# Why square taper cranks?



## jeff smith (Jan 27, 2010)

This question has probably been addressed so pardon if repeat. Putting together another 29er and either going SS or 1X9. Over the years, noticed that old-style square taper bottom brackets and cranks (i.e., White Industry ENO) are often the choice for SS builds. Question: What is the advantage and why the hype on square taper application with SS drivetrains?


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## Kaizer (Jul 19, 2010)

Spiderless setup maybe?


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## mitzikatzi (Sep 9, 2008)

At a guess. Bottom brackets/spindles come in different lengths allowing you to adjust chain line.


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## alexrex20 (Dec 20, 2005)

i'm still wondering why people use MTB cranks on a SS. BMX cranks make much more sense. they also have optional spindle lengths, and i think they look much cleaner.


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## asphaltdude (Sep 17, 2008)

A qood square taper BB requires no maintenance and lasts for ages.


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## jmctav23 (Oct 16, 2010)

asphaltdude said:


> A qood square taper BB requires no maintenance and lasts for ages.


For example? (This is a serious question, I'm a noob when it comes to bike parts and I will be looking to replace the craptastic cranks on my bike someday with something that requires no maintenance and lasts ages)


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## Orkje (May 3, 2006)

> For example?


Phil Wood. Looks great as well, though that's quite irrelevant, seeing as the part is inside the frame


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## alexrex20 (Dec 20, 2005)

jmctav23 said:


> For example? (This is a serious question, I'm a noob when it comes to bike parts and I will be looking to replace the craptastic cranks on my bike someday with something that requires no maintenance and lasts ages)


there's no such thing as maintenance free. but with that said, as long as you keep your bikes fairly clean and don't like to bury them in sand, then ANY bottom bracket should last the life of the bike.

square taper cranks are more prone to rounding off the square drive if the crank arms loosen up. it's a pretty common issue, much like BMX cranks. it's not high probability, but the possibility is there and it's well documented. there's a reason almost every manufacturer has gone away from square taper cranks...


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## jeff smith (Jan 27, 2010)

O.K., I understand the advantage (I guess) of the spiderless set-up with the ENO and some other crank designs but still not convinced on the advantages of the square taper. Been riding since the early 70's so have had my experience with the square tapers rounding off (either bb spindles or crank arms). Personally, having a hard time understanding the interest in square tapers with this issue, added weight, etc.


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## Nat (Dec 30, 2003)

I don't know if it's an advantage or not. I wanted 180mm cranks and the ones I picked happened to use square taper. My selection process was for cranks first, BB second.


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## TiGeo (Jul 31, 2008)

I run a square taper b/c I have an older Race Face crank that I wanted to use. I have never rounded off a BB - just keep everything tightened properly and the threads greased. They are simple, cheap, and easy to deal with. It seems to be that all this new external stuff is way overkill for a simple bike like a SS.


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## Saddle Up (Jan 30, 2008)

simple, inexpensive, classic good looks


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## p nut (Apr 19, 2007)

I prefer ext BB. Easier to set up (esp. with fine tuning the chain line on SS), remove/install, stiffer/lighter, etc. I've still got a ST XT cranks on my Monocog, but as soon as the chainring wears, I've got an SLX ready to go on. Which reminds me, I need to order HBC ring/cog soon.


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## umarth (Dec 5, 2007)

1. Cheap
2. Works as well as any other set up
3. Easy to find five bolt pattern cranks for it

I don't know if setting up the right chainline is that easy with square taper, but I tend not to use SS specific hubs. Now that is a ****ing easy way to get a good chainline...


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## p nut (Apr 19, 2007)

I think the price is pretty competitive now. My XT was $150, SLX was $100, which included all the rings and BB. LX is ~$80.

Used market, ST wins by a land slide. My ST XT on my Monocog was $8.


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## bad mechanic (Jun 21, 2006)

alexrex20 said:


> i'm still wondering why people use MTB cranks on a SS. BMX cranks make much more sense. they also have optional spindle lengths, and i think they look much cleaner.


...because it *is* a MTB? A SS isn't a big BMX bike, it's a mountain bike which happens to have a single speed. BMX cranks are heavier and a rider simply isn't going to break a Shimano LX crankset.


