b_young

Thanks to all for the reponses. I have been away for a couple of days.

I have a set of Mavics for my Sirrus that I can switch to the Roubaix so I am not concerned if the wheels do not hold up.

I am trying to work out a swap of the gears and it sounds like it may be a good idea. I would like a 53 or 54, 39, and a 27 with the 12-27 cassette. I can get the elite triple for somewhere between $1500-1700. We have a lot of hills in my area that I like to ride. I have been told by some the triple is not needed and others say get it. The only thing I am giving up by getting a triple to me is the weight. Big deal, I am heavy anyway. You don't gain a lot with the stock triple but you do get an extra low end gear or two. That would make a big difference on my Sirrus. But the Sirrus is a lot heavier bike so it may not be needed.
What would be an advantage of not getting a triple?

I am thinking I will keep the Sirrus for a while. It needs a new cassette, chain, and tires. At least now I will go up to 32's instead of the 25's and get a more comfy ride. Someone mentioned that it was a commuter and not a distance bike. I will agree with that but I have ridden to my in-laws 3 times which was 115 miles over hills which is why I am leaning to the triple.

From the comments above it sounds like I am getting the bike I am looking for. My LBS sells Felt bikes as well so I will look at the two listed above.
Thanks
Brian

b_young

I really want to ride this year. I am not sure which ride will be the easiest to get off work for. Which ride are you doing? My son is the one with Type 1. Do you have type 1? We lived in Hazelwood for a couple of years in 99 and 00. We missed it a lot.

Do you keep up with or heard of Team Type 1. They are a pro bike team.

scrapmetal

I have Roubaix full carbon with compact. Size 61 - I am 6'2" and 230, had to replace rear wheel for popped spoke, but other than that I love that bike.

sstorkel

The gearing you want isn't possible with any current derailleur.

Most front derailleurs that are designed to work with two chain rings only allow a difference of 16 teeth between the two rings. Derailleurs designed to work with three chain rings typically allow a difference of 22 teeth between the small and large rings. Rear derailleurs have similar limitations. Shimano will tell you, for example, that an Ultegra RD can handle a smallest sprocket of 11 teeth, 27 teeth as the largest sprocket, and has a "total capacity" of 37 teeth. Total capacity, is the difference between the largest and smallest chain rings added to the difference between the largest and smallest sprockets. So, for a compact double (50/34) used with a 12-27 cassette this number would be 31 (50-34 = 16, 27-12=15, 16+15=31).

With your proposed setup, you'd need an RD with a total capacity of 41 teeth and a FD that could handle a 26- or 27-tooth difference between the large and small rings. Not to mention the fact that you may have a difficult time finding a 27-tooth front chain ring that will work with a road triple's 74mm BCD (bolt circle diameter)...

Within the limitations of current derailleurs, the 50-34 compact double combined with an 11-28 or 12-27 cassette is really a pretty good compromise. As mentioned, if you play around with Sheldon Brown's gear calculator you'll see that there isn't a whole lot of difference between a 53/39/30 road triple and a 50/34 compact double. If you're able to ride up hills with your current triple-crank setup, you'll also be able to ride up them using a compact double.

FYI, the primary advantage of a double crank setup is faster, more precise shifting. The primary advantage of a triple crank is the large number of duplicated gear combinations, not the availability of additional easy-to-pedal gears...

b_young

SSTORKEL,

Thanks for the advice. I guess I should take a comp out for a week and see how it does. My LBS has tried to get me to get a comp and said I shouldn't notice a lot of difference except some hills I normally sit and ride I may have to stand a bit on. A lot of my riding is commuting 10 miles. Outside of that I do 40 -115 miles with hills and want something to help on the steep climbs. I know a lot of it is my weight and leg strength but gearing should help as well. This will be a lot better bike than I currently have and I am sure in itself will make some difference. Plus I won't be able to put my rack and pannier on it so that should help too. Looks like I still have some research to do. Thanks again.

sstorkel

I know this can be a nerve-wracking decision! A new bike is a lot of money and you don't want to end up buying the wrong thing. After years of riding a triple, I went through the same thing when purchasing my latest bike...

