34/50 compact double or a triple for tough hills ?

Ezy Rider

I have a shimano hollowtech II 34/50 compact double on my bike with a 12-25 rear cassette, last week I rode up a 20% gradient and jeez it was tough and I didnt enjoy it one bit. When I got to the top , I shudder to guess what my heartrate was :shock: . Would a triple hollowtech with its 30/39/50 chainrings really make that much of a difference on a 20% ascent ?

Im not going to MTFU over this, 20% was too much for me and I admit this. If climbing 20% using 30/25 wouldnt be dramatically easier than 34/25, then I will put the notion of a triple to bed.

What are your thoughts :?:

rozzer32

Put a 27 or 28 tooth rear cassette on.

Ezy Rider

rozzer32 wrote:

Put a 27 or 28 tooth rear cassette on.

how much different would 30/25 be to 34/27 ? i never understood the way you guys calculate these sort of questions :oops:

tri-sexual

you will get similar gearing with 28 tooth cassette
not a big fan of triple chainsets on road bikes

night_porter

+1

The closest gear to 30/25 is 34/28

So you could put a 12-28 and achieve the same lowest gear as changing the chainring to a triple but cheaper.

I do not have any magic formula but there is a Gear Calculator here http://www.sheldonbrown.com/gears/ I usuallyuse gear inches as the Gear Units.

You can put custom cassette sizes in to understand the benefit you would gain.

unixnerd

I use 30/25 to get up Cairngorm on a triple and I don't always need the lowest gear. 34/28 on a double is almost an identical ratio and you'll get away with a 28 (certainly a 27) on most mechs.

Much easier to try a new cassette than switch to a triple. If that's not enough change the rear mech to a long cage version and fit an 11-32 mountain bike cassette with a slightly longer chain.

Bozman

Practice and it'll slowly get easier(that's what i was told).

nmcgann

Ezy Rider wrote:

I have a shimano hollowtech II 34/50 compact double on my bike with a 12-25 rear cassette, last week I rode up a 20% gradient and jeez it was tough and I didnt enjoy it one bit. When I got to the top , I shudder to guess what my heartrate was :shock: . Would a triple hollowtech with its 30/39/50 chainrings really make that much of a difference on a 20% ascent ?

Im not going to MTFU over this, 20% was too much for me and I admit this. If climbing 20% using 30/25 wouldnt be dramatically easier than 34/25, then I will put the notion of a triple to bed.

What are your thoughts :?:

No. 20% gradients are weight-training-on-a-bike with just about any road bike gearing.

Getting used to climbing out of the saddle and going slowly works on this kind of ascent, but it's always going to be hard.

Bobbinogs

Ezy Rider wrote:

rozzer32 wrote:

Put a 27 or 28 tooth rear cassette on.

how much different would 30/25 be to 34/27 ? i never understood the way you guys calculate these sort of questions :oops:

It is all about inches, as Marge might say.

A 30/25 is 33", a 34/28 is 33.5", so they will feel exactly the same. Hence, if you have a compact already I would stick with it and change the cassette as per rozzer.

You might need a new rear hanger but then again you might not (you might get away with your current hanger, possibly needing a small adjustment to the b stop). Also, an extra chain link will probably be needed for optimal tension, lots of online guides to chain length but one link either way isn't enough not to use the bike until that is sorted.

A couple of my bikes are standard doubles (53/39) and I managed to get 13/28 onto both of them with just an extra link needed in the chain, which I had kept from new. This combo (39/28 ) is 38.5" so not as low as I would wish for really big hills but I managed to do large parts of Exmoor last w/e without suffering too much. The difference for me is the amount of standing, as in I can spin sitting down up a much greater portion of a steep hill with a triple running 30/25 but I still get to the top with standard gearing.

I do have one bike with a triple and love it. The bottom gear is 30/25, which is about as low as I have found to be manageable. The triple is my bike of choice for very hilly routes but I am more than happy to tackle a hilly route with 39/28 as long as the hills are not too steep and the route too long (over 75M).

