How To Remove Praxis Works Crankset

Jim'due south Tech Talk

By Jim Langley

Recently I discovered that some roadies are struggling to remove cranksets. And that the cranksets that are giving them trouble are really designed to exist hands removed. I know because I piece of work at a company that makes some of these cranks, Praxis. Some other company making cranks like this is SRAM.

Our sets are spec'd by several major makers, such as Specialized. And Specialized besides specs SRAM cranksets.

The defining feature designed to make these cranks easy to remove is something I still call a One-Key-Release, which I believe is a term Shimano coined circa 1980. Only the basic mechanism has been effectually even longer so it could accept been named otherwise at one point. Today, it's also chosen a self-extracting crank – which is a bit confusing since a wrench is required, removal doesn't happen on its own. And then hither, I'll stick with Ane-Key Release or OKR to simplify.

Why Remove Cranks?

Outset, in case you've never removed your crank, a reason to practice it is to bank check the lesser bracket, which is the assembly within the frame that the creepo spins on. With the crank removed you can reach the bearings and other components and feel them to make sure everything'south tight, clean and the bearings still plough smoothly.

With some cranksets – and sure Praxis cranks use this design, another reason to remove the crank is to swap the chainring size or blazon (single to double). That's something riders do more often now with bikes that work bang-up on dissimilar terrain. The gearing for hanging on fast group rides tends to be a lot higher than for gravel grinding, for example.

In the example of removing cranks to change the gearing, that'south something you'd desire to exist able to exercise in a hurry. That style if your ride plans changed suddenly, you'd always be able to take the all-time gearing. And that'southward one of the reasons cranks like this are designed to be easily removed.

How It Works

The manner the OKR mechanism works is that the bolt that is tightened to spike the crankarm (or both of them in older systems) is held captive inside the arm. Typically there's a cap threaded into the arm on peak of the commodities. The cap has a pigsty in it assuasive access to the bolt.

This cap that'south threaded into the crankarm gives the head of the commodities something to push against. Merely only when the bolt is unscrewed (turned counterclockwise). Backing out the bolt similar this makes its head crash-land into the cap and equally you go along turning, the bolt pushes the crankarm off the bottom subclass axle (also called a "spindle").

Cranks Are Press Fit On

Yous might wonder why you can't simply loosen the bolt and pull the arm off with your hand? That's because crankarms are pressed onto the axle/spindle.

This printing fit on the SRAM and Praxis cranks involves a mating spline, male on the spindle and female within the crankarm. When fully tightened, the spline and press fit ensure that even if the bolt loosens the crankarm will remain tight for some time.

"One-Key" As In Just 1 Hex Fundamental

With early One-Central Releases, you used a 6 or 7mm hex wrench for the commodities. Newer ones such every bit these I've been getting questions well-nigh removing, utilize an 8mm. The central thing to know is that only a single tool is required. That'due south part of what makes it so like shooting fish in a barrel.

Nonetheless, in terms of the endeavor to loosen and remove these crankarms, it can have a massive amount of force. They're tightened to over 50 newton meters, which is a lot.

That'south what threw these dwelling mechanics off. They tried using the allen considering they saw that there's a place for it in the crankarm – and also no wrench pigsty in the other arm. But, when they tried to loosen the commodities with the wrench it would not plow, no matter how difficult they tried.

Which naturally acquired them to deduce that removing the arm requires some special disassembly and tool that they needed to get.

Tips for Tight Cranks

Really, the OKR system works easily if 1) you realize it tin can be super hard to loosen the commodities; and 2) if you lot're prepared for battle with the right weapon and/or help! Here are a couple of suggestions:

For Praxis cranks with the organization I made a video showing how to utilise a simple trick to loosen the commodities. Be sure to insert the 8mm allen wrench all the way into the commodities first. I go over this in the video then have a look.

For the SRAM Red DUB crank I recently did battle with, I could not use the simple trick I show in the video. Considering their One-Fundamental Release bolt is on the correct crankarm. This means that the crank turns as you lot endeavour to loosen the bolt.

Information technology makes you lot desire to strap the crankarm to the chainstay, or an onetime play a joke on is to put something solid across and through the chainstays to block the creepo moving. However, with frame walls so thin on fine road bikes, that'southward asking for trouble – and the cycle in my repair stand was a $10K spankin' new Specialized Roubaix. I didn't even want to get out fingerprints on the paint.

Outsmarting the Crank Blueprint

So, first I bankrupt out a cheater bar to be able to gain leverage. I have ane that works well and was only $10. To go with information technology, I likewise accept an 8mm socket that was less than $five. Here's that bar: https://www.harborfreight.com/38-in-drive-17-in-billow-bar-67931.html. And here's the socket: https://amzn.to/2Wytdq0.

Of course, if you want to use a length of pipe, that can work, also. I prefer the positive connection the cheater bar gives you.

With the cheater bar and socket in identify, I stood over the bicycle, held the other-side pedal as tightly every bit possible and put all my weight on the handle of the bar to intermission the bolt loose. Right. Nothing happened. I kept trying, even bouncing on the wrench, and still the bolt would not budge.

I considered removing the left pedal and slipping a pipe over the non-drive crankarm to requite me the leverage to resist the force from the cheater bar. But, I decided confronting that worried it might scratch the brand new crankarm. Also, trying to use enough forcefulness on ane side and resist it on the other myself wasn't working.

Fourth dimension to Get Help

I hate not being able to get a chore done myself, merely I know when I'yard licked. And I likewise know that as far as upper torso strength goes I'chiliad as weak as a kitten. So, my next idea was to recruit Scott who runs our shipping section at Praxis.

With the two of united states, he could push button on the cheater bar while I held the left pedal to prevent the crank from turning nether the force. It took a few tries to figure out how to all-time hold onto the cheater bar and pedal while stabilizing the bike to protect it.

We did finally break the bolt loose. That's what it sounded like, also – a loud scissure. Merely it was simply the bolt freeing up, nothing breaking. And once information technology did, it was cake turning the bolt and extracting the SRAM crankarm.

Be Smarter than Your Tight Crank

I've simply described ii scenarios in this Tech Talk. The OKR crank you're trying to remove could be different. If you run into ane that'due south hard to remove, start by looking for instructions on proper removal.

Unfortunately, information technology's getting more difficult to locate instructions on manufacturer websites. I still endeavour there first since they're the experts, however, if I can't discover annihilation in a few minutes, I give up and search youtube. Information technology'south rare that I don't observe someone showing how to practice what I'm about to try. If you have a play tricks for removing a tight OKR creepo that will help your fellow roadies, please leave a annotate explaining.

Ride total: ix,709

Source: https://www.roadbikerider.com/self-extracting-cranks-tips/

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