Difference between a compact crankset and a normal one?

[bikenut2010]

Inzaman, thanks for that. Does that mean that any chainring with the same BCD as mine will fit my cranks?

correct...
If you have a shimano 130BCD setup you can get a 38T inner ring ( smallest on a Campy is 39 ), which with a 52 outer gives a nice spread of gears...I have that setup on my old Bertin with a 7 speed freewheel 14-28T and find it excellent. With a compact you can easily find your legs pedalling thin air on descents unless you have an 11 or 12T at the back, and even then you'll miss that 52 IMHO ...

 

[TGR]

LOL, i have had a short ride on my new bike and the only fault i could find is that the gears felt too low. On a smooth flat road, i used the top 3 gears. I could be over-estimating my performance and be comparing it with what i could do in my youth. Only time will tell, but my old bike is stuck on the big ring at the moment and i can just about cope with 52/12 - 15 although that is on the flat!

Big dreams and little fitness may cause me problems soon!

Thanks

 

[bikenut2010]

It's funny, when I'm out on a retro bike ( DT shifters) I generally leave the rear around the middle of the block, say 15 T, and just flip between chainrings for a climb or faster patch...I get into a nice rhythm but hear other riders in the bunch clicking away on their STIs or ergos for every bump or lump in the road...

When I'm on a modern bike, I'm the same, constantly fiddling...if it aint there you don't miss it!

 

[TGR]

I am smiling as i agree with your last comment so much. But, we have to try and keep up with technology. And, to be honest, on my short trips on the new bike, i have tried a lot of gears but kept to the top 3 after a while.

Too many buttons = too many things to go wrong!

 

[vivelesalpes]

Just to confuse things even more Campagnolo have introduced a 52 - 36 chainset : http://www.campagnolo.com/jsp/en/newsdetail/newsid_283_newscatid_3.jsp

(I know what you mean about downshifters / ergo levers. I'm constantly going up and down the cassette on my newer bikes wheras with my old Pug I just 'thug it out').

When I was a lad owt less than 42 on the little ring on the front and 21 on the back was considered weak. Today some younger riders look at me gone out for riding on a 52-39 in the Peak. How things change !

 

[TGR]

I think there was a restriction on gearing when i was a youth - and the 52 ring was too big for racing. Things changed on Sundays when out with the 'adults' the 52/12 was really needed for the flat and downhills. I think my small ring is a 42 and it was rarely used - really steep hills only.

I think that older riders were used to big gears and low cadence, nowadays it seems to be lower gears and higher cadence.

I am waiting for the better weather to test my cadence - global warming better hurry up!!!!

 

[Iwasgoodonce]

I have a cadence monitor as part of my Garmin 800. It would appear my prefered cadence is around 90 to 95. I still have non-compact ratios and around here never really go lower than third (19) gear. The small ring wears out quicker than the big.

I notice this when riding my tractors as well. I am on my sixth middle ring, (I ride them until the teeth disappear) but still have the original small/big ring from 1990.

It must be something to do with prefered cadence and sub-concience selecting the ratios to allow the cadence.

I prefer the look of non-compact.

 

[Sirreal]

I live in Sheffield and have the peak district for my training route. Campy 52/42 with a 12-26 rear does not make for an easy life. No cadence monitor, but I'm betting it's a bit low on climbs, and I fall over when I stall in clips
May of course be a case of older rider trying to do what I could get away with when I was 20 years younger of course. Will move to a 39 when I can get some money together but would be surprised if I need to go any lower.

 

[David B]

Compact double chainsets were (sort of) around before the marketing guys went for a big sales push - Stronglight offered models such as the 99 and then the 80, both of which which only had an 86mm BCD and were sold as, for instance, 38/48 or 36/46 double combos for touring and CX bikes.

David

 

[Old Ned]

A 'compact' is basically an MTB chainset without the granny ring fitted. I was using an XT crankset with 50/34 on a winter bike for ages before they were 'discovered' and produced commercially as doubles. For summer use I still prefer 53/39 with 12/25. Good spread of gears and allows me to keep up with the 'big boys' on longer runs.