I certainly wouldn't go to all the fuss and cost of adjusting a compact over to a triple (lots to change and tweak).

Anonymous

A 20% gradient is a mare with any gearing. But I'd definitely consider getting a 12-27 or 12-28 cassette. It is much cheaper than changing to a triple as this don't just need the chainset, but you are likely to need a front shifter too...

Paul E

I hardly use first chain ring on the triple on my bike, I had no choice as that was the only option on the sectuer elite.

After a trip upto Scotland with panniers etc I will be changing mine to a compact as I think I will use the gearing on one a lot more as I tend to just use the middle ring on my triple as it is anyway commuting.

brin

Bozman wrote:

Practice and it'll slowly get easier(that's what i was told).

+1.......and they were right

Cleat Eastwood

To get the figures for gear inches that you see bandied about (apart from sheldon brown who calculates something called Gain Ratio) you divide the ring at the front by the cog at the back and multiply by 27

so...

53 (big ring) and 19 on the back gives gear inches 75.3

which is the same as 39/14.

for your problem...

compact: 34 and 25 gives 36.7

34/28 gives 33

a triple would give you 30/25*27 = 32.4

Figures are helpful as a guide but at the end of the day 20% is a massive hill and hats off to you for doing it.

ForumNewbie

I currently have an Audax bike with a triple chain ring. My lowest gear is 30/27 which can get up just about anything even although I am not a strong rider. I am thinking of getting a new Specialized Secteur Elite but was initiallly concerned as it has a Compact Chainring 50/34, but then I saw it has an 11/32 cassette. When I looked into the gear ratios I found that the lowest gear on the Secteur 34/32 is actually a lower gear than my Audax's lowest 30/27 - so losing the granny ring shouldn't cause me any problems if I do eventually buy the Secteur.

Vega 165

I changed from a 11 25 rear cassette to a 11 28 (Shimano 105) huge difference especially when tired. Living in a hilly area the 28 gets used quite a lot and at the top of the hill instead of coasting while I got my breath back now I can carry on pedaling so I think I am faster now than before.

Ezy Rider

Cleat Eastwood wrote:

To get the figures for gear inches that you see bandied about (apart from sheldon brown who calculates something called Gain Ratio) you divide the ring at the front by the cog at the back and multiply by 27

so...

53 (big ring) and 19 on the back gives gear inches 75.3

which is the same as 39/14.

for your problem...

compact: 34 and 25 gives 36.7

34/28 gives 33

a triple would give you 30/25*27 = 32.4

Figures are helpful as a guide but at the end of the day 20% is a massive hill and hats off to you for doing it.

why are you multiplying specifically by 27 ? is that a static figure for all calculations irrespective of chainrings / rear cassettes used ?

micken

^ 27 is an avaerage approximation figure you use for a road wheel with a 23c tyre.

chrishd883

27 is the circumference of the standard 700c wheel / tyre combination.
As in one revolution of your wheels, yoiu travel 27 inches.

So - for example - one ot one gearing
Say 30 tooth chain ring and a 30 tooth rear cassette
Every pedal revolution would mean you've travelled 27"
So that gear combo is 27"

With a 30 tooth chain ring and a 15 tooth rear cassette cog you would travel twice as far
The wheel turnign twice ofr each pedal revolution.
So that gear combo is 54"

You can get the same gear range from a triple or compact
But they are different to ride - this topic can stir people up a little
Triples appear to be a little like marmite - you either love them or hate them.
They won't make it significantly easier & you can get the same gearing in a compact
The triple option - if set up for the same gear range - will offer smaller steps
which can be nce when you are tired.
For the record - I ride both triples and compacts.

Berk Bonebonce

Triples have the advantage of offering closer ratios if you use something like an 11-23 cassette, and you get 10 extra gears.

TommyEss

Ezy Rider wrote:

rozzer32 wrote:

Put a 27 or 28 tooth rear cassette on.

how much different would 30/25 be to 34/27 ? i never understood the way you guys calculate these sort of questions :oops:

That's the calculation right there - 30 / 25 = 1.2.

