Semi- compact or compact?

essjaybee7

Hi,

I'm relatively new to Road cycling (2 years) and I'm looking at getting a new road bike. I currently have a Triple crankset and I'm after advice on whether to go for a 50/34 or 52/36? I live quite close to the Lake District so a lot of my rides involve hills, many of which I can comfortably climb in the middle ring, however on steeper climbs there are times when I need to drop down to 'the Granny cog' - something that practice is now starting to eliminate, hence the semi or compact question. Can anyone advise please ?

markhewitt1978

Nobody can advise and if they claim to do so they are bullshitting you. They are just gear ratios, choose whichever works for you by simple means of front/back to work out what you're going to need.

imposter2.0

essjaybee7 wrote:

Can anyone advise please ?

If you need to ask, then the answer is 'compact'. Otherwise, see above.

londoncommuter

Correct steps are:

1) Put both options on here:

http://www.ritzelrechner.de/#


2) Agonise over preferred cadence, gaps in gears, straight chainline, cog size


3) Ignore steps 1 and 2 and buy whatever option you can pick up for the cheapest

craigus89

As above, it is up to you, but a jump form a triple to a semi-compact and a 28 on the back (It's rare to get bikes with semi-compact and anything bigger than a 28 on the back as standard) is quite a difference. I would stick to compact personally, especially in the terrain you live in.

mrb123

Compact front. 11-32 on the back if possible. Sooner or later you'll find yourself at the bottom of Hardknott and be very glad you made that choice.

markhewitt1978

MrB123 wrote:

Compact front. 11-32 on the back if possible. Sooner or later you'll find yourself at the bottom of Hardknott and be very glad you made that choice.

Regardless of what I said above if you aren't sure what you need this is the option to go for as it does everything.

essjaybee7

Thanks for the info folks, much appreciated!

joe2008

I live on Exmoor which, I guess, is similar to the Lakes. After going through everything from 53x42, standard, semi, compact, and, with the help of a power meter to persuade me to up my cadence substantially, I've found the best solution is 46 x 34.

With the 46 I can stay on the 'big' ring for much longer and it's a much nicer drop, than a 50, to the 34.

46 x 11 is actually a pretty big gear, bigger than the 52 x 13 that Merckx rode.

I ride a 29 sprocket (Campagnolo), but I'm tempted to switch to a 32 now that Potenza is available.

Tiesetrotter

If I was in the lakes and I am going to take on the hills. Compact with a 29 ........ 70km in after a good hard club ride and you'll look for the 29. You can get up there in a 25 with determination, but a 29 will be much nicer on the heart rate.

By the way I have Ultegra and Chorus. If you ever want to know the difference between the two, a good set of hills will let you know you'll always want Campag, it changes smoothly and instantly. Takes some loving but it's a step up from Shimano which works but it ain't smooth and it ain't instant in comparison, by a long way.

pilot_pete

Tiesetrotter wrote:

By the way I have Ultegra and Chorus. If you ever want to know the difference between the two, a good set of hills will let you know you'll always want Campag, it changes smoothly and instantly. Takes some loving but it's a step up from Shimano which works but it ain't smooth and it ain't instant in comparison, by a long way.

You should try Dura Ace Di2 then. Blows my 5 year old Record/ Chorus mix into the verge in terms of shifting speed (adjustable) and smoothness of shifting. It is quite simply sublime and in terms of love, it was instant! :P

PP

Bordersroadie

joe2008 wrote:

I live on Exmoor which, I guess, is similar to the Lakes. After going through everything from 53x42, standard, semi, compact, and, with the help of a power meter to persuade me to up my cadence substantially, I've found the best solution is 46 x 34.

With the 46 I can stay on the 'big' ring for much longer and it's a much nicer drop, than a 50, to the 34.

46 x 11 is actually a pretty big gear, bigger than the 52 x 13 that Merckx rode.

I ride a 29 sprocket (Campagnolo), but I'm tempted to switch to a 32 now that Potenza is available.

My winter bike has 46-34 and 11-28, and it's by far my favourite, for the reasons you state.

What crankset are you using for the 46?

Tiesetrotter

Pilot Pete wrote:

Tiesetrotter wrote:

By the way I have Ultegra and Chorus. If you ever want to know the difference between the two, a good set of hills will let you know you'll always want Campag, it changes smoothly and instantly. Takes some loving but it's a step up from Shimano which works but it ain't smooth and it ain't instant in comparison, by a long way.

