Relocating the Dropout Claw?
08-11-19, 03:11 PM
#1
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Relocating the Dropout Claw?
I知 working on a Peugeot UO10 with a dropout claw. What would happen if I relocated the claw to the rear to expose the entire length of the axle slot? I壇 re secure the claw with a couple of appropriate fasteners. I知 building a gravel road bike on the cheap and this hack would allow me to move the axle back about 1/2 inch. That would put the tire in a spot between the chainstays that is cleared out for an even larger tire. I知 tightly fitting a 38mm tire now and I bet I can use at least a 42mm tire after the hack.
This hack would also allow me to remove the claw nut on the cog side of the drive side dropout. Right now that nut interferes with the chain on the wheel I may use.
Has anyone done this? Are there any immediate problems you foresee except maybe needing a longer chain?
Thanks.
This hack would also allow me to remove the claw nut on the cog side of the drive side dropout. Right now that nut interferes with the chain on the wheel I may use.
Has anyone done this? Are there any immediate problems you foresee except maybe needing a longer chain?
Thanks.
08-11-19, 06:02 PM
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I'm wondering how your derailleur is going to lone up with the freewheel cogs but I certainly don't anticipate anything bad happening that you couldn't just as easily reverse.
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08-12-19, 05:38 AM
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As I understand you, you want to get rid of that portion of the claw that's in the slot so that you can move the axle back. The part of the claw that is in the slot has a function of providing alignment, strength, and rigidity.
If you do this you'll need to make sure that you have sufficient beef in the mounting screws. You'll still have the axle in the slot of the dropout and the claw, so that's good. But most claws have dogs or raised portions or even screws that provide another aligment point. The Campy type in the big picture below has two pins AND a nut that fits in the slot. The nut is shown in the reversed (wrong) position - the raised portion goes into the slot. The Huret has a stamped raised portion (not visible). By removing these from the slot you are losing a part that provides alignment and strength. I guess you could fabricate a claw with a larger footprint. Get steel of proper thickness, hacksaw and file to shape. I'd leave extra metal to allow me to put a screw or two through the new claw and the dropout. Drill the claw and the dropout and tap the dropout for mounting screws and the claw for the derailleur bolt. If the dropout thickness is less than the bolt diameter, you may want to use a shoulder nut, if you have clearance.
There may be designs that require less work, but remember that you are removing an anchor point for a device that needs a strong rigid foundation to function.
If you do this you'll need to make sure that you have sufficient beef in the mounting screws. You'll still have the axle in the slot of the dropout and the claw, so that's good. But most claws have dogs or raised portions or even screws that provide another aligment point. The Campy type in the big picture below has two pins AND a nut that fits in the slot. The nut is shown in the reversed (wrong) position - the raised portion goes into the slot. The Huret has a stamped raised portion (not visible). By removing these from the slot you are losing a part that provides alignment and strength. I guess you could fabricate a claw with a larger footprint. Get steel of proper thickness, hacksaw and file to shape. I'd leave extra metal to allow me to put a screw or two through the new claw and the dropout. Drill the claw and the dropout and tap the dropout for mounting screws and the claw for the derailleur bolt. If the dropout thickness is less than the bolt diameter, you may want to use a shoulder nut, if you have clearance.
There may be designs that require less work, but remember that you are removing an anchor point for a device that needs a strong rigid foundation to function.
Last edited by WizardOfBoz; 08-12-19 at 05:44 AM.
08-12-19, 08:27 AM
#4
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Thanks For the thoughtful responses. My claw looks like the one posted except the derailleur mounting hole is a through hole not a threaded hole. There is a nut that locates in that hole and accepts the smallish threads of the simplex derailleur. I’ll need a different claw with a threaded hole that’s compatible with the derailleur I’ll use to improve the gearing for gravel riding.
what if I had a frame welder attach the claw to the dropout with a bit of tig weld? I think if I attached the new claw with fasteners I’d weaken the dropout. Not sure where to go here. Tomorrow when the LBS opens I’ll rummage through his collection on dropout claws to see what might look good.
An interesting note, I ground on the claw and sparks came off sparkly like a medium carbon steel. I read a comment that in a crash the claw would deform in stead of the dropout. In the case of the UO10 it looks like the dropout would take the damage.
what if I had a frame welder attach the claw to the dropout with a bit of tig weld? I think if I attached the new claw with fasteners I’d weaken the dropout. Not sure where to go here. Tomorrow when the LBS opens I’ll rummage through his collection on dropout claws to see what might look good.
An interesting note, I ground on the claw and sparks came off sparkly like a medium carbon steel. I read a comment that in a crash the claw would deform in stead of the dropout. In the case of the UO10 it looks like the dropout would take the damage.
08-12-19, 09:41 AM
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Unlike modern frames of CF/Al with replaceable RD hangers that are pure aluminum and meant to deform as
a sort of frame saver, claws were used in the era of cheap steel frames and as you note have equally strong
steel RD hangers that were not meant to be frame savers.
a sort of frame saver, claws were used in the era of cheap steel frames and as you note have equally strong
steel RD hangers that were not meant to be frame savers.
08-12-19, 09:49 AM
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If you are considering having a frame builder weld or braze a claw to the existing dropout, also ask about replacing the dropout entirely with one that has a built it derailleur hanger tab or even one with a replaceable hanger.
08-12-19, 09:57 AM
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In looking at the dropout, I think you'd have at least one spot for a significant threaded hole for a bolt without weakening much. Not sure that the dropout itself is strong or thick enough to bear a welded-on derailleur hanger on its own - I think that you need something like the original claw to reinforce stuff. But again, keep in mind that the axle itself will aid in positioning.
