Serotta 3D dropout design drawings

[SPOKE]

I hope someone here may have an answer.....
I’d like to find out what individual or company may have the engineering drawings for the Serotta 3D dropouts. I have a friend that needs an Ottrott ST dropout replaced and I have the capability to make a replacement but would like to do it the easy way by programming my mill using the original drawing.
Can anyone point me in the right direction??
Cheers.....SPOKE

[lemondvictoire]

Ti Cycles does this repair... ticycles.com/news/2017/8/1/serotta-dropout-service

[David Kirk]

What generation do you need?

dave

[Ozz]

Ti Cycles does this repair... ticycles.com/news/2017/8/1/serotta-dropout-service

That was an interesting read....does the "Serotta crack" only happen on bikes with the ST (bearing) seat stays? I have not heard of this before, nor have I heard of a problem with the 3D dropouts cracking....

[SPOKE]

What generation do you need?

dave

Hi Dave,
I’m pretty certain the frame fits into the second generation version since the main triangle tube lugs are a good bit shorter than what’s on my original “Founders Edition” bike.

[David Kirk]

Hi Dave,
I’m pretty certain the frame fits into the second generation version since the main triangle tube lugs are a good bit shorter than what’s on my original “Founders Edition” bike.

If each of the ears has one small round hole in the center it's Gen 1 and I think I have that drawing....if it's a big oblong hole that's Gen II and I can't help you out at all.

dave

[SPOKE]

If each of the ears has one small round hole in the center it's Gen 1 and I think I have that drawing....if it's a big oblong hole that's Gen II and I can't help you out at all.

dave

Thanks Dave! I’ll see if Phil has a pic showing the dropout to verify.

[SPOKE]

Here’s the pics of the dropout and possible crack that I received a couple hours ago. According to Dave Kirk’s description this looks like a second generation dropout.

[mbrtool]

Is there any evidence of a crack on the cylindrical surface looking towards the cassette? Which would give the second picture some depth from the surface of the possible crack.

Ray

[Louis]

Here’s the pics of the dropout and possible crack that I received a couple hours ago.

I'd say that's almost definitely a crack - not a whole lot of doubt there.

[David Kirk]

That is for sure Gen II and also for sure cracked.

dave

[HenryA]

Laser welding might be a good answer.

[Brian Smith]

Useful photos, Spoke.
I would concur with the others that your dropout is cracked.
What you've got there is not a different generation of the same part, but rather that part is a titanium 3DXL ST dropout, as opposed to the earlier 3D dropouts, and in contrast to the 2 later versions of the 3DXL ST which contained design modifications, but these parts were not given new part names.

Someone was able to make off with the remaining inventory of parts such as these when the factory contents were being liquidated. To me, that would be the only economical remedy involving a replacement dropout. If the crack is shallow, a good grind and re-weld with some shaping thereafter could effect an appropriate and durable repair.

Alternatively, I think if one is capable of turning the original design file you seek into an actual part, the creation of the drawing file should be within said person's capabilities to create themselves. Really, the design files we had often weren't truly CAD-ready anyway, and I'm confident that the production parts, in any iteration, varied somewhat from the design files in a multitude of unmeasured ways. They were usually much more than close enough. I say all of this as someone who, for some years, had to produce these dropouts in quantity, within specification, without lapse, and without the ability to cover costs of a failed gamble. After a while of producing these in house, there were attempts to get these outsourced to ease the load, but even a very supportive vendor with better/larger machines and production systems of greater capacity couldn't touch us in economy, and they required much larger minimum order quantities than we were routinely able to accommodate in house.

If you really need to replicate this design, rather than improve it with a part of your own, the original design file is of limited use. I'm told that the files had been stolen (my description, not theirs,) and may be out there somewhere, but to me that's barking up the wrong tree. I haven't got them, nor would I use them if I did, nor provide them to others to use.

We replaced many sets of these due to cracks in the "peanut" (our term for the through-hole feature described above as "oblong") hole. I wonder how Trek made out when they produced bikes with a dropout that accentuated these parts' weakest feature... Anyway, we saw no failures in the revised parts, and those revised parts are the ones that are still out there in the wild somewhere.

Good luck with your remedy for this crack. I would consider a repair of the existing part, if not completely cracked, to be a wise choice. In case of a museum-quality restoration, designing and remaking your own version of the original part would be no less appropriate than making your own version from the original design file. I don't see that file being what holds you back, in any way.

[SPOKE]

Thanks for the info Brian! Looks like the first option is to attempt a repair of the dropout by grinding the crack then TiG welding & a bit of clean up by filing/sanding.

Useful photos, Spoke.
I would concur with the others that your dropout is cracked.
What you've got there is not a different generation of the same part, but rather that part is a titanium 3DXL ST dropout, as opposed to the earlier 3D dropouts, and in contrast to the 2 later versions of the 3DXL ST which contained design modifications, but these parts were not given new part names.

Someone was able to make off with the remaining inventory of parts such as these when the factory contents were being liquidated. To me, that would be the only economical remedy involving a replacement dropout. If the crack is shallow, a good grind and re-weld with some shaping thereafter could effect an appropriate and durable repair.

Alternatively, I think if one is capable of turning the original design file you seek into an actual part, the creation of the drawing file should be within said person's capabilities to create themselves. Really, the design files we had often weren't truly CAD-ready anyway, and I'm confident that the production parts, in any iteration, varied somewhat from the design files in a multitude of unmeasured ways. They were usually much more than close enough. I say all of this as someone who, for some years, had to produce these dropouts in quantity, within specification, without lapse, and without the ability to cover costs of a failed gamble. After a while of producing these in house, there were attempts to get these outsourced to ease the load, but even a very supportive vendor with better/larger machines and production systems of greater capacity couldn't touch us in economy, and they required much larger minimum order quantities than we were routinely able to accommodate in house.

If you really need to replicate this design, rather than improve it with a part of your own, the original design file is of limited use. I'm told that the files had been stolen (my description, not theirs,) and may be out there somewhere, but to me that's barking up the wrong tree. I haven't got them, nor would I use them if I did, nor provide them to others to use.

We replaced many sets of these due to cracks in the "peanut" (our term for the through-hole feature described above as "oblong") hole. I wonder how Trek made out when they produced bikes with a dropout that accentuated these parts' weakest feature... Anyway, we saw no failures in the revised parts, and those revised parts are the ones that are still out there in the wild somewhere.

Good luck with your remedy for this crack. I would consider a repair of the existing part, if not completely cracked, to be a wise choice. In case of a museum-quality restoration, designing and remaking your own version of the original part would be no less appropriate than making your own version from the original design file. I don't see that file being what holds you back, in any way.

[Mike Lopez]

Bill Holland has repaired many of these over the years. There were more than just a few of them over time so I'm sure lots of other guys have fixed them as well. Some of them are probably much closer to home.

If all else fails give him a call.

[GregL]

This thread is yet another example of why the Paceline is an amazing place. To have three former Serotta employees, all acknowledged experts in their fields, contribute advice on this subject is simply incredible. Thanks for the continuing education you provide, Dave, Brian, and Mike!

Greg

[HenryA]

Thanks for the info Brian! Looks like the first option is to attempt a repair of the dropout by grinding the crack then TiG welding & a bit of clean up by filing/sanding.

Seriously - find a laser welder and ask them about the job. Don’t start grinding or anything else until you do. TIG will create lots of heat. Laser not so much. The HAZ will be very, very small. Might be able to do the job without dissembly of the dropout from the frame.