mikeread

For one reason or another I find that the gear cable adjuster screws on the down tube (or headtube) break fairly regularly. Ok only every year or two :-)

I think this is due to the small size thread (m5), weakened by the hole in the center and combined with the constant vibration and weight and tugging of the cables. Packing a bike into a bike box doesn't help either, I always take a spare if I am flying.

So I have been thinking of alternative ways of doing the same job but better.

My first idea was to simply bump the size to m6 and make my own adjusters.

Then I thought why not put the adjuster screw on the other side of the anchorage boss, the bare cable side where it would not be subjected to all the usual destructive stresses.

The end of the outer cable would slot into the braze on and stop up against the end of the adjuster screw which is screwed in from the bottom. Adjusting the screw would simply move the end point of the cable to provide the adjustment.

I will try and post a sketch in a minute or two.

Does this make sense? Is there something I have overlooked that would prevent this from working?

I am aware most things have been done before, has anyone seen anything similar?

Thanks

Mike

Sketched two ideas - see next post. The upper idea would be more complex and would need something to stop the grub screw just turning with the adjuster - I haven't thought that far yet.

mikeread

Andrew R Stewart 

Why are your adjusters breaking so often? Before I would make a more complex, likely bulkier and not industry supported cable stop I would want to know what I was trying to avoid.

I'll also add that so many gear stops are placed way up the DT, many right on the head lug/ring. IMO this is too close to the bars for a smooth and tug free casing length.

Here's a couple of shots of how I do it. Andy

squirtdad

this is what dave kirk does Innovation | Kirk Frameworks

mikeread

I agree it will be bulkier but am not bothered about non standard - it is only me who will be using it.

I don't know for sure why they are breaking, my winter bike is the same layout as squirtdad's photo above and they are always failing, I suspect the location on the head tube doesn't help like Andy says

unterhausen

I have only broken them due to contact. That area collects cruft, so it's not likely that your knurled wheel idea will work for long. The brass adjusters that are available (Ceeway, Paragon, Dave Kirk I think) might do better.

My solution is to use down tube shifter bosses. IRD makes some stops that allow the cable to come out easily for packing.

Nessism

Paragon makes some nice robust stainless barrel adjusters and various sturdy looking cable stops. Maybe I'm not understanding the problem but these are worth a look regardless...https://www.paragonmachineworks.com/...tml?cat=77&p=3

unterhausen

The Paragon adjusters that don't have the o-ring are the Dave Kirk design, I think. Ceeway has some steel adjusters. I thought they carried the Pargon parts, but I don't see them.

mikeread

Ceeway have the brass adjusters, I assume these are the Kirk design ones. I have a parcel from Ceeway awaiting opening and there should be a couple of those inside.

I am still going to make some and see how they turn out. The current idea is a 5/16 UNF adjuster with the cable insertion almost right through. It sounds chunky but might look quite neat if I get it right. I will try 1/4 UNF as well but I dont think it will be strong enough with a 4mm hole almost right through. Just waiting for some stainless bolts to arrive before I can make something up.

mikeread

I did a bit of tinkering and came up with a bomb proof ?? gear cable adjuster. Not yet sure if I will use them on the down tube, make a boss for the head tube or not at all.

5/16 UNF hex head stainless screws were used to make the adjuster. This gives enough space to drill a deep 4.1mm hole for a nice secure gear cable fit (without the ferrule). The bit that brazes to the frame is simply an open ended threaded boss. Obviously the spigots to fix to the frame would be cut right down before brazing.

I thought they might look a bit too chunky but next to some of the alternatives I think they will look fine.