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## wjphillips (Oct 13, 2008)

My favorite ST BB are the one's with the cup-and-cone style bearings. It will be the last BB you ever buy since they can easily be rebuilt. The downside is that they are heavy (very heavy).

I suspect the reason the world moved away from ST is weight. With external BB you can dramatically reduce the weight of the bike.

The only new bikes I see nowadays with ST are wal-mart schwinns and huffys.


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## umarth (Dec 5, 2007)

p nut said:


> I think the price is pretty competitive now. My XT was $150, SLX was $100, which included all the rings and BB. LX is ~$80.
> 
> Used market, ST wins by a land slide. My ST XT on my Monocog was $8.


Yeah, I should probably say I'm a used parts kind of guy.


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## alexrex20 (Dec 20, 2005)

bad mechanic said:


> ...because it *is* a MTB? A SS isn't a big BMX bike, it's a mountain bike which happens to have a single speed. BMX cranks are heavier and a rider simply isn't going to break a Shimano LX crankset.


my Profile cranks with a Ti spindle weigh 55 grams less than my XTR 970 cranks, and are $200 cheaper. try again.


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## umarth (Dec 5, 2007)

alexrex20 said:


> my Profile cranks with a Ti spindle weigh 55 grams less than my XTR 970 cranks, and are $200 cheaper. try again.


While this has been discussed before, most bmx sets up are heavier, so arguing an exception isn't honest to anyone, including yourself.

Then there is the problem of the Profile wobble that won't be warrantied....

Try again?


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## mitzikatzi (Sep 9, 2008)

jmctav23 said:


> For example? (This is a serious question, I'm a noob when it comes to bike parts and I will be looking to replace the craptastic cranks on my bike someday with something that requires no maintenance and lasts ages)


Shimano UN54 Bottom Bracket Square Taper  about $25 (they make a cheaper version UN 26 which is $8)

These are well sealed and when fitted to your bike last for a very long time in all weather conditions. Some people find that they last much better than the external bottom brackets commonly used today which don't seem to be as well sealed against dirt and water.

Once a square taper crank is fitted provided you check that the "mounting bolts" are still tight there is not much that can go wrong.

Many say that newer external BB cranksets are stiffer but I can't tell the difference bteween my SLX crankset and my old M570 LX crankset.

If I was building an all weather budget commuter I would use square taper cranksets and a UN52 BB.


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## bad mechanic (Jun 21, 2006)

alexrex20 said:


> my Profile cranks with a Ti spindle weigh 55 grams less than my XTR 970 cranks, and are $200 cheaper. try again.


Except your weights don't add up. A M970 with only a 32t chainring will weigh in under 700g. Even with a titanium spindle, Profiles aren't going to be close to that with a 32t sprocket and BB cups.

Of course, then you still might have to deal with this:
http://www.bikeguide.org/forums/showthread.php?t=175319

Leave BMX components where they belong; on a BMX.


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## alexrex20 (Dec 20, 2005)

umarth said:


> While this has been discussed before, most bmx sets up are heavier, so arguing an exception isn't honest to anyone, including yourself.
> 
> Then there is the problem of the Profile wobble that won't be warrantied....


What exception? I compared the run-of-the-mill Profile cranks to the top-of-the-line XTRs (albeit one generation old). For the price of the Profiles, you will be running MTB cranks that weigh 900+ grams.

The Profile wobble is a well documented issue, but I liken it to the square taper wobble: If you install them correctly and make sure they never loosen up, then you will never run into the wobble issue.


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## alexrex20 (Dec 20, 2005)

bad mechanic said:


> Leave BMX components where they belong; on a BMX.


And what if I ride a 26in BMX bike? Some people - many people even - will sacrifice a little weight for a heckuva lot of strength (and price savings).


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## bad mechanic (Jun 21, 2006)

alexrex20 said:


> For the price of the Profiles, you will be running MTB cranks that weigh 900+ grams.


You can buy these for $90:
http://www.jensonusa.com/store/product/CR303A00-Shimano+Lx+Fc-M582+Crankset.aspx
Strip the big and small chainring, and have a 850g bombproof crankset.

Sorry, but I'm not a fan of unneeded weight on my bike.


