Chainset advice for newbie

Meerkat16

Hi all. As title states i am fairly new to road cycling and having recently bought a full carbon bike with a Tiagra groupset i am in a position to upgrade to Ultegra. i have got the 6700 shifters, front and rear Mech. Just after BB, Brakes etc and 6700 Chainset in Glossy grey to match other parts. My question is, my weakness at the minute is hills and currently running a 50/39 chainset. Someone has advised me to buy a compact rather than a double chainset. However as i am new to all this it is partly going over my head. i have seen a Double chainset running 53/39 which i quess has 3 more teeth than my current chainset. is it the amount of teeth which defines a double or compact or is there more to it than that? I am aware i can change to cassette to help with hills. I know the hills will get easier over time etc but if changing chainset now i guess i need to go down the compact route

Sprool

taken from a post at another cycling forum:
"Standard chainset has two rings with 53 and 39 teeth.
Compact chainset tpically has smaller rings, say 50 & 36 or maybe 50 & 34. Hence a compact can have slightly lower gearing than a standard. So compacts are popular with less experienced cyclists or for use in hilly areas where lower gearing is desired."


You can switch from standard to compact fairly easily.. although you may have to alter the position of the front mech a little and possible change the length of your chain by a link or two.

MichaelW

The reason a compact crank can use smaller rings is that the chainring bolts are in a smaller bolt circle diameter (BCD). Std=130mm, compact=110mm
You can put big rings on a compact crank.
Given that std rings are used by professional athletes and most of use are not as powerful, many more riders could benefit from compact cranks.

Other BCDs are available but less common.
You can put any brand of chain ring on a crank as long as it takes the same BCD.
The other useful dimension of a crank is its length which is a whole other debate.

Crimmey

I'd get a compact as it could prove a lot more useful for hills. You may 'spin out' on a super steep descent at 50-12 but in reality you are not going to lose a lot of time if you cant go a couple of extra mph for a miniscule percentage of ride time. A 50-11 is a bigger gear than 53-12. A standard will not make you a faster rider generally nor a compact, slower Even with a compact you can use a 28 small cog which is no shame and you'll be surprised at the number of seasoned vetertans that have swapped over. You might even thank me for it one day.
I have just bought an Ultegra 6700 compact from merlin inc BB for £125! I ordered the shiny silver but got the very sexy grey colour Not that I can ride at the mo, just made me feel better.

Wirral_paul

As above - go for the Compact. The 50 ring vs 53 of a standard chainset is near as makes no difference equivalent to a 1 tooth difference on the cassette (ie a 50-11 is very close to 53-12). The 34 chainring though will make a big difference on the hills, but you can still easily ride at 20mph on the flat on it.

If you then find you need even lower gears, then you have more flexibility by changing the cassette. I have a 12-25 and an 11-28 - and set the chain length on the 11-28 so can swap in about 5 mins.

simon_masterson

Compact might suit you. Some would have you think that they are a necessity, which I dispute because they are a recent invention; people coped before they were invented, and 28 (or even 25) cogs and triples were less common too. 52/42 - less common than it was - is also a nice combination. If you don't have a health condition and aren't infirm then you should be able to get up anything this country has to offer on 39/25; I say that only to make the point that training gets you up hills, and there's only so much your gears can do.

In your case, a compact might be a good compromise; they are common these days for good reason. 50 is a decent enough big ring. What rear cassette do you have? This is significant because if your lowest cog is 25t and you go from standard double to compact, you end up with the same lowest gear as you would if you stuck with the standard double and changed cassette to one with a 28t.

I shan't dwell on it because it's not a very useful point, but it's worth noting that pro racers will very often run standard doubles with 11-25 even for pretty big hills; switching to compact and bigger cassettes only for the mountain stages. Of greater relevance here, Marco Pantani used to run 54/44 with 11-23; he preferred to climb out of the saddle. The onset of compacts does coincide with the increased popularity of remaining seated and spinning. Your style may influence your gearing choice.

To be honest though, if you do REALLY struggle with hills, you can do better than a compact. Get a triple; with a 28 or even 32t MTB/touring cassette (assuming hub compatibility and replacement derailleurs) you could scale a wall, and you get smaller gaps between cogs and a better top gear.

oceheb

Ive also upgraded to compact and 32 rear cassette (still 105 rear derailleur). I must admit that you need this only in 'survival mode' for very long (steep) hills. when you get fit/loose weight you dont need this anymore and 11-28 will be fine for rear cassette.

Meerkat16

oceheb wrote:

Ive also upgraded to compact and 32 rear cassette (still 105 rear derailleur). I must admit that you need this only in 'survival mode' for very long (steep) hills. when you get fit/loose weight you dont need this anymore and 11-28 will be fine for rear cassette.

Thanks for all the advice which is very much appreciated.
Went for an Ultegra 6750 Compact 34/50 in Grey and Ultegra 11-28 cassette which should should be with me tomorrow.
Yes i am hoping things get easier the more i get out and when i start to get fitter and lose weight

drlodge

34-28 should get you up pretty much everything and I doubt you'll spin out very often on the 50x12. Good choice.

t4tomo

Simon Masterson wrote:

Of greater relevance here, Marco Pantani used to run 54/44 with 11-23; he preferred to climb out of the saddle. The onset of compacts does coincide with the increased popularity of remaining seated and spinning. Your style may influence your gearing choice.

He also had blood like treacle (for at least some of the time) and died a lonely cocaine overdose fueled death in a grubby hotel room, so a 44 tooth smalest chainring might not be the best idea for mere mortals!

Wonderful sight to see him attacking up hill though.