Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Reply
 
Thread Tools Search this Thread
Old 01-18-14, 12:26 AM   #1
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
Crankset Alivio sq taper or Deore external BB?

I am looking for a new crankset and BB and thinking of going with an Alivio M430 with UN55 or UN54 or IRD bottom bracket that will total about $80; or Deore M590 with the included external bottom bracket for about $100.

Are there major reasons to go one way or the other for a city-commuter? The price difference seems fairly trivial.
jsdavis is offline   Reply With Quote
Old 01-18-14, 12:37 AM   #2
Crescent Cycle
Senior Member
 
Join Date: Jan 2014
Bikes:
Posts: 260
If your BB shell isn't properly faced, a cartridge BB will work fine, but external bearing cups will have issues.

Other than that I think the Shimano external cup cranks are pretty neat and work well. You don't need a crank puller for them either. I've used my thumb to undo the preload cap, a tiny hex to flip up the safety latched, and multi-tool hex to loosen the crank. Not that you need to pull off the cranks often. I just have some bikes I change the configurations and chainrings frequently. I suppose if you get square taper crank creak, being able to tighten your cranks with simple tools helps.

I have not compared with the Alivio, but I know there are some square taper cranks that will get chainrub when I stand on the cranks. I don't get this problem with external cup cranks. I'm not sure if it is because of stiffness or chainring straightness. The chainrings are probably a bit better on the Deore as well, but if the Alivio has steel chainrings, steel will last longer.

For $20, I would get the Deore, even though in practice for a commuter there would be little difference. If you can think of something better to spend the $20 on, by all means get the Alivio.
Crescent Cycle is offline   Reply With Quote
Old 01-18-14, 02:41 AM   #3
CTZunow
Junior Member
 
Join Date: Jan 2014
Location: PNW
Bikes: Takara Challenge 67cm, Lotus Classique 65cm
Posts: 15
+1 on facing BB shell if you go with external. Though honestly I think square taper should be absolutely satisfactory for your purposes. Though I suppose other questions are important, such as gearing preference, chain line and 'q factor'. These can all change your 'ideal' crank options. I'd say that chainring straightness is probably much more likely to be the culprit of chain rub than bb interface. Either way, you aren't risking too much and I think both options will be satisfactory if installed correctly and maintained diligently.
CTZunow is offline   Reply With Quote
Old 01-18-14, 03:10 AM   #4
zukahn1
Senior Member
 
zukahn1's Avatar
 
Join Date: Oct 2011
Location: Fairplay Co
Bikes: Current 79 Nishiki Royal, Jeunet 620, 59 Crown Royal, notable previous bikes P.K. Ripper loop tail, Kawahara Laser Lite, Paramount Track full chrome, Raliegh Internatioanl, Motobecan Super Mirage.
Posts: 5,628
If this is a older bike more than ten years old that has standard square taper crank currently go with buying the sguare tapper and recomended sealed BB for $80.
zukahn1 is offline   Reply With Quote
Old 01-18-14, 03:15 AM   #5
Crescent Cycle
Senior Member
 
Join Date: Jan 2014
Bikes:
Posts: 260
Quote:
Originally Posted by CTZunow View Post
+1 on facing BB shell if you go with external. Though honestly I think square taper should be absolutely satisfactory for your purposes. Though I suppose other questions are important, such as gearing preference, chain line and 'q factor'. These can all change your 'ideal' crank options. I'd say that chainring straightness is probably much more likely to be the culprit of chain rub than bb interface. Either way, you aren't risking too much and I think both options will be satisfactory if installed correctly and maintained diligently.
I did try with some straight CNC rings and still got chain rub. I don't think it was just the interface, but the crank arm design was flexy too. I don't think it was frame flex since external cup cranks don't seem to have the same problems. I can't say how stiff the Alivio is, but I did notice stiffness improvements versus other, apparently worse square taper cranksets. I'm not talking about energy lost speculation or anything, just chain rub. I know some people like to say crank stiffness isn't noticeable.
Crescent Cycle is offline   Reply With Quote
Old 01-18-14, 03:25 AM   #6
CTZunow
Junior Member
 
Join Date: Jan 2014
Location: PNW
Bikes: Takara Challenge 67cm, Lotus Classique 65cm
Posts: 15
It isn't just the chainrings you have to consider, but the spider of the crank. Often times one of the arms can get bent, causing any chainring that is installed to get bent too. I don't think its impossible that the bb interface is at fault, but most the cranks I've pulled off well-ridden bikes over the years have their spiders out of round.
CTZunow is offline   Reply With Quote
Old 01-18-14, 03:35 AM   #7
catonec 
Senior Member
 
catonec's Avatar
 
Join Date: Apr 2009
Location: burlington VT.
Bikes:
Posts: 2,472
if you are changing your bb and crank out of necessity then replace it with something similar to what it had previously, Id assume a square taper cassette bb and lower end shimano crank.

