I keep breaking chainstays
 

First one was a 40 year old Schwinn Continental. I somehow managed to snap the steel beast's right chainstay near the rear wheel hub. I rode this bike as a commuter for many years, in conditions ranging from snowing at 10F to rainy at 100F. I had an experienced welder friend weld it back on and it has held well for 5 years since.

Second break was just recently on my aluminum Diamondback Podium 3. I snapped the right chainstay near the bottom bracket, at the weld. Since this is an aluminum bike, I've read it cannot be fixed safely unless a reinforcement pipe is somehow put in place, making it prohibitively expensive given a new frame might be the same cost or cheaper.

Possibly the chainstays are breaking due to a combo of my weight, riding style, weather conditions, and usage:

1. I'm a clydesdale at 220 lbs.
2. I lean more towards mashing at ~75 RPM, and I like off-the-saddle riding and hill repeats.
3. I ride year-round assuming no heavy rain or snow. Living near Chicago, the streets are salted so I don't know if that had a role in the chainstays breaking.
4. On the aluminum bike, I would often do hill repeats with my toddler in the carrier behind me, along with plenty of flat riding. This carrier attaches to the rear wheel hub.

So, some questions:

-Am I being too hard on the bikes, or am I just trying to justify what is actually a coincidence/random? After also breaking spokes, rims, chains, and pedals, I am starting to think maybe it's something I am doing.

-Are those carriers known to cause issues with frames breaking?

-Assuming proper welding technique, there's nothing dangerous about riding a welded steel frame, right? I'm actually thinking about pulling the carrier with this bike now.

Thanks!

Prior to the breaks, did you notice any rust or slow cracking and decay? Or were they just sudden and immediate total failures?

Maybe you are just too damn stong and should force yourself to adopt a higher cadence style.

Where to start, a 40 yr old cheap bike and a new aluminum cheap bike. Try a Surly something, start there. I weigh more than you. I find stuff breaks as well. Rims, BB's and frames as well. Try a good steel frame and/or a 29er hardtail. I have a Surly 1x1, a crosscheck and a karate monkey. All have take loads of used and abuse and has fared well.

Both were pretty sudden actually. I don't remember the Schwinn making a noise when it broke, but I was commuting home and suddenly the bike felt "wobbly." Granted it was 5+ years ago so maybe it did. I can't really see any rust because now it's welded over and grey. It looks fine elsewhere besides some paint wear.

The aluminum definitely made a noise and was sudden, but the derailleur slamming to the small sprocket when the shifter cable snapped (due to the chainstay snapping) was probably part of it. There is no rust or anything on this bike. Just a clean break through the weld area.

My knees would prefer a higher cadence style as well I'm sure. It just feels so uncomfortable.

Hello fellow bike wrecker/clydesdale! Thanks for the reply.

The aluminum frame was replaced free under warranty with a carbon fiber. Haha, probably not what you'd recommend, but I didn't really have a choice and it was free.

I wouldn't classify either as cheap, but certainly far from the best. The Continentals have a reputation for being durable due to the all-steel frame (I obviously can't attest to that however). Keep in mind this is the Chicago-Schwinn, not the Chinese Walmart bikes you see today. The Diamondback is a $1200 Raleigh frame with ultegra/105 groupset.

That being said, they are entry-level bikes (not mid to high level), so you could be right about my problem being the bikes themselves.

Touring frames can be strong. I can't remember which company sells "replacement" frames. But I think it was a name like Trek. The Trek 520 is well known.

Yea Trek has no time limit on their frames to the original owner .. hang on to the receipt and any Trek dealer
will run the replacement process for you.

may be a labor charge to move all the parts over.. thats a LBS Manager's choice..

This is Diamondback/Raleigh's policy. Lifetime warranty on the frame for the original owner, as long as you have proof.

I got charged $200 for my LBS to swap components though. Kinda steep, but the bike shop spotted me a handlebar plug before a triathlon to avoid disqualification, so I felt like I owed them (I'm sure that was their intent too; well-played LBS). I would be surprised if you DIDN'T get charged unless labor was built-in to the warranty.

Its all relative .. Compare with replacing the engine or transmission in your car. and It seems cheap

Sorry to be so blunt, but nothing lasts forever.

Frames flex in use, and eventually will fail. When companies offer lifetime guaranties they're just playing the odds.