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## alexrex20 (Dec 20, 2005)

bad mechanic said:


> Sorry, but I'm not a fan of unneeded weight on my bike.


Well you obviously don't ride a street/park bike. It's ok. I can forgive that kind of ignorance.


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## buddhak (Jan 26, 2006)

umarth said:


> 1. Cheap
> 2. Works as well as any other set up
> 3. Easy to find five bolt pattern cranks for it
> 
> I don't know if setting up the right chainline is that easy with square taper, but I tend not to use SS specific hubs. Now that is a ****ing easy way to get a good chainline...


Umarth nailed it.

If you use a Phil Wood BB you can fine tune the chainline, btw. For my set-up (freewheel on threaded hub) this is a must. Reason #3 gets 2-3 underlines and exclamation points from me.


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## bad mechanic (Jun 21, 2006)

alexrex20 said:


> Well you obviously don't ride a street/park bike. It's ok. I can forgive that kind of ignorance.


Cute, but wrong. My play bike is a Planet X Ridgeback which has been sporting an Octalink LX crankset since they first came out, and it's still going strong. It's being upgraded to a used Hone this year.


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## umarth (Dec 5, 2007)

alexrex20 said:


> What exception? I compared the run-of-the-mill Profile cranks to the top-of-the-line XTRs (albeit one generation old). For the price of the Profiles, you will be running MTB cranks that weigh 900+ grams.
> 
> The Profile wobble is a well documented issue, but I liken it to the square taper wobble: If you install them correctly and make sure they never loosen up, then you will never run into the wobble issue.


Yeah, sorry about that. I guess all BMX cranks are heavy and that yours is no exception. I think an LX crank is probably a bit lighter and cheaper than your set up and you can switch it to another bike without incurring a wobble. I kinda doubt it is very similar to the square taper wobble, but....


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## aka brad (Dec 24, 2003)

wjphillips said:


> I suspect the reason the world moved away from ST is weight. With external BB you can dramatically reduce the weight of the bike.


I would love to see your figures on this; or perhaps a dramatic difference in weight to you is about a 100gms, or so I'm told.



alexrex20 said:


> there's a reason almost every manufacturer has gone away from square taper cranks...


The reason seemed to be the need to create something to upgrade from ST using the same shell diameter; that usually doesn't work as well. The Octalink wasn't a bad product but suffered from no one could really tell the difference and cost twice as much; ISIS was a disaster (big axle, little bearings); so bad that one of the sponsors, Chris King never produced anything ISIS. The external BB suffers from poor seals and poor support for the cups which are outside the supporting shell; they been known to develop creaking because of this; Chris King seems to have addressed this with a re-greasing system so you can regularly replace the grease. The problem with ST is it work so well, is non-proprietary and no one was making any money because the bottom brackets are so cheap and last so long. Of course, I admit to being very cynical, and perhaps all these new BB's were truly meant to enhance the riding experience; or not

IMO, the only true upgrade worth buying will be BB30 which will soon be on all new Mountain bikes. Again, you'll have the bearings inside a structural shell. The big problem with BB30 is it's not an upgrade option as it requires a bigger BB shell.


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## alexrex20 (Dec 20, 2005)

umarth said:


> Yeah, sorry about that. I guess all BMX cranks are heavy and that yours is no exception. I think an LX crank is probably a bit lighter and cheaper than your set up and you can switch it to another bike without incurring a wobble. I kinda doubt it is very similar to the square taper wobble, but....


Those LX cranks may be lighter and cheaper, but they're nowhere near as strong, and they have no business being on a street/park/jump bike (that actually gets ridden the way it was meant to be ridden). My setup weighs in at just over 700g. That's not weight weenie territory, but it sure ain't heavy. If I wanted to save 100g, I'd eat 2 less eggs for breakfast.

And for the record, I only have one MTB with BMX cranks; the rest use traditional MTB setups.


