OMG: front derailleur choices

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OMG: front derailleur choices
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flag captaingrumpy
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Posted: Feb 27, 2016 at 12:16 Quote
Wife's bike had blown out chain and rings. Spider was 80/120 bcd so smallest possible inner ring was 26t. Her perfect rings would be a 24/38 paired with 11/36 in the back.

Found a great deal on new rings and 64/104 bcd spider. The rings are smaller than she wants: 22/36, but the set was really cheap: $20 so I figure we can make it work.

Install spider and rings and bikes shifts ok, problem is that when in 22 in front and above like half way in the back the chain is hanging off the bottom of the front derailleur. Makes noise, wife unhappy, etc.

I look at existing derailleur, it is a shimano xtr where rest of bike is sram x9. It doesn't have any adjustment so can't be made to stop rubbing. Odd... start picking at this thread and find out more than I ever wanted to know about front derailleurs. Used to be in the old days you could slide the front derailleur down, now with suspension in the way there's not really a seat post to speak of and the bolt on derailleurs need to be purchased in a size that matches the chainrings.

Found this posting that goes over the various mounting types:

http://support.canadabicycleparts.com/hc/en-us/articles/201134578-How-to-Buy-a-Bicycle-Front-Derailleur

Most interesting was calling Pivot (who made the bike.) Guy on the phone wasn't sure what part I needed but remembered that when that bike was setup in 2011 there was no sram part that would work and they had to install a "Shimano E2 Mount". He did say that this is also called an "S3" mount, top pull but didn't know if there was one made to fit a 22/36. Nice that they were available to help.

Another useful doc is this sram "frame fit specifications" and lists all the available front derailleurs:

https://www.sram.com/sites/default/files/x0_x9_x7_x5_frame_fit_specs_gen_000000002876_-_rev_b.pdf

Looking at sram product guide I found that there is an X0 S3 top pull for 22/36. Since cool kids don't use front derailleurs they are cheap now: I found a new one for $25.

Hopefully this part will work. Anyone have experience fitting a derailleur for a 22/36 on an aluminum mach 5.7?

Thanks!
flag TheRaven
Posted: Mar 1, 2016 at 8:35 Quote
Does it drag when the suspension is loaded and the bike is in sag? It's pretty normal for a chain to drag on an FD cage while on the stand and shifted to the 11t/12t/13t rear cog, however that will usually go away when the suspension is weighted. I used to tune with the bike upside down on the ground and 50% air in the shock to get some "sag" and and proper tune. I haven't needed to do that in recent years, maybe I just finally got good enough at tuning.
flag captaingrumpy
O+
Posted: Mar 2, 2016 at 13:35 Quote
TheRaven wrote:
Does it drag when the suspension is loaded and the bike is in sag? It's pretty normal for a chain to drag on an FD cage while on the stand and shifted to the 11t/12t/13t rear cog, however that will usually go away when the suspension is weighted. I used to tune with the bike upside down on the ground and 50% air in the shock to get some "sag" and and proper tune. I haven't needed to do that in recent years, maybe I just finally got good enough at tuning.

That's a great point, I totally didn't take sag into account. I'll need to see if it grinds while she's riding it with a small rear gear.

Doesn't really matter now as I've got a proper 36t fd and will put it on soon. I misspoke below, the x0 s3 top pull 36t fd was $18 including shipping, I guess cuz only l00sers use fd these days.
flag captaingrumpy
O+
Posted: Mar 4, 2016 at 21:25 Quote
Even with sag the xtr Derailleur won't clear the chain when in 22x11 (yeah crosschain, etch) pretty noisy off road.

Installed the new unit today. An x0 s3 36t top pull fd works fine on a 2012 pivot 5.7, even in the stupid gear.
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