General Cycling Discussion - Double vs Triple and Wrench Science

I might be looking to get a new bike and am wondering whether a double or a triple would be appropriate. I ride a triple right now, 32/42/52 I think, havent gone into the small ring once and Ive had it since feb. Not even on the hills around here in N. Va. I go to school out in AZ so dont have to worry about hills period there really. Even if I do encounter hills, wont a 39 ring be easier than the 42 I push up hills? Also, I did the wrench science measurement program. I was just wondering if anyone has found that to be pretty good in terms of measurements or if it is way off? good starting point? Im going to test ride the bike, if I seriously consider it, but I would like a starting point for frame size.
Thanks

The wrench science is a good starting point, but not the end all of getting the correct size for a bike. It uses common formulas to figure out the bike sizing, but this does not work for everyone. Go for a double if you don't use the granny :) Honestly the weight savings is very little when going double, and then you dont' have that granny gear if you ever need it in the future, but does provide a bit smoother shifting. Basicaly a trade off you have to figure out what is more important to you, ability to use it in the future (which you might never need), or smoother shifting and a slight weight savings.

I regularly use my small ring climbing the hills in the east valley (Arizona). I also understand that fountain hills has some pretty brutal hills. Try climbing to the radio towers on south mountain before you decide to drop the little ring! My knees can't take the stress of mashing the big gears up that hill (and last time I climbed it I passed several people with two chainrings who had to stop). Just a thought. I for one prefer the versatility of three.

You can just unbolt the Inner ring and you've got a double without spending any money on a new BB. Reset the stop on your derailleur. You might also be able to buy a 39 or 40 tooth CR to replace your 42. Any LBS can get a replacement ring if they don't have one in stock.


BTW, I like the poem. Yours?

I have been on tours in the rockies that involve climbing passes with miles of pretty steep grades. A lot of the riders gut it out in double chain rings. I suppose they get by in 39X28.

Personally, I much prefer to sit and spin so I find a triple to be very nice in that situation. The amusing thing is that I can be in a really low gear and keep up with the guys in the doubles because my RPMS are much higher.

I don't know if they do that because they like climbing that way or if it is just an affectation.

I think triples have a slight disadvantage over doubles. I think doubles have slightly better shifting. But the difference is not that big.

Originally posted by Pat
Personally, I much prefer to sit and spin so I find a triple to be very nice in that situation.

Yup, that's what keeps me in a triple. My knees say "spin" not "mash"!!!!

If your bike is Shimano equipped you can use a mountain bike cassette and rear derailleur with ANY of their 9-speed road groups--something like 38/48 chainrings and a 12-34 cassette is quieter running and better shifting than a triple for those of us who need the low gears.

I use the configuration that oscaregg mentions. 38/48 front and 11-34 in the rear. It is brand new (3 days) but it has been working great. I will let you know after I try it out on the local big hills.

I do prefer the double for the clean shifting. I have had problems with my triples.
-Duncan

The problem with Wrench Science is that they have such cool ads at various websites, but when you go the the actual wrenchscience website, you are left hanging(hehe)..Very frustrating.

I've got a triple and I hate it. It's a freakin pain in the booty to get the front der adjusted so that there is no rubbing in any gear, and then, because of the extra width, you get more severe cross-chaining. I say go double and get a cassette to compensate.

Also, weight savings. With triple, you have an extra ring, extra lugs on the crank set, and a long cage rear der.

No, the quote isnt mine, its scott martins, whoever that is. I found it on some website. I dont plan on tackling the rockies any time soon and Ive been 'gutting' it out in my triple but staying in my middle ring. Has anyone gone from a triple setup like I have to a double, like 39/52? Im just trying to figure out how much of a difference between a 42 tooth ring and a 39 tooth is.

Changing from a 42 to a 39 tooth chainring is about equivalent to shifting from a 26T to a 28T freewheel cog.

I know this is unusual, but I really like the close-ratio half-step-and-grannie setup I put on my Peugeot: 48-45-34 / 13-15-17-19-21-23. This gives me a 40-inch low gear (close to 39/26) with a short-cage SunTour Cyclone II derailleur. If I were using a modern 9-speed cassette, I would consider something like 46-38 / 12-26 or 48-38 / 13-26.

I regeared my 21-speed mountain bike with 48-40-24 / 13-26 and use the outer and middle rings on-road and the middle and inner rings off-road. Because of the smaller wheel diameter, this also provides a 40-inch bottom gear, excluding the grannie ring.

The big secret to getting both low gears and close ratios is to avoid wasting valuable combinations on gears over 100 gear-inches, which are suitable only for 60mph descents in the TdF. For the average cyclist, the traditional "Alpine" touring gear range of about 40 to 100 inches works very well.

I think I would stick with a 12-25 casseste. I just dont want to get a triple 'just in case' and just end up hauling it around.