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## umarth (Dec 5, 2007)

aka brad said:


> The reason seemed to be the need to create something to upgrade from ST using the same shell diameter; that usually doesn't work as well. The Octalink wasn't a bad product but suffered from no one could really tell the difference and cost twice as much; ISIS was a disaster (big axle, little bearings; so bad that one of the sponsors, Chris King never produced anything ISIS. The external BB suffers from poor seals and poor support for the cups which are outside the supporting shell; they been known to develop creaking because of this; Chris King seems to have addressed this with a re-greasing system so you can regularly replace the grease. The problem with ST is it work so well, is non-proprietary and no one was making any money because the bottom brackets are so cheap and last so long. Of course, I admit to being very cynical, and perhaps all these new BB's were truly meant to enhance the riding experience; or not
> 
> IMO, the only true upgrade work buying will be BB30 which will soon be on all new Mountain bikes. Again, you'll have the bearings inside a structural shell. The big problem with BB30 is it's not an upgrade option and requires a bigger BB shell.


I'm personally on the same page, but I am a little retrogrouchy and you certainly are, so let us just say we are being conspiracy theorists.


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## alexrex20 (Dec 20, 2005)

aka brad said:


> The problem with ST is it work so well, is non-proprietary and no one was making any money because the bottom brackets are so cheap and last so long.


I agree. I have White ENO cranks on one of my bikes with a Shimano UN53 BB. For $30 you can't beat that BB, especially considering it was the only (affordable) quality BB I could find at 120mm+ spindle length. The setup has turned out to be super reliable and is virtually maintenance free. I've never run into wobble issues with ST cranks or with BMX cranks.


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## Tone No Balone (Dec 11, 2004)

I'm about ready to replace my UN54 BB on my WI eno cranks.
Square Taper spins freely and lasts a very long time under heavy usage. 
The best $22 bucks spent in a long time!


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## milehi (Nov 2, 1997)

Grease or no grease on the tapers?


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## asphaltdude (Sep 17, 2008)

No grease here.


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## Sparticus (Dec 28, 1999)

Vader said:


> Grease or no grease on the tapers?


Follow manufacturer's instructions.

Personally I've never greased a square taper in 40 years of riding them.

--sParty


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## mitzikatzi (Sep 9, 2008)

No grease but remember to remove and reinstal your crankset at least once every year if not twice a year. 

Different metals "join" together over time.

Others say a very light coating of grease on the cranks. Shimano says no grease.


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## Sparticus (Dec 28, 1999)

alexrex20 said:


> i'm still wondering why people use MTB cranks on a SS. BMX cranks make much more sense. they also have optional spindle lengths, and i think they look much cleaner.


Still wondering?

--sParty


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## Sparticus (Dec 28, 1999)

alexrex20 said:


> I agree. I have White ENO cranks on one of my bikes with a Shimano UN53 BB. For $30 you can't beat that BB, especially considering it was the only (affordable) quality BB I could find at 120mm+ spindle length. The setup has turned out to be super reliable and is virtually maintenance free. I've never run into wobble issues with ST cranks or with BMX cranks.


 But... but... but you said...


alexrex20 said:


> i'm still wondering why people use MTB cranks on a SS. BMX cranks make much more sense. they also have optional spindle lengths, and i think they look much cleaner.


 ...so you have square taper cranks on your mountain bike but you don't know why anyone would use square taper cranks on their mountain bike?

Confused... unless trolling was involved.

--sParty


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## TiGeo (Jul 31, 2008)

I haven't ever greased the crank arms; I clean them and dry them before installing, thats it. Never had a problem. Note that I don't ride in the mud/wet condtions. The issue I see with greasing is that it may allow the crank to be forced too-far onto the spindle which will stretch the crank and start the wallowing process.


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## umarth (Dec 5, 2007)

alexrex20 said:


> Those LX cranks may be lighter and cheaper, but they're nowhere near as strong, and they have no business being on a street/park/jump bike (that actually gets ridden the way it was meant to be ridden). My setup weighs in at just over 700g. That's not weight weenie territory, but it sure ain't heavy. If I wanted to save 100g, I'd eat 2 less eggs for breakfast.
> 
> And for the record, I only have one MTB with BMX cranks; the rest use traditional MTB setups.


Sure, but let's not pretend for a moment that you thought this discussion was hinging on all the street/park/jump bikes we are riding. Not that the LX crank will break. Nor will they get the wobble your indestructible bmx crank will get if you take off the crank to spray a rust preventative into the frame once a year. Or service the bb. Or need a new chainring. Or...

Let's also be square that most bb and cranks intended for mtbs are as light (lighter, likely) than bmx cranks and less expensive in many cases.

