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I suddenly noticed a crack in my frame.

Is it practical for me to use glue to seal it off as a temporary solution?

enter image description here

Edit: Further information ...two incidents so far. Someone opened their driver side door on me and I slammed into it. That considerably weakened it. Then I fell again while turning a sharp corner, it broke it.

Update from 29th Jan 2019:

  • I went to a bike shop and they told me they could not replace it; I need to talk to the shop where I bought it from and get a replacement from them. Does it have to go this way? I would imagine this fork could be easily replaced.
Yu Zhang
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    Out of curiosity: what kind of riding are you doing on that bike? You have obviously over-stressed the fork. Or did you crash or get hit by something? What make/model of fork is it? – Argenti Apparatus Jan 27 '19 at 13:04
  • Curious as well, since with these tires he/she is probably not riding off-road. – Michael Jan 27 '19 at 13:58
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    @ArgentiApparatus Can't see much of the bike, and the pedals are nice commuter MKS ones, but the rim is not eyeletted and it appears to have either disk brakes or no brakes because can't see a cable. There's also a Kickstand, so I'd guess and suspect its a BSO that's done its service life. – Criggie Jan 27 '19 at 18:41
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    @Criggie I noticed the kickstand, kinda wondered if the OP had been riding big drops on a hybrid :-) – Argenti Apparatus Jan 27 '19 at 18:53
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    @ArgentiApparatus, two incidents so far. Someone opened their driver side door on me and I slammed into it. That considerably weakened it. Then I fell again while turning a sharp corner, it broke it. – Yu Zhang Jan 27 '19 at 22:06
  • If one were really into hacks, an the fork is some sort of fiber (hard to tell whether that or alloy), then it might be possible drill holes/grind slots running lengthwise down the side and glue in pieces of fiber rod. But you'd have to know what you're doing, and it wouldn't be worth the time and expense vs just replacing the fork. – Daniel R Hicks Jan 27 '19 at 22:21
  • In case the two "no" answers are not enough; There is no way to do a good repair of any metal for less the the cost of 10 new bicycles. – blacksmith37 Jan 27 '19 at 22:26
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    @DanielRHicks that is what broken cast metal looks like. For a comprehensive collection of broken things from different materials, checkout http://pardo.net/bike/pic/fail-001/000.html – ojs Jan 27 '19 at 22:29
  • @ojs - If that were cast steel it would weigh a ton (and be weak besides). And a standard strength AL alloy in that configuration would be designed to stress fracture. I figured there was enough irregularity at the break that it MIGHT be some sort of fiber. (I didn't see anything in your pictures that seemed to come close to this.) – Daniel R Hicks Jan 27 '19 at 22:44
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    If it was damaged in the first accident with the car then it should have been replaced at that point, by the person who was at fault in the accident. You are incredibly lucky that the actual break didn't cause more damage to you and/or others. – Criggie Jan 28 '19 at 06:36
  • @Criggie, you were right. The reason it was not replaced after the first accident was, this crack was not visible by then. I was making a deduction that it had been weakened by the first accident. – Yu Zhang Jan 28 '19 at 20:20
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    @Criggie, you can see a clear two-stage failure process in the fracture surface. The small, smooth-textured area on the outside front corner would be the crack from the first collision. The large, jagged surface is the break from the fall. If the paint's got any sort of flexibility, you wouldn't be able to see the initial crack unless you're bending the fork, and possibly not even then. – Mark Jan 28 '19 at 20:58
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    Re you update and new question - I updated my answer but you could ask it as a new question of you want more visibility and answers. – Argenti Apparatus Jan 28 '19 at 23:55
  • Re replacing the fork - you need something with the same steerer tube diameter, similar length, with mounts for your brakes, and to suit your wheel size. There's no need to have suspension, or the same kind of suspension. Buy a similar age used bike with frame damage and do a swap. Don't waste money on a new fork. – Criggie Jan 29 '19 at 07:38
  • @Criggie that didn't make any sense at all – ojs Jan 29 '19 at 16:25

3 Answers3

61

No.

The consequences of fork failure are likely to be severe and painful. This may only be a secondary fork crown but it's still structural. The fact that it's such a wide crack means something is already deformed and weakened. Any glue joint would be under huge stress and aluminium doesn't glue well. If this happened out on the trail it might be possible to ride back to civilisation at walking pace on a fire road, but I'd probably rather scoot the bike standing on one pedal. As your picture indicates it's indoors, you need a new fork before riding it anywhere.

I wouldn't even ride it to a bike shop.

More generally (thanks to cmaster): Never ride a bike where there's so much as a crack in a) the front axle, b) any part of the fork, including the steering tube, c) the stem, or d) the handlebar. There is zero backup for any of these parts, and failure usually means immediate loss of control and consequently unmitigated crash.