You should try Dura Ace Di2 then. Blows my 5 year old Record/ Chorus mix into the verge in terms of shifting speed (adjustable) and smoothness of shifting. It is quite simply sublime and in terms of love, it was instant! :P

PP

Yeah. All the people who have moved to Di2 have raved about it. Cost has kept me away really. I suppose the only issue then is where you prefer your buttons and of course price. Although I have seen a few problems on the road with electric ...... but then I have seen a lot of problems on the road with every groupset.

But this manual Ultegra is shocking compared to Campag.

joe2008

Bordersroadie wrote:

My winter bike has 46-34 and 11-28, and it's by far my favourite, for the reasons you state.

What crankset are you using for the 46?

I first used a 46 on cyclocross bike, FSA Gossamer 46x36.

I then switched my Campagnolo Centaur and Chorus crankset's with to TA Specialites 46 chainrings, initially to 46x36, but I've since found that a 34 also gives a great range of gears without a massive drop when shifting from big to small.

I hated the 34 when it was used with a 50 because of the drop (plus a 2/3 cog shift at the back) and because I had to use it too much.

I've also tried a 48, however, a 46 is just perfect for the terrain I ride over.

stueys

Tiesetrotter wrote:

Yeah. All the people who have moved to Di2 have raved about it. Cost has kept me away really. I suppose the only issue then is where you prefer your buttons and of course price. Although I have seen a few problems on the road with electric ...... but then I have seen a lot of problems on the road with every groupset.

But this manual Ultegra is shocking compared to Campag.

Seriously if you are riding 6800 and think the shift quality is shocking then there is a problem with your set up. I'd ask your LBS to check the hanger alignment as a start point.

Jerry185

Essjaybee

I'm two years in as well and have done some hills on my compact + 12-28. I'm talking 10 mile hills at 6% here, not just on its own, but part of a days riding + another six after that.
I was always thinking of getting a better bike (with a 32 rear cog) or just a whole new rear cassette 12-32 (with new chain and medium cage) but, eventually, through training, bike technique, spin classes and some better bike gear, I think I can cope with a 28 on the back. Putting a semi-compact on now would really set me back: good times aren't made by going fast downhill, they're made by going fast uphill

MikeBrew

I've done loads of faffing about with gears, mainly to try to find something kinder to my worn right knee. Always finding the drop from 50 to 34 problematic, I've ended up with 48/36 and an 11/32 cassette. Allied to going for shorter (170mm vs 172.5mm) cranks, I find cadence and power consistently higher, and have happy knees to boot.
Mine is a ten speed set up and, though I rarely use the 32, I find that next 3 largest cogs : 28 - 25- 22, mean that I can stay in the big ring in some situations where an 11/28 cassette would necessitate a drop to the small ring.

Alex99

markhewitt1978 wrote:

Nobody can advise and if they claim to do so they are bullshitting you. They are just gear ratios, choose whichever works for you by simple means of front/back to work out what you're going to need.

Sounds like advice to me!!!

stueys

MikeBrew wrote:

I've done loads of faffing about with gears, mainly to try to find something kinder to my worn right knee. Always finding the drop from 50 to 34 problematic, I've ended up with 48/36 and an 11/32 cassette. Allied to going for shorter (170mm vs 172.5mm) cranks, I find cadence and power consistently higher, and have happy knees to boot.
Mine is a ten speed set up and, though I rarely use the 32, I find that next 3 largest cogs : 28 - 25- 22, mean that I can stay in the big ring in some situations where an 11/28 cassette would necessitate a drop to the small ring.

Have you tried oval rings out of interest? Higher cadence and not grinding is definitely first port of call in protecting your knees, lots of people (including myself) have found oval rings help the knees and also help promote a faster cadence.

kirkee

Compact. Id say that for everyone less for super fast pro-esque riders, its got to be compact 34 50 at the front for riding variable terrain. Paired with the correct cassette its the best solution excluding a triple with regards to usable ranges. The only downside I have seen, especially with regards to newer riders could be the tendency to get into bad pedaling/cadence habits. By this I mean using the 50t outer ring way too much and not spinning very efficiently.

That said a 36 52 semi compact may encourage a newer rider to spin more in the smaller ring as the 52 will be a bit less usable more often. I was a long time rider of standards mostly 39 52 before compacts were out, I then weaned onto a semi compact a while back, within 6 months I realised that a 34 50 would make even more sense. I now have a pair of redundant semi compact rings in the garage that I may as well sell!