Pantah

This thread could easily go in several different areas but I figured C&V is where it's most relevant to most regular viewers.
As the title so states, I had a 1" threaded fork steerer fail during a ride. Snapped clean off at the base of threads. It's an aluminum fork with a steel steerer. No issues with the aluminum fork or any of the bonded joints. Here's a photo I took as soon as I came to a stop.



This, thankfully, happened at around 7mph on a lightly used road connecting to a bike path. I hit a bump about to turn right onto the path when the handlebars tweaked down pretty seriously. For some reason, my initial thought was the frame broke. Regardless, I knew something was wrong since the bars started doing their own thing relative to the front wheel and were quite wobbly. It was tricky using the brakes without the bars being anchored but I was able to safely come to a stop and unclip without any drama. When I came to a stop is when I fully realized what had happened. Through sheer luck, this did not happen in a much more inconvenient or downright dangerous situation, such as a 45+mph decent I routinely take on my regular rides, in traffic, etc.

I was with friends and we all had cell phones. After a few phone calls, a friend was able to come pick me up. I was 15 miles away from home so not the end of the world.

WHAT WENT WRONG: This is what is worth explaining.
Fork is the original that came with the frame, which is a 1991 Klein Quantum. It gave the original owner, who I bought it from almost 3 years ago, thousands of trouble free miles. In the first year he owned it, he swapped the original stem out for a Salsa with more rise to improve comfort. I kept the stem and got it powder coated to match. However, the shop did not tape off at the minimum insertion line and the powder coating has too much meat to allow the stem to fit. So, I had to do a bunch of sanding to get it to fit. Anyone who has hand sanded powder coating knows this is annoying and takes a while. I got it to the point where I thought it was dropping in far enough and left it at that. That was clearly not the case and ultimately the root of the problem. If you look at the photo, you can clearly see the stem had effectively no engagement with the steerer beyond the threaded section. The threads are the weak point as that is where the steerer tube is the thinnest. Because of the inadequate engagement of the stem, all of the loading from forces exerted on the handlebars was getting transferred perfectly to the weakest point of the steerer tube and caused an impressively clean break at the lowest thread.

This was not an issue before with the previous owner as the stem had at least 3 inches of engagement with the steerer before I got it powder coated instead of the barely 2 inches afterwards.

What am I going to do from here? Well, this happened yesterday morning so I haven't had the chance to fully figure out what my plan is but I do have options. Since this is the original fork in a very difficult to color match dayglo orange, I'd prefer to fix it. Far as I can tell, there's two possibilities there. First, since it's a pressed and bonded steerer tube, it's theoretically possible to remove the old, now threadless steerer and press in and bond a new one. The bonding material will make that difficult so I don't know how feasible that is.

The other possibility is, since it's thankfully a steel steerer, have it repaired, which I know can be done. It may also prove to be simpler and easier.
I am not confident enough in metal working skills to do either safely so I'm not going to tackle it. Sycip cycles is local and a highly skilled custom frame builder. He's already done several frame repairs for my brother and even repaired one of my frames so if anyone can do it, it's him. My brother has photos and all the details and specs so will ask him this next week.

If it can be fixed, which I think is likely, I'll have the opportunity to make some changes. First, there was much more thread than was needed, so I can have the threads start farther up from the fork crown. I will, of course, also sand off more of the powder coating to get the stem to get the engagement it needs. I may also have the stem lengthened but not by much. Half to three quarters of an inch at most, mainly to compensate for getting the stem to drop in farther. The handlebars are at a very comfortable height and I don't want to change that.

One change which I'm contemplating is converting the fork to threadless. I already have an old school Salsa 1" threadless stem that I could paint just like the old one. If I'm going to make the change to threadless, now's the time.

