vonfilm 

Any ideas on how to mount a 70's Pletscher "rat trap" rack using the braze-on bosses that came on my 1993 Trek 930 Single Track. I don't want to use the old clamp on mounts that scratch up the upper seat stays. If anyone has done something like that I would love to see some pictures.

FBinNY 

Go to the hardware store and look for angle brackets. Bolt them to the rack, then bolt the assembly to the frame.

Odds are that they won't be right, but now that you have the idea, you can modify them, or get a piece of stainless steel and make an exact width adapter for the frame, and drill it to match the holes in the rack.

Andrew R Stewart 

Sure, just cut, bend, drill a strip of hardware steel/AL to fir to fit bosses and contain the two holes for the rack's mounts too. Unless the frame bosses are weird of the angles really off this should be simple blacksmithy/fab stuff. Andy

Pompiere

This is what I did for my son's college bike. I just bent a strip of metal into a [ shape, with a hole at each end and two holes for the rack. Pro tip: drill the holes before you bend it.

francophile 

Calling @mrv in case he has plans. See the contraption in the pics here for the bike he submitted on the clunker challenge. Very crafty.

mrv 

Thanks for the shout out. Very kind of you to remember.
I bent a piece of aluminum. Filed the edge to a bit of a chamfer. Drilled holes where I needed them and got some nylon lock nuts from the hardware store.

francophile 

Hey, I used to fabricate all kinds of stuff in my shop in the pre-children days when I was working on vintage cars/trucks. This one stuck out in my head because it looked so damn genius, refined, simple, and the bends (in pics) look meticulously rounded.

If you polished that thing up, I reckon you could probably make some bucks on it

gugie 

I was going to answer "why bother, get another rack", then I saw this. Damn fine McGyver!

rhm

Same here! My first thought was, don't bother, it's a Pletscher rack! But that's pretty slick.

Cougrrcj

Dang, @mrv , that is a sweet solution!

Back in the day before rack braze ons, those of us that used Pletscher racks used a brake nut-mounted support that sold from Bike Warehouse (now Nashbar) that sold for around a buck...



I've had that rack and bracket on my S-10S since 1976! Never moved or scratched the paint!



.

mrv 

@Cougrrcj , @rhm , @gugie - Thanks for the kind words. Having spent a bunch of my parents money on an engineering degree a long time ago I appreciate the kind words having actually done something useful! Ha!

Hopefully some other folks will be able to use the idea. Or maybe Problems Solvers bike parts will steal it! (i'm sure that never happens in the bike world.....)

francophile 

Fortunately, boss spacing surely must vary enough they'd never be able to duplicate the exact design and anything that would allow for variation would also make this far less elegant. I think you're safe.

Andrew R Stewart 

mrv's Al strip is exactly what I was trying to describe.


A production one might be in two parts. each part would be in a "L" shape. The long legs would slide against each other allowing for differently spaced bosses. No someone needs to make a million bucks on this. I'll take my cut out of your second million Andy

Grand Bois

Very clever, but more trouble than a Pletscher rack is worth, in my opinion.

thumpism 

I knew the world would beat a path to my door eventually. I build my Cimarron in the '80s and the shop had a warranty return on a Pletscher that broke on one side right at the mounting piece. I made a matching cut on the other side, drilled two holes and...TADA!!!
7_Pletscher & generator.jpg

FBinNY 

Agreed, and if you scroll all the way back to the beginning you'll see where i sent the Op out to shop angle brackets, then told him to imagine fabricating a single part to do the job.

In cases like this, I prefer to give people a nudge in the right direction and encourage the to think and create rather than lay out a simple job for them. IMO it's a case of giving a man a fish vs teaching him how to fish.

RaleighBikeGuy

With a rounded file you can also shape it to fit directly to the brake bridge, drill a hole in the middle, and attach it with the brake bolt. A standard rack will be level on a 23" Raleigh Sports, for example. I'm sorry I don't have pictures but I'll try to take one and post it.

Glennfordx4

They do sell brackets for them like the one MRV built, I use them a lot as I had a bunch of nos Kobe racks that I put on a lot of the bikes I flip. We stock them at our shop, they may be Walds.

Glenn

top506

"solve the problem at hand with the materials at hand."

Gordon Pearce, circa 1968, or a minor paraphrase thereof.......

vonfilm 

I appreciate all the responses. I am still trying to decide what to do. I am not very well set up to fabricate sheet metal. I may end up taking the rack off my Trek 750 if I can't figure out how to mount the Pletscher.

That Pletscher carried my books all through high school and college.

Pompiere

Here is something that may work for you with no metal working required, only nuts and bolts. They are available at most any hardware store in various sizes.

Everbilt 3/4 in. Zinc Plated Corner Braces (4-Pack)-13542 - The Home Depot

edit: I just saw that FBinNY already mentioned this idea.

FBinNY 

OK, here's a no tools, no skill needed idea.

Buy 2 long 5x.8m screws in stainless. Thread them through the brazed-on, so they stick out between the seat stays. Now, mount the rack using the bracket it came with, positioned so the screws are resting on the ones you have sticking out. That will give you extra support and prevent sliding, though you should use electrical tape to protect the seat stays.

Bicicletta89

I found a part like this for sale. If the holes line up with my pletscher rack I’m thinking about doing something like this. I don’t have braze-ons but I’m wondering if P clamps would be strong enough?

I found one of the T-brackets that are sometimes used to hold up pletschers by attaching to the brake bolt but it’s pretty short and would leave the rack sloping sharply downward toward the seat stays.

Glennfordx4

They do make SS brackets like that, I have a few out in my shop. I still have a few NOS racks that are like the Pletscher style racks that came with them if you didn't want to use the clamp mount. Most that I've used bolt to the inside of rack braze ons.

Glenn
Sorry didn't realize this was a old thread that I posted to already