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Old 07-17-11, 05:33 PM   #1
Boyd Reynolds
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Mounting a front rack with no eyelets at all

Hi mechanics,

I've been searching and reading as much as possible trying to figure a solution to this problem, and I've learned a lot, but I haven't made a complete plan yet, and I'm hoping you all can help.

As I said in a previous thread, I'm converting a 1992 Trek 970 for touring use. I'm trying to figure out a way to mount a front rack to it, and what rack to use.

The problem is that the fork has no fender eyelets at all, and that it is huge tubular (just over 1.25") steel with the dropouts tucked way inboard. I hope you can see from the picture I took with my phone.

Ideally I'd like a rack for lowriders that also has a top platform, and I'd like to not spend a huge pile of money on it.
One possibility is a rack from Old Man Mountain that mounts to a special QR skewer. OMM doesn't offer one with both lowriders and platform, but if this is the way to go I'll make do with it. My question about this option is this: will it work with this oversize fork? I don't see how a rack can be pulled tight to the dropout with all that metal right above it.

Another option is to use p clamps or hose clamps near the bottom and mid-fork. I worry about putting any real weight on a p clamp in the bottom position. Tubus makes a cool little adapter
but it only fits up to 1.125". The one they offer for tubes bigger than that is just a hose clamp with a fitting for a bolt. Using p clamps or something like them is the way I'd prefer to go, because it would give me more flexibility to choose the rack I want. However, I have some questions about this one, too: Will p clamps or some other clamps stand up under load if I use them at the bottom of the rack? Will they change the geometry of the rack/fork relationship enough to be a problem? Will a standard front rack tolerate being spread this wide? The big fork means that the rack will have to fit around something like 1.5" more than a normal fork.

A third solution suggested by an engineer friend of mine is to weld a nut onto the fork to substitute for an eyelet. I don't really want to do this, as the fork will have to be repainted, and it's inelegant, but it might be the way to go. Will welding weaken the fork?

I looked for a replacement fork with proper eyelets, but found nothing.

I really did try to find this information with google, but didn't get there. Your input is appreciated.
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Old 07-17-11, 05:46 PM   #2
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P-clamps, particularly steel ones, are pretty strong, especially in the size you will need. I don't know if low-riders will work but a taller rack using the hole in the fork crown (for a caliper brake or a fender) as an upper mounting point should be pretty strong.

I would not weld anything to that fork. The metal of the blades is thin and the weld heat will compromise any heat treatment given it by Trek and is likely to distort them too.
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Old 07-17-11, 07:45 PM   #3
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It may not be the low-rider rack that you mention, but there are racks that attach to cantilever posts via some special double-sided nuts.

Velo Orange carries these: http://store.velo-orange.com/index.p...ing-bolts.html

Their Passhunter rack is a small top rack that works with cantis but does not come with low-riders. Velo Orange does sell a lowrider rack,the Daija Lowrider, however this secures via clamps and does not come with a top platform. You could combine the Pass hunter with the Dajia Lowrider and come up with what you are looking for functionally.

The other option that I've seen that uses cantilever posts to secure the rack to the fork, and includes lowriders and a top platform is the Nitto Campee rack. It is reputedly an excellent rack with removable pannier supports, however it is quite pricey at 230 USD (when bought from Soma).
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Old 07-17-11, 07:48 PM   #4
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This might be a question to ask on the frame builders forum. I'd suggest a steel Riv nut for fender mounts, but I'm not 100% sure they'd be up to supporting low riders. If the experts over there give the all clear on a Riv nut, that's what I'd do.
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Old 07-17-11, 08:36 PM   #5
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Originally Posted by jrecoi View Post
It may not be the low-rider rack that you mention, but there are racks that attach to cantilever posts via some special double-sided nuts.

Velo Orange carries these: http://store.velo-orange.com/index.p...ing-bolts.html

Their Passhunter rack is a small top rack that works with cantis but does not come with low-riders. Velo Orange does sell a lowrider rack,the Daija Lowrider, however this secures via clamps and does not come with a top platform. You could combine the Pass hunter with the Dajia Lowrider and come up with what you are looking for functionally.

