Should I sell my Mercian?

General cycling advice ( NOT technical ! )
pwa
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Re: Should I sell my Mercian?

Postby pwa » 25 Sep 2018, 4:11pm

amediasatex wrote:
Starting to feel the same. Or maybe we are both lucky?


Go with lucky, I get quite attached to my bikes (if I like them) and it makes me quite grumpy when they break, I would much prefer they didn't.

Breaking a frame every year seems a bit strange to me. I've got club mates riding the same frame for thirty years.


I've got some that are that old, and older, and some I've had myself for 10-15 years and still in one piece, so it's not like it's a new frame breaking after a year of use each time, just on average I seem to suffer a breakage in 'a' frame every 12-18 months or so.

I wouldn't suggest there is anything wrong with the way you treat your bikes, but I wonder what causes these failures. Do you buy frames with particularly thin walled tubes, very truncated lugs or something like that?

amediasatex
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Re: Should I sell my Mercian?

Postby amediasatex » 25 Sep 2018, 4:20pm

pwa wrote:
amediasatex wrote:
Starting to feel the same. Or maybe we are both lucky?


Go with lucky, I get quite attached to my bikes (if I like them) and it makes me quite grumpy when they break, I would much prefer they didn't.

Breaking a frame every year seems a bit strange to me. I've got club mates riding the same frame for thirty years.


I've got some that are that old, and older, and some I've had myself for 10-15 years and still in one piece, so it's not like it's a new frame breaking after a year of use each time, just on average I seem to suffer a breakage in 'a' frame every 12-18 months or so.

I wouldn't suggest there is anything wrong with the way you treat your bikes, but I wonder what causes these failures. Do you buy frames with particularly thin walled tubes, very truncated lugs or something like that?


The only common factor really is me and my riding!

Over the years I've broken welded and lugged steel frames, both lightweight and 'sturdy'. The Alu frames have all been quite substantial too, to be fair most of them were MTBs and used for actual MTBing, not abused but used as intended, but some were road bikes or commuters too, probably 70/30 split. The Carbon failures have been on fairly light frames but again, not super light or anything.

The two this year had nothing in common really...

One was a welded steel MTB frame used as a commuter but hadn't seen too much bad weather and was in good condition, less than 12 months old and cracked around the downtube from what appeared to be a dodgy gusset weld.

The other was a 3 year old welded Stainless Steel road frame, hadn't done huge mileage, mostly in good weather, literally only seen about a dozen wet rides and cracked around a seatstay, cause as yet unknown as it hasn't visibly initiated from any obvious defect or damage, but it is 'near' the weld with the brake bridge and roughly follows the line of where the HAZ would be but that could just be coincidence.

Both reputable brands, mid-range frames, not super fancy or lightweight, just bad luck

Grandad
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Re: Should I sell my Mercian?

Postby Grandad » 25 Sep 2018, 4:53pm

Oh yes, quite, I believe that we do need two bikes at least - and possibly a spare frame just in case

I had just one bike for racing, touring and daily commuting until I got married. The new home was 16 miles from where I worked with no direct public transport so a back up bike was essential.

I bought a second hand one that was being sold because the owner had got engaged. Was it to pay for the ring or had he been ordered to give up cycling :D

I added a trike conversion set to the spare for the winter rides to work. Tried it in the first medium gear 25 next spring and was hooked for the next 55 years. Sold the last one a few years ago but am now looking enviously at an electric Trykit conversion that comes out with our oldies group.

JakobW
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Re: Should I sell my Mercian?

Postby JakobW » 25 Sep 2018, 6:50pm

In _Bicycling Science_ Wilson states that most frames fail through Low-Cycle Fatigue (LCF); the peak loads that the frame and components see in bumps, setting off, honking up hills etc. are very high compared to the steady-state pedalling loads, and it is these overloads that cause eventual failure in thousands or tens of thousands of cycles (as opposed to the multiple million cycles one would expect from High-Cycle Fatigue). That might explain the propensity for some people to break frames and bits more easily; they don't necessarily lack mechanical sympathy, but even a modest increase in peak forces (eg. through higher peak pedal forces even at the same nominal power, a tendency to honk on the bars a bit more, or even just a liking for setting off in a higher gear) might easily have dramatic effects on LCF life.

fastpedaller
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Re: Should I sell my Mercian?

Postby fastpedaller » 25 Sep 2018, 9:13pm

OP - you could have sold it by now! Just saying :roll:

PH
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Re: Should I sell my Mercian?

