Compact Crank vs Semi-Compact

newcycle
newcycle Posts: 19
edited March 2016 in Road beginners
I have a currently 50/34 compact crankset, and everyone says I should buy a 52/36 semi-compact crank because I'm loosing speed on the flats compared to my friends.

Sometimes it is true, I feel I can't keep up with the crowd on the peloton because of my 50/34.
If i change to a 52/36, what difference will it make ?? on the flats ??

thank you,
«13456716

Comments

  • redvision
    redvision Posts: 2,958
    Semi compacts are seen by many now as the ideal chainset.

    But, have you tried changing cassette ratios?
    Far cheaper option to start with.
  • imposter2.0
    imposter2.0 Posts: 12,028
    edited February 2016
    newcycle wrote:
    I have a currently 50/34 compact crankset, and everyone says I should buy a 52/36 semi-compact crank because I'm loosing speed on the flats compared to my friends.

    Sometimes it is true, I feel I can't keep up with the crowd on the peloton because of my 50/34.
    If i change to a 52/36, what difference will it make ?? on the flats ??

    thank you,

    50/11 should be good for 35-40mph without getting into silly fast cadences - how fast are you travelling at the point when you can't keep up?
  • pblakeney
    pblakeney Posts: 25,593
    Get a cassette with an 11 tooth cog. 50x11 at 90 rpm = 32.2mph.
    If you can't keep up, pedal faster or find a group that doesn't go at race pace.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • Thanks alot guys !!!!! :D:D:D:D:D
  • stretchy
    stretchy Posts: 149
    If you are not spinning out then semi compact will not help you. Semi compact is too big for most people.
  • redvision
    redvision Posts: 2,958
    stretchy wrote:
    Semi compact is too big for most people.

    I don't agree with this.
  • webboo
    webboo Posts: 6,087
    PBlakeney wrote:
    Get a cassette with an 11 tooth cog. 50x11 at 90 rpm = 32.2mph.
    If you can't keep up, pedal faster or find a group that doesn't go at race pace.
    Or better still get one of those new cyclo cross bikes :wink:
  • stretchy
    stretchy Posts: 149
    redvision wrote:
    stretchy wrote:
    Semi compact is too big for most people.

    I don't agree with this.

    How many cyclists do you know can spin out 50-11 and not crap themselves and how many do you know that can spin 36-28 at 90 rpm up 10% climbs? Of course if you just hang around with cat 1 racers then don't answer :wink:
  • redvision
    redvision Posts: 2,958
    stretchy wrote:
    redvision wrote:
    stretchy wrote:
    Semi compact is too big for most people.

    I don't agree with this.

    How many cyclists do you know can spin out 50-11 and not crap themselves and how many do you know that can spin 36-28 at 90 rpm up 10% climbs? Of course if you just hang around with cat 1 racers then don't answer :wink:

    That's beside the point.
    A semi compact allows riders to climb in the middle of the cassette at the back, meaning a better chain line.
    Also the 52 means that the majority of riders would not spin out on a descent (probably).

    Tell me, if semi compacts are 'too big for most people' why are more and more bikes being fitted with them??

    And Fwiw I do know a few riders who can spin out on a 50-11 and not crap themselves. And they aren't cat 1 (at least they weren't last year).
  • singleton
    singleton Posts: 2,489
    The difference between a 52 and a 50 is 52-50 = 2 teeth. As a percentage of 50 that is 4%.
    So if you are able to push the gear, then for the same cadence you will go 4% faster.
  • stretchy
    stretchy Posts: 149
    edited February 2016
    Why on earth would you be able to climb in the middle of the cassette with a 36 chain ring when you can't with a 34 chain ring? At least that's the point you seem to be making.