If its "upgraditis " that initiated this change based on bling and street cred then go for the external deore.

being a city commuter the minimal performance/weight benefits are nominal, however the deore may make your bike more appealing to theives if that is a concern.
__________________
2010 Kestrel RT900SL, 800k carbon, chorus/record, speedplay, zonda
1997 Trek ZX6000, 6061w/manitou spyder, xt/xtr, time atac
catonec is offline   Reply With Quote
Old 01-18-14, 03:42 AM   #8
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
Both the Alivio and Deore come in 26/36/48 so no problems there. Also Shimano's site lists the Deore crank as steel for the small and middle rings and aluminum for the big ring. Does both Deore and Alivio have pins and ramps on the chainrings?

I am not familiar with Q factor or chainline.
jsdavis is offline   Reply With Quote
Old 01-18-14, 04:02 AM   #9
CTZunow
Junior Member
 
Join Date: Jan 2014
Location: PNW
Bikes: Takara Challenge 67cm, Lotus Classique 65cm
Posts: 15
Pretty much all new Shimano cranksets will have ramps and pins. 'Q factor' refers to the distant between cranks if they were clocked in the same direction. Think of it as how far your feet are spread apart from each other while standing. Wider Q is usually necessary for bikes with fatter tires or oversized chainstays. Some cyclist suggest that a narrower Q factor makes the bike easier to spin enabling more sustained efforts. But this isn't universal, some bodies work better with wider Q.

Chainline is how straight the chain runs from the rear cluster to the front ring(s). Ideally this is straight as possible, but variable derailer gears of course makes this variable. I wouldn't worry about this too much unless you are going from a double to triple or have exceptionally wide tires.
CTZunow is offline   Reply With Quote
Old 01-18-14, 04:30 AM   #10
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
It's staying as a triple though I honestly don't really need the 48 chainring.

I plan to use 700x35 if they fit, otherwise 700x32. Fairly typical hybrid setup.
jsdavis is offline   Reply With Quote
Old 01-18-14, 06:36 AM   #11
Myosmith
Lover of Old Chrome Moly
 
Myosmith's Avatar
 
Join Date: May 2011
Location: NW Minnesota
Bikes:
Posts: 2,548
I've got Alivio cranks on two of my older steel bikes and they perform well and are very durable. There is a some weight penalty over Deore, but not enough to worry about with a commuter. Just FYI, I think the 48/36/26 Alivio still comes with a polycarbonate chain guard that I find kind of nice on a commuter as it reduces the chance of getting chain marks on your pants leg.
Myosmith is offline   Reply With Quote
Old 01-18-14, 06:51 AM   #12
shelbyfv
Senior Member
 
Join Date: Jun 2007
Bikes:
Posts: 2,535
Deore is nicer than Alivio and the external BB is easier deal with. For $20 it would be an easy choice for me.
shelbyfv is offline   Reply With Quote
Old 01-18-14, 07:33 AM   #13
surreal
Senior Member
 
surreal's Avatar
 
Join Date: Mar 2002
Location: NJ
Bikes:
Posts: 3,084
Quote:
Originally Posted by shelbyfv View Post
Deore is nicer than Alivio and the external BB is easier deal with. For $20 it would be an easy choice for me.
+1
surreal is offline   Reply With Quote
Old 01-18-14, 08:49 AM   #14
clasher 
Senior Member
 
clasher's Avatar
 
Join Date: May 2009
Location: Kitchener, ON
Bikes:
Posts: 1,858
If you leave it locked up outside the deore crank is a lot easier to steal since they come off with allen keys. A small crank puller isn't hard to get or use though but alivio cranks are a lot of less of a target than deore parts. Both cranks have steel chain rings so there isn't much difference between them. I'd save the 20$ and use an alivio.
clasher is offline   Reply With Quote
Old 01-18-14, 09:11 AM   #15
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 28,687
What city and where do you leave the bike when you are at work or at school? If the bike is likely to be stolen or stripped, save the money. If the bike is pretty secure, go for the Deore and it's matching bottom bracket.
HillRider is offline   Reply With Quote
Old 01-18-14, 11:33 PM   #16
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
Went to LBS and and they happened to be clearing out used/take-offs bits and got a Truvativ 26/36/48 square taper crank for $20. Got a used SRAM 11-32 cassette for $10 too.