The other option that I've seen that uses cantilever posts to secure the rack to the fork, and includes lowriders and a top platform is the Nitto Campee rack. It is reputedly an excellent rack with removable pannier supports, however it is quite pricey at 230 USD (when bought from Soma).
Thanks for the suggestions. The passhunter will mount to my bike, but the platform is pretty small. The reason I want a top platform is to strap cargo to it, like a tent or a bedroll. When I was a teenager I had a Blackburn front rack (no lowriders) and I used it all the time to carry all kinds of random stuff. The Daija lowrider looks like a very nice piece of equipment, and not expensive either. I like the look of those U bolts to mount to the middle of the fork, though they might not fit around these big tubes. That rack is also designed to used fender eyelets at the dropout, a feature my rack doesn't have. If P clamps will work this would be a decent choice for me. I also like the idea of two separated racks, which might not be as strong, but would avoid the width problem. Hmm.
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Old 07-17-11, 08:37 PM   #6
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This might be a question to ask on the frame builders forum. I'd suggest a steel Riv nut for fender mounts, but I'm not 100% sure they'd be up to supporting low riders. If the experts over there give the all clear on a Riv nut, that's what I'd do.
If I don't get a solution here I will ask over there. I'd never thought of asking in that forum, but it makes sense. What's a riv nut?
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Old 07-17-11, 08:43 PM   #7
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If I don't get a solution here I will ask over there. I'd never thought of asking in that forum, but it makes sense. What's a riv nut?
A Riv Nut is a threaded insert that inslalls much like a blind rivet. They are very useful for mounting water bottle cages and fender mounts and such.
Here's a video I made showing how they are installed. They can also be installed without the specialized tool. The Park Tool site has a neat how to feature on that.
Riv Nuts are commonly available through industrial fastner suppliers.
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Old 07-17-11, 09:26 PM   #8
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QR on the bottom , for the support , P clips around the fork blade for the top..
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Old 07-17-11, 10:31 PM   #9
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I really don’t like the idea of installing rivet nuts. Any hole you drill is an automatic 3X minimum stress riser. Not a good thing in a fork. That’s why in traditional frame building practice there were always little (usually) diamond shape reinforcing plates around the bottle cage threaded holes and such. If you want to go there anyway, a good source for rivet nuts and aluminum “p-clamps” is Aircraft Spruce; http://www.aircraftspruce.com/. Almost all aircraft stuff is English threaded, but a #8-32 tpi thread is an almost equivalent to a 5-0.8 mm thread if the fit isn’t too critical. Aircraft Spruce also carries an alternate to rivet nuts called Nutserts. The p-clamps are listed as MS21919 clamps. The ever popular and flame attracting Rivendell has some racks and bits that might be useful to you: http://www.rivbike.com/.
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Old 07-18-11, 09:07 AM   #10
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QR on the bottom , for the support , P clips around the fork blade for the top..
OK, maybe someone has a picture of how a rack made for QR fits on a fork with giant tubes for blades? The skewer that I have just barely fits in there, so I'm worried that it won't work.
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Old 07-18-11, 09:10 AM   #11
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P-clamps, particularly steel ones, are pretty strong, especially in the size you will need. I don't know if low-riders will work but a taller rack using the hole in the fork crown (for a caliper brake or a fender) as an upper mounting point should be pretty strong.

I would not weld anything to that fork. The metal of the blades is thin and the weld heat will compromise any heat treatment given it by Trek and is likely to distort them too.
Somehow I missed this reply yesterday. This is the way I'd like to go, to save money and to have more choices in the rack I use. The fork does have a hole in the crown for a fender. Is this a better mounting point than the caliper brakes? I suppose it might be, since it won't interfere with the brakes.
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Old 07-18-11, 10:59 AM   #12
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Use a #20 304 stainless p-clamp(1 1/4) for the bottom
and a 1 1/4 u-bolt and strap for the midfork mount.Double nut the u-bolt strap so you don't crush the fork.

Quick,easy,strong.

Don't weld to the fork,you can have stuff brazed on.
Don't use a rivnut for the mid point mount,it will tear out of/distort the fork.Midfork mounts should use a tube through both walls of the fork,so that you don't distort/collapse it.

Braze something on or use something that clamps to the fork.

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Old 07-18-11, 05:41 PM   #13
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I really don’t like the idea of installing rivet nuts. Any hole you drill is an automatic 3X minimum stress riser. Not a good thing in a fork. That’s why in traditional frame building practice there were always little (usually) diamond shape reinforcing plates around the bottle cage threaded holes and such. If you want to go there anyway, a good source for rivet nuts and aluminum “p-clamps” is Aircraft Spruce; http://www.aircraftspruce.com/. Almost all aircraft stuff is English threaded, but a #8-32 tpi thread is an almost equivalent to a 5-0.8 mm thread if the fit isn’t too critical. Aircraft Spruce also carries an alternate to rivet nuts called Nutserts. The p-clamps are listed as MS21919 clamps. The ever popular and flame attracting Rivendell has some racks and bits that might be useful to you: http://www.rivbike.com/.
I agree about the inadvisability of installing riv-nuts in the stressed part of a fork blade. Note in Dan's video, he is placing the rivnut in a very low stress area.

BTW, it's a minor point but an M5x0.8 bolt is closely approximated by a #10-32 SAE bolt, not a #8.
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Old 07-18-11, 09:52 PM   #14
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That fork is so burly looking that I seriously doubt a couple of riv-nuts would compromise it to any sort of degree that could lead to an issue of any sort.

For most other forks I'd totally agree about not wanting to drill into the legs. But this fork is clearly intended for some semi serious urban jumping. A couple of riv-nuts to set it up for touring isn't going to compromise the ability to withstand a few potholes or or a few mis timed curb hops.
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Old 07-19-11, 10:38 AM   #15
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That fork is so burly looking that I seriously doubt a couple of riv-nuts would compromise it to any sort of degree that could lead to an issue of any sort.
The fork in the video is a suspension fork and Dan had to be sure he didn't drill into the suspension mechanism. The only place available for the riv-nut was where he put it.
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Old 07-19-11, 10:53 AM   #16
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The fork in the video is a suspension fork and Dan had to be sure he didn't drill into the suspension mechanism. The only place available for the riv-nut was where he put it.
Plus, the purpose was to attach fender stays, not a high stress application.
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