Bike pedal's threads damaged
 

Hi everyone,

I bought a new bike in November last year. Last month, the pedal came out. I tried to put it back in. But did it the wrong way and damaged the threads of the pedal and the other bit as well. I'm an idiot.

Took it to this bike repair centre and the guy goes will have to replace the whole "chain set" which will cost me £90 with the parts and the labour. I bought the bike for £90 to start with.

Is t possible to sort it out?

Thanks a lot

The "crank set" is what needs to be replaced. You damaged the threading on the crank arm, so it's no good. Crank sets start around $40 (what is that, £25?) and go up from there. So, plus the labor charge, you see why it's expensive.

You can replace the existing crank with a different one yourself if you:
A) get the correct crank. There are lots and lots of different cranks, so it's tough to match. Get all the specs from the repair centre before you leave.
B) have the tools. You'll need hex wrenches, maybe socket wrenches, a torque wrench, and the proper crank puller tool.

I don't know if they have bike co-ops or collectives in England. If they do, see if the kind folks there can help you do it yourself.

Thanks for taking the time to write the long reply. Much appreciated.

If it's just the pedal eye threads that are damaged on the crank arm, a decent bike shop should be able to put a helicoil in to restore the threads, better than new.

China Vs UK .. If a cheap chainset, the labour and parts to repair the threads of the crankarm
will quickly exceed just replacing the cranks itself.

just buy a new bike then ,. try to not screw up the next one .


At £90 that really undercuts Acidfast7's BSO single speed he says is such a bargain, by half or more..

I damaged a pedal thread on my mountain bike, stopped at the nearest bike shop, guy charged $40, and all has been good so far. He used an insert.

Or if you want to do it yourself heliciol kits are pretty inexpensive. They come with a drill bit, tap, and heliciols. Everything you need but the drill.

Chainset is UKish (Britspeak) for what we here call a crankset. Same item, different name.

Based on the numbers, I suspect the shop quoted what I call a "go away" price. Many shops don't like working on bikes they consider beneath their dignity, or what some here call BSOs (bicycle shaped object). So they quote a price so high that you'll pass.

You should be able to get a better price at a different bike shop, or possibly have someone save the crank with a thread insert coil. This part costs very little, so it's a pure labor job, but should be nearer to a quarter of what you were quoted. (not all shops do this, so ask a few.

Otherwise the best bet might be a local bike co-op if there's one near you (here's a list) These shops specialize on trepair of bikes like yours at low prices which keeps them on the road. They may have a used crank, or likely be able to do a coil on yours at a fair price.

So your next step is to wear out some shoe leather exploring the local options.

Or, you can buy a crank via the internet, and install yourself. It's not that complicated, and there are plenty of tutorials.

A few years ago a properly-installed pedal's threads failed and ruined the threads of the crank arm. Fortunately it was on the non-crank side. I bought a replacement arm for $10; it has worked since.

If your pedal's threads were 1/2-inch maybe you could tap it out to 9/16-inch and use a 9/16-inch-thread pedal.

Take it to another bike shop and see if they cant chase the threads on the crank arm, and if that works. At the very most a good bike shop should be able to put a heli-coil in the crank arm to fix the threads. Then just buy a new set of pedals. Much cheaper than replacing the whole crank set.

Which side of the chainset (crankset) is damaged ? The left side arm, or the right side arm that includes the chainrings ?

I second the opinion of getting a second opinion :D

I'm am preparing to put new pedals on my bike. Should I assume "righty, tighty. lefty, loosey"" probably doesn't apply for crankshafts?

A bicycle doesn't have a crankshaft. A "crankset" or "Chainset" (Brit) have pedals attached to them and usually refers to both crank arms and chainrings. The bottom bracket is the axle assembly inside the frame that contains the ballbearings and cups the the crank arms connect to.

The right hand pedal on the side with the chain is regular right hand thread. Put a dab of grease on the threads first.

The other pedal on the left side is LEFT hand thread. so that one is lefty-tighty and right-loosey.

They should thread in most of the way by hand. If it takes any force at the beginning, something is wrong and you risk damaging the threads and starting another thread like this one.

If you don't care to much about reusing the pedal you could braze the pedal and crank arm together.

Definitely not!!!!

Right pedals have RH threads, and left pedals have left hand threads. Rather than remembering left from right, remember that turning the top toward the front tightens either, and back toward the back of the bike backs them out.

...my currency converter tells me you paid 150 American dollars for this bike.

While it is certainly repairable, were I you and unable to do so myself (and I think this is the case),
I would just write it off as a learning experience and get another bicycle.

Mike,

I'm sure the Bike Kitchen sees lots of comparable bikes with similar problems, and gets these people rolling with a coil at relatively small dollars. Of course, the fix or chuck decision turns on what else may be needed, and the cost of the alternatives.

The OP needs to do an assessment of what he's willing to pay to fix this, and needs to be very cold blooded about it. He needs to be sure that he's covering all the bases so he doesn't end up putting dough into it only to find out he needs to spend more. Then he can shop the job and see if anyone will do it within budget.

I suspect that if there's a co-op, or a local fixit shop he'll be able to get this rolling for a small outlay. If it's otherwise fairly new, it's less than starting fresh. OTOH- if there are other issues, even if it's only worn tires and brake shoes, then he might not be willing to put another penny into it.

..yes, we do that here. I'm just not real clear on the availability of such things in a place where they speak in pounds instead of dollars.

Again, I think that absent free ( or nearly free) labor on this, it's not gonna pencil out. But we're all just guessing here.

The UK has a large network of co-ops or community bike shops or whatever they call them there. The OP has nothing to lose by shopping the job around.

ah, thank you. I seem to remember stripping the crankshaft thread on my new bike in my younger cycling days and never really figured out what I did wrong. What's odd is that the pedal would even go in if you are turning it the wrong way.

postscript to the above conversation between FB and me:

I had a feeling I was forgetting something, because I know that we usually don't do insert repairs of stripped crank
arm pedal threads on the lower end bikes that come from China right now in great abundance.

I worked a pretty busy day at the bike co-op yesterday, and ended up doing a couple of these for people of very
limited means, and in doing the fix, it became obvious that the reason we don't repair the cheap cranks is that there
is an overabundant supply of them (in relatively good shape in terms of wear...they usually have steel chainrings that
are riveted to the crank). The bicycles themselves usually fail in some other way and then get stripped for usable
parts long before the crank arms are a problem. WE have so many that I can sell someone a low end, Chinese crank
set for less than I have to charge for the rethreading inserts, which cost us about 8 bucks each side.

So while it seems nucking futs, what happened yesterday is I went to the drawer and pulled out usable cranks,
swapped them out, and tossed the old ones into recycling.

To the OP: If, in your country, the low end bike situation is similar and the co-op situation is usable by you, this is your best bet.:)

You need to be very careful when drilling out the old threads and tapping for the helicoil that you are perpindicular to the crankarm. Doing it with a hand drill, it would be very easy to get off-axis in an alloy crank arm. You may do better to take it to a local machine shop, or use a piloted reamer, rather than a drill.

+1, the issue isn't how the bike is repaired, but that there are low cost ways to do it. This is why I suggested a co-op in the first place. The mechanic at the co-op, can offer a coil, used crank, or low end new crank, all of which should be reasonable compared to simply scrapping the bike --- IF, the crank is the only serious (read expensive) problem.

I messed up a cheap set of Truvativ cranks. The pedal unthreaded while I was riding and stripped the last few threads as my foot pulled it out. What I did was thread the pedal into the crank from the opposite side. This cleaned up the damaged threads. Might try that first.

Warranty?