Aluminum frame fatigue / failure

[mikael17128]

I will try to be exact as possible here when I explain the symptoms. I have a 2001 Specialized M4 aluminum alloy frame road-racing bicycle. I have put 5000 miles on it since buying it used 7 months ago. I don’t know how many miles were put on it prior to my ownership. I have noticed two things that concern me:



#1 – I rode this bike and a Trek 5500 carbon frame on a CycleOps electronic trainer with a resistance rating of 250 watts. The aluminum bike’s bottom bracket moved from side to side laterally by about 1.5 inches with each pedal stroke. The carbon bike does not move more than 1/8”.



#2 – Last Thursday I was riding in a super-fast criterium type trainer with a 3 mile loop. Sometimes the bike would make loud pang-pang-pang noises coming from what sounded to be the head tube. I could also feel slight vibrations in the handlebars but not as much vibration as you would expect from the loud pang-pang-pang noises. There is one particularly sharp turn where I could consistently hear the pang-pang-pang-pang-pang. When I let off the gas the “panging” would stop but I also found myself a few places back.



Is it time for a new frame?



Thanks in advance,



MRW

 

[daveornee]

I will try to be exact as possible here when I explain the symptoms. I have a 2001 Specialized M4 aluminum alloy frame road-racing bicycle. I have put 5000 miles on it since buying it used 7 months ago. I don’t know how many miles were put on it prior to my ownership. I have noticed two things that concern me:



#1 – I rode this bike and a Trek 5500 carbon frame on a CycleOps electronic trainer with a resistance rating of 250 watts. The aluminum bike’s bottom bracket moved from side to side laterally by about 1.5 inches with each pedal stroke. The carbon bike does not move more than 1/8”.



#2 – Last Thursday I was riding in a super-fast criterium type trainer with a 3 mile loop. Sometimes the bike would make loud pang-pang-pang noises coming from what sounded to be the head tube. I could also feel slight vibrations in the handlebars but not as much vibration as you would expect from the loud pang-pang-pang noises. There is one particularly sharp turn where I could consistently hear the pang-pang-pang-pang-pang. When I let off the gas the “panging” would stop but I also found myself a few places back.



Is it time for a new frame?



Thanks in advance,



MRW

time for s close & careful visual inspection

 

[waxbytes]

Take it in to a good LBS. Bottom brackets can flex normally, but not an inch and a half! You "most likely" have a dead bb bearing. My limited experience with fatiguing aluminum tells me that an inch and a half of flex would have failed pdq in a crit race. Sort of like "pang, p-pang, crunch...slap....scream.....siren".

 

[boudreaux]

Bottom brackets can flex normally, but not an inch and a half! You "most likely" have a dead bb bearing.

How does that cause a 1.5" BB deflection?

 

[waxbytes]

How does that cause a 1.5" BB deflection?

Sorry if I was sloppy in my description. The part of the original post I was referring to was "The aluminum bike’s bottom bracket moved from side to side laterally by about 1.5 inches ". I took "laterally" to mean back and forth. On further thought I can't imagine a bicycle being usable with that much lateral play. Or flex.
Ignore my speculations.

Take it to a LBS.

 

[mikael17128]

Sorry if I was sloppy in my description. The part of the original post I was referring to was "The aluminum bike’s bottom bracket moved from side to side laterally by about 1.5 inches ". I took "laterally" to mean back and forth. On further thought I can't imagine a bicycle being usable with that much lateral play. Or flex.
Ignore my speculations.

Take it to a LBS.

It's a strange phenomenon. When I first put the thing on the indoor trainer and saw the BB and to one degree or another the chainstays sway back and forth I was fascinated. The mountain bike I had been using before did not flex in the least. Funny thing was, when I got the bike out on the road I could not mark any flex what-so-ever. I looked and looked and looked but no flex. Then back on the indoor trainer and there it was again. It may not have been a inch and a half but it sure as heck was 1". There can be no doubt about that.

I took one of the respondants advice and checked the frame over thoroughly but could not find any cracks or fissures. I still can't explain the pang-pang-pang. I just did a century yesterday and the thing rode fine, no pang-pang-pang. The panging sound only happens under stress, which is what has me worried!!! That would be the least opportune time for a (?catastrophic?) breakdown.

BTW, what's an LBS?

MRW

 

[waxbytes]

It's a strange phenomenon. When I first put the thing on the indoor trainer and saw the BB and to one degree or another the chainstays sway back and forth I was fascinated. The mountain bike I had been using before did not flex in the least. Funny thing was, when I got the bike out on the road I could not mark any flex what-so-ever. I looked and looked and looked but no flex. Then back on the indoor trainer and there it was again. It may not have been a inch and a half but it sure as heck was 1". There can be no doubt about that.

I took one of the respondants advice and checked the frame over thoroughly but could not find any cracks or fissures. I still can't explain the pang-pang-pang. I just did a century yesterday and the thing rode fine, no pang-pang-pang. The panging sound only happens under stress, which is what has me worried!!! That would be the least opportune time for a (?catastrophic?) breakdown.

BTW, what's an LBS?

MRW

LBS is short for Local Bike Shop.

 

[artmichalek]

Keep in mind that your frame is loaded much differently on the trainer than it is on the road. You aren't seeing any flex when you're out riding because there isn't a big metal clamp holding your rear axel. If it isn't flexing a lot out on the road, then chances are your frame isn't cracked. As for the panging noise, sound travels all over the place through an aluminum frame. Is the frequency of the noise on beat with your pedal stroke or the wheel roatation?

 

[mikael17128]

Keep in mind that your frame is loaded much differently on the trainer than it is on the road. You aren't seeing any flex when you're out riding because there isn't a big metal clamp holding your rear axel. If it isn't flexing a lot out on the road, then chances are your frame isn't cracked. As for the panging noise, sound travels all over the place through an aluminum frame. Is the frequency of the noise on beat with your pedal stroke or the wheel roatation?

That's a very good question. It was loud and rhythmic, the sounds were evenly spaced: pang...1/2 second...pang...1/2 second...pang...I plan to ride the same crit trainer on Tuesday or Thursday. I'll have to get back to you on whether it's in tune with my pedal stroke.

MRW

 

[martin_j001]

I've heard that "pang" sound before, and it was spokes in my case. Not breaking, but de-stressing. Then they broke..... Make sure to check out your spokes, even if its just using your fingers to check tension make sure that they are all about the same.

 

[mikael17128]

I've heard that "pang" sound before, and it was spokes in my case. Not breaking, but de-stressing. Then they broke..... Make sure to check out your spokes, even if its just using your fingers to check tension make sure that they are all about the same.

I just checked both wheels and found 6 of the 28 rear spokes to be very loose. I suppose this bodes well for the integrity of the frame .

Thanks,

MRW

 

[SKAUFMAN12]

I wouldn’t’ risk my life on it.

 

[martin_j001]

I just checked both wheels and found 6 of the 28 rear spokes to be very loose. I suppose this bodes well for the integrity of the frame .

Thanks,

MRW

There's your "pang". Its still worth having the frame checked out if you have any doubts whatsoever. I had an aluminum Giant, and after its third "paint crack" I took it back to the shop I bought it from. Whether it was paint or cracks in the al, it was replaced by Giant--and then sold immediately by me.