Amazing the difference a couple of teeth make!!

C3PO

I put an 11 speed standard crankset with a 11-25 cassette on my "good bike" a few months ago! It was great for the few A4 races I did but was hard work on the Wicklow routes that I tend to use .... so much so that I usually took the training bike with the compact instead!

So I "bit the bullet" recently and put a 12-27 cassette on instead. I know it's only approximately an 8% difference in gear ratio between the 25 and 27 but it totally transfers the bike for me! Up past Djouce and even the Devils Elbow are now comfortable without feeling my knees are going to explode and hopefully I'm now covered for most of the climbs I'm likely to encounter!
On the other hand I have noticed that I tend to "spin out" on longer, faster descents in the 12 but it's a compromise I'll live with for the relief on the climbs!

lennymc

you can get an 11 - 28 cassette.

DO you find you go up the hills faster or slower

Tenzor07

Yea 12-28 on mine with a compact crankset, works great for the hills though spinning out at around 65kph is a bit of a pain

C3PO

lennymc wrote: »

you can get an 11 - 28 cassette.

DO you find you go up the hills faster or slower

Not in Campag I don't think?

Much the same I think but my legs feel better at the top!

lennymc

C3PO wrote: »

Not in Campag I don't think?

Much the same I think but my legs feel better at the top!

ah right, i assumed you were on shimano/sram

colm_gti

Sorry to hijack OP, but I have a question....

Currently have a 50/34 and 11-25, and while I find any hill I've encountered in a spin/sportive/race to date more than manageable, I find I'm running out of gears up top on descents and during races.

I've been toying with the idea of switching to a 53/39 and 11-28, and was wondering if there would be a major difference between 34 + 25 and 39 + 28?

irishbuzz

I thought the thread title was referring to a nasty fall

lennymc

colm_gti wrote: »

Sorry to hijack OP, but I have a question....

Currently have a 50/34 and 11-25, and while I find any hill I've encountered in a spin/sportive/race to date more than manageable, I find I'm running out of gears up top on descents and during races.

I've been toying with the idea of switching to a 53/39 and 11-28, and was wondering if there would be a major difference between 34 + 25 and 39 + 28?

take a look at sheldon browns gear ratio calculator, it will show you the difference in the gearing and you should be able to work out a comparable gear on your current setup to emulate a 39-28.

C3PO

colm_gti wrote: »

Sorry to hijack OP, but I have a question....

Currently have a 50/34 and 11-25, and while I find any hill I've encountered in a spin/sportive/race to date more than manageable, I find I'm running out of gears up top on descents and during races.

I've been toying with the idea of switching to a 53/39 and 11-28, and was wondering if there would be a major difference between 34 + 25 and 39 + 28?

Very little - Gear ratio of 1.36 (34-25) and 1.39 (39-28)!

If you've an iPhone there's a handy app "Bike Gears" that does all those calculations!

colm_gti

C3PO wrote: »

Very little - Gear ratio of 1.36 (34-25) and 1.39 (39-28)!

If you've an iPhone there's a handy app "Bike Gears" that does all those calculations!

Oooh that hurts...my iPhone gave up the ghost last night

Might just bite the bullet and get a double so, cheers!

fenris

You could always put a triple on the front.

<gets coat>

manwithaplan

11-28 is a very gappy cassette. It probably won't bother you too much though.

secman

Currently riding on a 52/42 front ring and a rear cassette straight 13 to 19 and a 21 left to climb on. The bike is 20 years old, custom build Raparee with a Dura Ace Group set. Still going very well, but as i'm 55 now, not too sure about the climbing set up !!

My climbing ratio is a 2 to 1 set up !

Am I old enough now to get a granny ring ?

Secman

Surveyor11

fenris wrote: »

You could always put a triple on the front.

<gets coat>

Oi, there's no shame in a triple. Better to be looking at 'em than for 'em.:pac:

fat and slow

Here's a spread sheet to work out speed from gear ratio for different cadences, sean kelly does these calculations in his head.

So sean kelly does a calculation for a 7% gradient hill, he reccons an average tourer's speed going up is 15kmph. Then that rider using a compact and 27 cassette, will have a cadence of 90rpm. But the cadence will drop to 73 rpm if the rider uses a standard 39/25 ratio.

