Is it possible to get up hills on a compact set up

[ashtons99]

Im back to road biking after a long long break. Currently using an FCR2 which as a triple is a half decent climber. Im already though looking round at some expensive carbon drop bar stuff.

What concerns me is having spent 2k of my hard earned is whether i would actually be able to actually get to the top of hills on a compact chainset. Apart from Trek most of the 'boutique' bikes are all compact.

I thought i recall a thread about this but cant find it so my question is
....Can I get a gianribbldolanorbeafeltetc with a compact set up and still have half a chance of not pushing up hill.

 

[Dayvo]

If you can make head nor tail of it, this should be able to explain things for you.

http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3521

It's the range of gears you have available that matters.

 

[bonj2]

it depends what the hill is like
you can get up hills on a normal double chainset
but long hills/very steep hills/long steep hills/a lot of hills for a long time, any combination of one (or more) of those and a triple or compact is easier.
as dayvo says it's the range that matters.
on my double, i can use from 1 to about 5 or 6 on the small ring, and from about 2-3 (1 at a push) on the big - 5 or 6 on the small sort of roughly meets 2 on the big - whereas on a compact, you probably need to go right to the top of the block on the small ring to meet the bottom of the block on the big ring, so you're more likely to have the chain rubbing the front mech.
You may also need a long cage rear mech.

what about this- if you're getting a new bike just get a normal double then if it's hilly you can take your current bike with its triple.

you can stand up on hills and honk, or just grind - learn to 'heel' it and you can find extra torque from the hamstrings. riding fixed helps a lot with this

 

[Dave5N]

Yes. You can and you will.

 

[Will1985]

A compact should be easier than a double. Get one and be done with it. You can always change cassettes around, or even add 53/39 chainrings to make it a normal double.

 

[Randochap]

Depends.

 

[jimboalee]

There are a lot of 'Gear calculators' on the web and in magazines, but none say what gear should get you up what gradient.

I said something a while back and got a real scathing response. It was a 'general rule' for a 'first season' cyclist.

Let me ask all of you a question. "Why are the pedals NOT included in the weight of the bike?"

Its all about 'Dead weight', not the combined weight of the bike AND you.

A cycling coach can reasonably expect a novice cyclist to be fit enough to climb several flights of stairs without getting completely breathless. When you are cycling up a hill, you are effectively climbing several flights of stairs while carrying your bike.
So, to those ends, the gearing is calculated by using the weight of the 'dead' mass. It is also dependent upon a 'reasonable' power expectation.

Forward motion is reduced when upward motion is increased, until upward motion requires ALL the power available.
If you have a good idea of the power ( continuous ) you can produce, you can apportion that between forward and upward speed and then choose the gearing upon the cadence you use to ride those speeds.

Everyone is different. Different bike, different strength, different natural cadence.

Bike manufacturers in the sixties and seventies geared their 'Roadrace' bikes quite high, engineering lowest gear to be the 1/lbx1000 rule.
They expected the customers to be pretty fit already when the bike was bought.

Coming back to 'reasonable' power expectation, this is the reason 'Compacts' have become popular.

 

[Randochap]

There are a lot of 'Gear calculators' on the web and in magazines, but none say what gear should get you up what gradient.

I said something a while back and got a real scathing response. It was a 'general rule' for a 'first season' cyclist.

Let me ask all of you a question. "Why are the pedals NOT included in the weight of the bike?"

Its all about 'Dead weight', not the combined weight of the bike AND you.

A cycling coach can reasonably expect a novice cyclist to be fit enough to climb several flights of stairs without getting completely breathless. When you are cycling up a hill, you are effectively climbing several flights of stairs while carrying your bike.
So, to those ends, the gearing is calculated by using the weight of the 'dead' mass. It is also dependent upon a 'reasonable' power expectation.

Forward motion is reduced when upward motion is increased, until upward motion requires ALL the power available.
If you have a good idea of the power ( continuous ) you can produce, you can apportion that between forward and upward speed and then choose the gearing upon the cadence you use to ride those speeds.

Everyone is different. Different bike, different strength, different natural cadence.

Bike manufacturers in the sixties and seventies geared their 'Roadrace' bikes quite high, engineering lowest gear to be the 1/lbx1000 rule.
They expected the customers to be pretty fit already when the bike was bought.

Coming back to 'reasonable' power expectation, this is the reason 'Compacts' have become popular.

Readers' Digest version: Depends.

 

[jimboalee]

I was in a fortunate situation when I was young because Birmingham had a cycle track. It was 400m round and if a rider could ride 75 laps in an hour, he was producing about 0.25 hp continuous power. 175 Watts is a reasonable power to exert on a 'fast' section of flat road (18mph) or a hill up to 10%.

So knowing which gear you ride along at 18 mph, calculate the cadence.
Now using this cadence, calc the speeds in each gear.
The power vs speed curve is not linear and you will find a 10% gradient at 175 Watts will be 10.2 mph at 72 rpm on a 49" gear. This was the lowest gear fitted to a 20 lb dog-bolox race bike which was aimed at the club event rider.

OK, so a novice only covers 60 laps. His continuous Wattage is about 100. Now his climbing ability up a 10% is 6.8 mph at 61 rpm on a 39" gear. The magic 40" for a 25lb bike.