    People want a semi compact because they think they are closer to "pro". All a semi compact does is makes your climbing cadence slower and the max speed you spin out at higher. I can get 50mph out of my compact so tell me why i need to comprimise my climbing so i can hit 55mph for 3 seconds. To me that logic does not make sense whatsoever.
  • jrich
    jrich Posts: 278
    Semi Compact too big?!?!?

    If you ride anywhere mildly hilly then you're gonna spin out a 52. Lord knows what a compact must be like!!

    I don't why anyone would go full compact over a semi. With a 30+t cassette on the back and a 36t front you can climb anything.
  • imposter2.0
    imposter2.0 Posts: 12,028
    jrich wrote:
    Semi Compact too big?!?!?

    If you ride anywhere mildly hilly then you're gonna spin out a 52. Lord knows what a compact must be like!!

    I don't why anyone would go full compact over a semi. With a 30+t cassette on the back and a 36t front you can climb anything.

    Not really sure what point you are trying to make, but I live in a hilly area (west Wales) and mainly ride compact, either 50/38 or 50/34, usually with 12-25. When you get to the point at which you are spinning out on a 50t, then you are better off just tucking in and freewheeling anyway. By definition, the same would be true for a 52. I used to road race on a compact as well (as do plenty of other club level racers), and it was never a limiter.
  • singleton
    singleton Posts: 2,489
    I've got a compact on my winter bike and have no plans to change it.
    But, I have a semi-compact (or "faux-pro") 52/36 on my newer summer bike - because that's what it came with.
  • redvision
    redvision Posts: 2,958
    edited February 2016
    stretchy wrote:
    Why on earth would you be able to climb in the middle of the cassette with a 36 chain ring when you can't with a 34 chain ring? At least that's the point you seem to be making.

    People want a semi compact because they think they are closer to "pro". All a semi compact does is makes your climbing cadence slower and the max speed you spin out at higher. I can get 50mph out of my compact so tell me why i need to comprimise my climbing so i can hit 55mph for 3 seconds. To me that logic does not make sense whatsoever.

    Have a sit down mate, you seem a bit passionate and worked up about your compact.

    I never once said YOU should compromise your climbing so you can hit 55mph.
    And many congratulations on getting 50mph on your compact, I'm sure your mum is very proud.

    All I am saying is your claim that semi compact is too large for most riders is, in my opinion, wrong.
    It is a perfect solution for most riders as it gives them the best of both worlds.
  • paulmon
    paulmon Posts: 315
    jrich wrote:
    Semi Compact too big?!?!?

    If you ride anywhere mildly hilly then you're gonna spin out a 52. Lord knows what a compact must be like!!

    I don't why anyone would go full compact over a semi. With a 30+t cassette on the back and a 36t front you can climb anything.

    Yawn... :roll:
  • redvision wrote:

    All I am saying is your claim that semi compact is too large for most riders is, in my opinion, wrong.
    It is a perfect solution for most riders as it gives them the best of both worlds.

    Define 'most'. The vast majority of road cyclists are not pro riders, or even serious Amateurs, and upping the gearing by 2T on both chainrings is going to be a hindrance, not a help.

    It may be completely perfect for *you*, which is fantastic and why it exists. But don't try to then say just because it's right for you it's therefore right for everyone - which is a favourite of internet forums I know.
  • stretchy
    stretchy Posts: 149
    redvision wrote:
    stretchy wrote:
    Why on earth would you be able to climb in the middle of the cassette with a 36 chain ring when you can't with a 34 chain ring? At least that's the point you seem to be making.

    People want a semi compact because they think they are closer to "pro". All a semi compact does is makes your climbing cadence slower and the max speed you spin out at higher. I can get 50mph out of my compact so tell me why i need to comprimise my climbing so i can hit 55mph for 3 seconds. To me that logic does not make sense whatsoever.

    Have a sit down mate, you seem a bit passionate and worked up about your compact.

    I never once said YOU should compromise your climbing so you can hit 55mph.
    And many congratulations on getting 50mph on your compact, I'm sure you're mum is very proud.

