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Old 03-02-07, 07:44 PM   #1
JunkYardBike
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Dropout adjustment screws

I've been looking for a set of adjustment screws for a '79 Trek 530 frame with long horizontal dropouts. Most of my experience has been with vertical dropouts, so this is relatively new to me. Most other horizontal dropouts I've dealth with have been on low-end frames that always have a bracket type stop on one side.

So, a few questions for those in the know:

Are most of these screw holes standardized? Meaning, if I buy a set online, will they fit? I've only found two sets thus far (here and here), but neither indicated screw width or TPI. The one available through loosescrews.com did indicate length, but it is 10mm shorter than the existing (bent) screws.

Are these screws even necessary? I know they supposedly make resetting the rear wheel easier.

Does anyone know of any alternatives that are available and inexpensive? I've search the local Home Despot and bLowes, but they don't stock anything nearly narrow enough in width.
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Old 03-02-07, 08:10 PM   #2
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The screws on my Surly Cross-Check are metric M3 size. The ones that came with the bike looked easy to lose so I bought a spare set from somewhere (I can't remember where) and they fit fine, so I think this is a pretty common size. I Googled around and found a source for them at Nova Cycles.

Also, since I'll probably never actually convert this bike to fixed/single-speed, I really have no use for these screws, but I didn't want to leave the holes uncovered to rust. So, I bought some short M3 stainless steel cap screws from Fastener Express. This is an excellent source for small metric fasteners, especially in stainless. The screws I bought are just long enough to cover all the threads of the dropout adjuster holes. Combined with a little grease this should keep them clean.
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Old 03-02-07, 08:52 PM   #3
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Thanks for the reply. I'll be using them on a multi-geared bike. I should have searched the forums first. I found this thread in which Sheldon Brown writes:

Quote:
Originally Posted by Sheldon Brown
The purpose of these is to facilitate rapid racing wheel changes. Generally you start with them tightened all the way back, install and align the wheel, then adjust the screws so they bump up against the axle.

Once this is done, the wheel would automatically stop at the point and orientation you had previously determined.

Back in the day, it was often a fad to run the axle all the way forward in the dropouts. This is related to the superstition that believes short chainstays make a bike faster in some mysterious way.

Generally, it's better to run the axle farther back because that gives better chain wrap, so your chain and sprockets will possibly last longer and you'll be less likely to have the chain jump.

Shifting performance with modern derailer systems is usually best when the axle is directly above the derailer mounting bolt.

Sheldon "Doesn't Use The Silly Things" Brown
However, the idea of having the centering preset when reinstalling the wheel after servicing still appeals to me, unless the things are just going to bend again.
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Old 03-02-07, 11:10 PM   #4
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Unfortunately, I don't think they are standardized. For the most part they have the same hole size, but I have seen a list with different thread pitches for different manufacturers, which makes no sense. Campy uses M3*0.5, I've drilled and tapped a set of Simplex drops for those.
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Old 03-28-07, 03:42 PM   #5
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Quote:
Originally Posted by vpiuva
Unfortunately, I don't think they are standardized. For the most part they have the same hole size, but I have seen a list with different thread pitches for different manufacturers, which makes no sense. Campy uses M3*0.5, I've drilled and tapped a set of Simplex drops for those.
I too am looking for a set of dropout adjustment screws (for a Colnago) and was pleased to find this thread, up until I read your post that states they are not a common size/threading. Do you possibly still have the list you mention? If so, could you send it to me, or at least look up Colnago on the list?

Cheers,
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Old 03-28-07, 04:31 PM   #6
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Quote:
Originally Posted by JunkYardBike
I've been looking for a set of adjustment screws for a '79 Trek 530 frame with long horizontal dropouts. I've search the local Home Despot and bLowes,
That's a readily available part (including springs and nuts) from QBP so any LBS should be able to get you a pair. I don't remember the cost, but it wasn't much. If you're looking for a retail internet source, try "Loose Screws".
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Old 03-28-07, 07:30 PM   #7
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Quote:
Originally Posted by darrencope
I too am looking for a set of dropout adjustment screws (for a Colnago) and was pleased to find this thread, up until I read your post that states they are not a common size/threading. Do you possibly still have the list you mention? If so, could you send it to me, or at least look up Colnago on the list?

Cheers,
If your Colnago has Campy d/o you should be good to go with the M3*0.5. I just checked my c.'95 frame w/Columbus d/o and it was also M3*0.5, so between those two you should be covered.
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Old 03-28-07, 09:32 PM   #8
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Quote:
Originally Posted by Retro Grouch
That's a readily available part (including springs and nuts) from QBP so any LBS should be able to get you a pair. I don't remember the cost, but it wasn't much. If you're looking for a retail internet source, try "Loose Screws".
They are also quite common on ebay, at least for Campagnolo dropouts. There seems to be a glut of them for the Campagnolo 1010's on my Trek frame (I was lucky as vintage-trek.com had the specs for my frame).
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