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

Chainrings/cranksets frustrations

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.

Chainrings/cranksets frustrations

Old 10-17-16, 07:53 AM
  #1  
alathIN
Senior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 496

Bikes: Volagi Viaje (rando/gravel/tour), Cannondale Slice 4 (tri/TT), Motobecane Fantom PLUS X9 (plus tires MTB)

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Chainrings/cranksets frustrations

I've got a Tri/TT bike that came with a Vision 52/38 crankset and 175mm cranks (this one)
It works fine with the SRAM Rival front derailleur and SRAM RTC bar end shifters that came on the bike.

I have another crankset I prefer, SRAM Force 53/39 (this one)
When I install this crankset, I can't get the front derailleur to work properly. It is monumentally difficult to get enough cable tension to make the cage move over far enough to shift from the small to the large chain ring. If I can get enough cable tension to shift up from the small chain ring to the large one, I get interference with the derailleur and chain when running in the small ring.

The only difference I can figure between these two crank sets is the slightly larger outside diameter with the 53/39.

I did go through the usual front derailleur adjustment procedure, including positioning the derailleur - it all works great with the Vision crankset but not the SRAM crankset.

Is there some reason the derailleur would work with one crankset and not the other?
If so is it fixable?
I'd like to use the SRAM crankset if I could; the crank arm length is perfect for me, for one thing.
The Vision crank arms are slightly longer. Usable, fine, OK, but the SRAM ones are in that perfect/sweet spot.

BTW, if you're thinking "just switch the Vision chainrings onto the SRAM crankset," yes I'd love to do that but the one is 110 BCD and the other is 130.

BTW #2 - as I said the Vision crank set is usable, so I am disinclined to any mega-$ solution to this problem. If I could, say, pick up a set of chain rings on eBay for $30 and be able to use the SRAM cranks, I'd do it. But I don't want to spend $350 to get a slightly better fitting crank arm length.
alathIN is offline  
Old 10-17-16, 08:33 AM
  #2  
TimothyH
- Soli Deo Gloria -
 
TimothyH's Avatar
 
Join Date: Aug 2015
Location: Northwest Georgia
Posts: 13,210

Bikes: 2018 Rodriguez Custom Fixed Gear, 2017 Niner RLT 9 RDO, 2015 Bianchi Pista, 2002 Fuji Robaix

Mentioned: 201 Post(s)
Tagged: 0 Thread(s)
Quoted: 5894 Post(s)
Liked 9 Times in 7 Posts
Did you adjust the H limit screw so that the derailleur can move all the way out toward the big ring?

Shift into the small ring, tighten the cable pinch bolt and then pull the cable by hand to rule out the shifters.


-Tim-
TimothyH is offline  
Old 10-17-16, 08:55 AM
  #3  
alathIN
Senior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 496

Bikes: Volagi Viaje (rando/gravel/tour), Cannondale Slice 4 (tri/TT), Motobecane Fantom PLUS X9 (plus tires MTB)

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by TimothyH View Post
Did you adjust the H limit screw so that the derailleur can move all the way out toward the big ring?

Shift into the small ring, tighten the cable pinch bolt and then pull the cable by hand to rule out the shifters.


-Tim-
I did do your first suggestion.

Haven't tried your second; will do when I get home.
alathIN is offline  
Old 10-17-16, 10:49 AM
  #4  
dsbrantjr
Senior Member
 
dsbrantjr's Avatar
 
Join Date: Sep 2010
Location: Roswell, GA
Posts: 6,038

Bikes: '93 Trek 750, '92 Schwinn Crisscross, '93 Mongoose Alta

Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 592 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Did you switch the bottom brackets when you swapped cranksets? The Force may require a shorter BB spindle than the Vision.
dsbrantjr is offline  
Old 10-17-16, 10:55 AM
  #5  
cny-bikeman 
Mechanic/Tourist
 
Join Date: Apr 2007
Location: Syracuse, NY
Posts: 7,508

Bikes: 2008 Novara Randonee - love it. Previous bikes:Motobecane Mirage, 1972 Moto Grand Jubilee (my fave), Jackson Rake 16, 1983 C'dale ST500.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 474 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by dsbrantjr View Post
Did you switch the bottom brackets when you swapped cranksets? The Force may require a shorter BB spindle than the Vision.
+1 If you look you will most likely notice that the chainrings sit further out from the frame with the SRAM crankset.
__________________
There's no such thing as a routine repair.

Don't tell me what "should" be - either it is, it isn't, or do something about it.

