etherhuffer 

I have several old forks that am going to try my hand at silver soldering. Going to add bosses to fork, the kind that go through fork all the way. The forks have eyelets now on lower side of dropout. It looks like many forks with double eyelets have the pannier mounted to a top eyelet. Assuming the lower eyelet better positioned for fender stays.

Also, research says that the mid fork boss should be 180mm away from eyelet. This set up will not be for super heavy front loading. More of a sport touring sort of set up so weight not a big issue.

Any input appreciated.

veganbikes

You might ask the moderators to move this to the Framebuilders part of the forum. I wish I could help I do want to learn how to solder and braze and weld at some point.

unterhausen

Moved here from bike mechanics.

The consensus I've found is that lowrider bosses should be 165mm from the eyelet. Amusingly, I asked this question here some time ago

I think most production lowrider racks are designed with the idea that they are going to use the eyelet behind the front dropout since many bikes only have one eyelet. It always helps to have a rack in mind, and preferably have it in your possession.

Andrew R Stewart 

Having done quite a few low eider mounts for my (and wifes') touring bikes I'll second what Eric said. If you are not concerned about the bags hanging really close to vertical then disregard. But if you want the rack's top rail to be horizontal AND have the mid fork blade mount not interfere witht eh pannier's hooks I strongly suggest you have the rest of the bike and the rack on hand for a mock up before drilling or torching. I'll further add that following others' low point mount to mid fork mount is being blind to the variations that head angle, rake and rack combine to produce. In the shops I worked in i was often the wrench that installed lowrider racks (likely because few coworkers considered tourists worthy and the lack of practice that my doing it just continued). The number of less than best rack/bag fitting was more than the good set ups on most production bikes I have dealt with.

Get the rack, mock up with the bike level, only then drill.

I'll also add some aspects that I have rarely seen talked about. Some set ups like some stand off from the fork blade that the rack rail is located at to better handle the bag's hook design and to allow an over the ft wheel reinforcing rack loop fit between those top rails. You want the upper mount plate to sit flat against the fork mount if at all possible. When the lower dropout mount (the dropout eyelet) is below the blade the rack's strut will need its own stand off too. If the rack doesn't have its own fender eyes (my first lowrider rack did, the long gone Eclipse brand. Only a few of the Tubus racks have had this very nice feature) I would suggest adding a top of the drop out eyelet for the rack and use the lower one for the fenders. Andy (who hates one bolt having many functions)

tyrion

165mm between the 2 mounting points for Tubus Duo:

https://www.tubus.com/fileadmin/user...TZ_Duo_2.0.pdf

Steve B.

I had asked a question of this sorts a while back when I was fitting a front rack to a 25 yr. Old Miyata touring bike. An Axiom rack would not install correctly due to incorrect placement of the mounting point for the fork eyelet. I ended up with a Roswheel front rack that needed to be modified (drilled out) for a larger bolt then what Roswheel allowed. I could find no standards as to mid fork eyelet placement, the 180 number is a first for me.

etherhuffer 

Wow! Thanks so much! That helps clarify a lot of why I have piles of hardware around when I went from an old Raleigh R300 tourer to my Surly Long Haul Trucker. I was puzzled as to why my old rack would not fit the new frame. Now I know. But I had several racks from an old bunch of stuff and changed over to a different rack. Since I have two forks to mod, going to do a more careful planning on this.
And as for the comment on tourists being not worthy, isn't that the truth. Say 'touring bike' and the worker's eye glaze over........

etherhuffer 

Yeah, I was almost armed with the drill when you and Andy replied. Thanks for the info. One site said a norm was 180mm but looks like 165mm is more common. Looks like I get to braze on an eyelet and a fork boss.

Andrew R Stewart 

I have drilled mounting holes in the racks plate to better align a rack to horizontal before a few times. Just take care with placement WRT the other holes or slots and adding washers on both sides of the plate to spread the load. Andy

Steve B.

I can measure what my bike is, just not sure what measurement I am looking for - dropout to eyelet ?

etherhuffer 

Eyelet to the mounting boss on the fork.

duanedr 

Why do you want to use through holes? I can see for a new fork where the builder knows the tubing dimensions and knows the inside of the tube is clean so the brazing is complete, the through hole is fine. When adding after the fact the rust or rust preventative inside the blade might cause problems. I would opt for brazing to the front or rear of the blade.

Steve B.

Are you talking about the eyelet on the dropout the lower part of the rack mounts to ?

etherhuffer 

Yes, on the dropout

etherhuffer 

Well, When drilling the hole there is bare metal. And the surface will be sanded. With silver solder on both sides there should be plenty of connection. The majority of the load is 90 degrees to the boss. And with a full through boss, you can add a nut on the inner side as well.

bulgie 

Don't forget, when drilling thru the far side of each hole, all the chips created are going into the interior of the fork and you'll need to get them out somehow. When you have just a blade, not brazed to the crown yet, you can knock the chips out the open end.

I have done the thru-hole type BO on a finished fork at the customer's request, but it was a bit of a pain to get the chips out. I used the pencil-eraser-sized magnet on the end of my carbide scriber, it fits thru the 6 mm hole and collects the chips, but it's still not what I'd call easy. If you leave so much as a single chip in there, the fork will have a rattle. Pro tip: when you drill that second hole (far side of the blade), interrupt the cut frequently so you don't get long spiral chips that will be harder to pull out.