As for the bottom bracket, Does brand matter? Be it Shimano UN54/55, IRD QD55, etc. Sheldon Brown's site says I should use 113mm axle for Truvativ cranksets. http://sheldonbrown.com/bbsize.html

Last edited by jsdavis; 01-18-14 at 11:52 PM.
jsdavis is offline   Reply With Quote
Old 01-19-14, 01:34 AM   #17
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Madison, Wisconsin
Bikes:
Posts: 7,574
As far as square taper vs external the external is a big win for me engineering wise. Eliminates the press fits and uses a large hollow spindle instead of a small (usually) solid one. Nothing wrong with square taper though, it's worked great for decades.

My two winter commuter bikes have some of Shimano's crappiest old square taper cranks with riveted steel chainrings. There's a weight penalty but the rings will last longer and I have a box of these things... No sense for me to spend $90 per bike on nice Hollowtech cranks when they're going to get trashed in the winter anyway and I already have the parts to use up.

Quote:
Originally Posted by jsdavis View Post
Went to LBS and and they happened to be clearing out used/take-offs bits and got a Truvativ 26/36/48 square taper crank for $20. Got a used SRAM 11-32 cassette for $10 too.

As for the bottom bracket, Does brand matter? Be it Shimano UN54/55, IRD QD55, etc. Sheldon Brown's site says I should use 113mm axle for Truvativ cranksets. http://sheldonbrown.com/bbsize.html
Nice. Brand doesn't matter, just get the correct length. Sounds like you've got that figured out.
FastJake is offline   Reply With Quote
Old 01-19-14, 01:46 AM   #18
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 12,997
Nice scores! With a crankset like that, you may think about using a tighter cassette that tops out with with a 12 or 13T cog.
__________________
Quote:
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
RUSA #7498

Random parts for sale!
ThermionicScott is offline   Reply With Quote
Old 01-19-14, 03:02 AM   #19
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
Quote:
Originally Posted by ThermionicScott View Post
Nice scores! With a crankset like that, you may think about using a tighter cassette that tops out with with a 12 or 13T cog.
That would certainly be nice. I don't often use the 11 or probably even the 12 tooth cogs and I'll probably never use the 48 tooth chainring either. Much of the cassette is riveted together. The three biggest gears are not even complete gears - they are basically rings with teeth bolted to a gear carrier so the three gears share the same set of splines at the hub. Kinda like how the two bigger rings on a crankset are attached, but the gears are riveted instead of bolted. The next four gears are riveted together, but they are complete gears with their own splines at the hub. Only the two smallest are individual gears.

Interesting design - that gear carrier.

Out of curiosity, the crankset weighs in at 788g according to my kitchen scale. Is that considered heavy or light?

Last edited by jsdavis; 01-19-14 at 03:26 AM.
jsdavis is offline   Reply With Quote
Old 01-19-14, 04:08 AM   #20
catonec 
Senior Member
 
catonec's Avatar
 
Join Date: Apr 2009
Location: burlington VT.
Bikes:
Posts: 2,472
http://weightweenies.starbike.com/li...type=cranksets
__________________
2010 Kestrel RT900SL, 800k carbon, chorus/record, speedplay, zonda
1997 Trek ZX6000, 6061w/manitou spyder, xt/xtr, time atac
catonec is offline   Reply With Quote
Old 01-19-14, 04:23 AM   #21
jsdavis
Senior Member
Thread Starter
 
Join Date: Apr 2011
Bikes:
Posts: 1,188
Neato...
jsdavis is offline   Reply With Quote
Old 01-19-14, 12:41 PM   #22
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Madison, Wisconsin
Bikes:
Posts: 7,574
Quote:
Originally Posted by jsdavis View Post
Out of curiosity, the crankset weighs in at 788g according to my kitchen scale. Is that considered heavy or light?
Just a note on this, when comparing weight of a square taper crank to an external bearing crank IMO you need to look at the crank + complete BB for both systems. Since the external crank will have the bottom bracket spindle attached to the right arm and cannot be separated.
FastJake is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 04:54 AM.