There's always the route of just getting a complete replacement fork. However, a slightly complicating factor is my bike is tall. I'm 6'3" and comfortably ride a 61cm, which this frame is, making the head tube a monstrous 8 inches long. This means the old steerer was 9.5" long, or 240mm. Forks that tall are out there but not as common as what you would find on a 56cm frame. If I can find a good used threaded fork, it needs to be at least 9.5". If I go threadless, it needs to be around 11.5", or almost 300mm. That nearly puts me in brand new, uncut steerer territory.

THE TAKEAWAY. Stems have a minimum insertion line for a reason. If you're modifying a stem, such as with a powder coat, know before where that line is (I could not make it out with the powder coat, it does a good job of filling in stampings for things like that) or do some measuring to make sure your stem has good engagement with the steerer. I thought I was safely inside that margin but clearly wasn't.

merziac

@Pantah

That stem was not in far enough, the whole expander must be below the threads.

Aluminum fork, steel steerer, vibratory mismatch in the long run?

Did you start riding this more, harder than PO?

Also, a wire wheel on a bench grinder makes very short work of rust, paint and PC, 50 or 100 grit sandpaper to start then let er rip.

Pantah

Not to be rude but I did cover that, pretty extensively too. As soon as I came to a stop and pulled the handlebars and stem up and out of the frame on the side of the road, I knew what the point of failure was. I know it's a long post but part of why it's long is going over why that was a problem and how I got into this situation.

Resonate frequency of steel vs. aluminum is something I can confidently say wasn't a factor.

I'm riding it equally hard as the previous owner. He put a LOT of miles on it doing some of the San Francisco Bay Area's most famous routes and climbs, such as Mount Diablo, on a regular basis. He was also an inch or so taller than me and a tad heavier. He was fast and strong. The kind of use it's getting isn't really any different.

I have those tools but I was doing it by hand as I was trying to keep a clean line on my freshly painted stem, which I have found to be easier by hand. However, to get it ground down the rest of the way, I'm going to use power tools. Far as keeping a clean line on the paint, I'll figure something out.

AdventureManCO 

Ouch. But much rather an ouch for the bike and not for you. VERY glad you came out unscathed. Very grateful.

Thanks for showing pics of what happened. Good thing to keep in mind, especially as I'm working on a stem fit currently.

Steel1

Thanks for posting this valuable thread. I will check stem wedge vs threading whenever I pull the fork to re-do headsets.

gugie 

Many framebuilders can splice on a new section of steerer. Fitz Cyclez is in your area, try contacting him. If he’s too busy he might suggest someone else nearby.

mpetry912 

If the expander was only in as far as the threads, I am glad it never popped out while "just riding along".

you were very lucky

/markp

merziac

No worries, I get it, was just restating the obvious.

Seems like a good time to get a good steel fork on there but that's just me.

Pantah

To be fair, while it may be obvious to some, not everyone can loot at something like this and instantly understand what happened. Figured I'd go into detail for those who could use the explanation. Most any mechanic will get it right away.

Far as the fork is concerned, I the aluminum half of the fork has been perfectly fine so far. no signs of cracks or imminent failure of the bonding agent for the dropouts, though the latter can admittedly be almost impossible to catch before it happens.
It is, ironically, the steel part which gave me grief, though not due to it being steel. Still, getting a steel fork has crossed my mind and is one of many options on the table. That being said, I'm also entertaining the thought of going with a carbon fork, regardless of the ire it would bring to the C&V crowd. I think a carbon fork would be perfectly at home on this bike. Gary Klein was ever the innovator and not one to go with convention so it'd be fitting.

Again, just one of many possibilities. I'll update this when I figure out the solution. I'm doing a metric century in a month, Levi's Gran Fondo, and I REALLY want to do it on this bike, so that's my preferred timeline to get this sorted. I do have another, slightly newer carbon road bike I can use but it's not as comfortable on longer rides due to the handlebars being lower a couple other geometry differences.

NVFlinch 

Hey thanks for letting your incident hang out without excuses. Very valuable as a reminder for all of us retrogrouches who still ride 1" forks!

