Aaarggghhh! Any Rotor crank experts here? Struggling with a Rotor pinch bolt...

[texbike]

I occasionally struggle with a bike part, but man, this one is getting the better of me!

I'm attempting to remove a Rotor crankset (a 3D road crankset with the removable non-drive side arm), but am struggling with the pinch bolt (see the diagram below). I can't get this thing to break loose! I've confirmed that I'm turning the bolt (or a least attempting to) in the right direction, have used Liquid Wrench on both sides of the bolt and still can't get the bolt to let go. I've even managed to bend an allen wrench trying to get a bit more torque on the bolt with a breaker bar (pipe).

Am I missing something? For those familiar with Rotor cranks, is there a trick to these? The bolt is called a DTT (dual thread technology) and according to one of the online Rotor tech videos, it has different thread pitches on the same bolt. Could this be part of the the problem?

Again, I've used Liquid Wrench on the bolt (sat for a couple of hours) and have bent an allen wrench in my attempt to remove it.

Any suggestions outside of heating up the crank arm (which I would prefer not to do)?

Thanks!

Texbike

[nmrt]

Sorry that I cannot be of much help. but three weeks ago on the same crank (rotor 3D), I did exactly what you did and the crank came loose.

My only guess is the the bolt is on too tight.

[kppolich]

I had one of these go bad a while ago except my bolt stripped out and had to send it back to Rotor in Colorado to get it re threaded. My problem was the opposite of yours, I couldn't get it to stay tight. I'm guessing you have already removed the big hex load bearing bolt? Also, is there a plastic piece you can remove between the two sides of the crank arm bolt that can be flipped out? Follow the 2 red arrows
https://farm5.staticflickr.com/4730/38616923694_19b175fed9_b.jpg

[texbike]

Sorry that I cannot be of much help. but three weeks ago on the same crank (rotor 3D), I did exactly what you did and the crank came loose.

My only guess is the the bolt is on too tight.

Oh yeah, it definitely seems to be on too tight. ;)

I had one of these go bad a while ago except my bolt stripped out and had to send it back to Rotor in Colorado to get it re threaded. My problem was the opposite of yours, I couldn't get it to stay tight. I'm guessing you have already removed the big hex load bearing bolt? Also, is there a plastic piece you can remove between the two sides of the crank arm bolt that can be flipped out? Follow the 2 red arrows
https://farm5.staticflickr.com/4730/38616923694_19b175fed9_b.jpg

The pre-load bolt that fits into the end of the axle came out without issue. Not an issue there. I'll check out your 2nd suggestion. I didn't see anything in place, but will confirm.

Thanks for the suggestions.

Texbike

[Kontact]

Take a look that the crankarms are fully 180° out from each other. If not, use a soft mallet to move them back in the right direction.

[loxx0050]

Try a little heat? First go with a hair dryer and if that doesn't work maybe a heat gun (be careful not to go too hot so you don't soften the aluminum too much).

[AngryScientist]

I had one of these go bad a while ago except my bolt stripped out and had to send it back to Rotor in Colorado to get it re threaded. My problem was the opposite of yours, I couldn't get it to stay tight.

just to chime in - i also had this exact problem a while ago. i wound up just using a nutted bolt for years until i found a NOS crank arm on ebay. the system used for this particular model of rotor cranks is not ideal.

[texbike]

Take a look that the crankarms are fully 180° out from each other. If not, use a soft mallet to move them back in the right direction.

Try a little heat? First go with a hair dryer and if that doesn't work maybe a heat gun (be careful not to go too hot so you don't soften the aluminum too much).

Thanks for the suggestions so far. This thing is eating my lunch!

The arms looks like they're in the right position, so I think we're good there.

I had Liquid Wrench on the bolt for over 12 hours, added a bit of heat via a blow dryer as suggested (thank you for that - I would usually use a blow torch on the car projects, but not such a good idea here), and a bit of impact via the allen wrench and a hammer. The bolt STILL won't budge! Wow! Good times...

Any other suggestions before I throw in the towel and take it to a shop? However, I'm not sure what the shop would do that I haven't already done... :(

Thanks!

Texbike

[loxx0050]

I prefer to use dead blow hammers for pesky bolts...but sometimes you gotta bring out the big guns.

You got an impact wrench? Use a hex head socket of the appropriate size. Probably use the smaller one though. But it might be time to think of buying a replacement nds arm on ebay.

