Potential Catastrophic Frame Failer Averted ….sort of.
- Thread starter e-beach
- Start date
liveforphysics
100 TW
Buk___ said:
In a decade of testing batteries my lungs have been exposed to a lot of nasty fluorine containing vapors and gases that scarred them inside, so even if I sprint until black-out it's not enough to make passes on healthier stronger riders, so my passing options happen almost exclusively in technical sections. That said, I still get passed in technical sections myself sometimes, so I can't be the only one who trains for aggressive obstacles on a road bike. My guess would be everyone in a cyclocross race qualifies as the 'outlier' group of riders who are rougher on bikes than most.
MadRhino
100 GW
Cyclo cross had gained a lot in popularity here, since I quit about 10 years ago. It is a very tough disciplin. Courses are designed to push participants to their limits of strength and aerobics. I was too old to be competitive, but had a lot of fun trying.
I was riding a Specialized Tri-Cross Expert double, alu-carbon. I guess that most are carbon today, and your steel frame must be one among very few in the races.
In DH too, carbon frames are taking over, about half of them right now. The other half are alu. Trying to find a steel DH frame, one would need to look at 20 yr old bikes.
I was riding a Specialized Tri-Cross Expert double, alu-carbon. I guess that most are carbon today, and your steel frame must be one among very few in the races.
In DH too, carbon frames are taking over, about half of them right now. The other half are alu. Trying to find a steel DH frame, one would need to look at 20 yr old bikes.
speedmd
10 MW
I ride my circa 1150 gram (54) full carbon frame cross bike on some well worn rocky bike trails also with many of the mtn bike group in the fall. Not racing any longer, but still can stay with many of the fast guys on the climbs. Bombing the down hills, is difficult to stay with them unless it is somewhat smooth without flatting much too often. Lots more work for certain on a ridged frame narrow tires and no suspension. Head sets don't last very long and wheels do get messed up a bit too often. A few of the A riders were riding steel frames up until the last few seasons, but no longer. They have mostly gone to single chain rings up front and 11 speed now. Most fast builds are down to 16 pound area now. Most of the newer frames are even lighter than mine which built up well under 18 pounds with medium weight stuff. Way stiffer and stronger than my classics that are near 20 pounds with near equal components. I would not even think about jumping the logs and boulders on my steel bikes that I regularly do on the carbon one. Only so much you can expect from small diameter tubing. Carbon forks would take some 6- 8 ounces off them. They are relegated to fair weather rides only these days.
craneplaneguy
10 kW
This entire thread reminds me why so many bike people have been also plane people (going WAY back....): lightness and strength, lots of both, in one package, is a pretty good trick and the discipline attracts a certain kind of person. If my plane had half the tech of a high end bike, it'd weigh a lot less, but they don't sell enough planes compared to bikes, so they are relatively low tech and expensive, I'm always amazed how cheap a high end bike is, considering how trick they are.
liveforphysics said:
After some more thinking and verifying.
Whilst those drops and jumps are almost certainly fatiguing your steel frame -- ie. slowly reducing its yield strength -- your peddle strokes and road chatter (and bodysway and breaking and accelerating...) are not.
On an Al frame *all* of them would be continually reducing the yield strength.
Once the yield strength drops far enough, the bigger impacts start to permanently deform the frame. That creates new stress risers, in the form of kinks and ripples in exactly the highest stressed areas, and failure occurs shortly after.
Chalo
100 TW
And yet at the end of the day (quarter-century, to be accurate), the steel frames usually give up first. Go figure.
MadRhino
100 GW
Way back, before planes and bikes. Riding and flying are the same in ancient languages, and it was a tradition to give bird names to the best horses.craneplaneguy said:
MadRhino
100 GW
Epyon said:
Let me guess. That is what they asked me for the 2018 V10 carbon... Too much IMO. My MK1 will ride another year.
The thread got long with side discussion about frame material, steel vs alu
liveforphysics
100 TW
MadRhino said:
We obviously need to ride together my friend. It would be an honor and pleasure for me. You're right that almost everything else there is carbon with just a couple other steel bikes. Cyclocross is 98% rider and 2% bike, so I use steel just because I crash a ton and carbon frames don't like to tumble through rock gardens as much as steel. I've been riding more mellow-ish as my broken back is still recovering and randomly likes to spasm and drop me if I get too wild.
MadRhino
100 GW
Sure we should ride, especially since I’d love to ride the long trails in your area. We’ve missed one occasion last summer, but here you would have found the mountains ridiculously small. Although some trails are very challenging, the courses are repetitive.
I chose the Tricross because its top tube is wide and flattened, sitting so comfortably on the shoulder. Now the son of my friend has it and enjoys it as much as I did. Here cyclo cross got added to cross fit training, that is very popular now. Too aerobic for me.
