A little more clarifacation on compact gearing

trevtherev

I am still a little confused over the above...now please remember guys that I am not bike technically minded.....so hear goes..I still have in my possession an old raleigh elan which has a double chainring and index gearing....so what is the difference between eg (Kenesis racelight tk) which has a compact gearing ( two chain rings?) and my old raleigh bike. I find the raleigh bike hard to ride as it does not have low enough gears so I presume that compact gears although having only a double chainring will have a greater assortment/range of gears. I need clarifacation because when I get a new bike in Dec under the CTW scheme a lot of my favourite choices have compact gears. I hope this is not too confusing and look forward to your replys I can see one good advantage with the compact setup is less weight and prob less servicing.

N0bodyOfTheGoat

I will have a wild guess that your old Raleigh has 52 and 42 teeth chainrings. On a modern "standard" chainset, it is now more common to see 53 and 39 teeth chainrings. A "compact" chainset commonly comes with a 50 and 34 teeth chainring, although sometimes (like on my Felt for example) the small chainring can be a 36.

Typically, a lot of bikes tend to come with something like an 11 to 23 teeth cassette (cogs on rear wheel), just like my Felt.

On way normal route back home, Chessel Avenue is my challenging hill. According to www.Bikely.com , it climbs 38 metres over 838 metres of road. Now the other night, I took a small insight into the world of a single speeder, trying to get all the way home in my 50 tooth chainring and 21 tooth sprocket. Having got at least 75% of the way home like this without too much fuss, things were about to change...

If my small chainring had been a 42 tooth, I very much doubt I would have made it up Chessel Avenue, as I am a mere irregular bike commuter these days doing no other aerobic sport. Fortunately, dropping into the 36 chainring got me up to the top of the road. If I had had a 34 tooth chainring, my legs would not have been burning quite so much and my lungs may not have been on the point of explosion!

Like I wrote earlier, my Felt came with 11-23 range cassette. I very rarely use the 11-15 sprockets at all, due to my level of fitness and the hilly nature of my commute, in fact I very rarely tend to use my 50 tooth chainring! Consequently, I have a 16-27 cassette waiting to be installed in the near future. This will give me a more realistic set of twenty gears that I am likely to use on a daily basis for the time being.

k-dog

The newer bike is probably easier to ride (especially uphill) because of 2 things:

1. smaller front rings - that's what a compact is - this make them easier to turn.

2. it probably has more gears on the rear so you will have a bigger range - making it easier to be in the right gear for the terrain.

biondino

Nitrous, your highest gear is only going to be a 50/16, which is about 80 gear inches - what happens when you go down a big hill? You'll be struggling to get much into the 30s with such low gearing (and I have a 12-27 cassette with my compact so I'm hardly Mr Macho) - sure, you won't need the highest gears very often but when you do, it'll suck that they're not there!

N0bodyOfTheGoat

biondino wrote:

Nitrous, your highest gear is only going to be a 50/16, which is about 80 gear inches - what happens when you go down a big hill?

Short answer: I will happily freewheel!

Long answer: Until my mid twenties, I was an aerobic sport addict. I did TaeKwonDo sparring to a decent amateur national standard with almost daily training; casual tennis/ squash/ badminton/ football/ cycling.

I then took up smoking at a relatively late age; stopped all the aerobic exercise; became a hermit (rarely ventured outdoors due to crazy sleep pattern and depression); gained quite a few kilos of unconstructive weight. Thankfully, most of these negatives were gradually overcome, starting in 2004.

Being 34 going on 35, the odds of me having the fitness of my early twenties again is extremely low. The four years I spent doing very little must have easily wasted away all the power and stamina I used to have and it would not surprise me if it had a very negative affect on my body in the long term. I do hope to improve my aerobic fitness as an ongoing aim, but moving around units of upto 100kg all day long does not leave me bubbling with energy at home time

oldwelshman

34?!!! Your at your physical peak so why would you not gain your old power aerobic fitness again?
I am 47 and have as much aerobic fitness as I ever had since returning 2 years ago after 23 years away from cycling, but not quite the same power. I did try using my old bike with 42/52 13/21 and was surprised to see how I struggled up climbs Thought some one let my tyres down!!
You can easily get fit again, for one dont put that silly rear sproket on 8)

N0bodyOfTheGoat

Well its bought now and it really will encourage my legs to wander into the murky realms of the 50t chainring on a regular basis. Even at my current fitness levels, having just got back on the bike again this week for the first time for a few months, I know I will have at least 5 ratios useable with the 50t (20-21-22-23-25... NOT the 27 as this will put extra strain on the transmission).

This easier cassette will not last forever and I hope to "upgrade" to either a 14-25 or a 12-27 at some point next year. :shock:

unclemalc

oldwelshman wrote:

34?!!! ......You can easily get fit again, for one dont put that silly rear sproket on 8)

I came back to 'serious' cycling a few years ago after a long lay-off. I am 52 with very dodgey knees and about a stone in weight that really does not want to leave home, so I haul ~85 K around.
I ran a 52/39 - 12-23 for a few years and avoided steeper hills because I simply could not get up them with the 39-12 gear.
Then I discovered the Compact set of 50/34. Coupled with a 12-25 cassette I can now do 12% hills without tooo much trouble.
You can get 11-30 cassettes - I ran one with a 53/39 chainset for a while and although the 39/27 gear was useful and the 53/11 was a complete buzz going downhill, it meant a lot of doubleshifting around the 'middle', most-used gears - but - its out there if you fear 27 is not enough on the back.
But don't start with a '16'.....you'll be freewheeling most of the time.

Bugly

"ran a 52/39 - 12-23 for a few years and avoided steeper hills because I simply could not get up them with the 39-12 gear" :shock:

Surely you mean 39-23 that was your lowest gear :oops:

redddraggon

Does your frame take a 16t smallest sprocket? I know some frames don't even take a 13t......

John.T

Trev. Use Sheldon Brown's gear calculator to see what difference changing front rings and rear cogs makes. If you change 'gain ratios' to 'gear inches' this equates to the size of penny farthing wheel that would travel the same distance for one turn of the pedals. Just input your current rings and cogs and the compact ones and see the difference. Any change more than about 5" is very noticable.
http://sheldonbrown.com/gears/
Sheldon's site is a mine of useful info and should be bookmarked on any cyclists computer.
http://www.sheldonbrown.com/

unclemalc

Bugly wrote:

"ran a 52/39 - 12-23 for a few years and avoided steeper hills because I simply could not get up them with the 39-12 gear" :shock:

Surely you mean 39-23 that was your lowest gear :oops:

...perhaps that's why my knees are knackered... :shock:

Cheers for pointing that out - yes 39/23.... :oops:

Bugly

:oops: sorry I am a pendant

meagain

It's all very complicated this 'ere gear stuff, ennit?
With my 61" fixed I may not often be in the right ratio, but then I can never be in the wrong one!

edindevon

Bugly wrote:

:oops: sorry I am a pendant

Is that in addition to be a pedant?

On topic, I'm a 43 year old recreational rider and a low gear of 34 / 25 is enough to get me up all of the hills in East Devon.

Edindevon