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

Oval 520 crankset help please

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.

Oval 520 crankset help please

Old 04-19-17, 06:30 AM
  #1  
wp1234
Newbie
Thread Starter
 
Join Date: Apr 2017
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Oval 520 crankset help please

My first post on here but not my last.
I was hoping someone could help me with a crank arm problem. My left oval 520 crank arm came right off my bike last night and although I have worked out how to put it back ( with an 8mm +16mm hex) there seems to be something missing as the arm is rubbing on the bottom bracket . Does anybody know if there should be a washer or spacer in the assembly ?
Many thanks in advance.
wp1234 is offline  
Old 04-19-17, 08:52 AM
  #2  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 16,749

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Srewart 650B ATB

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3632 Post(s)
Liked 2,578 Times in 1,617 Posts
First I'm unsure what your "oval" reference means. Is this a name? (And if so then a capital first letter would help indicate this).


Taper square crank arms rely on their fit onto the spindle taper to have 100% of interface contact, the arm's hole's walls/faces must be flat so to contact the steel spindle's flat taper faces. The typical failure is when the arm is allowed to become loose on the spindle (as in a lack of proper retaining bolt tightening) and the steel spindle wallows out the arm's square taper. (I explain this to customers as being like when you stick a snow shovel into the snow bank the shovel is very well held. But when you wiggle the shovel back and forth the snow gets pushed away from the shovel's blade and now the shovel is loose and likely to fall over). I suspect your arm's tapered hole is now quite distorted and the arm will no longer fit snugly and likely, with the also enlarged hole, fit further up the spindle's taper. I suspect this arm will no longer stay put with any amount of retaining bolt tightening and will fall off in short order.


The arm likely needs replacement, a minor cost of $15-$20 at most shops. Don't expect an exact copy will be available as the source that Trek uses to get crank sets is different from the source that the shop does. But the same tapered hole (and it's rotational configuration), arm length and any slight curve/offset (as in straight, low profile or super low profile) the arm has should be available. Hopefully in a color that's close too.


For the future- the retaining bolt needs to be initially tightened to about 30 foot lbs of torque. I strongly suggest that after the first few rides this torque is revisited to insure any bedding in (remember the arm is a "soft" AL and will slightly mold it's self to the harder steel spindle) is compensated for. And check the drive side retaining bolt while you're at it.


BTW if your LBS isn't willing to explain all this when you buy the arm from them you need to vote with your $ at another shop that does value a smart customer. Andy.
Andrew R Stewart is offline  
Old 04-19-17, 08:54 AM
  #3  
Standalone 
The Drive Side is Within
 
Standalone's Avatar
 
Join Date: Dec 2007
Location: New Haven, CT, USA
Posts: 3,398

Bikes: Road, Cargo, Tandem, Etc.

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 120 Post(s)
Liked 40 Times in 27 Posts
By oval do you mean biopace? On an old Trek 520 maybe?
__________________
The bicycle, the bicycle surely, should always be the vehicle of novelists and poets. Christopher Morley
Standalone is offline  
Old 04-19-17, 09:45 AM
  #4  
wp1234
Newbie
Thread Starter
 
Join Date: Apr 2017
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Thanks for the replies so far- by oval I mean the model of crankset - Oval Concept 520 made by ovalconcepts from Germany . The bike is a Fuji Sportif
wp1234 is offline  
Old 04-19-17, 10:30 AM
  #5  
SquidPuppet
Calamari Marionette Ph.D
 
SquidPuppet's Avatar
 
Join Date: Dec 2013
Location: Coeur d' Alene
Posts: 7,862

Bikes: 3 Chinese Gas Pipe Nerdcycles and 2 Chicago Electroforged Boat Anchors

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 2357 Post(s)
Liked 29 Times in 25 Posts
Unusual. I have no answer.

SquidPuppet is offline  
Old 04-19-17, 10:36 AM
  #6  
well biked 
biked well
 
well biked's Avatar
 
Join Date: Jul 2005
Posts: 7,419
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 121 Post(s)
Liked 110 Times in 64 Posts
Oval Concepts was an independent company when first started, but the parent company of Fuji, based in Philadelphia, bought the brand in 2010, and Oval has been the "house brand" of Fuji since then. Some Oval Concepts parts can still be purchased separately also.
well biked is offline  
Old 04-19-17, 03:07 PM
  #7  
Kopsis
Senior Member
 
Kopsis's Avatar
 
Join Date: Apr 2008
Location: St. Pete, Florida
Posts: 1,258
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by wp1234 View Post
My first post on here but not my last.
I was hoping someone could help me with a crank arm problem. My left oval 520 crank arm came right off my bike last night and although I have worked out how to put it back ( with an 8mm +16mm hex) there seems to be something missing as the arm is rubbing on the bottom bracket . Does anybody know if there should be a washer or spacer in the assembly ?
Many thanks in advance.
The Oval 520 (and 720) borrows (licenses?) the SRAM GXP design. There is a bearing shield that fits over the splined end of the spindle between the BB and the left crank arm.
Kopsis is offline  
Old 04-20-17, 05:51 AM
  #8  
wp1234
Newbie
Thread Starter
 
Join Date: Apr 2017
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Kopsis View Post
The Oval 520 (and 720) borrows (licenses?) the SRAM GXP design. There is a bearing shield that fits over the splined end of the spindle between the BB and the left crank arm.

Thanks you for the info - super
I don't suppose anyone has a picture or a plan of what the spline looks like ?
wp1234 is offline  
Old 04-20-17, 06:38 AM
  #9  
Kopsis
Senior Member
 
Kopsis's Avatar
 
Join Date: Apr 2008
Location: St. Pete, Florida
Posts: 1,258
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Here's a photo of the bearing shield:

shield.jpg

I have no idea if SRAM sells replacements for these or if you have to buy a complete GXP BB. Also note that some Oval cranksets come with BBs made by Praxis. They're GXP compatible, but I don't know how closely their design matches SRAM's (in other words, a SRAM bearing shield may or may not fit a Praxis GXP BB).
Kopsis is offline  
Old 04-20-17, 07:32 AM
  #10  
wp1234
Newbie
Thread Starter
 
Join Date: Apr 2017
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Kopsis View Post
Here's a photo of the bearing shield:

Attachment 560089

I have no idea if SRAM sells replacements for these or if you have to buy a complete GXP BB. Also note that some Oval cranksets come with BBs made by Praxis. They're GXP compatible, but I don't know how closely their design matches SRAM's (in other words, a SRAM bearing shield may or may not fit a Praxis GXP BB).


Super and very many thanks
for your help
wp1234 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jonwvara
Classic & Vintage
60
05-17-18 11:34 PM
Insidious C.
Classic & Vintage
8
05-17-18 10:39 PM
carlosponti
Bicycle Mechanics
25
05-10-18 06:10 PM
Shinkers
Bicycle Mechanics
4
02-19-16 11:28 PM
rstarr
Bicycle Mechanics
6
03-15-11 01:25 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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.