion that takes the lead further towards the centreline in a slight curve.

There won't be much of it left! :( An alternative is to fit a V-brake and use the guide as a stop. It works quite well, especially in a size as big as a 19, and the wear you have wouldn't then be an issue.

I know you said you wanted to keep the bike in 1996 style, but you needn't feel guilty about affording yourself a luxury - XT V-brakes came out in 1996, so if you had owned the bike then you might well have fitted them.


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 Post subject: Kona Dog Collar
PostPosted: Tue Oct 12, 2010 10:21 pm 
Dirt Disciple
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Joined: Thu Oct 07, 2010 10:34 am
Posts: 34
Location: South Coast
Anthony,

As I said it is slightly confusing considering the lack of wear on most of the other components, perhaps it was poorly positioned and had an increased side load, along with a rider who tended to constantly use the rear brake this might explain it.

I did consider avid single digits but will keep the Curve OMs for the moment.

Actually boring out to 6mm will leave approx 1.5 mm material for the insert to sit in on the top and bottom and about 3mm to the outer edge, if I can get away with 5mm I will, but there will still be a slight disruption outside the edge of the insert from the wear. the insert will be machined for a slight interference fit so will form part of the whole structure once pressed in.

In any case I need to have a temporary fit of an alternative so that I can measure up in detail and then decide if the machining is viable.

ff


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 Post subject:
PostPosted: Wed Oct 13, 2010 8:15 pm 
Old School Hero
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Joined: Tue Oct 12, 2010 6:06 pm
Posts: 186
Location: Arundel
hello mate ive had a good rummage through my parts today and only found one dog collar, ( i swear i had 2) unfortunatly i do need it to rebuild my humuhumu. hope you get some luck and ill ask my bro as he has some more spares.


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 Post subject: Dog Collar
PostPosted: Wed Oct 13, 2010 10:09 pm 
Dirt Disciple
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Joined: Thu Oct 07, 2010 10:34 am
Posts: 34
Location: South Coast
Beaver,

No problem, I will probably take mine off the bike and try and solve the problem over the half term week - then post on the repair!!!

ff


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