I am buying my first roadbike but cannot decide on a triple or double chainring. Any comments
Triple or double chainring
Tue, 07/06/2004 - 7:20pm
Tue, 07/06/2004 - 7:27pm
#1
First road bike
If you plan to race, double. Otherwise, triple.
Wed, 07/07/2004 - 10:28am
#2
depends on the race...
...you'll have a hard time at the mount washington hill climb race without that triple. ;)
Tue, 07/06/2004 - 10:43pm
#3
Probably triple . . .
Get a triple unless you know (that's KNOW) you don't need it. It's a lot easier (and cheaper) to convert a triple to a double than vice versa.
Yes, a triple is heavier. Typically (I'm told) about 90-110 grams heavier. For reference, that's the weight of two gulps of water (1/2 a cup).
Wed, 07/07/2004 - 6:51am
#4
Get a triple.
Going from a triple to a double means removing a chainring and getting a new bottom bracket while going the opposite direction means a new crank, new bottom bracket, new rear derailleur, and (possibly) front derailleur.
Also, consider _all_ the places you are likely to ride. Around here, I ride a 48-36-24 triple with a 12-23 cassette, and I haven't used the 24 yet this year. However, on Friday, I'm going to do a tour of the Dolomites. Having a triple there will be essential.
- Christian
Wed, 07/07/2004 - 7:47am
#5
I'm impressed . . .
"
""However, on Friday, I'm going to do a tour of the Dolomites"".
Wow. What's on for Saturday?
[Have a great trip!!]
"
Wed, 07/07/2004 - 10:23am
#6
> Wow. What's on for Saturday?
The first ever schnitzel ride. It goes to Valter's Schnitzels in St. Mamaronego.
See you when we're back!
- Christian
Wed, 07/07/2004 - 9:15am
#7
Get a micro-double
110mm BCD crank with 33/48 chainrings and a 12-30 cassette - most of the range of a triple without the complexity. Disadvantages - you give up closely spaced gears and that huge top gear that you push when you're going 35mph.
Wed, 07/07/2004 - 10:21am
#8
If you're going to go weirdo-gearing-freak like Evan and me, I would suggest the following:
Sugino PX double crank with 42-28 rings and a 9sp 12-27 cassette. The PX uses TA Pro 5 Vis chainrings (80mm bcd) but clears modern front derailleurs, is cold-forged, and has exceptionally narrow tread (or Q-factor, if you prefer). This combination will basically allow you to ride almost everything in the 42 ring, allowing you almost to dispense with front shifting altogether. And I think the gearing is nicer than on a 48-33, as a 48-33 spends a lot of time in crossover gears.
I only recommend this if you're really gearing-obsessed, however. But I may try it on my bike when I'm back from my trip.
- Christian
Wed, 07/07/2004 - 5:02pm
#9
What brand and length bottom bracket do you use with your Sugino PX - when you use it as a double?
Thanks,
Tony
Wed, 07/07/2004 - 8:22pm
#10
Re: PX
Shimano UN-72 113mm bottom bracket. Q-factor (tread) is about 155mm. You might also be able to use a 110mm bb, at least if you offset 2-3mm to the right.
Do you like the 34? My only complaint on my 48-36 Zephyr is that the 36 is a little too small, and I end up spending a lot of time (19mph) on 36-12 or 48-16 or 48-15. It doesn't help that 36-12 and 48-16 are duplicates. If I do swap my Rambouillet to the 42-28 PX then I will get a racier bike with 48-38 and 12-25, I think.
BTW, Tony, I might start a support group for gearing nuts. Given that you're conversant in Sheldon Brown custom cassettes and want technical details on a Sugino PX setup, I'd say you're guaranteed a founding member spot.
- Christian
Wed, 07/07/2004 - 5:00pm
#13
"I agree - I use a 34/48 TA Zephyr and 9-speed cassette, either a 13-30 (Sheldon Brown ""Century Special"") or stock 13-25."
Wed, 07/07/2004 - 8:36pm
#14
Hmmmm
"Good ideas, and these cogs do work better than most ""compact"" doubles. Still, would you really recommend this for a ""first road bike""? It sure isn't standard spec, so the OP will have some negotiating to do on the terms of the swap out for non-standard cassette, cranks and rings (and can you get a 33 on a 110 bcd crank? I thought the minimum was 34). As Christian points out, that can be fun if you already are a gear phreak, but what if you aren't?
Pros: You said something about avoiding complexity, but I'm not sure what complexity you're referring to. You also save little bit of weight. And it is a double, which matters if you are male and French, but as for the rest of us . . . .