By all means, people should have bmx cranks if they so desire.



sParty said:


> Confused... unless trolling was involved.


No, no. alexrex20 just swings by from time to time to disagree in confrontational ways. I'm sure this will happen less in the future since he was both incorrect with his assertions and not really following his own advice.


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## boomn (Jul 6, 2007)

umarth said:


> Sure, but let's not pretend for a moment that you thought this discussion was hinging on all the street/park/jump bikes we are riding.


Confused the heck out of me too. I thought we were talking about "why people use MTB cranks on a SS" *MTB*, and then suddenly he pulls in park bikes to justify his side of the argument


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## alexrex20 (Dec 20, 2005)

Sparticus said:


> Confused... unless trolling was involved.
> 
> --sParty


It seems you're the only smart one in here, sparty.


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## alexrex20 (Dec 20, 2005)

umarth said:


> No, no. alexrex20 just swings by from time to time to disagree in confrontational ways. I'm sure this will happen less in the future since he was both incorrect with his assertions and not really following his own advice.


Actually, my assertions defended both sides so really I'm correct on both accounts.


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## aka brad (Dec 24, 2003)

mitzikatzi said:


> No grease but remember to remove and reinstal your crankset at least once every year if not twice a year.
> 
> Different metals "join" together over time.


I have never heard this and all my experience shows this has does not happened with the exception of titanium galling; seatposts get stuck all the time but are the result of rusting steel and corroding aluminum from surfaces that are not mated under pressure, allowing the perfect conditions for corrosion. As far as ST cranks I have removed cranks that have been on for 20 years with no apparent "joining." I have heard of folks stripping out crank pullers (yes time can make removal quite a bit harder, but it has not been cold welded together), but this is almost always the result of not properly seating all the possible threads. By constantly R&R ST cranks you risk degrading the plastic deformation that holds them together. I say if it's working best not to fix it.:thumbsup:


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## CHUM (Aug 30, 2004)

for the grease vs. no grease crowd:

for PW ST BB's:
Is it recommended that grease be applied to the axle taper of my Phil Wood bottom bracket before installing cranks?
*We recommend that a light film of grease be applied to the taper. This is only a recommendation for Phil Wood bottom brackets, as our taper was designed with grease in mind. *

just so ya know 

side note: i posted a while back that i over torqued my enos....that wasn't the case....my cranks are fine...it had to do with narrow chainline, BB shell width and my specific frame...

blah


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## umarth (Dec 5, 2007)

I grease mine very lightly and it hasn't been an issue.


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## Sparticus (Dec 28, 1999)

alexrex20 said:


> It seems you're the only smart one in here, sparty.


 Not really. Somebody else PM'd me to say that they were going to post the same thing until they saw my post.

So there are at least two of us. The other person shall remain nameless, but in any case it feels good to finally get a little recognition.  Thanks so much. Maybe I should consider changing my handle to sMarty.

--sParty


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## Sparticus (Dec 28, 1999)

umarth said:


> I grease mine very lightly and it hasn't been an issue.


You use Vaseline, don't you?

--sParty


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## boomn (Jul 6, 2007)

alexrex20 said:


> It seems you're the only smart one in here, sparty.


in that case all instigating and arguing is suddenly so funny!

No hard feelings, I've just never understood the appeal of trolling


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## boomn (Jul 6, 2007)

p nut said:


> It was me.
> 
> I am Smarticus.


No, I am Smarticus!


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## p nut (Apr 19, 2007)

Sparticus said:


> The other person shall remain nameless...


It was me.

I am Smarticus.


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## umarth (Dec 5, 2007)

Sparticus said:


> You use Vaseline, don't you?
> 
> --sParty


Guess we're not talking about the same 118mm spindle here, are we?


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## [email protected] (Oct 17, 2009)

aka brad said:


> I have never heard this and all my experience shows this has never happened with the exception of titanium galling; seatposts get stuck all the time but are the result of rusting steel and corroding aluminum from surfaces that are not mated under pressure, allowing the perfect conditions for corrosion. As far as ST cranks I have removed cranks that have been on for 20 years with no apparent "joining." I have heard of folks stripping out crank pullers (yes time can make removal quite a bit harder, but it has not been cold welded together), but this is almost always the result of not properly seating all the possible threads. By constantly R&R ST cranks you risk degrading the plastic deformation that holds them together. I say if it's working best not to fix it.:thumbsup:


http://en.wikipedia.org/wiki/Galvanic_corrosion

I had an old road bike I used as an indoor trainer. Sweat acted as a electrolyte and I basically welded the steel and aluminum components of the stem and fork together.