I'm going out to re-re-check all of my fork/stem measurements (Nah, I just like fondling my bikes).

Oh, and happy-happy-joy-joy that you're OK. Believe me, being in a walker after a bike accident is no fun.

Pantah

It's something I've honestly never thought of before when swapping stems. It was always a case of "don't let the stem stick up far enough to see the min. insertion line and you're good". All of my past assumptions aside about what I thought the reasoning for that was, NOW I more than just know, I understand, which I feel is an important distinction. Something to be said for f**k around and find out.

Glad this helps. It's something I'll do from now on when I put an older bike together. It's so easy to check with the stem out and headset off. Two quick measurements and you can know beyond a shadow of a doubt that you're good to go or you're not.
Now that I think about it, I really need to check my commuter. The stem is installed correctly and it's even by the same brand (CODA stem on a Cannondale) but I recall it being rather short. Something I'll do in the coming weeks.

I think I've heard that name before. Current plan is to talk to Jeremy Sycip (Sycip Bicycles) since I've got a personal and professional connection, primarily through my brother, though I definitely appreciate the mention, it's always good to know my options and I'll keep them in mind.

Right!? I could have easily found myself in the hospital with that kind of failure. It's come up in conversation with friends more than once now that if it was going to fail, which it was, it happened in just about the most ideal conditions possible. Not only was it at low speed with no cars on flat ground with friends nearby but it was also an absolutely gorgeous, warm, sunny day.
When it happened, I wasn't even mad, angry, scared, maybe a tad spooked, I was mostly surprised. All I could do really was chuckle as we all looked at what happened.

There's a saying in the world of flying that came to mind during this and that was "Any landing you can walk away from is a good landing", which has been the mindset I've had. I walked away unhurt and that's what counts. The bike doesn't even need to be replaced, it can be fixed.

himespau 

Glad to hear you were able to safely control it and have a plan. As someone who rides similarly sized bikes, I hear you on the difficulty of finding replacement forks. Nashbar, when they were still a thing, used to sell a carbon fork (with steel steerer) that went up to 240 mm and was my go-to, but it had rather long threads (so it could be used with a variety of sizes of frames). I still have a search for them on eBay but haven't seen one pop up in years.

79pmooney

In any case, you need a new or repaired steerer. So, see to it the new one has threads that stop much further up. One or two usable threads below the headset, not 13 plus. You could also lower your current stem several millimeters simply by using a thinner lockwasher in the headset (which includes most ever made so you have lots of choices).

As said above, the expander in you stem MUST be below the threads. (It's also a nice safety feature. If the steerer ever does break again, your stem at that expander is keeping your front wheel attached to your handlebars, giving you limited but enough steering and lowering the heart rate peak substantially. You didn't say but I'd put money down that you experienced quite a spike even if you didn't record it.)

Edit: If I decided I wanted to go with a steerer replacement, I'd call Ti Cycles. Dave Levy has seen it all and knows many repair options and also when those options are poor choices. If he cannot do it, he'll tell you in that phone call. He's not cheap but won't take you for a ride. A replacement steerer will probably kill the paint but he may know a repair that can be done midway with the heat far enough away.

Murray Missile 

I've always read that this could happen but had never heard of an actual incident, I can now check that one off the list! Glad you were able to get it stopped, even at 7mph that still had to be quite a "pucker" moment!

repechage

A comment regarding stem insertion, for decades now, stems were marked with a minimum insertion line.
The formula was before thick risers, 5mm, 10mm were not a thing yet.
adding that stack I think points to the stem should insert an additional amount into the steerer, even if the threading is modest, there is a bigger lever at work.
So, with a plus 5mm spacer, 60 mm of insertion for argument’s sake instead of 55 mm.
many reasonable builders set the threaded area of the steerer to not have threading much beyond the headset assembly zone.
‘this fork with the excess threading suggests a replacement fork.
a “technomic” high rise stem would probably place the expander well below the steerer thread region.
a test don’t guess situation.

good that there was no vicious gravity storm here.

smd4

Glad you’re okay. Lucky indeed.

