Double or triple?

[Chris James]

Anyhow, I don't like triples, on a mountain bike or a road bike. I dislike changing front rings and don't like poor chain line.

46/30 on my road bike, both have a 11/32 9spd cassette.

Most of the time I'm on the 46 ring with the good chain line giving me the use of the whole cassette, most normal hills are manageable on 46x32.

Hello johnyC, welcome to Cycle Chat.

I wouldn't normally want to start arguing with a new poster ... but you have contradicted yourself in the post above.

One of the main advantages of triples is that they encourage much better chain lines. By riding hills in the big chian ring and the big sprocket you are picking your worst possible chain line due to your reluctance to shift chain rings.

A much better chain line would be achieved using a triple and avoiding extremes. Your suggestion of big ring / big ring is a total no no as far as chain line is concerned.

 

[johnyC]

Chris,

perhaps I didn't explain very well. The 'big' ring on my chainset is where the middle ring would be on a triple. The line from there to the biggest sprocket is not extreme, it's not a 'no no', it works.

 

[Chris James]

Chris,

perhaps I didn't explain very well. The 'big' ring on my chainset is where the middle ring would be on a triple. The line from there to the biggest sprocket is not extreme, it's not a 'no no', it works.

I understand that, however I would never use the largest sprocket and the middle chain ring combination due to bad chain line.

Typically with a triple you should use the granny ring with the largest sprockets up to just over half way across the cassette (say the 6th/7th sprocket on a 10 speed), if you require a higher gear you change to the middle chain ring and knock down a sprocket or two. This leaves you about one gear higher than you were before. If you require higher gears you would progress up the cassette until you got to about 8th cog (on a ten speed) before changing chain rings.

You should never use extreme lines on any setup, whether that be standard double, compact double, or triple as it is inefficient and increases wear in the drive chain.

In practice this means, for a well setup triple, that you ride in the granny ring for long uphill stuff, middle ring for undulating terrain / flat, and big ring for downhills / riding fast on the flat.

In general I agree with your bit about a 46 ring often being big enough for general riding. As I said in an earlier post I had a 48/36 chainset on an old bike and it was quite good. Unfortuantely due to its age it had a 5 speed (14-24) freewheel and I found the gaps between gears annoying and that I was forever changing gear at the front when on rolling terrain. If it had been matched with a close ratio 10 speed cassette it may have been more user friendly.

 

[MacB]

Chris,

perhaps I didn't explain very well. The 'big' ring on my chainset is where the middle ring would be on a triple. The line from there to the biggest sprocket is not extreme, it's not a 'no no', it works.

Makes perfect sense to me, all you're saying is you make up a 9 speed bike with a bail out to a smaller ring at the front for really steep bits. But you probably only use the 2 or 3 easiest with the small chainring.

Basically the same sort of conclusions that I've come to, a 46/11 will give about 114inches, over 30mph at a reasonable cadence. By adding a larger ring the gears you gain, outside of the middle ring range, will only be above this ratio. How many of us need a huge gear to pedal like a nutter downhill?

 

[jimboalee]

It makes sense to me too.

The 'Little' ring is only used on steep climbs.

The 'medium' sized large ring runs to all 9 sprockets.

JohnyC's set up allows him to ride a 40lb bike up a 10% without problems.

A REAL tourist. Hat's off.

 

[Chris James]

It makes sense to me too.
.

Sheldon brown agreed with me, I quote:

'Try to avoid the gears that make the chain cross over at an extreme angle. These "criss-cross" gears are bad for the chain and sprockets. Especially bad is to combine the inside (small) front sprocket with the outside (small) rear sprocket. This noisy, inefficient gear causes the chain to wear out prematurely.'

http://www.sheldonbrown.com/gears.html

 

[tyred]

If I read the post correctly, JohnnyC has positioned the outer ring to use the whole cassette and uses it like a single front chainring set up the vast majority of the time, only dropping into the small front chainring combined with the large rear sprockets when he really needs them. Makes perfect sense to me

 

[MacB]

Sheldon brown agreed with me, I quote:

'Try to avoid the gears that make the chain cross over at an extreme angle. These "criss-cross" gears are bad for the chain and sprockets. Especially bad is to combine the inside (small) front sprocket with the outside (small) rear sprocket. This noisy, inefficient gear causes the chain to wear out prematurely.'

http://www.sheldonbrown.com/gears.html

which is not what was said on here, Johny C was saying he had a 2 ring setup with the outer ring lined up as if it was the middle of a triple. This gives access to the full rear cassette and covers most of his riding. his inner ring, in the same place as the inner ring on a triple is only used for really steep bits, so small to big.

