Crank Arm Thread Gone

choicer

I must have not correctly installed my left-hand pedal and it fell off a few weeks back.

The threads within the crank arm are badly worn. The threads on the pedal are fine.

Has anyone repaired their own crank arm? I've seen videos on a Unior kit but not sure you can get it, or something similar, in Ireland. Or, is it better to ask a bike shop to repair?

Its a Claud Butler Exp 1.0 and Shimano Crank.

Thanks!

MrFireCoalMan

Check out Helicoil kits. They get used for the likes of stripped spark plug thread etc, might be worth a look. Hope this helps.

TheBlaaMan

Depending on whether it is the drive side, or non-drive side, and the version (Sora, Tiagra, Ultegra etc) a replacement arm might be worth looking for .........?

f1000

full new crankset for €19 here

https://www.alltricks.com/F-11932-pedaliers/P-210238-shimano_crankset_tourney_fc_ty501_6_7_8s_black_48_38_28_170mm

Eamonnator

O.P.
Is this similar to your bike?

https://claudbutler.co.uk/product/exp-1-0/

Type 17

If it's a square-taper crank (or even a not-too-expensive Hollowtech one), most decent LBSs will have a few spare used ones (people get a whole new chainset when the rings are worn, so the LH crank is replaced). Cheap new (probably non-Shimano) ones are also available as a part.

Tell them it's a Shimano, so they know to check if the one(s) they have have the square-taper hole 45 degrees from the line of the crank arm, not zero degrees (many other makes).

Call and ask them if they have one (save a visit 'cos of Covid).

choicer

Eamonnator wrote: »

O.P.
Is this similar to your bike?

https://claudbutler.co.uk/product/exp-1-0/

That is the bike.

choicer

TheBlaaMan wrote: »

Depending on whether it is the drive side, or non-drive side, and the version (Sora, Tiagra, Ultegra etc) a replacement arm might be worth looking for .........?

TBH, I've no idea what drive sides are.

magicbastarder

it's non-drive side, as you mentioned it's the left hand side. 'drive side' just means the side all the gearing apparatus is on.

choicer

magicbastarder wrote: »

it's non-drive side, as you mentioned it's the left hand side. 'drive side' just means the side all the gearing apparatus is on.

Ah right, thanks! I assumed that but better to be safe than sorry.

LollipopJimmy

Anybody else open this thread wondering why the mods deleted a thread about crank arms?

MojoMaker

Yep, I did

magicbastarder

i hadn't spotted that.
if i deleted this thread, would we have 'crank arm thread gone thread gone' thread?

Paul Kiernan

Are we any closer to working out what exactly the OP is looking for (BB type, crank model, colour, size, etc.)? I might have one lying around in the garage!

choicer

Paul Kiernan wrote: »

Are we any closer to working out what exactly the OP is looking for (BB type, crank model, colour, size, etc.)? I might have one lying around in the garage!

Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.

grogi

choicer wrote: »

Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.

You can repair it and I really appreciate the non-consumptionism attitude, but it will be much more hassle and probably cost than a simple replacement.

Click

Repair makes sense when you have vintage or high performance cranks, not the simplest square tapers.

cletus

As above, you can repair the threads, and the easiest DIY method would be to use a helicoil kit. However, if you don't have the kit, or drill bits, taps etc, the outlay is probably more than the cost of a crank

*Edit* had the reply window open for a bit before I posted, and grogi got there ahead of me

Paul Kiernan

I presume it's square taper (not hollowtech)? In square taper each pedal bolts on to a central spindle. In hollowtech the spindle and drive side arm are all one piece, which slides through the bottom bracket and the lhs crank then bolts onto that using two small pinch bolts.

Your best bet is probably to just buy a cheap one like the one referenced above for 19 euro. You will probably need a tool to replace it though!

LollipopJimmy

I like the idea of repair but they are usually quite soft and the repair may not last. Replacement will be cheap and quite easy.

Eamonnator

choicer wrote: »

Howdy. Its a left side pedal arm for a Claud Butler Exp 1.0. From looking at the spec its this: Shimano 170mm Alloy Crank, 48-38-28T Chainrings

But I'm also wondering if I can just repair the existing arm rather than replace it. I haven't used the bike as much as I'd like so the arm is in good condition, bar the threads gone.

I don't think, it would be worth the time or money to repair it.
I reckon you should be able to get a replacement in your local bike shop.

Type 17

Totally pointless trying to repair the thread on the old one - at this price point they are almost a consumable (in fact shops sell the whole chainset when the teeth on the (non-removable) rings is worn).

It looks like a Shimano FC-M311, which is linked to in post 4 above. LH cranks for this come in around €20 in your LBS (I've sold perfectly fine used ones for €10).

Make sure you get one the same length - almost certainly 170mm, but match the old one - could also be 172.5 or 175mm but unlikely at this price-point.

Eamonnator

O.P.
I've just had a root in my spares box.
I have an F.S.A. Tempo square taper left side crank arm 170mm.
I have a suspicion, that it will do as replacement for yours.
If you can post a photo of your crank arm or if anyone else can confirm, that it'll work, You can have it F.O.C.

Type 17

Unfortunately, FSA is one of the brands that has the square-taper hole at zero degrees to the line of the crank arms, whereas Shimano is one of the brands with the SqTa hole at 45 degrees, so if you mix them, the crank arms will be at 135 degrees (instead of 180 degrees) to each other. Nice offer, though.

Eamonnator

@Type 17
Mine is different to that one. Mine seems to have the same profile as the Deore one, that you reference. I'll try to post a photo in a little while.
I can't remember where I got this. I think it may have been on a Peugeot 653, that I bought here to renovate.

Eamonnator

This is the one I have.

Type 17

That'll be fine - note how the hole on the left is diamond-shaped, as we view it, rather than square shaped.

Funny, most FSA stuff is square-oriented.

Eamonnator

O.P.
If you want this P.M. your details.
I'm in Drogheda, so I guess, I'll have to post. I'll cover the cost.
You can pass on the favour.

choicer

Eamonnator wrote: »

O.P.
If you want this P.M. your details.
I'm in Drogheda, so I guess, I'll have to post. I'll cover the cost.
You can pass on the favour.

Hi there. My apologies for not responding to this very kind offer before now. Personal life stuff happened and so my focus moved away from bikes for a time. However, I did manage to get it sorted but again, thank you so much for the kind offer.

Eamonnator

choicer wrote: »

Hi there. My apologies for not responding to this very kind offer before now. Personal life stuff happened and so my focus moved away from bikes for a time. However, I did manage to get it sorted but again, thank you so much for the kind offer.

No problem.
Glad you got sorted.

CramCycle

For anyone who comes across this thread, I got a helicoil put in, no problem for 25 euro by my LBS. Considering the outlay and hopefully the few times I would need it, this was quite reasonable and well worth doing if you are in a rush or can't find a like for like replacement