Here's what I'd suggest: run Sheldon Brown's gear calculator and plug in the numbers for your current chain rings and cassette. The 2009 Sirrus, for example, has 48/28/28 chain rings and an 8-speed 12-25 cassette. The calculator will tell you that the three easiest gears are 36.0, 32.9, and 30.2 gear inches. Next, plug in the numbers for the bike you're thinking about buying. A 2009 Roubaix Compact has a 54/30 compact double and a 10-speed 12-27 cassette. The calculator says that it's easiest gears are 33.8 and 30.0 gear inches. Guess what? Between these two combos, the Roubaix actually has a gear that's slightly easier to pedal than the Sirrus! And that's before you factor in the lighter weight or any other factors!

When I plugged the numbers in, I found that my 10-speed road triple had one easier gear than a compact double. So I rode my current bike around for a couple of weeks and purposefully made sure not to use that gear. I was able to complete all of my normal rides without using the gear that the compact double would eliminate, so I felt confident in choosing the compact double for my new bike. You could do a similar experiment with your current bike to see how much, if any difference, you'll notice should you decide to switch to a compact double.

That said, there really isn't a huge difference in weight or performance between a compact double and a triple. If you feel more confident choosing the triple, because that's what you're familiar with, then by all means do it. I will suggest, however, that you don't do what I did: start with an 8-speed triple, then buy a 10-speed triple, then do the research and decide that a compact double is the way to go...

billydonn

I've been lurking and the exchange you guys have been having has been interesting. I have a road tripple and recently bought a new road double which I'm changing to a compact, so I've been thinking about this stuff. My advice is +1 on using the compact demo bike and see if you like it. But I would also do the gear calculations sstorkel mentions with the three or four easiest gears, and not just with the last, easiest, gear. As sstorkel mentions... don't forget the possible 11-28 casette. Cost= about $100ish for the SRAM.

b_young

Thanks, it is exactly what I am trying to avoid. I have a 07 sirrus 8 speed. Help me with one other thing. I plug the numbers in the calculator and I get the ratios. I am not seeing how you get the gear inches?? I have a few spreadsheets in excel that I have been playing with on this. I wish I would have found that calculator on SB site.

b_young

Is the 11-28 a 9-speed? I don't see a combination for a 11-28 in the 10 speed at least by the calculator.
Thanks

sstorkel

The calculator hasn't been updated since Sheldon passed away... and probably a while before that. The 11-28 cassette is sold by SRAM (OG-1070). Technically, Shimano says that a 27-tooth sprocket is the largest you should use with their rear derailleurs, which may be another reason that 11-28 isn't on the form.

FYI, you can enter up to 10 sprocket sizes manually in the "custom cassette" area of the form if there isn't a pre-defined cassette that matches what you need.

On the Sheldon Brown gear calculator, the third entry on the input form says "Gear Units". His default is "gain ratiio", which is some crazy number that takes the leverage provided by different length cranks into account. You can also select "gear inches" which is what I normally use or speed at various cadence levels (e.g. "MPH @ 80 rpm" if 80 is your standard cadence).

StanSeven

You're giving up smoothness of shifting. A triple is not as smooth as a double, especially shifting on the front der. Find a bike with a compact setup. It gives you just about the same geaering as a triple when you figure out all the usuable gearing combinations without all the headaches.

sstorkel

Let's be fair: current-day triple-crank setups don't really have any headaches. The Ultegra SL triple I owned was installed in, literally, 5 minutes and after a minor tweak at the 500mi mark didn't require any adjustment over the remaining 5000mi that I owned it. It never missed a shift and only dropped the chain once (due to a stupid simultaneous front/rear shift on my part). If only my top-of-the-line SRAM Red compact double were so easy to get along with...

gapwedge

My 09 Roubaix Expert just arrived at the LBS. I am so looking for forward to getting it on the road. my pedals are due in Monday, but the weather next week here does not look promising. It is a triple Ultegra SL and maybe the double compact would have been a better choice. At my stage and weight I am not too concerned either way. As I progress like I think I will, I will give the compact double a closer look. For now until I get the Roubaix on the road, my Sirrus Expert is doing just fine. Had a nice 20 miler today in mid 60 degree weather. Strange weather to say the least.

billydonn

The 11-28 SRAM ten speed casette works fine with my Ultegra RD. Just be sure not to put in the spacer that is used behind the casette with the Shimano x-12 casettes. Sizing up the entirety of the thread, I'm kind of leaning toward recommending the OP go ahead and get the tripple. My tripple shifts really well and there is less cross-chaining than with the double.