Add to that, heavy riders and steep terrain mean higher stresses and flex, therefore faster failure.

Chainstays are especially prone to failure from hard climbing. Changing chain tension, flexes the rear triangle to the right, flexing the right stay into an S bend. Steep hills usually mean the rider is using a small chainring, giving him greater leverage to tension the chain more. A heavy rider climbing steep hills with a 24t granny is the triple whammy, and it's only a matter of time.

Of course bikes could be built stronger, but we're in a sport where weight is a premium. They don't build sports cars the same way Ford builds F-100 pickups, likewise bikes are built to a purpose.

The bright side to all this is that companies do offer those lifetime frame warranties, and most or all don't have rider weight exclusions. So heavier riders with below average frame life are covered.

The other bright side is that chainstay failures are very unlikely to cause injury (though I'd keep bus or cab fare with me at all times).

Your weight and riding style pretty much define why you're breaking chainstays. Still, I'm impressed you managed to break a Continental. Unless it was rust related.

I would seriously try to spin more. It does feel uncomfortable at first but once you get used to it you'll never go back. Your knees will thank you and you'll get a better cardio workout. A knee injury forced me to spin. I'm glad it did.

Or just keep buying bikes with lifetime frame warranties and cash in on something that almost no one else ever does.

Ford hasn't built an F-100 since 1983 :p They still make the F-150 of course.

That's about the last time I rode in or even looked at a pickup. It's amazing I still remember that Ford calls their pickups F-xxx.

Totally understandable. The Schwinn I can understand broke because it's very old. My dad purchased it before I was born and used it to lug me around in one of those death chambers that are mounted behind the saddle.

There's minimal rusting however. I broke this commuter when my extent of bike mechanic knowledge was making sure the tubes were inflated and chain was lubed. I do remember it acting wobbly for a little while, but I was always in a rush to get where I needed to go and kept putting off looking at it. Then all of a sudden it was unridable, and that's when I noticed the chainstay had snapped. I wish I knew what was happening before that. Nowadays, I love working on bikes and would have jumped at the challenge.

On top of that, I put probably 200+ hilly miles towing a 40 lbs bike carrier. That's got to be the triple whammy. For the record, no granny for me :).

This was certainly the case for both. With the Schwinn commuter, I was about a mile from home, but I had regular shoes on so I walked home. It was unfortunate that it was Halloween and I was trying to race home that day to hand out candy.

The Diamondback broke literally pulling out of my driveway, but it took me about an 1/8th of a mile to realize what had happened.


Me too, especially after reading how unbreakable they are. No rust visible but it's hard to see post-welding. The left chainstay is not rusted.

I agree. What do you currently spin at? Any good approaches to ease the transition?

If you're spinning below 60 RPM most of the time you're going too slow. I think an ideal cadence for normal riding is 70-90 RPM but if you can push it, the higher the better. I haven't had a cadence meter on any of my bikes for a while so I honestly don't know.

You can try a fixed gear where the gear ratio is low enough that you have to spin more than you push. It will be especially effective when riding downhill. Make sure it has a front brake of course.

I could resell my Custom built Touring bike frame and fork you wont break it's chainstays the builder and I made it up from his cargo bike
frame materials .. loop stays of 3/4" .049 wall 4130 steel tube form the chainstays, seat and top tubes ..

This be the gospel for clydesdales. Or Ti.

We built up a new Lynskey for a bloke last week... special stuff.

I usually ride at 75-80, so this isn't too bad given the range you suggest. I used to be about 65 before I installed a cadence sensor and focused on spinning more a few years ago. However, I LOVE attacking hills off the saddle, which probably puts a lot of strain on the frame.

Thanks for the suggestion. I don't have a single speed, so I could just try to stick to one sprocket lower than I usually ride.

Hi,
My name is Mike, and I am an Uber Clyde (265) and I wreck stuff too...

40 years is pretty durable!
That had a good run. Please note that the chainstay is now heat stressed (happens on all welds, but re-welds, well...)

Comfortable? You're worried about comfortable doing hill repeats as a clyde, WHILE TOWING!!!!
Dude you rock!

p.s.
I built up a Disc Trucker with "wheels for the apocalypse" and inadvertently took it airborne while loaded with a pack... I was sure something would break... But was lucky. So I'll second that steel is rather durable.

