Help I need smaller gears - what can I do? A GUIDE
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Just going to pop a 12-27 on my 50/39.
Do you really think I need a new chain by moving up from 12-25?0 -
StanwaySteve62 wrote:Just going to pop a 12-27 on my 50/39.
Do you really think I need a new chain by moving up from 12-25?
No way of telling without trying. There's a range of acceptable chain lengths for a certain cassette, and if you fitted the longest possible when you put it on, it should be fine. If the shortest chain was fitted, you make not be able to get into Big-Big and that could spell disaster.0 -
I've got a BBB 12-27 in the post from Ribble and a new chain just in case. Once I've got it fitted I'll report back.0
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Read the whole thread and clicked many a link. Great friendly advice here - useful as I'ma bit gutted after buying a lovely carbon frame road bike and finding I have to push it up my milestone conquered hills. New bike was meant to make me FLY up them!!
So as this bike doesn't have ration for all conditions (and of course I'll keep working on my fitness)I need to make it less high geared.
Thoughts are to go for a combination of a higher low gear than my 27 rear and a smaller front than my 34. Spec:
# Chainset: Truvativ Elita compact 50-34 9I cant find the cranklength spec anywhwre)
# Cassette: SRAM 12-27T 12, 13, 14, 15, 16, 17, 19, 21, 24, 27
# SRAM Rival mech
What do you think are the best products and is it do-able without making the chain too tight in the new 'granny gear' gear? I am a bit gutted to lose hard won hilly ground and its the Dragon ride next year too...
Cheers
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Further (mind numbing!) 'will it fit' research to the above shows a 33 is available here http://www.spacycles.co.uk/products.php ... b0s149p433 for the 'small' cog at the front, which will drop it from a 34 to 33. The other manufacturers wont go below a 34. Wonder why?
Also it looks like SRAM will shortly do a 11 - 32? http://www.fudgescyclestore.com/index.p ... 9&o=115650 Could be all I need if it goes with my current compact Sram Rival road kit?
Any advice gratefully received! Thx.
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Companies such as Stronglight and TA do 33 tooth 110BCD rings to fit any compact cranks including Campag UT.
You will need a SRAM Apex rear mech to use this cassette. And a longer chain.Also it looks like SRAM will shortly do a 11 - 32? http://www.fudgescyclestore.com/index.p ... 9&o=115650 Could be all I need if it goes with my current compact Sram Rival road kit?0 -
Thanks John. Looks like my best bet is that 33 Stronglight small front and maybe a 28 bigger rear then. Hope that makes a bit of difference - cant really use Sheldon Brown's calculator as I cant find the length of my crank arm to work the resultant difference out properly.
Cheers0 -
DieselE wrote:Thanks John. Looks like my best bet is that 33 Stronglight small front and maybe a 28 bigger rear then. Hope that makes a bit of difference - cant really use Sheldon Brown's calculator as I cant find the length of my crank arm to work the resultant difference out properly.
Cheers
Crank length has nothing to do with Gear inches or MPH at certain cadences in different gears. Sheldon Brown has a calculator you can you.0 -
You don't need to use the crank arm length. It does not affect the gear ratios. I just set the calculator to 'gear inches' as they are what I understand. They are the equivelent size of penny farthing wheel that would travel the same distance for one revolution of the pedals. Thus any ring/ sprocket combination that gives the same 'gear inches' will be the same ratio. For instance 50/19 and 34/13 are almost the same.0
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DieselE wrote:Thanks John. Looks like my best bet is that 33 Stronglight small front and maybe a 28 bigger rear then. Hope that makes a bit of difference - cant really use Sheldon Brown's calculator as I cant find the length of my crank arm to work the resultant difference out properly.
Cheers
All you need to do is measure the crank from axle to axle
Or as a very rough guide use your frame size:
small frame under 54cm = 170mm
meduim frame size 54 to 58 = 172.5mm
large frames = 175mm
The crank length in gear inches is not that important and only effects it very slightly.CAAD9
Kona Jake the Snake
Merlin Malt 40 -
33 front and 28 rear gives me 7.4mph per 80rpm (31 gear inches)
The stock 34 and 27 gives 7.9mph per 80rpm (33.1 gear inches)
Is that about equal to 10% 'easier' uphill??? shock:
I wonder if that is worth it as it will probably cost me close to £100? Still I'll have freshly removed kit in the drawer impatiently anticipating a fitness hike or commuting in Holland
Thanks for the input - appreciated.
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John.T wrote:
Crank length does not affect gear inches at all as this relates to one turn of the pedal not how far the pedal has traveled as in gain ratio.The crank length in gear inches is not that important and only effects it very slightly.
You are correct. Looks like I've been looking at "Gain Ratio" on Sheldons calc.CAAD9
Kona Jake the Snake
Merlin Malt 40 -
Thanks - as its my only real option I guess 6.5% 'easier' will have to do and the rest is up to me! Just so annoying I cant get up Castell Coch drive any more (for now!)!!! D0
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I've fitted the BBB 12-27 and it works a treat with the short Campag Centaur rear mech and 50-34 compact chainset. Didn't have to lengthen the chain. Had to slightly adjust the rear mech travel screws and fine tune the shifting which is to be expected when changing a cassette.
Tried out the 34-27 combination earlier this evening and it does make a difference on very steep climbs. Thought my max heart rate was 176 bpm but found out this evening it's actually 180! :shock: To say my lungs where hanging over the handlebars is an understatement..0 -
redddraggon wrote:DieselE wrote:Is that about equal to 10% 'easier' uphill??? shock:
The 33/28 gear is 6.5% smaller than the 34-27 gear.