For a steeper hill 10% sean kelly reccons that the tourer's average speed will drop to 12kmph. Using a compact/ 27 cassette the cadence will be 73rpm. using a standard and 25 cassette the tourer's average cadence drops to 59.

ps. try out different front and back combinations in the spread sheet, eg 53/11
50/12

Plastik

I went from an 11-27 to an 11-23 and enjoyed the compact much more. I still had a compact/11-27 on the other bike, took it out one day, and was absolutely all over the place. Impossible to find a 'right' gear. Too heavy, too light, everything in between. Got rid and put a 12-25 on instead. The bigger 27/28 cassette's are definitely very gappy.

A lot of people believe that you won't get strong on a compact, but FWIW one of the strongest guys in our club races on a compact, and he's only a point off an A1 upgrade.

MB Lacey

I'm about to buy a bike that has a 12/30 cassette!
Initially I thought, ok well the 30 will give me loads of easy gears for hills - but from reading the posts here maybe I should ask them to change it to a 11/28? (which they said they would do if I wanted). I'm not hugely fit/ slim enough to float up hills on a 25, but I'm not unfit either.

manwithaplan

Plastik wrote: »

A lot of people believe that you won't get strong on a compact, but FWIW one of the strongest guys in our club races on a compact, and he's only a point off an A1 upgrade.

My winter bike is a compact and you can get plenty strong enough going up hills in the big ring while staying in the saddle. I prefer the standard double for racing but it probably doesn't make much difference. I should really spin a higher cadence anyway.

In getting the winter bike ready, I've just ordered an 11-23 to replace the worn out 11-25 (which itself replaced a worn out 12-27). Having survived your lot's Wicklow painfest on Sunday on 53/39 with 11-25, I should be alright hacking around North County Dublin on that.

@MB Lacey - a 30 tooth sprocket is fairly extreme but I wouldn't go changing your order. Cassettes are replaced regularly enough anyway, so give it a go and if you don't need the last sprocket or two, you can go for a tighter cassette next time.

smacl

MB Lacey wrote: »

I'm about to buy a bike that has a 12/30 cassette!
Initially I thought, ok well the 30 will give me loads of easy gears for hills - but from reading the posts here maybe I should ask them to change it to a 11/28? (which they said they would do if I wanted). I'm not hugely fit/ slim enough to float up hills on a 25, but I'm not unfit either.

I wouldn't go changing it until you're sure you don't want it; with 9 other gears you still have plenty to choose from. If you're into longer cycles the lowest gear you would want at the start of the day is different than the one you want on a steep hill 120k into your spin. I'm running a triple with 30/28 as my lowest gear, which I rarely use, but when I want it, it's great to have. I've cycled past people pushing bikes up hills on sportives on a few occasions, and I'm guessing the bulk of them were better, fitter, stronger cyclists than I am.

Undercover Elephant

smacl wrote: »

I wouldn't go changing it until you're sure you don't want it; with 9 other gears you still have plenty to choose from. If you're into longer cycles the lowest gear you would want at the start of the day is different than the one you want on a steep hill 120k into your spin. I'm running a triple with 30/28 as my lowest gear, which I rarely use, but when I want it, it's great to have. I've cycled past people pushing bikes up hills on sportives on a few occasions, and I'm guessing the bulk of them were better, fitter, stronger cyclists than I am.

+1

The effective difference between 11-28 and 12-30 is that the two lowest gears are lower (GR 1.36 & 1.21 vs 1.26 & 1.13) and you lose one gear at the top end. To put that into perspective, my triple's lowest GR is 1.2 (30/25).

At 110rpm on a compact, you would spin out at 60kmh instead of 65kmh, though I suppose you could always learn to pedal faster.

monkeypants

irishbuzz wrote: »

I thought the thread title was referring to a nasty fall

I thought it was going to be a cross between dating and series of redneck pics.

C3PO

MB Lacey wrote: »

I'm about to buy a bike that has a 12/30 cassette!
Initially I thought, ok well the 30 will give me loads of easy gears for hills - but from reading the posts here maybe I should ask them to change it to a 11/28? (which they said they would do if I wanted). I'm not hugely fit/ slim enough to float up hills on a 25, but I'm not unfit either.