34 / 28 = 1.21428571

So they're very similar gears - 50/12 - your current top gear , = 4.16666667

N.B. I'm aware that this isn't really calculating the gear, but to give a rough and ready guide to allow you to compare ratios, then it's all you need.

TommyEss

Ezy Rider wrote:

rozzer32 wrote:

Put a 27 or 28 tooth rear cassette on.

how much different would 30/25 be to 34/27 ? i never understood the way you guys calculate these sort of questions :oops:

That's the calculation right there - 30 / 25 = 1.2.

34 / 28 = 1.21428571

So they're very similar gears - 50/12 - your current top gear , = 4.16666667

N.B. I'm aware that this isn't really calculating the gear, but to give a rough and ready guide to allow you to compare ratios, then it's all you need.

tx14

if the road situation allows it, you can zigzag your way up. it lowers the effective gradient, as you have to move more distance to get to the same height.

Ezy Rider

i watched guys do it that way on youtube clip of fargo street and its 32% ( :!: ) gradient

jamlala

Cheapest option for starters (other than training harder!) is to get a new cassette fitted with as large-a cog as you can get without having to change the gear mech. Cost including fitting in my LBS was about £40. Triples etc will cost you one hell of a lot more!

tincaman

I changed to SRAM apex long reach derealiur + apex 11-32 cassette + new chain, total cost £95, weight saving over a triple about 250g

Bar Shaker

tincaman was just going to say about the SRAM road 32. You could ride up the side of a house with that.

jejv

Seems like your comparing a Shimano 50/34 compact double with a Shimano compact triple 50/39/30.

But a 110/74mm compact triple will go down to a 24T granny. And a triple road mech will handle 50/38/28, and quite likely 50/36/26 - or something like that.

So yes, a 50/39/30 does seem a bit pointless, but - say - 50/36/26 might be worthwhile.

dombo6

I have had both a 52/39 with a 12-28 cassette and now a 12-25 with a 52/39/30 triple. The 12-28 cassette was easily handled by a standard 105 rear mech. Psychologically the triple can be better, knowing you have that bail out gear to get up anyything. What you need depends as much on how far you've already gone as the steepness of the hill. On last week's Dragon I did the first ascent of 6-7% Bwlch happily in 39/23. 60 hilly miles later and i crawled up it in the 30/25. I can climb my local 18-20% hills in the 39/25 also but often after a longish ride it's nice to slap it into the granny and twiddle. Compacts look nicer and if you can fit a 12-28 cassette with a 50/34 then your lowest gear is the same as 30/25.

dennisn

TA Specialties sells a 33 tooth front compact ring which will help just a little bit more with those hills, if you choose to go that way. If I'm going to the mountains I always switch to my 33 with a 28 on the back and it works pretty good. Plenty of gears. I normally use a 36 front ring where I live(it's flatter than a table top around here - the biggest climbs are highway overpasses).

Berk Bonebonce

Dombo6 wrote:

I have had both a 52/39 with a 12-28 cassette and now a 12-25 with a 52/39/30 triple. The 12-28 cassette was easily handled by a standard 105 rear mech. Psychologically the triple can be better, knowing you have that bail out gear to get up anyything..

A 25 sprocket and a 30 chainring might get a fit and lightweight individual up anything, but not your average Joe up a hill more than 20%.

Using a cassette with wide ratios sucks; there is too large a gap between each gear. A triple offers closer ratios so that it is easier to find the 'right' gear. This is why they have close-ratio gearboxes on racing cars.

Ezy Rider

Berk Bonebonce wrote:

Dombo6 wrote:

A 25 sprocket and a 30 chainring might get a fit and lightweight individual up anything, but not your average Joe up a hill more than 20%.

.

I am 41 and the 20% climb I did just wasnt nice in any shape or form, I grit my teeth and cursed at myself to complete that section. I am not a challenge shirker by any means, but I know what is just too much for me. At 21 I would have kept at it, but at 41 its just too much for me