[CiclistiCliff]

PB Blaster?

If it’s galled up, it’s not coming out

[FlashUNC]

https://cdn.protoolreviews.com/wp-content/uploads/2014/06/Torch-on-Sawzall.jpg

[texbike]

PB Blaster?

If it’s galled up, it’s not coming out

Hmmm. I forgot about PBB. I have a can of it. I'll give it a shot (pun intended...).

https://cdn.protoolreviews.com/wp-content/uploads/2014/06/Torch-on-Sawzall.jpg

Haha! Sadly, this has already crossed my mind as an option.

Texbike

[Veloo]

Seems overly complicated but I guess they couldn't just copy the Shimano pinch bolt cuz of patents or copyrights(?).

https://www.youtube.com/watch?v=nrEXRcZkn34

[weaponsgrade]

I've got a set of Rotors and just removed the arms not too long ago. I use anti-seize on the bolts and haven't had a problem. I'd give PB Blaster a shot. I've had success with that on past projects. Another thing I'd try is to see if a large crescent wrench can be used to give more leverage - instead of slipping a piece of tubing over the L-portion of the hex wrench. I'm guessing the hex wrench started bending at that 90deg curve. So, stick the hex end into the bolt, fasten the crescent wrench onto the hex wrench and as close to the bolt as you can, and then muscle away. If your hex wrench has a ball end - don't use the ball end part since it's likely to snap off.

[m_sasso]

1.) Get an allen bit like this: https://cdn.mscdirect.com/global/images/ProductImages/0669055-23.jpg

Place it in the socket head bolt, once in the bolt give the bit a few sharp blows with a hammer. Then try loosing again, however forget destroying allen wrenches. I would use something like this, should be available in a 3/8 or 1/2 inch drive:
http://www.gearwrench.com/MagentoShare/media/catalog/product/cache/17/image/1200x1200/9df78eab33525d08d6e5fb8d27136e95/G/W/GW_80421_FRNT_MAIN_27.jpg.

2.) Try a hand held impact driver like this:
https://images-na.ssl-images-amazon.com/images/I/81mphvvw4qL._SX355_.jpg

3.) Still no go, borrow or rent a power impact driver:
https://www.rona.ca/images/11975351_L.jpg

4.) Sawzall, hack saw or cutting wheel in the crank arm gap cutting the bolt with out destroying the arm and replacing the bolt.

[AngryScientist]

just re-read - if you're just using an "L" allen key, go get yourself a well made 3/8 drive ratchet hex in the proper size. you'll be able to apply a lot more torque safely that way.

https://images-eu.ssl-images-amazon.com/images/I/619WEIBtrXL._SL1500_.jpg

[texbike]

Thanks for all of the additional suggestions. I just returned from Mellow Johnny's where they took a look at it. Their diagnosis? "Yep, it's stuck". They muscled away at it a few times and gave up.

I hadn't thought about using the allen headed sockets (been using the L shaped wrenches), but have some hex head sockets as well and will give them a shot. I should be able to get a bit more torque on them with a proper ratchet.

One of our forumites was nice enough to give me a call earlier and suggest a penetrating solution that I'm going to give a shot as well. If neither of these approaches work, I'm going to break out the dremel and just cut the bolt.

Again, thanks for all of the suggestions. If nothing else, I've learned about an effective penetrating fluid from a forumite (thanks Tom!) that you can make at home (https://www.jalopyjournal.com/forum/threads/penetrating-oil-showdown.350800/ ) and about a hand-held impact driver (thanks Marc!).

I'll update you guys on the progress later....

Texbike

[texbike]

OK, an update just for entertainment purposes. Perhaps I've been too committed to removing the crank arm without destroying it or the pinch bolt, but so far, the bolt is winning.

I've tried Liquid Wrench, PB Blaster (fortunately already had these in the garage), a combination of acetone and ATF (also in the garage already), Oil of Wintergreen (at least the garage smells nice now!), and CFC Freeze-Off. No luck with any of them. I've managed to bend two L-shaped allen wrenches, break one flat head screw driver, and break two 3/8 drive hex-head sockets off on this damn thing! Crazy. It's actually become a bit of a joke at this point. However, it's time to cut this thing off. Headed to the store to buy a dremel cutting wheel...