    All I am saying is your claim that semi compact is too large for most riders is, in my opinion, wrong.
    It is a perfect solution for most riders as it gives them the best of both worlds.

    Ok, so you can't answer my question but no need to get petty. Nice grammar by the way, i'm sure YOUR mum is very proud.
  • redvision
    redvision Posts: 2,958
    stretchy wrote:
    redvision wrote:
    stretchy wrote:
    Why on earth would you be able to climb in the middle of the cassette with a 36 chain ring when you can't with a 34 chain ring? At least that's the point you seem to be making.

    People want a semi compact because they think they are closer to "pro". All a semi compact does is makes your climbing cadence slower and the max speed you spin out at higher. I can get 50mph out of my compact so tell me why i need to comprimise my climbing so i can hit 55mph for 3 seconds. To me that logic does not make sense whatsoever.

    Have a sit down mate, you seem a bit passionate and worked up about your compact.

    I never once said YOU should compromise your climbing so you can hit 55mph.
    And many congratulations on getting 50mph on your compact, I'm sure you're mum is very proud.

    All I am saying is your claim that semi compact is too large for most riders is, in my opinion, wrong.
    It is a perfect solution for most riders as it gives them the best of both worlds.

    Ok, so you can't answer my question but no need to get petty. Nice grammar by the way, i'm sure YOUR mum is very proud.

    That's bloody swipe texting. :oops:
    Now fixed.

    http://www.cyclingweekly.co.uk/news/lat ... ing-171057

    Enjoy :wink:
  • imposter2.0
    imposter2.0 Posts: 12,028
    Posting CW click-bait articles as 'evidence' of anything should be an automatic fail, IMO... ;)
  • redvision wrote:

    They mention Canyon there which is an interesting one as they fit 52/36 on everything, but usually with a 11-32 cassette.

    Now my lowest gear is 34/30 = 1.13. The lowest gear on Canyons is 36/32 = 1.12, almost identical.

    So you maintain the low gearing, but you also gain at the high end.

    Of course this ignores that I could easily go 34/32 if I wanted and get even lower if I felt it necessary.

    My point? That there is no "right" solution, you pick what you think's going to work best.
  • redvision
    redvision Posts: 2,958
    Imposter wrote:
    Posting CW click-bait articles as 'evidence' of anything should be an automatic fail, IMO... ;)

    Lol :oops:
  • term1te
    term1te Posts: 1,462
    I switched from a compact to a semi for two reasons. I use the bike on rollers and was spinning out at 50-11, and having lots of long hills around here I was spinning faster than felt comfortable descending. That said, I went to Italy last year and put the compact back on for the Mortirolo. I'm going back this year, and am still not sure if I'll stick with 36 or go down to 34 again. I have an 11 -28 cassette, anything larger than that looks odd to me.
  • redvision wrote:

    They mention Canyon there which is an interesting one as they fit 52/36 on everything, but usually with a 11-32 cassette.

    Now my lowest gear is 34/30 = 1.13. The lowest gear on Canyons is 36/32 = 1.12, almost identical.

    So you maintain the low gearing, but you also gain at the high end.

    Of course this ignores that I could easily go 34/32 if I wanted and get even lower if I felt it necessary.

    My point? That there is no "right" solution, you pick what you think's going to work best.
    Exactly! There is no right or wrong, it's surely just personal preference. I have compact, semi and a standard on the TT bike.
    I don't notice a huge difference between them. Still can't help thinking aero framed bikes look crap with piddling little compacts on them though :)
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  • bigmat
    bigmat Posts: 5,134
    I have raced (road, crits, TTs) on a compact (50/34) with no issues. I did reach the point where the 50 was a hindrance last summer when I was doing a TT and on a long descent I was spinning out in 50/11 - well, not spinning out exactly, but I felt I would benefit from a bigger chainring as it would give me more choice for cadence and a better chainline. Anyway, I fitted a double which was fine, but then built up a TT bike so the double is now on that. Put the compact back on the road bike but have recently bought new chainrings and decided to try 52/36 as a compromise. FWIW my winter / training bike has a double fitted (53/39) and that is fine for London and the Kent lanes. I am hoping semi-compact wll be a good compromise to cover rolling road races, crits and maybe the occasional trip to the Alps etc (I have previously used a compact there but always with a pretty small cassette - 23 or 25).