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## skankingbiker (Jan 15, 2010)

1. I know how to work with ST
2. They are cheap
3. They are reliable
4. They allow me to adjust for chainline
5. I am not a world-class racer and have no need to spend my money on the latest, greatest titanium, carbon fiber coated negative-weight bike part.

In short....if it aint broke..don't fix it. Same reason I still run tubes, a chain, and cable-pull brakes.


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## Sparticus (Dec 28, 1999)

umarth said:


> Guess we're not talking about the same 118mm spindle here, are we?


It may not be long but it's as big around as a tuna can.

--sParty


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## aka brad (Dec 24, 2003)

[email protected] said:


> http://en.wikipedia.org/wiki/Galvanic_corrosion
> 
> I had an old road bike I used as an indoor trainer. Sweat acted as a electrolyte and I basically welded the steel and aluminum components of the stem and fork together.





> Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact and immersed in an electrolyte. The same galvanic reaction is exploited in primary batteries to generate a voltage


Galvanic corrosion enhances or speeds up corrosion, it does not weld dissimilar metals together; again, they only place I have seen this occur is a seatpost; but one has to wonder how much you sweat seeing the definition says "immersed" :eekster: . The most common way to separate that type of bonding corrosion is the use of ammonia or cola.

I would suspect that the reason Galvanic corrosion is not an issue with a square taper connection, is the connection is so positive that there is no way an electrolyte solution can make it's way onto the mating services or that oxygen is even present; and I'm pretty sure you need oxygen for corrosion to form.


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## jeff smith (Jan 27, 2010)

Well, this topic seems to be of interest and has become pretty diverse in covering many related topics regarding crankarms and bottom bracket interface. Some great info from many, particularly input from obvious wrench experience and knowledge from aka brad, mitzikatzi, and others not mentioned. The little spats were entertaining also. Conclusions I have come to from this input and similar years of riding and maintenance steers me to think that square tapers live strong - maybe more so to industry's poor attempt at something better or perhaps due to haste at being caught up in making things more profitable and cost productive (sorry, ISIS, ext. BB, and Octalink have not been totally overwhelming). However, with provision that they are checked and maintained regularly, square tapers can and do work well and offer many options in mtb ss cranks and what is available and applicable to the ss mtb biker in square taper market (i.e., spiderless cranks, five-arm spiders/rings, 180mm arms, etc). Yeah, you sacrafice some weight perhaps but that's not really an issue with my riding and in this build application. Grease on metal to metal contacts has been standard for decades, but don't think that you can sweat like a pig and drip into a dry seat tube and seatpost or run a bottom bracket/crankset thru the swamp for five years and not have it bond or fail. Similar checking of crankarm bolts and all nuts and bolts frequently and with proper tourque will save save bb and cranks from early wear and tear and prevent destroying soft metals with over-wrenching. Adjustablility/alignment seems to be something that can be accomplished with all via spacers, bolt lenght or cup adjustment. But with all said and to quote Nat, "My selection process was for cranks first, BB second." So, being really drawn to this crank at this point realizing that you get what you pay for, I am strongly leaning toward saving the bucks a bit longer and going with an ENO single speed and the best square taper I can afford. And then, just using some good common maintenance sense in keeping it spinning.


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## mitzikatzi (Sep 9, 2008)

jeff smith said:


> ...wrote stuff....


 :thumbsup:


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## milehi (Nov 2, 1997)

[email protected] said:


> http://en.wikipedia.org/wiki/Galvanic_corrosion
> 
> I had an old road bike I used as an indoor trainer. Sweat acted as a electrolyte and I basically welded the steel and aluminum components of the stem and fork together.


I have to admit, the grease or no grease question was an inside joke on this site from the 90's.  I never grease the tapers if using aluminum cranks. I had a set of steel IRD Vortex cranks that would get a very light coating of grease.


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