I would change to an 11/28 (assuming a compact crank?). I'm a reasonably strong climber of the "big guy, sit and grind it out" variety and never have need of anything bigger than a 25 with a compact. The 11/28 will be less "gappy" and you will appreciate the 11 on fast descents! As a matter of interest what length derailleur cage was going to be fitted with the 12/30 cassette?

MB Lacey

It is a compact crank, yes.
I don't know the length of the derailer cage but This is the bike with the 12-30 cassette, you might get the info you wanted from there?

When you say the 11/25 or 11/28 is less 'gappy', I don't know what you mean.

I do see the benefit of having the 11/28 for speed, but I could do with slowing down somewhat when I cycle anyway, so a 12 might save me from crashing!

C3PO

MB Lacey wrote: »

When you say the 11/25 or 11/28 is less 'gappy', I don't know what you mean.

Ideally each ring on a cassette would have have one tooth more/less than the ring beside it so that each time you change gear you would get a small, consistent increase or decrease in the gearing. Obviously with a 10 speed set up and a cassette that ranges from 12 to 30 teeth this is not possible and the gap between some gears will be quite noticeable! This doesn't bother some people at all but other people find it really irritating!

manwithaplan

MB Lacey wrote: »

When you say the 11/25 or 11/28 is less 'gappy', I don't know what you mean.

Gear changes between sprockets of only one tooth difference feel nice and smooth. The chain doesn't have far to rise and fall, the small difference between gears allows you pedal on and keep the power down uninterrupted and there isn't a 'clunk' as you shift. The derailleur only has to give and take up a small amount of slack each time.

When there are two tooth differences between gears (probably three teeth at the upper end of a 12-30?), everything is a bit clunkier and the bigger adjustments make it harder to find the sweet spot. The bigger gaps between the number of teeth is why wide-range cassettes are called "gappy". However, you have to trade smoothness for range if you don't have the power to push your easiest gear at a reasonable cadence up a steep hill.

MB Lacey

Thanks for explaining.
I guess at beginner level the larger range is more important, once I turn pro :rolleyes: I'll spend the €50 on getting an 11/28

smacl

manwithaplan wrote: »

When there are two tooth differences between gears (probably three teeth at the upper end of a 12-30?), everything is a bit clunkier and the bigger adjustments make it harder to find the sweet spot. The bigger gaps between the number of teeth is why wide-range cassettes are called "gappy".

Great explanation, though its also worth remembering that not all teeth are equal. Moving from 11 to 12 (1 tooth) represents a bigger percentage shift (8.3%) than moving from 28 to 30 (2 teeth for 6.6% change), which is why the 1 tooth gaps are stacked at the smaller end of the cassette. The tiagra 12/30 is (12, 13, 14, 15, 17, 19, 21, 24, 27, 30), if you want really gappy try the SRAM PG1050 11-32: (11-12-13-15-17-19-22-25-28-32)

J Madone

Plastik wrote: »

I went from an 11-27 to an 11-23 and enjoyed the compact much more. I still had a compact/11-27 on the other bike, took it out one day, and was absolutely all over the place. Impossible to find a 'right' gear. Too heavy, too light, everything in between. Got rid and put a 12-25 on instead. The bigger 27/28 cassette's are definitely very gappy.

A lot of people believe that you won't get strong on a compact, but FWIW one of the strongest guys in our club races on a compact, and he's only a point off an A1 upgrade.

Wouldn't matter what he was riding, he'd still fly.

Kildafornia

I've had 12/25 compact for 2 years and I like it. I find I commit more to hills so even though it hurts me more, I always get to the top ahead of my mates.

Having said that I just bought a set of fulcrum racing 1's (:D) and an 11/28 cassette to go with it. I hope it doesn't make me soft!

Question for you though: do i need to change the derailleur cage or anything else?. Ultegra everything incl replacement cassette.

C3PO

Kildafornia wrote: »

Having said that I just bought a set of fulcrum racing 1's (:D) and an 11/28 cassette to go with it ..... Question for you though: do i need to change the derailleur cage or anything else?. Ultegra everything incl replacement cassette.

Cage should be fine. Your chain may be a bit short though - check (carefully) whether the derailleur is ok in the 50-28 combination! I know you should never use that when you are cycling but .....!