Compact Chainset?

Paulq

Apologies for the basic question but my previous bikes have always had triple chainsets as I'm a big lad and need a granny ring for the hills these days. :roll:

I have been nosing around today and really like the look of the Specialized Allez 08 series but am unsure what a 'compact' chainset is and haw that would give me an advantage over, say, a double or triple chainset.

Thanks

Paul

Smokin Joe

A compact chainset has a smaller bolt circle diameter than a standard and can accept smaller chainrings, typically 34 or 36t inner and 48 or 50t outer to give you smaller gear ratios.

Whether one would be suitable is an entirely personal thing based on how low you need your gears to be compared having a granny ring on a triple. Work out the lowest gear you feel you need on your present set up and if you can get that with a compact go for it, if not then stick with the triple.

pjh

A Compact won't be quite as low geared as your triple (generally speaking). Therefore if you regularly need the granny ring .. you might be wise to stick with a triple.

I moved from a triple to a compact a month ago and on certain hills I find it 'quite a bit tougher'.

Having said that I'm still getting up them and I'm sure there's a benefit (leg strength) eventually

willbevan

I bought my first road bike in october after beingused to an old MTB (didnt do much on itmind you, ivedone more riding since october than in the first 26 years of my life lol) and found a standard double execptional hard goingto work (last 1/2 mile of my comute raises 200ft) and my legs werntthestrongest. So switched to a compact rapidly, which wasa lot better, butstill hard going for me compared to the tripple and lower gearing +smallerwheels on the MTB.

Now my leg strength has improved, butif I was doing touring or doing alot of uphill milage I think I would prefer a tripple.

If you dont realy need the extra low gears then a compact is good, less overlap of the gears, but can be anoying if your cruising on the borerline between the two chainrings and need to switch down or up a lot on them. Being honest I wish I had got a tripple lol

Will

JWSurrey

Unless you're a fashionista, like my hypocritical self, I'd go with the triple!
The spacing between the ratios will be that much closer, as the rear cassette can be that bit tighter due to the extra chainring; you'll probably get a greater range (better top and bottom gear), as stated above.

If you get bored, you can always spend more to have less / save a few grams in weight with the compact.

With the triple, you'll get a different shifter if it's Shimano (though it will look identical) - not sure about the others, a longer deureilleur arm, poss. a slightly deeper front mech. and obviously the triple ring chainset. I think the chain may be slightly longer too.

If Campagnolo, you'll have a solid bottom bracket as the triple doesn't use the hollow "ultra-torque" variety - which is why when you look at the specs, you need to add the b.b weight to the total mass increase - which is still not huge.
If Shimano, it'll allegedly shift better than a Campag. triple.
Not sure about the FSA chainsets.

To get an idea, though it may be a little abstract, check out the "gear inch" calculator - the best one is on the sheldonbrown.com website.
You can see the difference between top and bottom gear options.

I have two bikes both with compacts - they're fine for everything I want to do, though I often curse the fact I don't have even lower gears - If I had a triple, I'd curse the lack of a fourth chainring!
The Campag. is set up with a 13-29 cassette, and standard compact ratio of 50/34.
The Shimano road bike as 12-27 with 50/34

You will find the smallest ring a Campag. will take is 34, and the biggest inter-ring difference to be 16 teeth. (front mech. clearance and deureilleur swing, I guess).
I believe an independent now makes a 32 tooth chainring for Campag.

Mettan

willbevan wrote:

So switched to a compact rapidly, which wasa lot better, butstill hard going for me compared to the tripple and lower gearing +smallerwheels on the MTB.

Will

Will - a possible/useful addition to go with your Compact might be an 11-32 or 11-34 cassette - you'll then have access to very low gears - admitedly those casettes have a large spread (and you might need a long cage rear mech) but if you're not racing etc that 32T or 34T would come in handy as a bail out gear at the end of a longer ride.

willbevan

Mettan wrote:

willbevan wrote:

So switched to a compact rapidly, which wasa lot better, butstill hard going for me compared to the tripple and lower gearing +smallerwheels on the MTB.

Will

Will - a possible/useful addition to go with your Compact might be an 11-32 or 11-34 cassette - you'll then have access to very low gears - admitedly those casettes have a large spread (and you might need a long cage rear mech) but if you're not racing etc that 32T or 34T would come in handy as a bail out gear at the end of a longer ride.

I have a 28T as the max at the moment, and funnily enough am looking at a 34T at the moment, but will have to get a new rear mech as the sora rear mech I have only just copes with the compact and the 12-28t on it at the moment. I am sort of refusing to spend more money on the bike and saving to buy a better one at the moement (£405 so far lol)

thanks for the advice though

Will