Gear Ratios

[gummibear]

For 3 weeks now i did a test to try and decide if i need a compact crank or not.I only started riding 3 weeks ago after a 6 month layoff(only rode 1-2 days a week).i rode 3 days a week for 1hour and 2 hours on Sunday.all the rides were on the same routes. All the routes have a few hiils.

Week 1

53x39 crank and 11-23 cassette

 

Week 2

50X34 crank and 11-21 cassette

 

Week 3

53X39 crank and 12-25 cassette

 

This last week my overall heartrate for the week is lower including the long ride.my cadence avg is about the same.My avg speed on all my rides this week are also higher.and the time is shorter on all the rides.

Now is this me getting fitter and do i then keep with week 3 gears and forget about the compact crank set

windblown2007-12-10 05:46:43

[Mudsimus]

Just use the 53-13 12-25. If you use any of the other you will always be in two minds.

 

Personally I think compact cranks are BS.

[FlyingCheetah]

IMHO:

It all depends on the route. Heavy hills, go for the 50x34 and the 12-25. Flats: 53x39 and 11-21, otherwise the 53-39 and 11-23 should be fine.

 

[Kriek]

I use a 52-39, 11-23.Found it to be just right for me.

[Sequoia]

I normally use 53-39, 11-23 and can get up Pompstasie-se-bult. Did the Burger on a lowest gear combo of 42-21 and almost died.

[gummibear]

IMHO:

It all depends on the route. Heavy hills' date=' go for the 50x34 and the 12-25. Flats: 53x39 and 11-21, otherwise the 53-39 and 11-23 should be fine.

 

[/quote']

 

the 50x34 was borrowed so i cant just change it i must decide if i want to buy it....but i dont think so.i think i will stay with my cranks for now.

[JasonW]

Just use the 53-13 12-25. If you use any of the other you will always be in two minds.

 

Personally I think compact cranks are BS.

 

Damn, that's a weird chainring combo!

[porky]

Heavens Windblown,you cant dertermine your ideal gear ratio by just duplicating the ratio someone else here uses, there are too many variables.

Body weight and structure, age, do you prefer to spin or grind and the terrain you will be training on are just a few of the points to consider, a 20 year old fit and healthy cyclist could probably fly up a mountain on a 11-21 rear, but a 45 year old (moderaletly fit) middle aged fella with a bit of extra weight might need a 12-27 just to see the top in the saddle.

 

My suggestion would be to go to Sheldon Browns web page (www.sheldonbrown.com) and read up on understanding gear ratios first - then make an informed change.  

 

 

porky2007-12-10 13:27:39

[widget]

Yes, I agree Porky, a gear ratio is just a reflection of you preferance - just because you climb well with an 11 sproket, dosnt mean you are better than the guy who climbs with a 27 sproket.

 

Simoni, one of the best climbers in the world routinely uses a 36/29 combination and / or a 43/27 on some of the mountains - a gear ration you ride is no indicator of anything except "thats what suits you".

 

As most average cyclists fall into a range the wide range clusters are usually fine (ie)12/25/27 but even then, you will find yourself favouring three or four combinations over the rest.

 

The narrow band clusters are great for young fit or well trained individuals as they are used to a heavier work load but no good for the "more moderately fit" individual. 

 

Read what Sheldon Brown has to say about crank lengths / gear ratios and decide if you need a compact crank.

 

widget2007-12-11 02:13:44

[gummibear]

thanks porky.i had a look at that site.

[Canaris]

THe compact cranks are designed spefically to accomodate those who prefer cadency over power.   (and for those who do not have powerful legs).

 

 

 

You may find on very steep climbs that the pro's will go for compact cranks over an excessively large gears in the cluster, but the trade off is that you may run out of gears when decending.

 

 

 

But each to his own. Ask yourself "do I really need a 11 on my cassette or should I go for a 25 rather?"

[NotSoBigBen]

Know someone who rode with an MTB cassette at R4V!!!! Guess it gives the same effect? Not sure how well the RD coped but ja whateva it takes I guess!

[Gumpole]

THe compact cranks are designed spefically to accomodate those who prefer cadency over power.   (and for those who do not have powerful legs).

You may find on very steep climbs that the pro's will go for compact cranks over an excessively large gears in the cluster' date=' but the trade off is that you may run out of gears when decending.

But each to his own. Ask yourself "do I really need a 11 on my cassette or should I go for a 25 rather?"[/quote']

 

I have to jump on this before the power fundis do

 

Powerful legs do not = slow cadence (eg Armstrong).

 

 

[madmarc]

Here is my 2 cents worth. Sheldon Brown needs to get a job because to understand his site you will need a phd in physics. go to www.machinehead-software.co.uk and downlod his gearcalc pro software. The demo version only lets you calc based on a 7 speed, and you have to pay 15 pounds to get the full version. But if you are calculating gear ratios to increase (A) hill climbing you wil only need to use 3 of the larger cluster gears and your small ring or (B) downhil or flats you would use the big ring and the last 4 - 5 cluster gears as input values. So the 7 ratios still give a wealth of info.

I have the same dilema and have been doing a lot of theoretical calculations off this software. the best thing is that the software gives you your speeds at a given cadence in each ratio. this means that you can select gears, input differnt cadence values and check the improved speed based on your selection.

 

My problem was on the 94.7 I rode a 3:24 and expected to do a 2:45, my average speed at the bottom of the dome hill was 35.6km/hr, which was in line with a time of 2:45. But the dome hill, cosmo city and the highway killed me (reducing the average speed to 27.7 km/hr), not to mention blue hills and the camel humps. I realised that I could not increase cadence on these gradients and had to make like Ulrich and chugg away like a diesel tractor.

to do this i needed to increase my current 23/11 to a 25/12 or a 26/13 in order to make it easier to pedal, but i needed to know with these ratios, what my speed would be (obv. lower) but i assumed a 20% increase in cadence as it is easier to pedal and then reviewed the speeds given.

 

The end result is a 40min improvement in my time (purley theoretical at this point) the next step is to take the ratios on the bike with a tacx trainer and record the power reading for my current cluster and then, with the new clusters i will take the cadence readings when pedaling at the same power level as well as the speeds.

 

However the above scenario would only be good for the 94.7 and you will need to re-evaluate your ratios for other races with different profiles. i believe i will need 3 different clusters. 1) 94.7, Jock & Africycle tour 2) Argus 3) Hyper 2 Hyper, Ride for site, Macsteel Classic etc.

 

PHEWWW i hope you don't need a phd to read all this BS

[Johan Bornman]

For 3 weeks now i did a test to try and decide if i need a compact crank or not.I only started riding 3 weeks ago after a 6 month layoff(only rode 1-2 days a week).i rode 3 days a week for 1hour and 2 hours on Sunday.all the rides were on the same routes. All the routes have a few hiils.

Week

 

 

Cut cut cut cut

 

Now is this me getting fitter and do i then keep with week 3 gears and forget about the compact crank set

 

Others have already given you good advice on gear ratios but I want to point out that your experiment is flawed. You're just fooling yourself if you believe your data.

 

The result you produced has nothing to do with the gears and everything with how good you felt on the day or indeed, week. The exercise physiologists here will probably chip in and explain how prolonged stress in short cycles such as your three-week cycle affects the body.

 

But, heart rate is related to all sorts of things, not to mention wind speed, how much sleep you've had, when you're riding and your health.

 

If the gears feel fine to you, ride with them.

[gummibear]

thanks for all the info.