Postby PH » 26 Sep 2018, 12:52am

bigjim wrote:I've been cycling 55 years. I've never had a steel frame failure. I've had a few crashes and I'm a heavy powerful rider. None of my club mates have mentioned steel frame failures.
I've never come across it, off anybody I've spoken to. I've only ever heard of it on the net. Carbon or Ali either, but they are fairly recent additions to cycling IMO. The only frame failure I personally hear about are TI. A few riding acquaintances have experienced this. Jobst Brandt damaged his by riding into a ditch. He says it wrinkled. I've had two frames written off. One by Royal mail and the other by baggage handlers.

Only been riding half that time, but this otherwise reflects my own experience. Had one frame crack (ti), had one written off (Alu) and that's it. In the group I ride with I know of three failures over the same time, snapped dropout (steel) split seat tube (steel) downtube crack (alu) plus a couple crash damaged. It's possible I haven't heard of them all, but an average of a frame every two years would have resulted in well over a hundred rather than four, I wouldn't have missed that many.

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RickH
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Re: Should I sell my Mercian?

Postby RickH » 26 Sep 2018, 12:55am

My only frame breakage (apart from bending a frame once when I was hit by a parked car!) in over 40 years was a cracked rear dropout on my old steel 80s MTB. That was probably because I was running it with the rear sprung out to get a 130mm oln hub in (it started life as a 5 speed & I was, by that stage, running it as 7 speed).

Even my vitus 979 (with bonded alloy forks) survived nearly 20 years (until it got pinched from the garage) despite being ridden off road on 23mm tyres fairly regularly. And it was used for regular commuting for several years with Freedom Bikepacking Limpet low riders (that fixed with a U tube through a sleeve on the panniers clamped by the front QR & velcro strapping round the fork legs).

Some people seem to give their bikes a hard time. :?

... Or maybe I just live a charmed life? :D

PH
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Re: Should I sell my Mercian?

Postby PH » 26 Sep 2018, 12:57am

amediasatex wrote:Both reputable brands, mid-range frames, not super fancy or lightweight, just bad luck

With that sort of luck, I'd only buy frames with lifetime guarantees, you could save a fortune.

Brucey
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Re: Should I sell my Mercian?

Postby Brucey » 26 Sep 2018, 12:12pm

JakobW wrote:In _Bicycling Science_ Wilson states that most frames fail through Low-Cycle Fatigue (LCF); the peak loads that the frame and components see in bumps, setting off, honking up hills etc. are very high compared to the steady-state pedalling loads, and it is these overloads that cause eventual failure in thousands or tens of thousands of cycles (as opposed to the multiple million cycles one would expect from High-Cycle Fatigue). That might explain the propensity for some people to break frames and bits more easily; they don't necessarily lack mechanical sympathy, but even a modest increase in peak forces (eg. through higher peak pedal forces even at the same nominal power, a tendency to honk on the bars a bit more, or even just a liking for setting off in a higher gear) might easily have dramatic effects on LCF life.


In essence I agree with that line of thought. However it is worth noting as few things;

1) that (as in spoke fatigue) in the final throes, the crack may be advancing even when the frame/wheel is subject to quite low stresses that normally wouldn't be any trouble to it. Often these stresses are the ones that administer the 'coup de grace' to the frame (or spoke etc) and folk say "I went over a bump/pushed hard on the pedals, and I broke my frame/handlebars/spoke etc" . Which is a natural enough thought I suppose but in fact the real damage was done long ago, by some combination of defective design/manufacture, or some application of service stresses that initiated a low cycle fatigue failure. Also

2) quite often a frame is made in such a way as it is already a mess of very high internal stresses; really a frame like this needs some stress-relief treatment (much as wheels do) and in the absence of it almost any modest service stresses may cause a fatigue crack to propagate from a bad stress concentration. By definition a welded frame must contain yield magnitude residual stresses and many brazed frames are far from stress free too. It is not perfectly understood what happens but it is arguably the (very occasional) application of high stress that gives a stress-relief effect and (somewhat counterintuitively) helps to protect the frame from fatigue.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

bikepacker
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Re: Should I sell my Mercian?

Postby bikepacker » 1 Oct 2018, 5:26pm

Just to update you. After giving it some thought over the last week I have decided to leave it hanging on my garage wall for the time being. The low price second hand bikes are fetching it would not be worth selling. Maybe at some future time I will strip it down and sell all the parts separately, that way I would get much more than selling the complete bike.
There is your way. There is my way. But there is no "the way".

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pedalsheep
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Re: Should I sell my Mercian?

Postby pedalsheep » 1 Oct 2018, 5:49pm

Wise choice! I've known loads of people who have regretted selling a bike but no one ever regrets keeping it as you can always change your mind.
'Why cycling for joy is not the most popular pastime on earth is still a mystery to me.'
Frank J Urry, Salute to Cycling, 1956.