If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

Please respect others by taking the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!
cny-bikeman is offline  
Old 10-17-16, 01:27 PM
  #6  
alathIN
Senior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 496

Bikes: Volagi Viaje (rando/gravel/tour), Cannondale Slice 4 (tri/TT), Motobecane Fantom PLUS X9 (plus tires MTB)

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by cny-bikeman View Post
+1 If you look you will most likely notice that the chainrings sit further out from the frame with the SRAM crankset.
OK, it looks like it's time for me to learn something.

Both crank sets are labelled for BB30, and that's what's on my bike. (one of the links I provided was to a non-BB30 variant of the same crank set, now that I go back and look at it).
I used the same spacers and wavy spring washer that came on the original crank.

Is there something I am missing or not understanding here?

You've got me curious now, I may have to put the SRAM crank set back on and see if it sticks out farther from the frame.

If it does, it is apparently out of the range of adjustment for this derailleur. Would that mean I'd need a different FD to make this work? In that case I will probably just stick with the Vision crank set that is working.
alathIN is offline  
Old 10-17-16, 01:42 PM
  #7  
jimc101
Senior Member
 
Join Date: Oct 2007
Location: West Yorkshire, United Kingdom
Posts: 5,406
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 274 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by dsbrantjr View Post
Did you switch the bottom brackets when you swapped cranksets? The Force may require a shorter BB spindle than the Vision.
As long as they are both BB30 cranks, the spindle length is irrelevant, as the SRAM & Vision will have made the cranks/spindle length to the BB30 specification.

For the user the only way they can change it, is by cutting the spindle down/it off, either way, this is destructive, and would turn the crank into scrap.
jimc101 is offline  
Old 10-17-16, 02:36 PM
  #8  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 11,376

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1654 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Are the rings the same WRT the shipt points? The exact lift pins, ramps, tooth profiles? And I'm not meaning are both big rings equipped with these shifting aids but with the exact types.


I suspect that the rings have somewhat different pins, gates, ramps and tooth profiles in general. Sure both companies will use the same terms but you aren't riding a term or ad claim. My suggestion is to get a Shimano large ring that fits the arm you want. Don't worry about the small ring. Andy.
Andrew R Stewart is offline  
Old 10-18-16, 01:31 PM
  #9  
alathIN
Senior Member
Thread Starter
 
Join Date: Jul 2014
Posts: 496

Bikes: Volagi Viaje (rando/gravel/tour), Cannondale Slice 4 (tri/TT), Motobecane Fantom PLUS X9 (plus tires MTB)

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Andrew R Stewart View Post
Are the rings the same WRT the shipt points? The exact lift pins, ramps, tooth profiles? And I'm not meaning are both big rings equipped with these shifting aids but with the exact types.


I suspect that the rings have somewhat different pins, gates, ramps and tooth profiles in general. Sure both companies will use the same terms but you aren't riding a term or ad claim. My suggestion is to get a Shimano large ring that fits the arm you want. Don't worry about the small ring. Andy.
OK, you just went over my head. I don't know any of those terms.

I do know that I tried a 53t FSA chain ring and had the same problem.

If companies tend to make their gears with a "family resemblance," it's odd because Vision is the TT/tri brand for FSA, made by the same company. The Vision 52t works great, the FSA 53t doesn't.

My hunch is that it has something to do with the spacing or diameter - either the SRAM crank set puts the large chain ring out just a smidge further, or the 53t chainrings are just a smidge too big, or some combination of the above - and the FD just can't reach.

I don't know if this is a possible contributor or not, but the derailleur adjustment procedure usually says something like "adjust the position of the FD to be parallel to the chain rings and about 1-3mm clearance on the large chain ring."
I have always worked way closer to the 1mm end of that spectrum.
Would putting the FD too close to the chain ring cause this kind of problem?
alathIN is offline  
Old 10-18-16, 03:26 PM
  #10  
Andrew R Stewart 
Senior Member
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Posts: 11,376

Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1654 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Yes to your last question. The chain has to get raised above the tops of the teeth before it can ride over and settle back down. For whatever reason how the chain's side is contacted by the cage effects this lifting ease of the chain.


My first post spoke to the differing subtle tooth and lift pin designs that different companies use (and evolve over time). Many have found that Shimano does a better job at this then others for the most part. SRAM and FSA less so. Any one company can and do have more then one tooth/gate/ramp and lift pin designs across their lines of offerings. it's very common for companies that make badge label products often save their newest (not always their best...) for their own "branded" products.


So I suggest you first play with the der height. You can also remove the chain and watch the der's movement and see if it can move well over the large ring without the chain as a hindrance. A good assessment technique is to separate the various aspects of a system to see if each is up to it's specific task, or not. Andy.
Andrew R Stewart is offline  

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

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.