The importance of the minimum insertion line, for both stems and seatposts, has been known and discussed a billion times for the last 50 years or more. It’s not a suggestion.

That it still isn’t heeded is sort of shocking.

70sSanO

My vote would be to get a new steel fork and steerer.

I’d probably opt for threadless. Cane Creek makes a 1” threadless headset in their 40 series. I have a mtb with a 1” steerer and Salsa threadless stem.

But there is a concern with a clamp diameter of 25.4 and drop bars.

John

Steel1

All my bikes are well within min insertion limits. However I just went and checked the one bike that I have concerns with. It had a replacement fork, with lots of threads, and had not been cut yet. So there was a lot of spacer. This is the way I got frame/fork/headset from previous owner.

I am using a 3T Record 84 stem with slot and cone shaped nut (not the angled wedge type).

Even though stem was inserted 20mm deeper than the minimum insertion line, the bottom is only about 4mm past threads, probably 3 if you subtract the chamfer at the tip 😮
I will definitely cut the fork to get additional stem length past the threads. I will keep same stem insertion depth and accept lower bar height.

Not only will it be more robust, but will be lighter and look better as well. 😀

oneclick 

I'd have a *good* look at all the roots of the threads with a loupe.
Once a crack starts, it doesn't stop.

RustyJames 

A trip to gugie and the steerer was replaced. All was well in the magical kingdom.

FWIW - I bought the bike with the steerer already broken.

Pantah

70sSanO What concern is there for 25.4 clamp diameter and drop bars? I'm genuinely curious what the worry is as I can't think of any, aside from the relative scarcity of 1 inch threadless stems.

Looking back at old photos and other old Salsa stems I have, they don't actually have a minimum insertion line, just a hard line where the paint stops. There was no mark to not heed after it got repainted since all the old paint was gone and the shop painted it top to bottom. Yes, I could have compared it to another Salsa stem laying around, I could have measure it had I known what I know now, but I didn't.



Steel1 That's a LOT of thread on that fork. To have the stem in that far and still not have it in far enough is a bit nuts. Thanks for sharing it too, great example of how you can do everything correctly but still not be right or safe.

70sSanO

A lot of older road bars were 26.0mm, except Cinelli. The older steel Salsa stems that I have seen are 25.4mm for mtb flat bars.

There are road bars that are 25.4mm clamp diameter, but you would need to find one you like.

John

smd4

Cinelli made some in 25.4.

Velo Mule

It appears that this could be a valid repair considering that you have enough steerer tube length, which it sounds/looks like you do. I would be tempted to delete the threaded headset if you get the steerer tube repaired.

It is always interesting watching Paul work on things.

Pantah

Velo Mule : Yeah, since it broke right at the base of the threads there's still a whooping 7.5 inches of steerer remaining, so it should be more than plenty for an experienced frame builder to work with. The only concern is too much heat getting to the base of the steerer since it is possibly bonded into an aluminum fork (it is at the very least pressed in). This is where having a large frame with a long head tube and consequently long steerer will be helpful with the longer tube allowing more heat from welding to dissipate.

Good to know, wasn't something I was aware of, mainly due to my lack of early 1 inch threadless bikes. I do have a late steel frame Specialized Allez, last of the steelies before going aluminum, carbon, and carbon/aluminum, that has a threadless steerer but haven't built it up. My only 1 inch threadless Salsa it currently sitting on that fork, I'll have to pull it off and measure the clamp diameter. A quick ebay search has revealed some options, namely a good looking older CODA with the correct dimensions. I think it would be amusing to put a Cannondale part on a Klein.

Far as bars go, I'm sticking with my older Salsa Moto Ace. Wonderful handlebar and I'm rather fond of vintage Salsa components. They're well made and they used to be based out of Petaluma, not 20 minutes from where I grew up and am back to living in today.