Cons: As you point out, while you get most, you don't get all of the breadth of a triple and it comes at the price of wider spacing.
The smaller number of available ratios on a compact double also imposes a certain stringency in nailing exactly the combinations you want and shifting accordingly. Triples are awash in duplicate gears, so chances are the ""next"" useful gear is a click away from the one you're in. Who cares if you can also find it on one or even both of the other rings? Many engineers find duplicates offensive; I find them a relief.
Moreover, the smaller inner ring that lowers the lowest gear also lowers the highest gear available on that ring. Result: you have to cross-over to the big ring sooner, perhaps toggling back and forth in the middle of the cruising range (depends on the rider and his preferences). One of the things I like about well-designed triples is that virtually all of the cruising gears can be reached from the middle chainring.
For a ""first"" road bike, I'd go for a Veloce 52/42/30 triple mated to a 13-29 10 speed cassette. Same high as your proposed compact and an equivalent low. But the spacing is closer, and the middle ring runs from 38 to 85 gear inches with five of those being single step gears. And you'd still have room to drop the granny from 30 teeth to 26 or even 24 should the circumstances require."
Thu, 07/08/2004 - 10:54am
#15
"Peter writes:
> For a ""first"" road bike, I'd go for a Veloce 52/42/30
> triple mated to a 13-29 10 speed cassette.
FWIW, this is what my better half has, and she's very happy about the shifting on her bike.
The Shimano near-equivalent would be 105 52-42-30 with a 12-27.
This is also what I would recommend for a first bike, since it's likely to be available on a pre-built bike. If the bike is being built up from a frame, I would still recommend a 110bcd triple 48-38-26 or 48-36-24.
- Christian"
Thu, 07/08/2004 - 11:14am
#16
Don't get confused by all of the gearing choices. It's your first roadbike. A standard triple setup will cover you from central park to Bear Mountain (and be usable if you head to France). If you're not a strong rider, it can be really discouraging to not have enough gears.
And as said, its easier (and way cheaper) to go down to 2 than up to 3.
Thu, 07/08/2004 - 9:36am
#17
My 2
1) Link to Sheldon Brown's Gear Calulator:
http://www.sheldonbrown.com/gears/
2) My current set up on an Independent Fabrications Planet X cyclocross:
Front: Ultegra Triple Crank and bottom bracket, Ultegra triple front derailleur with a Truvativ 48T (shifts fine) and Shimano 42T, 26T
Rear: Shimano XT rear derailleur with a Tiagra 14-25 9-speed cassette. (The Tiagra was the same weight as the Ultegra and $20 cheaper.)
Nice setup for the most part. Lots of fine adjustment in the middle of the range and deep gearing for hills. 48-14 seems to be all I need on the top end.
Down side is a large gap on hills going from the 42T to the 26T which requires me to shift down three cogs on the rear cassette.
There's also some duplication with the 48T and 42T. Would like to try a 39T middle ring if I could find one with the proper pins and steps, etc.
I swap the 14-25 cog for an XT 11-32 if I'm doing loaded touring.
3) I suggested the following to a friend with a Shimano 105 double:
Replace the 53T with a Truvativ 48T and do the back with a XT 11-32 cassette and XT rear derailleur.
The trick is that 48T ring works with the 39T to neatly fill in the gaps on XT mountain cassette. A lot of front derailleur shifting, but you get the fine adjustment of a road set up in the middle to go with the deep gearing.
Thu, 07/08/2004 - 11:40am
#18
Thanks for the comments
All replys were helpfull, now its time to spend a liitle money
Fri, 07/09/2004 - 8:00am
#19
Moot perhaps, but ...
A 48-34, 12-27 is a wonderful gear combination. I rode in the Dolomites using a 39X27 as a bottom gear years ago, but decided a lower gear would allow more spinning. I just completed a DC in CA with 16,000+ feet of climbing, much of it on grades over 10%. The 34X27 was great, though I would not have minded a 34X29 for Fort Ross (2.6 miles, 11.5% at mile 160). The range is a bit better than a standard 53-39, 13-29, so I am not sure about this talk of crossing over. The gears IMHO are beautifully spaced. As for top end, 100 rpm gets you going over 32 mph in a 48X12 (52X13 equivalent), so no complaints there.
Where compacts get trick is the 50-34 setup, where the gear spacing between big and small ring is less than ideal. Still, if I were touring in the Alps again I would swap my 53-39, 13-29 on one of my bikes for a 50-34 once the Campy compact and matching FD comes out.
Fri, 07/09/2004 - 7:10pm
#20
Excellent article on the subject
http://peterwhitecycles.com/chainrings.asp
He sells a broad range of cranks and chainrings.
