Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

upgrade crank

Notices
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.

upgrade crank

Old 07-11-12, 06:37 PM
  #1  
Newbie
Thread Starter
 
Join Date: Dec 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
upgrade crank

I want to put ultegra 6700 series cranks on my 2009 Trek 1.5, is this possible and if it is what would i need to do it. I know it is a little overkill but i like the bike.
dain is offline  
Old 07-11-12, 08:09 PM
  #2  
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 27,274

Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones

Mentioned: 150 Post(s)
Tagged: 1 Thread(s)
Quoted: 6147 Post(s)
Liked 4,092 Times in 2,325 Posts
Originally Posted by dain
I want to put ultegra 6700 series cranks on my 2009 Trek 1.5, is this possible and if it is what would i need to do it. I know it is a little overkill but i like the bike.
You'll need tools to take the old crank off. If it's a conventional BB you'll need a crank extractor, some Allen wrenches to remove the crank and something to remove the BB. If it's a external BB, you'll need the same tools as you do for installation...an Allen wrench and a BB tool. You could even use the same BB.
__________________
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!



cyccommute is offline  
Old 07-11-12, 08:38 PM
  #3  
Newbie
Thread Starter
 
Join Date: Dec 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
if i have the square BB can i change to the external BB or would it matter. By the way i will probably have a real bike mechanic do it even though i am a machinist and have a very good mechanical backround.
dain is offline  
Old 07-11-12, 09:22 PM
  #4  
Banned
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,598

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,354 Times in 861 Posts
strip down the frame entirely, since square taper and external BB have nothing in common,

except they thread into the same frame threads.
then you are looking at 2 sets of tools to buy, one to remove, the other to install,

making the shop service labor rate a wash, unless you want to get the tools anyway..
fietsbob is offline  
Old 07-11-12, 11:21 PM
  #5  
Newbie
Thread Starter
 
Join Date: Dec 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
maybe i will try it, i have the park tool website to help on tork setting, it cant be that bad.
dain is offline  
Old 07-12-12, 02:05 AM
  #6  
Senior Member
 
Drew Eckhardt's Avatar
 
Join Date: Apr 2010
Location: Mountain View, CA USA and Golden, CO USA
Posts: 6,341

Bikes: 97 Litespeed, 50-39-30x13-26 10 cogs, Campagnolo Ultrashift, retroreflective rims on SON28/PowerTap hubs

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 550 Post(s)
Liked 325 Times in 226 Posts
Originally Posted by dain
if i have the square BB can i change to the external BB or would it matter. By the way i will probably have a real bike mechanic do it even though i am a machinist and have a very good mechanical backround.
I wouldn't have a "real" mechanic do it or expect him to get it right even though I'm a professional computer guy who traditionally wouldn't be trusted with a screw driver.

There's _very_ little you need to know.

1. Bottom bracket threads vary, although the vast majority are British / ISO at 1.370 or 1.375" x 24 threads per inch. You need to get the correct part. You also need to note the non-drive side cup thread direction which is left-handled (counter-clock-wise to tighten).

2. External bearing bottom brackets depend on the shell end faces being square. Quality frames seem to come machined that way. If it's shiny metal and not paint it was faced. In the (unlikely?) event you still have paint there you might take it to a shop to get it faced because in a lifetime you're unlikely to save $300 in labor charges to offset the tool cost to do it yourself. Width may be important for bearing life. Use your calipers to measure and validate it's in spec. If you lack a pair ~$20 will get an idiot proof digital set from Harbor Freight.

3. Use anti-seize so you can remove the bottom bracket after it's weathered for the decade you might get out of it.

4. Follow whatever directions come with the bottom bracket and/or crankset regarding wave washers, crush washers, O-ring seals, and whatever else is required.

5. Some click-type torque wrenches don't click when turned anti-clockwise. Tighten the non-drive side crank about like the right side if this is the case for you and you're using a normal bottom bracket.

6. Use a torque wrench to install the crank bolts). Let me re-iterate: Use a torque wrench to install the crank bolt(s). Torque to the high end of the spec. Modern non-square bottom brackets often have the splines bottom against a shoulder and they may not get there at the low end. This is less critical now that we don't have splines on the drive side which carries the ring spider with non-square mounting affecting front derailleur operation although you don't want issues where things get loose and you destroy the left crank arm.

I wouldn't expect a "real" mechanic to get this right. Too many are either ignorant (bad) or just don't care (worse). As a person who can read and follow directions you'll do as well when they're doing their job and much better when they're not.

Last edited by Drew Eckhardt; 07-12-12 at 09:49 AM.
Drew Eckhardt is offline  
Old 07-12-12, 02:22 AM
  #7  
Senior Member
 
Drew Eckhardt's Avatar
 
Join Date: Apr 2010
Location: Mountain View, CA USA and Golden, CO USA
Posts: 6,341

Bikes: 97 Litespeed, 50-39-30x13-26 10 cogs, Campagnolo Ultrashift, retroreflective rims on SON28/PowerTap hubs

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 550 Post(s)
Liked 325 Times in 226 Posts
Originally Posted by fietsbob
strip down the frame entirely, since square taper and external BB have nothing in common,

except they thread into the same frame threads.
then you are looking at 2 sets of tools to buy, one to remove, the other to install,

making the shop service labor rate a wash, unless you want to get the tools anyway..
For the first bike.

Even as a one-universal-bike guy additional bikes with traditional bottom brackets seem un-avoidable. You get a comfort bike for your previously non-cycling wife, you herniate L4-L5 in a horrible sneezing accident and get one to match until you recover well enough to ride a regular bike with some forward lean....

Bike-friendly cities also tend to have bike-cooperatives where you can use their tools.

Sometimes there's a shop where you can rent a stall (the Sports Garage in Boulder used to work like that)

The same workshop (Techshop) I pay monthly membership fees to access all sorts of big goodies (I couldn't buy a CNC router/mill/water jet/laser even if I had space for it) also has bike tools.

Last edited by Drew Eckhardt; 07-12-12 at 09:46 AM.
Drew Eckhardt is offline  
Old 07-12-12, 07:56 PM
  #8  
Newbie
Thread Starter
 
Join Date: Dec 2010
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks to all for the info i will be sure to return to this forum in the future, you guys have been a big help.
dain is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
providencebikes
Bicycle Mechanics
18
01-21-18 08:46 PM
HerrKaLeun
Bicycle Mechanics
18
08-08-17 06:41 PM
IcedEarth27
Mountain Biking
13
05-25-17 09:02 AM
Amesja
Bicycle Mechanics
5
08-19-11 05:11 PM
kmcrawford111
Bicycle Mechanics
1
02-20-10 12:37 PM

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.