Left crank thread ruined...PLEASE HELP
I bought a road bike a few days a go. Like an idiot I hand tight the pedals and a few days later one of them fell out. I tightened properly second time. But I go to cycle again just to realize that thread is screwed. So my question is what do I do? Do I call the place where I bought the bike and ask for replacement? Or is there a way for me to fix it? Please help!
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I assume you know the left (NDS) pedal has a left hand thread (anti clockwise to tighten)? You could run a tap through to clean the threads but obviously you need the correct one (and they are not cheap). If it is totally knackered you will need to replace the crank arm. Given your current level of mechanical expertise I would leave that job to the bike shop.Rose Xeon CDX 3100, Ultegra Di2 disc (nice weather)
Ribble Gran Fondo, Campagnolo Centaur (winter bike)
Van Raam 'O' Pair
Land Rover (really nasty weather
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bbrap wrote:I assume you know the left (NDS) pedal has a left hand thread (anti clockwise to tighten)? You could run a tap through to clean the threads but obviously you need the correct one (and they are not cheap). If it is totally knackered you will need to replace the crank arm. Given your current level of mechanical expertise I would leave that job to the bike shop.
It still tightens fully, but as soon as I start to pedal it falls out and hangs by the tip 0 -
bbrap wrote:I assume you know the left (NDS) pedal has a left hand thread (anti clockwise to tighten)? You could run a tap through to clean the threads but obviously you need the correct one (and they are not cheap). If it is totally knackered you will need to replace the crank arm. Given your current level of mechanical expertise I would leave that job to the bike shop.
Also do you think I should try a thread locker??0 -
New crank it is. Was the bike new or secondhand? Might be able to get away for a day or two by putting a couple of turns of PTFE tape on the thread before inserting but it does sound comprehensively shagged.Rose Xeon CDX 3100, Ultegra Di2 disc (nice weather)
Ribble Gran Fondo, Campagnolo Centaur (winter bike)
Van Raam 'O' Pair
Land Rover (really nasty weather )0 -
bbrap wrote:New crank it is. Was the bike new or secondhand? Might be able to get away for a day or two by putting a couple of turns of PTFE tape on the thread before inserting but it does sound comprehensively shagged.
I bought it 5 days a go...
Do you think the place where I bought it from have the same crank because I can't find one online as I am looking for exact same one. 0 -
Laurynas wrote:...
Also do you think I should try a thread locker??
Certainly not. You should actually be using anti-seize since the thread on each pedal spindle is designed to tighten with use, not the opposite. If you tighten the pedal properly (don't go mad, just gentle torque) and it doesn't stay in then something is wrong. As above, you don't give much reassurance so I would get the shop to have a look. It could be something simple, it could be a re-tap job or is could be a crank arm replacement...0 -
Take it to a proper bike shop and they should repair it. Cost around £20.0
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Another vote for taking it to the place you bought itFFS! Harden up and grow a pair0
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Did you fit the pedals the first time or did a shop do it? If you bought it in a shop near you take the bike back and ask them to have a look. If you bought it mail order and fitted the pedals yourself take the bike (or just the left crank and pedal) to a decent shop and get them to repair it.0
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Not sure about Halfords; you could phone and ask them.
Sounds like the thread is pretty damaged if the pedal keeps falling out, so just retapping it won't work. If you're to rescue the damaged crank it probably needs to be helicoiled. A decent bike shop should be able to do this, but again, phone around first to find out if they can and how much they'd charge.
Depending on the chainset / bottom bracket you may find that a new crank is a cheaper option...0 -
What type and size do you need and where about's are you? I think I've got a spare 172.5mm Shimano Tiagra NDS lurking somewhere.0
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Actually, might be a 175mm. I'll check if it might be useful.0
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londoncommuter wrote:Actually, might be a 175mm. I'll check if it might be useful.
From his other post it seems he has an FSA Vero square taper chainset, so Tiagra HT2 no good to him...0 -
Veronese68 wrote:
I think you should clarify that ...
IME, some staff at halfords are capable, others appear to be totally inept - so it's not possible to give a definitive answer unless a specific halfords is mentioned.
In the same way, it's not possible to vouch for LBS as a whole - but, given that their survival depends on their ability to do the job, the chances are any LBS will be a better bet than the local Halfords.
However, if the bike was from a retailer and the pedal fitted by them, then I'd be taking it back and asking them to resolve it because it should never have come off in the first place and I'd hazard a guess that the wrong sided pedal (there is a left and right pedal with opposite threads) have been force fitted - and thus the whole crankset will be stuffed.
