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Cervelo's and SRAM eTap

Last post 05-13-2017 6:08 PM by Kookie. 10 replies.
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  • 03-17-2017 1:24 AM

    • maustin
    • Top 500 Contributor
    • Joined on 04-06-2010
    • Hobart, TAS
    • Posts 39

    Cervelo's and SRAM eTap

    OK, thought I'd post this as an FYI for anyone considering putting eTap on their Cervelo. I've had three different set ups to date: 1. 2009 R3 with SRAM Red eTap 50/34 compact cranks 2. 2016 S3 with FSA SL-K 52/36 midcompact cranks 3. 2016 S3 with SRAM Red eTap 50/34 compact cranks. At some point in the next few weeks I'll swap out the SRAM compact for a set of SRAM 52/36 midcompact cranks, but I'm not expecting anything outlined below to change significantly. Basically, eTap works well on all three setups. Its probably best with the SRAM Cranks, but only by a small margin. For some reason, on my FSA cranks I was noticing chainrub on the large chainring when I had the chain on the small chainring and the smallest or second smallest sprocket on my cassette. Yes, this is a fair bit of cross-chaining, but its not an issue with the SRAM cranks and is a small nuisance given you are supposed to be able to get all 22 gears without any sort of chain run. Three things that needed a little bit of extra attention when setting up. This was all to do with the FD. RD set up was straight forward. 1. There's very little clearance between the low limit screw and the inside face of the DS crankarm, so make sure you screw the low limit screw in as far as possible whilst still getting correct FD operation, otherwise you'll get a nasty scribe mark on your shiny new cranks. I learnt this the hard way :-( 2. Similarly, be careful with how far outboard you allow the FD cage to go when in the large chain ring position, as there isn't a huge amount of clearance between the FD cage and inside face of the DS crank arm. Took me awhile to work out what the annoying "click-click" was when I had the bike set up in the stand! Just needed to adjust the high limit screw to fix this. 3. The position of the braze on FD mount on both my bikes was such that I wasn't able to get the FD as low as I ideally needed it so as to get the top of the tallest tooth on the large chainring lining up with the marker on the inside face of the FD cage. Basically, I had the FD as low down on the mount as it would go, and I was still about 0.5mm too high. Turns out this didn't affect shifting at all. eTap is great to use, easy to set up and I've not had to adjust it at all in the 6 months I've been running it on my bikes. It also talks to my Garmin 820, so I can get all sorts of useless stats at the end of a ride - in particular total number of front and rear shifts. Seems I do about 50-100 rear shifts for every front shift! Cheers, Mike
    That's what you get when you suffer - you get results
  • 03-22-2017 10:51 AM In reply to

    Re: Cervelo's and SRAM eTap

    I'm struggling with planning an upgrade for my 2012 R5. It presently has 1st gen SRAM Red with some 2nd gen components. Specifically, I switched to the exo gram chainrings, which although specced as "11 speed" work fine with my 10 speed setup. Also swapped in the xg 1090 11-28 cassette, which is MUCH quieter than the old one. My LBS put in the yaw derailleur, and all these work fine. However, my old knees are really starting to want an even lower gear, as we have some real steep inclines in northern NM, so, I'm contemplating options. 1. What I'd like: SRAM etap wifi with 50/34 and 11/32. However the R5 frame has the front derailleur hanger problem and the FD cannot be lowered quite enough to work properly, at least so says the LBS and also SRAM if you call them. One solution, proposed by a good mechanic at the LBS, is to file the FD mount 2-3 mm to get the FD in the right place. Obviously there is some risk in this, but it may be within bounds of structural strength. 2. The other notion, that just occurred to me today is to switch the chain rings to 52/36, or possibly 52/34. Either of those would still give me a lower climbing gear, and the 52T chainring allows (according to SRAM) a 4 MM higher FD position. I don't know if the 52/34 will work, although it is technically outside the bounds of what etap is specced for. 3. Or, go the cheap route and switch to the 2013 Red aeroglide RD, and put on a PG 1070 11/32. This is much lower cost, of course, and is all within SRAMs official specs. I'm mostly looking for advice on (1) filing the FD mount, and (2) trying a 52/34 chainring setup with etap. Both of these are attempts to work around the FD mount issue and I'm wondering if these will work well.
  • 03-22-2017 6:14 PM In reply to

    • maustin
    • Top 500 Contributor
    • Joined on 04-06-2010
    • Hobart, TAS
    • Posts 39

    Re: Cervelo's and SRAM eTap

    OK, keeping to the two issues you are keen to resolve, these are my comments: 1. Get your LBS to look VERY carefully at what is actually preventing you moving the eTap FD down as low as you need it to go. On my 2016 S3, its not actually the bottom of the FD mount, but the top part that is preventing me moving the FD down as low as it needs to go when I run my 50/34 chainrings. If i could easily post pics I could show you what I mean, but basically there is a recess in the eTap FD that the FD mount on the frame fits snugly into. However, if you try and shift the FD down to the bottom of the FD mount, the top of the FD mount fouls on the top of this recess. I estimate there is another 2mm of movement availble on the FD mount if you grind down the top of the FD mount to prevent this happening. I can't see this would have any significant impact on the mechanical integrity of the FD mount, as there is plenty of material at that point and you don't really need to remove much. 2. I normally run a 52/36 and there are no issues getting the FD into the right position, so I would be confident that this could be made to work for you as far as the large chain ring goes. Can't comment about a 52/34, but from what I've read its too much of a difference to be made to work. I'd say a 52/36 and 11-32 cassette would give you a pretty good set up for hills. I live in a very hilly area (regularly faced with > 10% climbs) and I run a 52/36 with an 11-28. I used to run a 50/34 and 11/28, but save that for when I go to Europe and am doing > 3000m of climbing every day for 2 weeks!
    That's what you get when you suffer - you get results
  • 03-22-2017 8:50 PM In reply to

    • rwm
    • Not Ranked
    • Joined on 05-01-2011
    • Posts 31

    Re: Cervelo's and SRAM eTap

    I put etap wifli on my 2011 RS.  I filed the top of the FD mount to allow placement per the spec, but I'm not sure if this was absolutely necessary.  I'm running new 50/34 X-Glide rings with an 11-32 cassette.