Guys - thanks for your help here. Ive fitted 33 front and 28 rear with no issues - well I cant do small front with small rear as the derrailuer touches the casette. That's no issue though as that is not anything I'd do or need.
Thanks again - just re-claimed Castell Coch drive
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8)My Bikes
1978 BSA javerlin
1987 Mike Mullet 531c
2008 Giant TCR0 -
not sure how to make quick sense of so many pages of comments on the gears topic. Am a returnee to the bike after 20 years off. Yep, middle aged bloke with a better bike than I deserve 'because I'm worth it'. Just getting my head around all this talk of normal vs compact doubles vs triples. I'm reasonably fit (from running though) and have been riding once a week on North Downs. Have Shimano Ultegra std double 53/39 and 12/25 cassette and have had to work very hard to get up hills like Hogstrough and Sundridge. Haven't dared to try Brasted Hill yet or Toys Hill from South Side. Question is, for this area am I being stupid riding these gears (obviously I am in 39x25 for the worst hills) - should life be easier or will it just come much easier with more time on the bike?0
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Hello and welcome
The more you ride, the easier it'll become but having lower gears will make it easier on your knees etc.
You can get a 105 cassette 11-28 which might just give you that little bit extra or go compact.
Depends what funds you have and how regularly you ride these hills?0 -
SRA66, Good to see you back on a bike.
I started mtn biking 2 yrs ago and got a roadie 6 mths ago.
It ran a 53/39 and an 11/23 x 10 speed cassette. I couldn't climb anything on it until I put an 11/27 cassette on.
I've climbed every hill here bar two (24% grade) since the change.
It's a 15% ratio change and it made all the difference on the hills.
It also had a 172.5mm crank length.
I've changed that to a 165mm crankset to ease my knee problems and at the same time I decided to buy a triple. It now has 1 more gear (that's it....only one) but I can now sit and pedal until the knees cry or I can still stand as well.
The cassette made the biggest difference for climbing.
The cranks made a big difference for flat rides enabling me to cover some distance at speed now.
P.s. Forgot.....my short cage derailleur can handle a 27; my lads s.c. derailleur runs a 28 cassette.
Changing to a triple means changing front derailleur and shifters.0 -
thanks guys - looks like an easier cassette might be the quick fix for now, at least until I get better at the climbing.0
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could probably climb a wall with that! There's hope for us all then...0
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Another one here looking for an easier way up these hills! I've got my eye on a few hills up to 25% and think I will struggle with my current set up. I'd like to stick with my double chainrings which are 52/39 but my rear cassette is either a 12/25 or 13/26 Shimano HG-50 8 speed (can remember without looking).
My current rear mech is a standard shimano 2300, does anyone know what the maximum amount of teeth are that this is recomeneded for? I've got my eye on...
Shimano HG-40 11-30T
Shimano HG-50I 11-30T (anyone know what the 'I' stands for?)
SRAM PG850 11-28T or 11-30T
I like the idea of a slightly smaller gear too for the fast descents. So would I need to change anything else to make any of the above compatible? Chain? Rear mech? Anything? How much difference would an extra 2 or 3 teeth make?
Any help would be much appreciated!If you do what you have always done, you will get what you always got....0 -
Your RD-2300's specs are here:
http://cycle.shimano-eu.com/publish/con ... type-.html
It'll only handle up to a 26T sprocket, on paper. Shimano tend to be conservative, though - it'll probably cope with 28 in practice.
If you swap it for, say, an Alivio rear derailleur (18 quid from CRC), then you could use an 11-32 cassette. That will give you a low gear that's about 23 percent lower than your current set up.John Stevenson0 -
John Stevenson wrote:If you swap it for, say, an Alivio rear derailleur (18 quid from CRC), then you could use an 11-32 cassette. That will give you a low gear that's about 23 percent lower than your current set up.
Now that sounds like a bloody good idea, thanks!
Am I right in thinking the Alivio is a MTB Derailleur? Will I need a longer chain if I were to fit a 11-32?If you do what you have always done, you will get what you always got....0 -
Read through the whole thread and was wondering if anyone's tried the new SRAM Apex combo of long cage rear mech with 11-32 cassette? I'm currently running an Ultegra compact 34-50 with 12-27 on the back (I like to spin up climbs) but at 4 months pregnant I'm now 5kg heavier and finding those gears a struggle up anything over 12%. My knees do not like 50rpm.
Don't want to have to mess about with a triple, so a bigger cassette seems the best option right now. I can live with the spacing, I just want to ride hills a few months longer. Seems like my options are the new SRAM or the Shimano MTB mech/cassette. Anyone have a preference for which runs better?
Unrelated but FWIW (for the other posters debating between going to standard from compact for bigger gears) you can get 38T/52T chainrings in 110BCD which is a nice middle ground. My husband runs that with an 11-28 on his racing bike so he can still hit the steep hills with some spin yet keep up on the downhills.0 -
Yes and Yes. The Alivio is a long cage mech (MTB long) so more chain needed there and the cassette will need at least 1 more link for the 32. Probably about 3 more links all together.Am I right in thinking the Alivio is a MTB Derailleur? Will I need a longer chain if I were to fit a 11-32?
I have been using this for some time with 12/27. It means I can change between 50/34 or 52/38 with no other changes. Much more convenient.Unrelated but FWIW (for the other posters debating between going to standard from compact for bigger gears) you can get 38T/52T chainrings in 110BCD which is a nice middle ground. My husband runs that with an 11-28 on his racing bike so he can still hit the steep hills with some spin yet keep up on the downhills.0
