Problem!

Headhuunter

I think I might have threaded the bike frame where the mudguards and pannier rack attach but I'm not sure... If I screw the normal allen key bolt directly into the frame bypassing the mudguard and rack, it seems to go in fine but when I put the rack and guards in, it won't screw in tight anymore (it used to). I've found 1 extra long screw which seems to go right through and tighten up holding both the guards and rack onto the frame however this morning it shook loose a bit and by the time I arrived at work it had partly come undone.

What do you think has happened? Is there any solution?

meanredspider

a Nyloc nut on the other side? Put the longer screw through and tighten the nut (if you're struggling for room, remove the wheel and put the screw in from the inside outwards).

spasypaddy

new bike time

kelsen

The Puncture Fairy's cousin, the Fettle Imp, is running up to your bike and loosening the bolt everytime you stop at the lights. Solution is to not stop at red lights and the problem will go away.

cyclingprop

Rucksack.

Ben6899

S5 with Zipp 303s. And a backpack. That should fix it.

Failing that, MRS' idea might also work...

drays

meanredspider wrote:

a Nyloc nut on the other side? Put the longer screw through and tighten the nut (if you're struggling for room, remove the wheel and put the screw in from the inside outwards).

wot 'e sed

i snapped one of the bolts when I fitted the rack to my hybrid!!! I blame the threads being full of paint! i drilled out the bolt and fitted a longer bolt with a nut on the end. Job done.

veronese68

If you don't have room for a nut on the back because clearances are too tight you might get away with some Loctite* on the thread.
*Simple explanation for HH as I know he's not the most technical, not meant to sound patronising.Loctite is a liquid that goes hard stopping the screw from undoing itself through vibration, but you can still undo it if you have to.

Fireblade96

^^ Loctite is the answer.

Headhuunter

Veronese68 wrote:

If you don't have room for a nut on the back because clearances are too tight you might get away with some Loctite* on the thread.
*Simple explanation for HH as I know he's not the most technical, not meant to sound patronising.Loctite is a liquid that goes hard stopping the screw from undoing itself through vibration, but you can still undo it if you have to.

Thanks all for the suggestions. It's weird that the bolt goes in easily without the mudguard and rack in place but when they're there I can't get it to tighten. Thanks for the siple explanation, if I put this Loctite stuff on the will I ever be able to get it undone again?

Ben6899

Headhuunter wrote:

If I put this Loctite stuff on the will I ever be able to get it undone again?

With a quality screwdriver / closed spanner; yes.

veronese68

Headhuunter wrote:

Veronese68 wrote:

If you don't have room for a nut on the back because clearances are too tight you might get away with some Loctite* on the thread.
*Simple explanation for HH as I know he's not the most technical, not meant to sound patronising.Loctite is a liquid that goes hard stopping the screw from undoing itself through vibration, but you can still undo it if you have to.

Thanks all for the suggestions. It's weird that the bolt goes in easily without the mudguard and rack in place but when they're there I can't get it to tighten. Thanks for the siple explanation, if I put this Loctite stuff on the will I ever be able to get it undone again?

Yes, there are different strengths available. The one you would use is called threadlock and can be undone again. The reason you can put the screw in tight without the rack and guards is probably because the outermost threads have stripped. Without them the screw goes further and so can reach good threads. A longer screw will help with this. If you have clearance to put a nut behind that would still be best, but if it's drive side and space is tight against the cassette so you can't use a nut you may have to use Loctite. Loctite is fearsomely expensive and you will only need one drop so ask your LBS to do it rather than buying a bottle of the stuff.

Headhuunter

Veronese68 wrote:

Headhuunter wrote:

Veronese68 wrote:

If you don't have room for a nut on the back because clearances are too tight you might get away with some Loctite* on the thread.
*Simple explanation for HH as I know he's not the most technical, not meant to sound patronising.Loctite is a liquid that goes hard stopping the screw from undoing itself through vibration, but you can still undo it if you have to.

Thanks all for the suggestions. It's weird that the bolt goes in easily without the mudguard and rack in place but when they're there I can't get it to tighten. Thanks for the siple explanation, if I put this Loctite stuff on the will I ever be able to get it undone again?

Yes, there are different strengths available. The one you would use is called threadlock and can be undone again. The reason you can put the screw in tight without the rack and guards is probably because the outermost threads have stripped. Without them the screw goes further and so can reach good threads. A longer screw will help with this. If you have clearance to put a nut behind that would still be best, but if it's drive side and space is tight against the cassette so you can't use a nut you may have to use Loctite. Loctite is fearsomely expensive and you will only need one drop so ask your LBS to do it rather than buying a bottle of the stuff.

Thanks... It's the non drive side so I could put a longer screw in and a nut on the other side. I found a website (which I can't find anymore) which listed about 20 different types of Loctite Threadlocker... It seemed to be available in as little as 10ml bottles but there seemed to be many, many different types...

meanredspider

The only problem with threadlock is that it's typically quite expensive - especially if you buy Loctite. A nyloc nut is a cheap and simple solution and will do the job perfectly.

Headhuunter

meanredspider wrote:

The only problem with threadlock is that it's typically quite expensive - especially if you buy Loctite. A nyloc nut is a cheap and simple solution and will do the job perfectly.

Does it have to be nyloc in your opinion?

kelsen

Headhuunter wrote:

meanredspider wrote:

The only problem with threadlock is that it's typically quite expensive - especially if you buy Loctite. A nyloc nut is a cheap and simple solution and will do the job perfectly.

Does it have to be nyloc in your opinion?

No, you can also use a normal nut with some Loctite to keep it in place...

meanredspider

Nyloc is the safest - easy to get hold of and won't fall off. B&Q or Halfrauds or anywhere will stock them in the right size.

Headhuunter

Thanks all. Veronese is right, I'm a bit of a techno idiot...can't believe I managed to strip the thread...I love bikes and cycling but the nuts and bolts fettling side does my head in. I wish the fettle imp would fettle things to perfection whilst I'm in bed

graham.

If the bolt tightens without the mudguard, but won't with it, then I suspect it is the bolt that has lost it's thread, not the frame.
Without the guard you will be tightening on an undamaged part of the thread.

Headhuunter

Graham. wrote:

If the bolt tightens without the mudguard, but won't with it, then I suspect it is the bolt that has lost it's thread, not the frame.
Without the guard you will be tightening on an undamaged part of the thread.

That's what I was hoping but it's the same with a couple of different bolts, the only one that works is a longer one that comes right through

veronese68

Unfortunately as frames are often ali and the screws are steel the frame will tend to go before the screw. The way to prevent this would be to make the screws out of something soft, like plasticine.
MRS is completely right about using a nyloc nut and a longer screw as the easiest option. Nyloc will stop it vibrating loose. Apologies for the Loctite diversion, I was just aware that clearance can be tight on the driveside. I know this as a friend managed to knacker a freehub on his cheap hybrid by using a screw that was too long and gradually undid the lock ring.