    I get a little chain rub on the little tab at the top front of the FD cage when in the big-big combination. Oddly enough, moving the FD up a little would probably fix this.

  • 03-25-2017 9:54 AM In reply to

    Re: Cervelo's and SRAM eTap

    On a 2016 r5 running a 50-34 shimano crank with etap. Thinking of doing the FD mod. That being said, the front shifting isn't particularly bad. Just my OCD lol. Would it be possible for you share a photo of the FD mount mod? regards,
  • 03-26-2017 11:45 AM In reply to

    • rwm
    • Not Ranked
    • Joined on 05-01-2011
    • Posts 31

    Re: Cervelo's and SRAM eTap

    This is not my post but pics and more info here. http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=140566
  • 03-26-2017 7:27 PM In reply to

    Re: Cervelo's and SRAM eTap

    Many thanks!
  • 03-28-2017 10:22 PM In reply to

    Re: Cervelo's and SRAM eTap

    Just wanted to drop my 2 cents and experience here with a 2015 R5. I have 50/34 and 52/36 ring combos for 110BCD Sram Red etap crankset. I also have xg1190 11-28, xg1190 11-32 and pg1170 11-36 cassettes. My etap groupset is WiFli version. On the R5, 50/34 is garbage honestly. I had no luck setting it up with a good compromise. It's either chain rubbing on front derailleur cage or shooting out from the outer chainring. I've played with the limiters, FD position, setup... everything. There's just not a perfect setup. I've tried it with all of the above cassettes too. While 32 and 36 were much worse, 28 was subpar but ok. 52/34 however has been a different story. Every combo of cassette works perfectly with perfect shifting. Sram says anything larger than 32 cassette won't work but I use 36 with zero problems. Shifts perfect. The reason they say it doesn't work is because if you cross chain on the big big rings, derailleur might get snapped off. But who crosses like that? I've never made that mistake in my life. If you have enough length in your chain so it doesn't snap off, then you have the chain too loose on the small small cross chain. So what I do is set it up somewhere in the middle and never cross big big. Shifting is perfect every time now. 32 and 28 cassettes have absolutely 0 problems.
  • 04-23-2017 4:57 PM In reply to

    • Kookie
    • Top 50 Contributor
    • Joined on 02-04-2012
    • Toronto
    • Posts 402

    Re: Cervelo's and SRAM eTap

    Shoot!

    I wished I read this thread more carefully regarding the click-click with the DS crank arm rubbing the outer FD cage.

    The first day I rode my S5+etap it was perfect. Went to the LBS the following weekend and decided to install a k-edge chain catcher. The following two rides I heard this tick-tick every time I was in the big chain ring. After the 2nd day of riding I put it on the repair stand and FINALLY noticed the crank arm rubbing the FD cage (left a scratch on the crank arm).

    Had to adjust the limit screws after a few chain drops (one chain suck) and one chain thrown outside to the crank arm.

    2013 Cervelo R5 SRAM Red
    2017 Cervelo S5 SRAM eTap
  • 05-13-2017 5:54 PM In reply to

    Re: Cervelo's and SRAM eTap

    I finally took the plunge and put SRAM etap on my 2012 R5. No issues, but... The problem that has been identified is that the SRAM etap FD has an overhang that hits the top of the braze on mount on the R5 frame. This prevents the FD from being installed in the position SRAM recommends. Specifically, if you look at this: https://www.sram.com/sites/default/files/techdocs/gen0000000005175_rev_b_frame_fit_spec_2017_road.pdf On page 12, the spec for the vertical distance from the center of the crank to the FD mounting screw is, for 50/34 chainrings, 141 mm. However, the overhang on the derailleur and the length of the braze on mount means that the lowest you can position the FD is about 145 mm. This also explains why a 52/36 chainring setup works fine, because the crank-to-mounting bolt distance for that is supposed to be....145 mm! I had my first ride today with the FD setup at the 145 mm position, and....it's just fine! In fact, it all worked great, and the setup is everything I was hoping for. (I'm running the medium cage RD with an 11/32) I think the top of the braze on mount could be filed or Dremeled a couple of mm with no issues, and that would get the FD so close to SRAMs specs that I think it would work for everyone.
  • 05-13-2017 6:08 PM In reply to

    • Kookie
    • Top 50 Contributor
    • Joined on 02-04-2012
    • Toronto
    • Posts 402

    Re: Cervelo's and SRAM eTap

    Good to know about the R5 and eTap for mid-compact. I might put eTap on my 2013 R5 next year (has 52/36)

    Edit: I rode my R5 today and it shifted perfectly especially the FD, not one hesitation. Right now it shifts better than my eTap!  

    2013 Cervelo R5 SRAM Red
    2017 Cervelo S5 SRAM eTap
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