If it was bought from a consumer then AFAIK you have no legal recourse.0 -
The OP admits to hand tightening the pedals in the second sentence, so I'm guessing an online purchase and the retailer is unlikely to help here...
And it sounds like the damage may require a helicoil insert0 -
If LBS or halfords can't insert helicoil, then what are the best options? Because someone recommended buying a whole new crank set. But the things my crankset is good. ITs just the left crank thread. Its a 175mm FSA/VERO so can I just buy any brand as long as its 175mm?0
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Any machine shop should be able to heli-coil it. Google might be your friend if you don't know a local placeFFS! Harden up and grow a pair0
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You could try threading the pedal (or if you have another one as it's thread will be cleaner ) from the reverse side of the crank to recut and clean the threads. If this is successful try rethreading from the correct way with a bit of plumbers threadlock tape. This may help it grip the bits that have been damaged.0
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Did I read you are a student ? Anyone doing engineering that you know ?0
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If it wasnt the bike shops fault and you want to get riding asap, just get a replacement
http://www.ebay.co.uk/itm/ETC-Shimano-P ... XScu0cP1cQ
If its a JIS square taper the above will get you back on the road. As its a very hi stress interface part I would not bother with a repair or helicoil.Caveat - I buy and ride cheap, however, I reserve the right to advise on expensive kit that I have never actually used and possibly never will0 -
As above, not worth the hassle of trying to bodge a f***** crank arm. Buy the left arm or set if its cheaper and get a shop to show you how to do it.0
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SmoggySteve wrote:You could try threading the pedal (or if you have another one as it's thread will be cleaner ) from the reverse side of the crank to recut and clean the threads. If this is successful try rethreading from the correct way with a bit of plumbers threadlock tape. This may help it grip the bits that have been damaged.
Total boll0cks. :roll:
If a 9.99 crank will do, that is the cheapest fix, but a repair is quite simple and will not be a bodge. It will be as good as new.0 -
my lbs helicoiled mine I think it was £12.0
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lesfirth wrote:SmoggySteve wrote:You could try threading the pedal (or if you have another one as it's thread will be cleaner ) from the reverse side of the crank to recut and clean the threads. If this is successful try rethreading from the correct way with a bit of plumbers threadlock tape. This may help it grip the bits that have been damaged.
Total boll0cks. :roll:
If a 9.99 crank will do, that is the cheapest fix, but a repair is quite simple and will not be a bodge. It will be as good as new.
The OP has stated in the second post that the pedal threads in fully but then unwinds itself eventually. This is not a crossed thread or you would never get that far. No suggestion the pedal is loose inside the crank arm as in the outer part at broke from the rest. If anything its probably just missing a washer from the end as a nut and bolt only stop when you nip it tight. The fact it winds in fine suggests to me all is ok until this point. The threads could be slightly damaged on the way but not enouth to cause cross threading. You dont have to be an expert in bikes or pedals to understand how a fooking nut and bolt works0 -
SmoggySteve wrote:lesfirth wrote:SmoggySteve wrote:You could try threading the pedal (or if you have another one as it's thread will be cleaner ) from the reverse side of the crank to recut and clean the threads. If this is successful try rethreading from the correct way with a bit of plumbers threadlock tape. This may help it grip the bits that have been damaged.
Total boll0cks. :roll:
If a 9.99 crank will do, that is the cheapest fix, but a repair is quite simple and will not be a bodge. It will be as good as new.
The OP has stated in the second post that the pedal threads in fully but then unwinds itself eventually. This is not a crossed thread or you would never get that far. No suggestion the pedal is loose inside the crank arm as in the outer part at broke from the rest. If anything its probably just missing a washer from the end as a nut and bolt only stop when you nip it tight. The fact it winds in fine suggests to me all is ok until this point. The threads could be slightly damaged on the way but not enouth to cause cross threading. You dont have to be an expert in bikes or pedals to understand how a fooking nut and bolt works
I think he (lesfirth) meant to quote the previous posting (AK_jnr) not SmoggySteve's .....FFS! Harden up and grow a pair0 -
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Bushes and taps to repair damaged pedal threads in cranks are available - a decent bike shop with a good mechanic should have them. I've used them in the past to change the RH thread on a couple of drive side cranks to LH threads so I could use the cranks for the synchronising chain on a tandem, as it was a lot cheaper to modify some existing cranks I had rather than purchase a tandem crankset. The modified cranks are still in use and functioning perfectly well almost 25 years later.
Park Tool have a good description on their web site of the repair procedure: http://www.parktool.com/blog/repair-help/pedal-bushing-repair-kit-procedure0