Aluminum is probably the most likely material to fail under the conditions you're talking about. Large strong rider + trailer = lots of force and frame flex. Aluminum also suffers from metal fatigue if its repeatedly flexed, meaning it will eventually break. Carbon fiber and steel both have an elastic limit, where they can repeatedly flex without any damage.

The average rider won't usually stress a frame enough to fracture it, but it sounds like you're riding harder than average especially including the trailer. The new carbon fiber frame will probably be fine. The trailer will likely break either frame eventually, but you can hope that your toddler out grows the trailer before that happens. A steel "touring" frame would be designed to handle much larger loads, but I wouldn't worry about until you break your current steel frame again.

I wasn't sure whether heat stress is a problem for steel frames. I know for aluminum it is bad news.

Haha, thanks. I like the pain hills provide :). My legs just don't want to spin at 80+ RPM. They'd rather lean towards mashing. When I go off-the-saddle, I am probably rocking a cadence of about 40-50 RPM. Fortunately I can't go off-saddle when towing otherwise the carrier swings around with every pedal stroke.

a lot of information in this thread
is not information but poorly formed opnions

first
steel is just as likely to break if it is used outside its intended design
and most lightweight steel frames probably have tighter design conditions than cheap aluminum
robust steel like a surly will probably last a lifetime
but lighter stuff like surlys sister brand salsa probably less so
but in my experience
well made aluminum frames have as good or better service life than steel

the main point i think needs to be clarified is gsa103s comment about fatigue limits
called elastic limits in his post

yes steel has a fatigue limit
which is the amount of stress that the metal can withstand repeatedly without suffering a fatigue failure

this only means that if the stress in the material is below a certain threshold it will not suffer fatigue failure
and this threshold is often incorrectly given as the elastic limit
which is the point at which the metal permanently deforms
or bends
but actually
the fatigue limit is generally much lower than the elastic limit
meaning the bike can still suffer fatigue failure without showing any signs of damage

as for aluminum
no there is no fatigue limit
or threshold of stress below which it will last forever
but if the stresses are relatively low
when considering
use and or abuse
design
and construction
the frame can last billions of cycles
or hundreds of thousands of kms
before failure

also
when comparing inexpensive steel to inexpensive aluminum
the aluminum will generally have a higher strength to weight ratio
so the bike can be significantly lighter and stronger than an inexpensive steel frame

lastly
aluminum frames are built with fat tubes to avoid flex and reduce internal stresses in the material
to keep the frame lasting a long time
while lightweight high end steel is built with thin wall skinny tubes
as the added strength can tolerate higher stress and more flex
but this makes them less ideal for bigger and stronger riders

of course
all these comments are generalizations
as there are steel and aluminum and carbon frames that are more than strong enough
and ones that are comparatively feeble
so as always
and especially for clydes
buyer beware

Makes sense. I am currently overhauling the crank on the steel Schwinn, but I plan to use that as the towing bike. I'd feel better about breaking that old bike than my carbon.

Judging from the sound of this, I should ask if you've ever minded your pedal stroke for a couple of months or so... it takes concentrated practice to build the muscle memory necessary to turn stomping into a nice smooth spin, which uses less effort once you have the muscle memory.

Obviously the bigger guys are going to move slower, but AFAIK there's no reason you couldn't be quite happy at say, 75-80rpm.

Once I switched to clipless pedals a few years back, I did spend a while focusing on spinning more. I think starting out I was at 60 RPM. Pretty slow. I installed a cyclocomputer with cadence so I'd make sure I was above 70 RPM. It wasn't too difficult to pass that benchmark. After posting last week, I've been monitoring my cadence and it is around 75-80 RPM when on the saddle. Not too bad.

I think the off-the-saddle riding is the trouble area. I've been trying to spin up hills more often. That's kind of a bummer though because I love "dancing on the pedals" as Phil Liggett would say. Granted, there's not much grace to my 220 lbs frame mashing the pedals, but fortunately I don't ever see myself cycling so the illusion is easily maintained :). Unfortunately for my bikes (and knees), my lungs and legs can go off-saddle for quite some time without having to stop.

I can't see "spinning" when off-the-saddle. What's an acceptable cadence when going off-saddle, or is that not really monitored?

I'm curious as well what cadence one would want to strive for off-saddle. I'm looking at ANT+ Cadence/Speed sensors for my Garmin so I can track where I am and work on improving.