Just thought you guys might get a kick out of this. There's a reason I'm not a professional wrench. ;)

Texbike

[Veloo]

It's time to start capturing all these attempts on video then upload to Youtube, hopefully it goes viral, make a few bucks and get a whole new crankset.

[texbike]

It's time to start capturing all these attempts on video then upload to Youtube, hopefully it goes viral, make a few bucks and get a whole new crankset.

Seriously! If only I had thought of that earlier. :rolleyes:

Oh well, the deed is done. Less than a minutes worth of attention from the cutting wheel and the bolt let go. It sounded like a shot from a .22 as the bolt gave way (that really caught me by surprise!). The crank is now removed and it's time to find a NDS crankarm or just another crankset as it appears that the remnants of the bolt (along with the broken off hex head from the last socket used) are still firmly in place in the arm.

Thanks for all of the suggestions. While frustrating, it was actually kinda fun in a "kick me in the nuts" kinda way...


Cheers,

Texbike

[Kontact]

Seriously! If only I had thought of that earlier. :rolleyes:

Oh well, the deed is done. Less than a minutes worth of attention from the cutting wheel and the bolt let go. It sounded like a shot from a .22 as the bolt gave way (that really caught me by surprise!). The crank is now removed and it's time to find a NDS crankarm or just another crankset as it doesn't appear that the remnants of the bolt (along with the broken off hex head from the last socket used) are still firmly in place in the arm.

Thanks for all of the suggestions. While frustrating, it was actually kinda fun in a "kick me in the nuts" kinda way...


Cheers,

Texbike
See if the knuckleheads that designed it want to warranty the arm.

[weaponsgrade]

Congrats. Have you thought about drilling the bolt out and retapping the threads?

[kppolich]

Email info@rotorbike.com and attach this thread. They'll take care of ya!

[BobC]

this probably will not work, but you tried pretty much everything else .

Leave it outside in the cold overnight (you live in Milwaukee, yes?). Try to torque it while it is still very cold.

[CiclistiCliff]

Heat cycle it. Freezer for a couple hours, then heat gun/propane torch and repeat. Thermal expansion properties of the materials are different, sonit may loosen. Extract bolt and drill/tap for M6?

[texbike]

Leave it outside in the cold overnight (you live in Milwaukee, yes?). Try to torque it while it is still very cold. Austin actually, although it is forecast to feel like Milwaukee over the next few days...

Congrats. Have you thought about drilling the bolt out and retapping the threads?

Heat cycle it. Freezer for a couple hours, then heat gun/propane torch and repeat. Thermal expansion properties of the materials are different, sonit may loosen. Extract bolt and drill/tap for M6?

Both good suggestions. I'll give them a shot if I can get the broken bit of hex head out of the bolt. No success there yet. ;)

Email info@rotorbike.com and attach this thread. They'll take care of ya!

Thanks for the email address. I'll send them a note and see what options they suggest.

Cheers,

Texbike

[OtayBW]

Thanks for the email address. I'll send them a note and see what options they suggest.
Let's hope they don't send you a pic of the Sawzall! :rolleyes:

[weisan]

tex pal, I got a suggestion.

if you bring to Yellow Bike Project our friendly local co-op, they might be able to help you.

Unlike mellow johnny and the other expensive places, they are not dealing with $10k bikes everyday but $50 walmart bikes that were left out in the sun for 2000 years, crankarm that have been contaminated by nuclear radiation, saddles that have mad cow disease ....you get the point.

If they can't do it, no one can.

[CiclistiCliff]

tex pal, I got a suggestion.

if you bring to Yellow Bike Project our friendly local co-op, they might be able to help you.

Unlike mellow johnny and the other expensive places, they are not dealing with $10k bikes everyday but $50 walmart bikes that were left out in the sun for 2000 years, crankarm that have been contaminated by nuclear radiation, saddles that have mad cow disease ....you get the point.

If they can't do it, no one can.


Good mechanics are good mechanics, doesn’t matter where they work.

I’d take it to a machine shop. It’s be out in a matter of minutes

[Kontact]

The crankarm was removed in post #20. The only question now is what's necessary to replace the bolt.

I don't understand why Rotor designed these bizarre bolts. I have seen plenty of problems, but haven't seen what issue they solve. So I would hope Rotor would acknowledge that building a crank with an unserviceable bolt you can't lubricate is their fault, not their customers'.

[Black Dog]

Congrats. Have you thought about drilling the bolt out and retapping the threads?

My thoughts exactly.