Chris H
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    Fork failures will also be extremely quick, and instinctive braking at that instant will make it worse. – Criggie Jan 27 '19 at 18:45
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    Exactly. Never ride a bike where there's so much as a crack in a) the front axle, b) any part of the fork, including the steering tube, c) the stem, or d) the handlebar. There is zero backup for any of these parts, and failure usually means immediate loss of control and consequently unmitigated crash. Don't play with your health and life like that. – cmaster - reinstate monica Jan 27 '19 at 20:45
  • Totally agree with the above comments - although once (close to 30 years ago when I was young and stupid) I did the same damage on day 2 of a cross-country MTB race. I was silly enough to complete the event - although in mitigation, most of the down-hill bits were on a soft soil surface so I calculated that if I did crash I wouldn't damage myself too much. – Penguino Jan 28 '19 at 20:35
  • I often scoot on one pedal, but I doubt that this is a safer option when something's broken, especially in the fork – asymmetric load and you don't have as good feeling in the handlebars, to prevent hits of the front wheel. I'd rather put the saddle very low and coast with both feet ready to touch the ground and center of mass far back on the rear wheel. – leftaroundabout Jan 28 '19 at 21:26
  • On a motorcycle this could be braced. These forks are not round. and one may want to think about unseen damage and how "true" everything is. The purpose of this member is stop spreading or "bowing" of the forks. As such it may be redundant for a mild ride, OP is obviously getting by. OP is going to need to replace the assembly, but may be able to use another design. – mckenzm Jan 29 '19 at 02:01
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    @leftaroundabout the advantage however is that there is nothing between you and the ground - if the bike fails, you just walk away. If the front fork fails while riding, either you are flung, or you and the bike make a (possibly messy) intersection. – Baldrickk Jan 29 '19 at 09:51
  • @Baldrickk it can still get messy if the fork breaks, wheel jags to the side on which you're scooting and thus the bicycle rams into your feet, with nothing on the other side to prevent it. If you're sitting on the saddle, you have a leg on each side to prevent the bike from falling even when the fork breaks completely. – leftaroundabout Jan 29 '19 at 11:45
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    @leftaroundabout sure, it can still go wrong, but it's less likely to drag you down with it if you are already halfway off. – Baldrickk Jan 29 '19 at 13:39
  • @leftaroundabout if you're scooting and it fails completely, the bike is likely to smack you in the leg. If you're riding, it (or the ground) is likely to hit you somewhere more delicate. – Chris H Jan 29 '19 at 13:46
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    Can we add cmaster's comment to the answer, as comments are subject to deletion? – Mathieu K. Jan 29 '19 at 15:00
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    @MathieuK. I've tried to incorporate it without diluting the specifics of this answer. – Chris H Jan 30 '19 at 14:17
47

NO!!

That's not a "crack" – it's broken in two! You need a new fork. Your current fork has completely failed. Any attempt to repair it will create a massive weak spot which will just break again. Anything going wrong around your front wheel has the possibility of throwing you over the handlebars into the path of a truck.

Furthermore, a significant piece of structural metal on your bike has broken. Unless there was a pre-existing crack, whatever did that must have applied a huge force. Check very carefully that nothing else on your bike is damaged.

Community
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David Richerby
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    'That's not a "crack"' - It's just a flesh wound... https://www.youtube.com/watch?v=UijhbHvxWrA – WernerCD Jan 27 '19 at 16:39
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    The picture's not the best in the world, but it looks like there's a very substantial manufacturing defect: about half the thickness of the metal at the point of failure appears to be slag inclusions or some similar metallurgical defect. The crack itself looks like it's fatigue-related. Between the two, it wouldn't take very much force to break the fork -- all the more reason to replace it, but the rest of the bicycle is probably in fine shape. – Mark Jan 27 '19 at 22:51
  • @Mark I'm not convinced. Admittedly it's almost 40 years since I studied metallurgy, but I can't see any obvious defects. (Note: I think we are all agreed on the first para of the answer, and it can't hurt to follow the advice in the third.) – Martin Bonner supports Monica Jan 28 '19 at 13:54
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As others have said the fork is trash and the bike should not be ridden.

Given the nature of the incidents that led to the fork breaking (described in comments), the rest of the bike should be checked for damage, especially the front wheel and headset area of the frame.

Update:

Re: fork replacement: any decent bike store with a competent repair shop should be able to order and install an replacement equivalent fork, even if it is of a different brand. If the fork is branded the same as the rest of the bike, that may be why the bike store told you to go to the store you bought the bike for. Find a different store that is more willing to help.

Argenti Apparatus
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  • this is also an opportunity to shop for a different brand of fork (should you so desire) if your frame can accept other forks. – Jasen Jul 29 '22 at 10:47