cheeseflavor

Just got note from the painter, that after sandblasting my '87 Schwinn Super Sport, he found a crack in the dropout on the drive side of the frame. I'm a large rider and was wondering if you all think this can be fixed by welding:



TIA,

Steve

Zaphod Beeblebrox 

boy that is in a scary spot.

20grit

i'd try to replace the dropout. that's going to be one of the higher stress spots on a dropout.

cheeseflavor

My thoughts exactly. I'm 240# right now, end of summer 210#. And it's drive-side, so there's the additional torque involved. But, I'm not a frame builder. Speaking of which, wonder if I should have posted this in the FB forum?

Steve

unworthy1

Yes it can be ground out and Tigged, but take it to somebody who's done these before...it won't look as pretty as having a fresh one brazed in, but then you won't have to find a fresh one, either

unterhausen

If you post it in the framebuilding forum, you'll probably get the same crew answering you, including me. I would find a person to tig it. If they are any good at all, there will be no problem making it look like new.

Sixty Fiver

You can either replace the dropout or have a competent frame builder repair it.

Just had this Miyata 1000 repaired and reinforced so that it is better than new... this is more important than having the dropouts be an exact match as this bike's new owner is six five and 240 pounds and this is a high stress point on any frame.

SingeDebile

whats that green beast in the background?

Sixty Fiver

Regarding the above picture... the frame in the rear is a specially designed touring frame and it's builder also repaired the Miyata.

He specializes in building frames that are designed for larger riders and people who do expedition touring and when he says the Miyata dropout won't fail, I know it won't fail.

Sixty Fiver

Custom made touring frame... 66cm / 26 inches.

Sixty Fiver

I have sent out quite a few nice frames to get repairs... seems like a lot of early 80's Japanese frames suffer from a very similar dropout failure on the drive side but are otherwise very well made and well finished bicycles.

The single repair cost $60.00... replacing both dropouts pushes the cost up a fair degree and then there is also the matter of having the rear stays repainted to match.

In most cases these have been well ridden and well loved touring bikes and models that are not easily replaced and I have a number of frames I would repair before I'd replace them if they suffered the same type of failure.

Since the Super Sport is in for re-painting anyways the repair cost will not add a lot to the total restoration cost.

Chombi

Replace it! The bike is stripped of paint right now and it is the most ideal time to catch this iwith a replacement. In the end you will end up with a more perfect product that you will be happier with in the future.

Chombi

cudak888 

+1.

-Kurt

noglider 

$60, wow, that's a lot less than I thought it would be!

Sixty Fiver

My local frame builder offers pretty decent rates on these kinds of repairs... and he does house calls.

You'd have to add the cost of new dropouts if you were looking to replace them and this is actually a little less work than repairing a dropout as the fitting is easier.

He brought me a custom made touring fork for that Miyata 1000 and thought $120.00 was a steep price... before he started building frames he was a machinist and engineer so can fabricate almost anything and has his own powder coating shop.

He also builds his own cartridge bearing hubs which are outstanding... I plan to build some wheels around his hubs for my touring bike at some point.

top506

I had this:



beveled and TIGed. Came out fine. Granted, I'm 165 lbs.
Top

Charles Wahl

Here's a thread about my similar crack and TIG repair. Came out looking great, except that the dropout and stays are all chromed, and that's sacrificed.
https://www.bikeforums.net/showthread...dropout-repair

I've never even ridden the bike; waiting for the right time to build it up properly.

unterhausen

I still think that fixing the dropout is a better choice. Interesting that there are a number of suntour dropouts with failures in the same place. Maybe the welder could build fill in the triangular hole just a little to help that area out; seems like it's a weak point.

I really would hate to have a halfway decent bike with mis-matched dropouts. It would make wheel placement somewhat problematic and it will probably look funny and may actually be a little weak. I think I have some of those Suntour dropouts though.

Torchy McFlux

TIG welding a cracked dropout is a half-assed repair that I'd expect from a metal shop in the boonies. Do it properly and get a new one brazed in there.

Sixty Fiver

If a single matching dropout cannot be found you will need a matching pair and there is nothing half assed about repairing a dropout if the work is done well.

The decision to do this would have to be based on the frame being worked on... if it was rare bike would want the correct dropouts to be used but if the frame was to be used as a daily driver a well repaired dropout would work fine.

Those Suntour dropouts do seem prone to failure as I have seen more than my fair share of them with cracks at the same location... they are rather fine and seem to suffer most when they are used on bikes that see harder use like mtb's and touring bikes.

That Miyata dropout (a Suntour) had a small filler piece added to strengthen the cracked area and it's owner is a six foot five guy who curbs out at 240 pounds and lays down a lot of power... this was information that my frame builder had before he did the repair and his suggestion was to repair it and increase the strength in this area rather than replace it with a matching dropout.

He's been doing this for 30 years... I trust his advice on such things and his pre-frame building experience was as an engineer, machinist, and welder.

He does have a "pretty is as pretty does" attitude towards building frames and parts and I have known people who have ridden his frames and hubs around the planet and never had a moment's worry about them failing.

Torchy McFlux

Well, good for him.
I've got a little experience myself as a machinist and brazer in a framebuilding shop, and speaking from that, I wouldn't butt-weld an old cracked forged steel dropout and call it done - "reinforced" by dumping on the brass or not. The idea of patching a now highly heat-affected and probably fatigued (which is why it broke) part that is as critical and repeatedly stressed as a dropout would keep me (and my insurer) from sleeping well at night.
Having perfectly matching dropouts isn't as important as having a frame that won't fail.
My 2 cents.

edit: I meant forged, not cast. And this is a proper dropout repair: https://mtmetalworks.com/pages/photo-...ame-repair.php

unworthy1

it's not cast, it's forged...and when my guy did it it wasn't "butt-welded", either.
I personally have no doubts about the strength and reliability of a Tig-weld-repaired DO if it's done right, and that's a big IF. I also trust my frame repairman, and if he had told me that mine needed to be removed and a new DO brazed in place, I'd have taken that advice. He certainly can braze every bit as well as Tig weld, and he would have charged me more, I'm sure, so it wasn't done for his enrichment.
BTW, mine was a cracked Campy 1010B, another short forged dropout that is very prone to cracking...it's not just a SunTour (or Tange) malady.

JohnDThompson 

I actually have a set of those dropouts I pulled from a frame years ago:

Charles Wahl

's funny: the guy I took my Motobecane to does framebuilding and customizing and repairs, and he's expert with both brazing and welding. I had actually found NOS replacement dropouts and brought them along, giving him the option to do either a dropout replacement or TIG repair -- and I said that any cost difference didn't matter. He advised doing the TIG repair, and I took that advice.

unterhausen

I know you're kidding, but I recently replaced some dropouts and I was really surprised how easy it was. Most of the heat goes on the dropouts. Getting the new ones in there straight was a pain, but taking the old ones out went well.