trrrrrev

Hi, wondering if someone could advise..

I recently bought 2 new pedals for my pinarello bike. They arrived as both LEFT pairs, I didn't realise this until cycling and the R pedal kept unscrewing itself and falling off.
I then tried to replace my old pedal, but this didn't fit in the crank, so I think the crank has been stripped.

I'm not really sure how to proceed, I would guess my options are the following:

1) Repair crank with current L pedal (So both pedals Left)
2) Repair crank with new pedals (R + L)
3) New crank with new pedals (R + L)

Any advice appreciated!
Travis

cxwrench

Wait...how does this happen? What kind of pedals are they? How could you not notice the left pedal was nearly impossible to get into the right crank arm?

sch

As above, the mind boggles, it would take incredible persistence and determination, to say nothing of the torque needed
after 2-3 turns and a strange blindness to the bits of aluminum falling out of the end of the crank for this to have happened.
Best have a qualified bike mech look this over and verify what happened. Best approach would be having the crank
repaired with an insert and the pedals replaced IMO. Scatological terms not available, it is nearly impossible to thread
a L hand thread into a R hand receptacle without so much force being needed that......

Another ? if pedal is cleated then how did the OP ride, the cleat would have been backward on one pedal...
Absent some pix maybe a troll hunt is in order. BMX pedals on a pinarello?


Another thought: a more likely by far scenario than getting a L male thread into a R female crank is that
the OP simply cross threaded the pedal when it was screwed in. This requires significantly higher torque
than properly screwing in the pedal but still a LOT less torque than driving a L male into a R female which
would be extremely difficult to get started as the threads would never engage.

cb400bill

Pic Assist - https://www.bikeforums.net/g/picture/22978260

cxwrench

One screwed in fine and the other was a massive effort...and you didn't think that was somehow weird?

bikemike73 

I think I would bring it to a bike shop and have them repair it. Depending on how bad it is, shouldn't be too bad.

If you do bring it in to the shop, I would clean the bike first.

Good Luck and keep us posted !!!

squirtdad

option 2 or 3.. options 1 you will have the pedal falling out all the time if it is even feasible

and I do not want to arm wrestle with you

trrrrrev

Hahah thanks for the advice. It took a bit more effort to get the R pedal in, but it still went in... so I didn't question it... until the pedal fell off.

Is rethreading quite a big job then? I think I'll get a fresh set of pedals...

SurferRosa

I'm not sure what I would do, but that would be among my last options.

cxwrench

A 'bit' more effort? C'mon, it doesn't happen like that. You're basically cutting threads with...threads. That doesn't happen easily.

WizardOfBoz

Unless the threads were non-standard, the effort of threading a 9/16x20tpi LH into an RH or vice versa would be huge.

JoeTBM 

Rethreading might not be an option as most pedal shafts are steel and it looks like your cranks are aluminum.

The (right) crank arm may need a heli coil or replacement arm I wouldn't trust just a rethreading.

Kapusta

Something in this story is wrong.

I can’t see how it would even be possible to get the wrong pedal screwed in past the first few turns. Pretty sure my wrenches would break or strip where they grab the pedal before the pedal went half way in.

And even if you did manage - through the use of a breaker bar, pipe wrench and a vice, maybe -to screw it in, it would never come loose without the same breaker bar and vice.

Get a new crank arm and set of pedals.

TiHabanero

I had to helicoil two cranks this summer at the shop for the exact same blunder! Is it something in the food we eat? The air we breathe? The vaccine? LOL no matter what it is, seems to be a thing this year.

squirtdad

you've boggled the threads in the crank. so to fix a shop would need to do a helicoil. essentially this is drilling out the boggled threads, retreading for an insert, install the insert which has the correct pedal threads.

looking at you pictures I would suggest finding a replacement cranks set and ensuring that you have a right and a left pedal

Iride01 

Options 2 or 3 are the best, IMO.

If you repair the crank then take it to someone that knows how to properly insert helicoils. And it needs to be a left threaded helicoil. Some bike shops might not have experience with helicoils nor may they even have a left threaded tap. So if they have to buy the tools, then they'll probably charge you more. So try to find a shop that has done this before and since they'll probably still have the tools it won't cost as much... hopefully. Nor do you really want a noob installing your helicoil.

You might also find a local machine shop or job shop that has experience with helicoils, but they might be more unlikely to have a left threaded tap.

You might find it just as inexpensive to get a new crank if you can find one. Either way you need a left side pedal. Are the people you ordered from going to send you one?

Option 1 you don't want to consider at all unless you always pedal backwards. Normal pedaling will might loosen a right threaded pedal on the left side. I lost the link to a very good motion graphic that explains and shows why.

wheelreason

Happens more than one would think. I've seen them inserted all the way in. Had an English cup in an Italian bb and vise versa too. The power of YT video experts I guess, It's all good, makes me money. We don't do thread inserts, new crank. 27.2 seat posts in a 27.0 seat tubes are fun too.

trrrrrev

Ok, I think I will take the bus.

wrk101

When working on bikes, NEVER force anything and whenever possible, thread parts by hand (no wrench until final tightening), At this point, find a replacement drive side crank arm, ebay, bike co op, or whatever.

If something is giving you resistance, stop. Don't grab a wrench and force it. Steel pedal spindle into an aluminum crank arm, you have seen what wins. Helicoil repairs work, but are often more costly than replacement.

Trakhak

As suggested earlier in the thread but not yet confirmed, trrrrrev almost certainly cross-threaded a (correctly threaded) right pedal when installing it into the right crank.

3alarmer 

...for an alloy crank like the one you show in the photo, the only repair that will work long term is to bore out the pedal mounting holes a little larger with the appropriate ream and tap, so that either a threadsert or a helicoil can be inserted. The stuff to do it is available on the web, but given what has transpired thus far in your adventure, your best bet is to call around and see if anyone does these repairs local to you.

I have done them for myself, and over at the bike co-op for people locally. I don't do them for other people any more.

Anyway, when you talk on the phone, ask if they do helicoil or threadsert repairs to alloy crank pedal holes. Without that, I fear your crank is more aluminum recycling fodder.

Iride01 

Hmm, just realized I got the OP backwards and thought the left pedal was the issue with two right pedals.

None of you chastised me for this! What's becoming of BF? Is this some new tolerance for the mistakes of others or are y'all just use to me rambling incoherently about absurd hallucinations I have? <grn>

3alarmer 

...I missed it because I was listening to "Rage Against the Machine."

ClydeClydeson

I find it hard to believe, as I am sure many others do, that a L threaded pedal was 'accidentally' threaded into a R handed thread crank. Unless I see a picture of two identical pedals both with L threads I don't believe it. Much more likely the R pedal was just not threaded in straight and was not fully threaded in, leading to it pulling out the threads of the crank.

cxwrench

^This^