DPDISXR4Ti

While cleaning my bike the other day I discovered this...


FWIW, the frame is a 7005 aluminum, circa 1995 Crestone Peak Hard-tail with an AMP fork. Crestone Peak existed for about 10 minutes, not that I'd expect much manufacturer support on a 15 year-old bike.

Suggestions?

brockd15 

I think you've got a great excuse to start frame shopping.

rhenning

A good aluminum heli arc welder could fix it but i will cost more than the bike is worth. Roger

AEO

yep, toast.
time for a new ride. Be picky and buy a bike that doesn't have the same issues, if any, your cracked one has.

3alarmer 

Good thing you noticed this before Christmas.
You now have something to tell people when
they ask what you need. Hint: it is not a
heliarc welder.

Mike Larmer

skilsaw

If Santa brings you coal, instead of a new bike,
I think you could continue to ride that bike for some time.
I don't think it will lead to a catastrophic failure where
you shoot forward off the bike to kiss the earth.

But, if you are like me, any excuse is a good excuse to buy a new bike.

longbeachgary

My daughter's 6 year old Specialized Allez developed a crack like that and Specialized replaced it free of charge. Lots of frames have a lifetime warranty to the original owner.

AEO

nah, that'll split right down the middle and shatter into a million pieces on the first bump it hits.

Flying Merkel

My Specialized Rockhopper developed the identical crack. They gave me a replacement frame 12 years after original purchase. Yer frame is copulated. Re-place

LarDasse74

New frame. It might last for a long time before the crack spreads, or the crack might suddenly wrap around to the weld and the cause the headtube to fall off and send you underneath a bus. 15 years is a reasonable life span for a lightweight frame.

Chombi

That's a goner....The way it looks, that crack goes well into the tube to the interior wall of the head tube for sure. You'll have to do full penetration welding and filling to get that close to it's original stregnth, and that will require a lot of prepr work and grinding/filing down to original shapes/profiles so you can re-install a headset = more than the bike is worth, most likely. I guess that's the end of your long relationship with Crestone Peak........unless you find a used one to replace this one...Make sure you check the head tube on it very carefully if you do so....

Chombi

DPDISXR4Ti

Why are you thinking that Roger? I forget what the frame cost - couple hundred, and it's otherwise still in perfect shape.

LarDasse74

Not what the frame cost but what it would cost to replace it... a similar era good quality aluminum frame would be cheap used, and a modern basic frame (likely similar quality) can cost very little as well... Maybe $300 for a non-branded or lesser known brand or $300 for one with a brand name on it.

merlin55

doesnt nashbar have generic frames for about $100

DPDISXR4Ti

Probably, but I'm not looking to downgrade - this frame is somewhat unique. I'm thinking a reinforcement plate over the repair would help in ensure that a catastrophic failure wouldn't (most likely) happen.

FBinNY 

If you want to keep this going as a "B" bike you can do a down 'n dirty ugly repair with a $1.50 hose clamp. Knock out the upper cup, run some acetone into the crack to clean it, then apply a hose clamp to tighten it closed.

Unfortunately the super glue won't be strong enough so you'll have to leave the clamp on permanantly (I didn't say it would be pretty). If you want to do a nicer job, replace the clamp with a machined SS collar with a slight interference fit and a wall thickness of about 0.060" to 0.080". Consider making 2 of the collars, and add one to the bottom to shore that end up.

Also after it's clamped and glued, and the glue has set have someone ream the headtube to spec. It's likely the ID is at the low end of the range and excess interference in the cups fit contributed to the failure (that and age).

davidad

Aluminum has a finite number of flexes before it cracks. If you have had it for 15 years I would say you have gotten your money's worth. Even if you have it welded it will crack somewhere else.
Get a new one.

LarDasse74

Unlikely it would be a 'downgrade.' The $100 Taiwanese frame today is as good or better than the mid-quality aluminum from 15 years ago. For $100 you will likely get a butted, shaped tubing aluminum frame that has been heat treated and possibly powder coated. Lighter and stronger that what you have, probably. Aluminum from yesteryear had a bit of a reputation for cracking but not so much any more. I'm not saying your repair plan won't work, just that you get a lot ofr your $100 these days. And I am not generally of the mind that 'newer' = 'better' but in this case it likely does.

DPDISXR4Ti

Thanks for the feedback. I'd actually been thinking about using structural adhesive along with some AL sheeting and a hose clamp. I've recently built a car with that stuff, so why not a bike?

HillRider

Apparently you don't want to hear that the frame should be replaced so go ahead with whatever repair you deem suitable and safe. If it were mine, it would be gone immediately. I can't believe that frame has any particular and superior features that can't be replicated in a newer, probably better made, frame at reasonable cost.

kvnrvn

if you want to try to save the frame, this might work in combo with drilling a hole to stop the crack.

https://durafix.com/

JohnDThompson 

IIRC, 7nnn series aluminum needs to be heat treated after welding.

DPDISXR4Ti

Well, that would kill off any lingering thoughts on welding.

I started disassembling the head-set tonight - thought it best to start a new thread on my issue there, as it's more of a generic repair question - here's the direct link to it...
https://www.bikeforums.net/showthread...3#post11876993

AEO

on an airplane, you'd drill a hole at the end of the crack to stop it from propagating and then glue on a doubler plate, while holding it in place with rivets.
not that you'd be able to translate that directly to bikes, but the idea isn't so different.

DPDISXR4Ti

I think it translates pretty well for this. It's more or less the approach I'm considering - structural adhesive with mechanical fasteners as secondary.