Compact Cranks

[Silby]

I am looking at changing my cranks.

What is the difference between normal cranks and compact cranks? What are the advantages of compacts?

Any suggestions?

[Marius]

WEIGHT.

[Marius]

Cons. You spin out faster./

[Delgado]

Some longer gear ratios...... 50/34 (Compact) V's 53/39 (Standard)

[FanieFiets]

baie beter. Punt. die ander laat jou heeltemal teen die bulte suffer. Ek spin eers op 90 km/h plus (en dit gebeur elke dag, ahahah) uit so dis nie te veel van 'n worry vir my nie.

[Wolweseun]

Compact is nicer for very hilly rides like Nelspruit Area and if you tend to spin rather than grind a big gear as well as weight

Zipp Vuka is probably the nicest at the moment

 

[Marius]

The Stronglight cranks looks nicer to me. Marius2008-03-27 08:16:47

[shade]

if you riding on +10% gradients alot, then go Compact.. otherwise here is SA the average guy don't need that gear ratio..

[FanieFiets]

if you riding on +10% gradients alot' date=' then go Compact.. otherwise here is SA the average guy don't need that gear ratio.. [/quote']

 

or 5% gradiean and you are big like me!

[Iwan Kemp]

Compact:  50/34

Pro's:

Climbing made easier cause of smaller chainrings. This means in granny or anything near you'll be able to pedal at a higher cadence and will be able to settle into a rhythm sooner/easier. This will save a lot of energy/muscle power for when you needit most...Suikerbossie!

Lighter

Cons:

If you have sooooper strong legs you will loose a couple of gears in the back cause you won't need to go that light. At very high speeds they will spin out. Not once on Helshoogte or any of the Argus descents did I spin that much that it bothered me.

Flat races you won't need it that much

Normal: 53/39

Pro's:

Won't spin out as quick

If you're strong you won't need a smaller granny

Con's:

Effectively pushing a bigger gear upclimbs which can tire you quickly

Heavier

I have a compact crank on my Felt and I'm loving it. Makes climbing easier and saves my legs.

[Gumpole]

i think some of the advantages of a compact not mentioned before are:

 

pros: (if you dont need the 53-12), you can use a 12-23 cluster instead of a 12-25, so the gear ratios are closer to each other... or rather spaced out better!

 

pros: compared to a 12-25 cluster you use a 11-23 with a 50/36 crank... and the 50/11 is faster than the 53/12, also the 36/23 is slower or easier than the 39/25.    only marginally but if you are riding a 12-25 on the back you should rather be using a compact.

 

pros: (I think) the 36 ring can easily be changed to a 34 for ultra hilly routes (maybe mpumalanga) or left as 36 for Argus and other 'normal' hills.

 

cons: with the 39-53 and an 11-23 you can change the cassette or get  a pair of lightweight wheels and install a 12-27 for hilly routes. A compact cannot be changed to go faster (until somebody invents a 10-21!!)

 

 

[javadude]

My 34 / 26 up suikerbossie was a real pleasure. The downhills i just freewheeled, so couldn't care about top end.

 

I suppose it depends on your priorities. If you really need to outsprint Boonen to the line then you may need that 53 / 11 after all.

[Ox_Wagon]

I have a compact and it is the best thing since sliced bread.

[fandacious]

just not as nutritious

[Johan Bornman]

At the end of the day, it's about gear ratios.

 

With a compact crank you'll get a lower low gear and lower high gear. With a standard crank it's the other way around.

 

To see if it'll work for you, divide the number of teeth on your sprocket (s) by the number of teeth on your cassette (largest and smallest). Now do the same on the compact crank and see if those two extremes are available to you on that configuration.

 

Gear ratios on a bicycle are measured in distance advanced per crank revolution.

 

To calculate that, you divide the no of teeth on the chainring by the number of teeth on the relevant sprocket and times that by the wheel's circumference - typically 2080m on a road bike and 2050 on a MTB.

 

However, expect the duh look when you ask your bike shop for a combination that equals an advancement of X. This calculation is useful though if you are really fussy about your gear ratios and want to compare the similarities between them on two different bikes.

 

Every cyclist who hits keyboards for a living should have it all set up on a spreadsheet... or am I over-estimating the power of too much free time at work?

 

 

[Windbreaker]

Exactly, .... and the minimal difference in weight does not factor in the real world.