stapfam

The RD can only take so many teeth before it runs into problems. What was happening on 26f and 28r was that the upper RD jockey gear was running on the 28t on the cassette. Not enough movement on the RD to handle the number of teeth on the front plus the rear and the total was 43 which greatly exceeds the stated capacity of the RD. By shortening the chain I could pull that 26/28 but could not get anywhere near the 52/28 without locking up the drive chain. That 26 granny just gave too many teeth to change but by going to a 28t granny it was just about acceptable. You can adjust tension on the RD to pull the mechanism away from the cassette and this was all I had to do on the Tiagra set up when I went to the 12/30 from a 12/25.

This is the reason that anyone trying to run the MTB cassettes of 11/32or 34 will normally have to change the RD to a long reach version to be able to cope with the teeth change.

volosong

Slightly off topic, but since we're discussing triples and doubles, and switching between them.

The below is concerning the Ultegra 6700 group.

If I want to switch from a triple to a compact double, I understand that the left shifter has to be replaced, (I have one, send by mistake and vendor didn't want back). Do I also have to change the front derailleur and/or rear derailleur? My guess is that the rear would be okay. I'll just need a longer chain than a typical compact double. But the front derailleur of the double and triple are different. It looks like the biggest difference is the inner cage. It is pretty large on the triple compared to the double. Can I get by with just switching the crank and shifter?

stapfam

Depends on the Brifter. When I got Boreas built up I went for 105 brifters as at that time Ultegra was not available as suitable for a triple. The 105 brifters would do either. I may at some later date have wanted to go for a triple and did not want the expense of buying new brifters.

However when I did change from compact to Triple- I had to buy a new front dérailleur. The double did not have enough throw for a triple. Whether a triple FD would work on a double I do not know.

Camilo

Um, because we're out for a bike ride, not a walk? Because walking up a hill pushing a bike is not as enjoyable as riding slowly?

pexio

+1 At 80 rpm, with a 26 granny and a 28 big cog, my speed is 5.9 mph which is significantly above "walking speed". My knees prefer spinning vs mashing and I like neither to get off and walk nor stop and rest.

rdtompki

We will have lift-off this weekend. The triple crankset arrived in the "post" this am. I have a new FD, chain, RD and cable so come Wednesday evening or so I'll do the change over. I came face-to-face this past weekend with my need for a triple having to grunt up two climbs in what for a youngster would be very low gearing, 34-32. 12-15% grades leave me wanting more and going to 30-32 will make a very nice difference getting my lowest cadence at least into the mid-60's. This weekend will be an excellent test as the club ride I'm doing duplicates the longest climb (~3000') from this past weekend. Will be an excellent comparison.

My mid-30's son cruises up hills like these in a 39-28 which he would call his mountain gearing - the energy of youth. In 3 weeks or so I will have a small window, maybe 2 days to kick his butt as he gets on a bike for the first time after breaking his leg; unfortunately, he's already on a trainer 2-3 weeks after the injury due to the marvels of modern medicine.

BTW, the nice thing about the FSA road triple is that the inner chainring is 74mm BCD so I could easily put on a true granny and use a 12-27 cassette for virtually anything. Long term this might be the way to go.

billydonn

Steve
You should be able to use the triple brifter to shift the double. Limit screw on the fd will keep you from using the extra click on the brifter. You should change the fd. RD can stay the same.

rdtompki

The installation is complete (FSA SL-K light triple, SRAM X.9 RD, Ultegra triple FD) and a longer chain as I left the 11-32 cassette. My LBS accepted a new SRAM 12-28 cassette in trade for an Ultegra 12-30 which I expect will be my everyday gearing.

Took the first ride on Saturday, 60 miles with 4400' of climbing. The 30-32 combination was plenty low enough and I expect 30-30 to be fine as well. Didn't quite have the RD dialed in so the 32t cog was a bit of hit or miss; somehow things always shift differently on the bike versus the stand. FD shifting with my Campy shifters was also very good. I couldn't use the double K-edge chain catcher so order a triple version online.

I could easily see going smaller than 30t up front at some point since that chain ring is strictly bailout, but time will tell.

All this is very individual. I do think the standard 34t is a bit low. 50-36 would appeal if I were 10 years younger and combined with 12-30 would get up most hings.

billydonn

Yep, you need the K-Edge triple chain catcher alright. And shifting Shimano/SRAM derailleurs with Campy brifters? I'd really like to hear more about that... like what exact model of Campy brifters you're using. How is the RD shifting? I asked about that in the Mechanics Forum recently and received many discouraging words. Tell me more, por favor!

rdtompki

I've been using Campy Chorus 10-spd brifters with SRAM 10-spd RD (both X.9 on the tandem and Rival on my single) for a total of about 10K miles. The shifting is near perfect, even though the Campy pull is slightly non-linear. Total total cable pull is almost identical. I know DaveSSS expresses skepticism every time this comes up, but it does work very well. I was put on to this by my LBS; apparently a number of Cyclocross racers use this setup, generally just with one chain ring. I do really like the Campy shifters especially on the tandem where we do a lot of shifting.

I first tried a Jtek and wasn't completely happy with the shifting. Then I inadvertently tried a SRAM X.9 9-spd RD and this definitely doesn't work. The newest 10-spd RD, as I indicated above, are a near perfect match. For my triple conversion I needed to replace my Rival RD with and X.9 to get the desired chain wrap capacity; the Rival would have been max'ed out with the 12-27 cassette and I wanted the option to put on an 11-32 (or larger) RD in case of a particularly nasty ride.