Duane's mention of rust preventative is a good point — if this fork has any petroleum type goop like Framesaver in it, you'll want to wash that out with solvent or else you'll have smoky flames coming out the hole while you're trying to braze it.

For a while there (late '80s early '90s maybe?) those racks that need the thru-type BO were popular with my customers, so I was putting them on a lot, but almost always before brazing blades to crown. My preference was two separate H2O top-hat BOs, with the diamond reinforcements mostly because they look nice. Then two separate screws, one from each side, rather than a thru-bolt and nut. Functionally the same, just an aesthetic preference.

Mark B

etherhuffer 

Yeah, I thought about the chips/swarf in the hole thing. Pearl of the day: Inside your Sonicare toothbrush head is a magnet, and you can pull these off and trim them for small recesses. I have one that can get into 5mm/1/4 " holes. I had to trim the magnet down but it works well. Glued it to a small stick. I think the last time I chased metal filings was a helicoil I did. Not fun

Andrew R Stewart 

So I just measured my touring bike's eye to blade mount. It is 180mm. This is the first time I have done this measurement as when I added the lowrider blade mounts I just marked the spot that placed the rack's bag hooking rail horizontal. But I use the Tubus Ergo which, like the current Tara, has the horizontal rail able to change its angle to the rest of the rack (the end connected to the rest of the rack has a bolted connection). This rack feature further opens up the ability to fit a range of fork blade lowrider locations. So on another fork this eye to mount could well be different. Andy

etherhuffer 

Interesting. I am going to measure my bikes, then head to Recycled Cycles and measure a few there too. The consensus so far has been 165mm most common followed by 180mm. Thanks for measuring, more data is always useful.

Andrew R Stewart 

Do pay attention to the rack's aspect to all this. Many (and the "grandfather" of modern low riders, Blackburn's FL-1) had the distance between the lower/dropout mounting hole a fixed distance from the upper/mid blade mount hole/slot. This fixed distance limits rack alignment WRT the bag hanging down vertically. Look at how the rack sits and thus how/where the bag has to also be. Perhaps bring your own pannier to check.

The other aspect not yet mentioned and not generally a big deal is how high off the road is that upper/midblade mount. Or more to the point, how close to the ground are the pannier bottoms? One of the reasons why I wanted my rack's horizontal rail to be high up the fork is the bike is a 559 ISO w/ 1.5 tires. Everything else the same a 559 VS 622 bike will see the pannier bottoms about 2.4" lower down to the road. Even with the higher location on my bike I have still rubbed the pannier bottoms on the road when the road has a lot of crowning (when u turning) and on really tight/banked switchbacks. This is why before "bikepacking" bags became "the way" off road we used classic above the tire racks. Andy

I should add that the road rub was with by big panniers, Arkel GT-18, which are rather large for a front low mounted bag at 2200ci a pair

etherhuffer 

I used both Novara Transit and some cheap Nashbar bags on front. We are credit card tourers so not a huge load. The Raleigh R300 Touring was my main bike, and lots of clearance. I am going to look at that one first then the new Long Haul Trucker. The fork in question is for an ancient Fuji S12S Ltd that is trashed paint-wise, but can make a nice sport tourer. My Fuji Gran Tourer died of a cracked seat stay and not worth repairing, so all the hardware will move to the new/vintage frame.

etherhuffer 

Fuji R300 165mm
Aftermarket Fork on Trucker (Soma) 225mm Big difference.
Yeah, looks like rack choice first, drill later. Thanks for all the help guys, far more to consider than I thought. Measure twice, drill once!

mdarnton

I have spent some time on this problem. The first conclusion I came to was that the mid-fork mount isn't really weight-bearing. It keeps the rack from tipping forward or back, that's about it. My bike doesn't have these holes, but it has a steel fork and I bought threaded inserts to install instead of using the (Axiom) u-clamps, but then decided to look around some more.

At that point I found Pelago racks. They come in steel. They mount on the dropout eyelet and the fork crown. You can get a small, medium, or large (pizza) platform for the top, which I really like! (Got the medium). Their low-rider rig is in the form of replacement legs for the normal, non-bag mounting platform rack, and they use the same fork-end holes, no mid fork mount at all. Not everyone has the low-rider accessory legs--you have to look around.

So what you get is a nicely-designed steel rack, securely mounted, with your choice of platform sizes, and a low-rider below that. All for a pretty reasonable price. And you don't have to drill any holes in your steed.

etherhuffer 

Interesting looking racks. I had seen their bikes a few years ago, but not the racks. Will look more

bulgie 

Blackburn was originally spec'd as 6-1/2", which coincidentally is 165 mm. That puts some bags too close to the ground even with 700c tires on pavement, definitely too low for just about any odd-shaped obstacle off-road.

Bruce Gordon lowriders were spec'd at 7-1/2" or 190 mm, better for rough-stuff.

Custom-made racks can be anywhere, but choosing one of those "standards" might help later if you break/bend the custom rack — you can mount a stock rack. I'd never use 165 myself though, these days. (Yes I made forks with BOs at 165 BITD, but that was specifically to fit Blackburns, which are too cheesy to give a second look nowadays with all the better choices we have.) Though Gordons aren't exactly thick on the ground, they're at least sometimes available used, so maybe consider 190 mm?

The original lowriders (Rene Herse et al., as far back as the '50s I think) attached to racks with a top platform and didn't use a mid-fork BO. Nitto still makes that style, tubular steel, high quality workmanship but $$.

Mark B