You get the same impact if you ride a triple but never use the outer chainring.

 

[ShinSplint]

Wish i'd never asked

Seriously though, some good ideas... still none the wiser though lol

 

[asterix]

I have never been any the wiser either. So in order to play safe my renovation project will have a double. The inner will be 36 and the outer 47 (yes, 47). At the back I'm attempting 9-speed, 11 to 32. It's still in bits though so I obviously haven't tried it.

Pre-renovation it was 30/48 with 6-speed 14/25 and 'comfortable' up 33% in the North York Moors (unladen). The old down-tube shifters will be replaced by bar-end jobs.

My other bikes have triples and I never (deliberately) use the middle ring with the outer cogs as it seems unnecessary (I have high-torque, low speed legs).

 

[johnyC]

jings Geordie, I'd cause bother in an empty hoose

Anyhow, a picture speaks a thousand words, or something like that. here's some photies:

road bike:

mountain bike:

extreme gear:

 

[Chris James]

which is not what was said on here, Johny C was saying he had a 2 ring setup with the outer ring lined up as if it was the middle of a triple. This gives access to the full rear cassette and covers most of his riding. his inner ring, in the same place as the inner ring on a triple is only used for really steep bits, so small to big.

You get the same impact if you ride a triple but never use the outer chainring.

My last word on the subject.

I don't know precisely what spacings johnyC has used on his bike, but standard road doubles have the large ring at 46mm from the bike centre line with the small ring at 41mm.

Road triples are setup with the middle at 45mm. So any adjustments johnyC has done are likely to only improve matters from the universally agreed bad big / big combo by a matter of 1mm.

Even assuming his big ring is where the normal middle ring would be on a triple, I personally do not use the middle ring / big sprocket combination. I only use the middle 6 cogs on my 10 speed cassette as I prefer to avoid what I would consider to be a bad chain line, with resultant increased wear. The photo of the chain running back from the rings to the cassette doesn’t change my view. I would consider that to be an unacceptable chain line. Whether I like it or not is not really relevant, it obviously works for johnyC, but I brought it up because he said triples give worse chain lines yet seems to have devised a system which makes greater use of sub optimal chain lines!

IIRC correctly, the 9 speed cassette is actually 1mm wider than a ten speed one (hence the requirement for a spacer on a ten speed cassette), so a 9 speed is likely to have a worse chain line than a 10 speed at extreme lines.

In addition, I would find the jumps in gears unacceptable on johnyC’s setup. By using a 46 tooth ring with 11-32 cassette the gaps between each gear are almost double that of a 42 ring with a 12-25 cassette.

So I would say that JohnyC’s setup is interesting and he is well pleased with it, but that it is non standard for a reason.

 

[johnyC]

more double trouble,

most recent ebay special, before the Kona:

I built this one with a 44/28 chainset and 7spd cassette. The old Cannondale frame has a 130mm oln back end and I wanted to reduce the dishing in the wheel. To me it was the lesser of two evils. I hope Chris doesn't throw me on the fire for this, but I built the cassette up from assorted sprockets, grinding the spline to allow alignment of the ramps. It was 13/34 from memory, there were some big jumps in the lower gears. But I chose them to suit my needs, it wouldn't suit everybody.

ebay special mark 1:

built around a Cougar cyclo-cross frame, also with a 130mm rear and 7spd cassette. The chainset was a Cannondale with the spider reversed, this got the rings very close to the chainstay, sorry I didn't measure it. The 'cycle wear' is a match worn ice hockey jersey, Dino Bauba's from the last year of my team, Ayr Eagles, at the Centrum. It, like the two aforementioned bicycles, were given away for charity.

To sum up then, there have been no wear issues, extraneous noise etc with any of these bikes. But I've said enough myself, I'll get my coat.

 

[Plax]

I haven't got a clue when it comes to gearing. I think both my bikes are 48/38/28T.
I just know going to work I'll be in the largest chainring most of the way switching to the middle chainring on the flat. Then going home I'll be in the smallest chainring most of the way home. I have on a few occassions managed the hills keeping on the middle chainring but I reserve that for when I'm feeling energetic. A colleague claims to have cycled up the Llanberis pass on a fixie, but 'm not sure I should believe him.

 

[jimboalee]

JohnyC's gearing has been "Masterfully" thought about.

It demonstrates a knowledge now lost in the world of triples and 'compacts'.