What's the deal with that hole in seatstay bridges?

[opa...@gmail.com]

I'm putting some new SKS Longboards on my wife's Novara Randonee.  I love the new cream ones and am thinking about a set for my Atlantis (I have the pinstriped grey ones on it).  I've put these on before on my Atlantis, read the SKS instructions, watched the Riv video on installing them, but of course my reality is always different than what is shown in the pictures!  

My question is... what determines the orientation of the threaded hole in the seatstay bridge?  On my Atlantis and my wife's Randonee, the seatstay bridge threaded hole faces "down", so that if you put a long rod into the hole, it would intersect the rear hub at some point (roughly).  However, in the Riv video, the SKS instructions, on 2 separate old Schwinns, an old Raleigh, and even an old Diamondback mountain bike, the threaded hole in the seatstay bridge faces "out" like you'd want for mounting a reflector, brakes, fenders..., or basically 90 degrees from the way on my Atlantis & the Randonee.  What's the deal?  Why would you ever want it to face "down"?  I guess cantilevered brakes are ruled out automatically to mount (which I assume is what the hole is for anyway, and not fenders).  Mounting fenders becomes a bit more of a pain as well, by the way. 

P.S. Where does one get those spacers Riv shows in their video ("one finger's width")?  I'm using a carved wine cork on my Atlantis for a spacer!

Cheers

Robert Opalko

[benzzoy]

Threaded seatstay holes that face "down" are arguably more appropriate
for fenders, or at least for the fancy ones like Honjos. With these
fancy fenders, you will drill a hole in the fender at the appropriate
location and then attach the fender to the frame using only one bolt;
Neat, elegant and simple. There is no need for any sort of bracket,
although occasionally, spacers (even cork ones) are required.

In the Riv video, the hole (unthreaded and differentiate) is for
attaching the caliper brakes and a bracket piggy-backs on this and
attaches the fender. You can actually get a dual-holed seatstay
bridge with holes 90-degrees apart, with one (unthreaded) for the
brake caliper and another (threaded) for the fender.

I don't remember seeing any seatstay hole that faces "out" being
threaded. I remember them as unthreaded and undifferentiated ("front"
and "rear" holes are identically sized), and likely used to mount
reflectors (as you stated) or maybe simply vent holes for welding/
brazing.

I don't even know if it is advisable to mount plastic fenders directly
without brackets. In my experience, plastic fenders are significant
heavier than aluminum fenders, so I imagine extra reinforcements to
spread the load and reduce stress will be necessary.

[Minh]

A picture might help. http://flic.kr/p/aP39b6

[Phil Brown]

On Dec 1, 6:47 pm, benzzoy <benz...@yahoo.com> wrote:
> I don't even know if it is advisable to mount plastic fenders directly
> without brackets.  In my experience, plastic fenders are significant
> heavier than aluminum fenders, so I imagine extra reinforcements to
> spread the load and reduce stress will be necessary.

Works fine. I've had a couple of bikes worth for many years.
Phil Brown

[Smitty-A-Go-Go]

"P.S. Where does one get those spacers Riv shows in their video?"

They can be found on the fastener isle of any hardware store... look for a drawer marked "spacers". You want "M5" spacers for standard rack and fender mounts. M5 is the diameter. They come in a handful of widths. I use aluminum but they also have stainless steel. If you want to get fancy you might be able to find a brass bushing in the "bushings" drawer that'd work too. The aluminum ones are something like 20-50 cents each depending on the width. 

Or... the truly resourceful just use a piece of a cork. :-)

[Hank]

On my NashBike Cyclocross with a hole parallel to the seatstays, I
drilled two small holes in the top of the fender and used a zip-tie to
affix the rear fender. Worked great.

[Chris]

Metric Unthreaded Spacers from McMaster (http://www.mcmaster.com/#catalog/117/3240/=f6us4x).  The threading size is M5 (at least on my Sam and wife's Betty).  I'd go with 10mm OD (outside diameter) and get a few in different lengths.  

The best fender installation writeup I've read is from Bicycle Quarterly, but i think plastic fenders are a bit different.