An absolute beginner only covers 50 laps ( 12.5 mph ). His continuous power is about 70 Watts. This means to get up a 10%, he'll need a 35" gear, ( which was the lowest on my Dawes Giro 500 – entry level 'sports' bike ); spin it at 57 rpm for a speed of 5.8 mph.


Yes, it "Depends", all right.
Is it a little clearer now?

 

[Chris James]

Its all about 'Dead weight', not the combined weight of the bike AND you.

If you have a good idea of the power ( continuous ) you can produce etc.

Jimboalee, if this is true, then one might expect that the same rider, with the same power output, would go up a steep hill 50% faster on a 8kg bike rather than a 12kg bike, using the same gearing.

Do you believe this to be true? I don't.

Re the OP, you can compare the gearing on a compact and your triple and cycle up hills that you find hard on the triple in the same gear as the bottom one on your compact.

eg

compact 50/34, 12-27 10 speed cassette, bottom gear is 33 inches

triple 52/42/30, 12-25 10 speed cassette, second to bottom gear is 34 inches.

So in this case, if you could climb your local hills in 2nd gear on yuor triple then you could get up them with bottom gear on the compact.

But, as many threads on here argue, the difference between triples and compacts is not just the range of gears but how they are distributed.

 

[peanut]

A compact should be easier than a double. Get one and be done with it. You can always change cassettes around, or even add 53/39 chainrings to make it a normal double.

yes +1 I just switched to compact doubles 50x34t on both my bikes after 20 years of 53x38t doubles
I have put on 2 stone and needed a lot of help on any slope.

The beauty of compact doubles is you only change the chainset. No other part of the transmission system needs changing which saves a lot of unecessary cost.

Changing from a 39t small ring to 34t on the compact is not huge but combined with a 27t or even 28 t sprocket on the cassette has given me an extra 10" reduction in gearing effectively an additional 4 or 5 gear changes

 

[jimboalee]

Let's take my Spesh SWorks. 7.6 kg. 39 x 25 (42") and whizzes up a 10% at 9.3 mph at 77 rpm.
Now my Dawes Giro 500, 11.5 kg and on 30 x 19 (43") gear, I go up a 10% at 53rpm at a miserable 6.5 mph.

To be quite honest, the Spesh goes up a 10% on 39 x 19 ( 55"), at 59 rpm.

 

[Chris James]

Let's take my Spesh SWorks. 7.6 kg. 39 x 25 (42") and whizzes up a 10% at 9.3 mph at 77 rpm.
Now my Dawes Giro 500, 11.5 kg and on 30 x 19 (43") gear, I go up a 10% at 53rpm at a miserable 6.5 mph.

To be quite honest, the Spesh goes up a 10% on 39 x 19 ( 55"), at 59 rpm.

Your examples don't sound like real world examples, but rather calculations. 77 rpm (not 80?), 9.3 mph (not 9.0) etc.

I shall have to dig out my copy of Bicycling Science as I seem to recall it contradicts your assertion. Off the top of my head they talk about a handful of seconds at the top of large climbs per kilo of bike.

Also, given that bikes are built down to the UCI limit of 6.8 kgs nowadays, but in the 50s a good bike would be , what, 10kg?

In 1952 Fausto Coppi climbed Alpe d'Huez in 45 mins 22s. In 2006, fifty years later and with the benefit of highly modern training and nutritional methods, Frank Schleck clkimbed the Alpe in 40mins, 46s. On a bike that was probably 30% lighter.

By your theory he should have climbed it in about 30 minutes. The best ever time up the Alpe is 37 mins 35s by Pantani. The sub 40 minute times co-incide with the EPO boom years, not lighter bikes.

 

[jimboalee]

Of course they're calculations. Calculations based on results from recorded data off my Garmin on a regular basis.
There has been much chatter lately about gearing for hills, so in this recent nice weather, I've had my two bikes out quite often, over the same route, clockwise and anticlockwise, but not both at the same time.

My Garmin is recording distance and elevation. From the hundreds of data points in the 50 km route, I can plot my climbing speed vs gradient after rejecting any 'outliers' - obvious duff datapoints. MS Excel plots a 'best fit' polynomial.

The coefficients for the 4th order poly are entered on my spreadsheet to give a 'theoretical' curve and I compare this with the recorded 'spot' datalogs during the climbs. It's a 'fair' fit. +/- 1%

This has been done for the two bikes. The difference IS noticeable. The 17lb Spesh with a half full bottle DEFINITELY is easier to ride up a hill. That's not a surprise. The surprise is the slow speed I ride The Dawes.

BTW, the Cd of the Spesh is 0.80. and the Cd of the Dawes is 0.95. Shall we discuss that?

 

[peanut]

....Can I get a gianribbldolanorbeafeltetc with a compact set up and still have half a chance of not pushing up hill.

to answer this we really need to know what your current setup is on your bike.
Let us know what teeth your cassette has and your chainrings and we can then show you some examples of advantages and disadvantages of compact v standard double v triple

otherwise Jim and Chris are going to rabbit so far off topic we'll all end up catatronic


by the way a hearty welcome to the forums ........ tsk ........where are your manners guys ?