    Ultimately it all depends on the rider and the type of riding you are doing - there is no "right" answer, but for the OP I suspect changing to a semi-compact is completely unnecessary and will make no difference whatsoever!
  • Bobbinogs
    Bobbinogs Posts: 4,841
    noodleman wrote:
    redvision wrote:

    They mention Canyon there which is an interesting one as they fit 52/36 on everything, but usually with a 11-32 cassette.

    Now my lowest gear is 34/30 = 1.13. The lowest gear on Canyons is 36/32 = 1.12, almost identical.

    So you maintain the low gearing, but you also gain at the high end.

    Of course this ignores that I could easily go 34/32 if I wanted and get even lower if I felt it necessary.

    My point? That there is no "right" solution, you pick what you think's going to work best.
    Exactly! There is no right or wrong, it's surely just personal preference. I have compact, semi and a standard on the TT bike.
    I don't notice a huge difference between them. Still can't help thinking aero framed bikes look crap with piddling little compacts on them though :)

    Some might argue that seeing big biffas twiddling along at 14mph on an aero framed bike on the flat looks a bit crap too :) I don't, btw, but I think a lot of the trend for semi gearing comes from perception...as in self-perception. Whilst the semi can be right for many, there are not many combinations that cannot be achieved with a compact and the right cogs at the back. There are a lot of riders out there who would desperately like to have a Standard double for the look and 'kudos' but their ability simply doesn't match their desire. The cycling industry probably cottoned onto this and now offer the semi option as something that might be a good choice for some, whilst also helping other enthusiastic amateurs feel better than the nodder on a compact even though the gearing offers nothing unique.

    FWIW, I have bikes with a standard double and compact (53/39 and 13-28 & 50/34 and 12-27, so both fairly similar albeit one has a lower gear or two when really needed). Gets me up and down most things. However, we all ride different parcours and at different paces...and even those of us that are fairly similar ride with different preferences for spinning so it really is about horses for courses. I would buy a semi if I thought it was right at the right time, but I don't need to currently change anything I have.
  • singleton
    singleton Posts: 2,489
    Term1te wrote:
    I'm going back this year, and am still not sure if I'll stick with 36 or go down to 34 again. I have an 11 -28 cassette, anything larger than that looks odd to me.

    I'm heading to the alps for a short trip in August with my new 52/36 setup which is currently matched to an 11 speed 11-28 cassette. I was wondering whether I should change the front ring from a 36 to a 34 - so going with a 52/34 for the trip....

    Best of both?
  • bigmat
    bigmat Posts: 5,134
    Big jump! Still, the Alps is mostly big climbs and big descents, so it will probably be fine.
  • dennisn
    dennisn Posts: 10,601
    Why wouldn't you simply buy a 52 and a 36 tooth set of chainrings for your compact crank? Why bother with a new crank?
  • imposter2.0
    imposter2.0 Posts: 12,028
    Singleton wrote:
    Term1te wrote:
    I'm going back this year, and am still not sure if I'll stick with 36 or go down to 34 again. I have an 11 -28 cassette, anything larger than that looks odd to me.

    I'm heading to the alps for a short trip in August with my new 52/36 setup which is currently matched to an 11 speed 11-28 cassette. I was wondering whether I should change the front ring from a 36 to a 34 - so going with a 52/34 for the trip....

    Best of both?

    Depends on your fitness, but I would take a 34 as a 'nice to have' - you don't have to use it.