I ride only DH bikes now, heavier but comfortable on the rough. I don’t do much crank work anymore but with power, I have found a new fun in uphill jumps.
I chose the Tricross because its top tube is wide and flattened, sitting so comfortably on the shoulder. Now the son of my friend has it and enjoys it as much as I did. Here cyclo cross got added to cross fit training, that is very popular now. Too aerobic for me.
I ride only DH bikes now, heavier but comfortable on the rough. I don’t do much crank work anymore but with power, I have found a new fun in uphill jumps.
speedmd
10 MW
MadRhino said:
Interesting derivation in the language. I always thought of flying along while in brief contact with the ground as much more interesting and exciting than flying up in a plane. 8)
e-beach
10 MW
So for $65.00 I picked up a used Trek 4500.
It came with some extra welding......They must have learned something somewhere.
At 21 inches it is really 1 inch too long for my stumpy legs,......
but it has a huge triangle to put my battery. Didn't take long to swap some parts and now I have a safe peddle bike. 8)
The rest of the work will go on starting this weekend. If I push it, might only a take a few days.
@Speedmd: After giving it a good think, I have decided to retire the old Liahana frame. I agree, it served it's purpose and gave me many miles of dependable riding.
@LFP: Thanks for the offer of rapping my frame, but after looking around I now see I can get a cheap peddle bike around here for $65 or less. If I look around maybe $35.00. Besides, some of the parts from the Trek don't swap well to the old bike so I guess it is going to the big recycle bin in the sky, or where ever it gets hauled to by the city. We should get lunch together before you leave town.
So, I will be pulling parts off the old frame, use what I need or can. If possible, sell some parts for a reduction in overall cost of a new bike, and/or donate some parts to the Bikerowave, which is a very-cool coop bike shop in my city. I am all for keeping them going.
Thanks all for the posts.
It came with some extra welding......They must have learned something somewhere.
At 21 inches it is really 1 inch too long for my stumpy legs,......
but it has a huge triangle to put my battery. Didn't take long to swap some parts and now I have a safe peddle bike. 8)
The rest of the work will go on starting this weekend. If I push it, might only a take a few days.
@Speedmd: After giving it a good think, I have decided to retire the old Liahana frame. I agree, it served it's purpose and gave me many miles of dependable riding.
@LFP: Thanks for the offer of rapping my frame, but after looking around I now see I can get a cheap peddle bike around here for $65 or less. If I look around maybe $35.00. Besides, some of the parts from the Trek don't swap well to the old bike so I guess it is going to the big recycle bin in the sky, or where ever it gets hauled to by the city. We should get lunch together before you leave town.
So, I will be pulling parts off the old frame, use what I need or can. If possible, sell some parts for a reduction in overall cost of a new bike, and/or donate some parts to the Bikerowave, which is a very-cool coop bike shop in my city. I am all for keeping them going.
Thanks all for the posts.
craneplaneguy
10 kW
speedmd said:
Flying real low in a light airplane, like fence post height, nape of the earth, terrain following, is the crack cocaine of flying. Super fun, addictive, and obviously can be hazardous. Did I say it's REALLY fun?
speedmd
10 MW
Glad you found a good older frame at a reasonable price. Big Name brand also. Nice space for batteries. Like the added plate where your old one broke. With some good brake pads it should be a long lasting safe ride.
MadRhino
100 GW
2old said:
I don’t know the specs of a casting tape repair, but I know the risk of riding a fishtailing bike. Rear triangle lateral stiffness is the major safety requirement at high speed, because it can send you high side in a turn even if you had done everything right.
Titanium bikes need to be overbuilt on the rear, because of high flex factor of Ti. Because of its high flex though, Ti is not crack prone. Most Ti bike frames are sold with lifetime guarantee and even when they aren’t, manufacturers are usually willing to repair, so that is the first thing to check for.
Very few welding shops are equipped to repair a Ti bike frame, because Ti need to be welded in a gas chamber and those are usually too small. So casting tape may be a last solution, if the bike is not ridden fast.
Chalo
100 TW
2old said:
I doubt the tape can be wrapped tight enough and thick enough to do the job right in that location. I'd only try that trick after having the thing welded first.
liveforphysics
100 TW
2old said:
You could give it a shot. Get the surfaces sanded to be rough and cleaned with acetone, and if you can get the right amount of snug wrappings into the area it might work out fine.
Chalo
100 TW
2old said:
For what it's worth, titanium requires no heat treatment and a well-done welded repair should be good as new. Lashing fiber and resin on there will make later welding extremely difficult, though.
MadRhino
100 GW
Chalo said:
I can’t see why. I mean, Ti can be heated high temp without damage, turning any resin leftovers to ashes. It could be sandblasted with many powder types without any wear, even acid cleaned before welding if needed. So I believe that any temporary repair that is not physically damaging the tubing, can be cleaned easily before welding.
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