Weight Weenies

Will the new front D be backwards compatible?

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No

while I agree that it is likely not going to be backwards compatible, I dont think that is a question anyone can currently answer. I mean they also said the crank was not backwards compatible if I remember correctly (I could be misremembering)....while I am sure the crank will work better with the new derailleurs I am guessing it will work just fine with the old ones as well. We will know more pretty darn shortly as isnt it due out in ~10 days?

If to believe James Huang from Bikeradar, It will be compatible, Sram says in their booklet that it wont be, but they state best conditions, crankset spacing is the same, so the only reason they say it wont match is because of trim, if you wont mind that trim bit, go buy it

There's a bit of a write up here:

http://www.cyclingtips.com.au/2012/03/bikes-of-the-bunch-new-sram-red-on-bmc-team-machine-slr01/

and while your there check out the Baum Pista

Chainring spacing from tooth to tooth is slighty wider. 1.4mm iirc. The much more sculpted ramps on the chainrings makes this possible.

I'm just going by what I read below. I guess you could challenge the technicalities to work out whether it can be made to work.

http://http://www.bikerumor.com/2012/02/01/unveiled-new-2012-sram-red-lighter-quieter-more-aero-better-ergonomics/


Now the bad news: It’s not compatible with the current gen (original) Red levers. Because of the modified pivots and links, SRAM had to change the cable pull. Those looking to upgrade in sections will at least need to get the new levers along with the front derailleur. It’s optimized to work with the new X-Glide chainrings.

Hi Guys,

Just built up my SRAM Red 2013 with FSA K Force Light Ti Chainset, seems to work fine. It didnt realise that the new shifters dont have trim, but the FD seems to accomodate this well. FD cage vell close to crank arm thou, also on my Giant TCR ISP I had to apply pressure to the FD and tighten at the same time to get the FD to align, never had this problem with old RED, also the 1-2mm cap between the cage and chainring (50t)is hard to get, the old RED have two fixing holes to choose from, 2012 only has one.

It will not be compatible. Check p42 in this http://issuu.com/sram/docs/sramred2012_en?mode=mobile

I won't believe any info regarding compatibility until someone actually TRIES it.

sovereign wrote:I won't believe any info regarding compatibility until someone actually TRIES it.

+100

sovereign wrote:I won't believe any info regarding compatibility until someone actually TRIES it.

We just (finally) got the stuff in-house, I'll be trying old shifters/new FD, new shifters/old FD combos today. Already tried new shifters, new FD and old crankset/rings, which works better than old FD/old rings, but not as good as going with the whole New Red system. Probably 80-90% as well. Without trim and with the slightly different ring spacing, you get slight chain rub in 39/11. But who rides around in their 39/11?

Please don't forget to try new crankset with old Red front d and shifters and new crank with new Red front d and old shifters. Trying to get the new cranks to work with my old Red without having to spend a bunch of loot. Thanks.

VNTech wrote:

sovereign wrote:I won't believe any info regarding compatibility until someone actually TRIES it.

We just (finally) got the stuff in-house, I'll be trying old shifters/new FD, new shifters/old FD combos today. Already tried new shifters, new FD and old crankset/rings, which works better than old FD/old rings, but not as good as going with the whole New Red system. Probably 80-90% as well. Without trim and with the slightly different ring spacing, you get slight chain rub in 39/11. But who rides around in their 39/11?

I've been told by a "knowledgeable engineer" that the FD cable pull is the same, it's just that the 2012 eliminated the "trim" spots, so it's very possible to run the 2012 FD with older SRAM shifters.

Also, although the spacing between the teeth on the rings is wider, that's all done in the rings (i.e. the thickness of the ring mounting tabs is the same as previous cranksets) which means that the 2012 rings should be able to be mounted on other cranksets, the only issue being that the "drop pin" won't be inline with the crankarm since the 2012 Red mounting hole pattern is rotated 180 deg. relative to the pin (and the shifting ramps, of course).

Of course, on the "flip side", this also means that you can run the 2012 Red crankset (including the Quarq S975) using older rings and older shifters together. This might be an option for some who may want to "upgrade" to the new Quarq without having to spring for the 2012 Red gruppo. Again, the only real "downside" is that the chain "drop pin" isn't in the right spot...not that huge of a deal IMHO.

So...my take on the whole thing is that if you want to run the 2012 front derailleur, you should run the 2012 Red rings with it as well. Other than that, the choice of crank, year of SRAM shifter, etc., is all up to the user. You'll get the vast majority of the FD performance just keeping the FD and rings together as a "matched set".

For some reason, I have a feeling that sometime in the future we may be seeing versions of the 2012 "yaw" derailleur packaged with rings intended to retrofit onto older cranksets (i.e. the mounting hole locations, and thus the drop pin in the correct spot relative to the crankarm)...but, perhaps that's just wishful thinking on my part

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Unfortunately no. I don't think SRAM realized that the fervor they would create by making it necessary for riders to use SRAM's own crank and BBs so that their new Red front derailleur would shift correctly. Oops!