Changing from a compact to 53/39 and cassette question.

The Noble Nudge

Just about to upgrade to a new bike and was wondering about gearing...
I do a lot of hills on my current set up 50/34 front and 12/28 on the rear..

I am thinking of putting a 53/39 on the front to improve my top speeds...am I right in thinking that if I put a 12/30 or 11/30 cassette on the back it would help my climbing (im pushing 96kg)...rather than suffer with the 28 on the back??
or am I gaining anything by doing that??

I don't want to buy the bike and have to change the crank a few weeks in??
I can live with changing the cassette as I have a spare.

youtheman

On your current set up your lowest gear ratio is 34/28=1.214. If you go with the 'Standard' then your lowest will be 39/30=1.3 (or 7% higher than before). So question is: can you handle 7% more effort in the lowest gear.

Another option would be to go for the modern 'mid compact' of 52/34 and keep the 28.

My understanding is that anything bigger than 28 on the back need a 'long reach derailleur'.

Another option is to change the front chain rings if you get a new ring with the same BCD (Bolt Circle Diameter). Normally 130 mm for the 53/39 and 110 mm for the 50/34. I think the new mid compact is also 110 mm so you can change over from one to the other (though you need to make sure the number of bolts is the same, normally 5 bolts, but the new Shimano is 4 bolt I believe).

Simple really .....!

I do a lot of hills on my current set up 50/34 front and 12/28 on the rear..

If you are doing a lot of hills I wouldn't bother with a standard double. Keep the compact up front.

Do you often find yourself spinning out the 50 x 11 gear a lot?

mcgratheoin

The Noble Nudge wrote: »

I am thinking of putting a 53/39 on the front to improve my top speeds

Are you spinning out in the top gear on your compact?

The Noble Nudge wrote: »

am I right in thinking that if I put a 12/30 or 11/30 cassette on the back it would help my climbing (im pushing 96kg)...rather than suffer with the 28 on the back??
or am I gaining anything by doing that??.

It will help your climbing if you put a 30 on the back with your current compact - if you switch to a 53/39 chainset, you'd need to put a 32 on the back just to make it equivalent to the compact with 28.


BTW, what bike are you thinking of getting and could you get a semi-compact chainset - i.e. a 52/36

iwillhtfu

Keep the 50/34 if you regularly climb hills and change the cassette to an 11-28

Increase your cadence. There aren't many average cyclists that'll spin out on the flat in 50-11.

07Lapierre

http://philsroadbikingblog.blogspot.ie/2012/04/oh-change-cassette.html

The Noble Nudge

ronoc wrote: »

If you are doing a lot of hills I wouldn't bother with a standard double. Keep the compact up front.

Do you often find yourself spinning out the 50 x 11 gear a lot?

Its not that I spin out all that often but was on a 53/39 set up recently not sure of the back gearing but I didn't feel like I had the strength to push the bottom gear.
I seemed to be hovering in around the middle of the cassette....

Trial and error at the minute I am staying on the top ring a lot for flats...but straight into the bottom for climbs

The Noble Nudge

mcgratheoin wrote: »

Are you spinning out in the top gear on your compact?


It will help your climbing if you put a 30 on the back with your current compact - if you switch to a 53/39 chainset, you'd need to put a 32 on the back just to make it equivalent to the compact with 28.:cool::cool:


BTW, what bike are you thinking of getting and could you get a semi-compact chainset - i.e. a 52/36

Shimano 6800 groupset on the bike...52/36 could be just the ticket,
They have 50/34 and 11/25 listed as whats on it.

mcgratheoin

The Noble Nudge wrote: »

Shimano 6800 groupset on the bike...52/36 could be just the ticket

52/36 with an 11-32 cassette should give you the best of both worlds then. Unless you're racing then the larger gaps (compared to a 12-25) shouldn't really cause you a problem and you'll have an extended range compared to your compact.

petethedrummer

You're wasting your money. Just get a regular compact. You only need a double if you're racing or a whippet thin climbing god who doesn't race.

It looks pretty awesome having 53/39 up front but when that's coupled with a 30t granny gear on the back it kinda dilutes the awesomeness.

The Noble Nudge

petethedrummer wrote: »

You're wasting your money. Just get a regular compact. You only need a double if you're racing or a whippet thin climbing god who doesn't race.

It looks pretty awesome having 53/39 up front but when that's coupled with a 30t granny gear on the back it kinda dilutes the awesomeness.

And now I'm back to where I started :D
Defo not racing or whippet thin and will never be a climbing god just not walking and I haven't yet is good enough for me....
Not really worried about awesomeness.;)

Vincenzo Nibbly

I'm considering this for a bike that I sometimes use for racing. Currently got 50/34 up front and 25-11 cassette:
w w w. chainreactioncycles.com/ie/en/fsa-super-t-road-compact-n10-11-chainring/rp-prod129960

Is anyone running 52 with 34? Does it work ok? Any issues?

Cyclewizard

The Noble Nudge wrote: »

And now I'm back to where I started :D
Defo not racing or whippet thin and will never be a climbing god just not walking and I haven't yet is good enough for me....
Not really worried about awesomeness.;)

id highly recommend staying with the compact, i have bikes with both and miss the compact on longer decent climbs, keep your cadence high

petethedrummer

The Noble Nudge wrote: »

And now I'm back to where I started :D
Defo not racing or whippet thin and will never be a climbing god just not walking and I haven't yet is good enough for me....
Not really worried about awesomeness.;)

I've stopped racing and have a double on my race bike. I'm replacing it with a compact as soon as I get round to ordering one. I can't see any scenarios where I'll miss the double. Even at low level racing a standard double isn't necessary.

The Noble Nudge

petethedrummer wrote: »

I've stopped racing and have a double on my race bike. I'm replacing it with a compact as soon as I get round to ordering one. I can't see any scenarios where I'll miss the double. Even at low level racing a standard double isn't necessary.

What sort of distance and height are you covering Pete?
Ive about 1600km done this year not far off 21,000m climbed?

The Noble Nudge

Cyclewizard wrote: »

id highly recommend staying with the compact, i have bikes with both and miss the compact on longer decent climbs, keep your cadence high

43km covered 880m climbed last night average cadence if I remember correctly approx 80 last night??
Im no Quintana but as an average cyclist what cadence should I be at??

Cee-Jay-Cee

I'd only go for a standard set up if you find that your not using the lowest climbing gears and able to manage the hills on the 3rd or 4th largest cog on the cassette. If you regularly use the 34/28 then get the same again.

I changed my groupset recently and considered the 52/36 with 12/32 cassette but the big gaps in the last 3 or 4 cogs on the cassette put me off so stuck with compact and 11/28 which hasn't failed me yet.

quozl

The Noble Nudge wrote: »

43km covered 880m climbed last night average cadence if I remember correctly approx 80 last night??
Im no Quintana but as an average cyclist what cadence should I be at??

Depends on yourself to a fair extent, but I had a look at mine on strava for comparison and 50km with 1017m of climbing (very similar distance/elevation ratios to yours) and I averaged 85 rpm.

On a flatter spin, 132km with 1340m of climbing, I averaged 96 rpm.

That's what seems to work best for me. I wouldn't want to go down to 80 RPM and I definitely wouldn't want to go below that. People are different though.

petethedrummer

The Noble Nudge wrote: »

What sort of distance and height are you covering Pete?
Ive about 1600km done this year not far off 21,000m climbed?

I haven't a clue! On and off commuting. 3 or 4 hours in Dublin/Wicklow mts every second weekend.

My lowest gear on the race bike is 39x27 which is manageable if I'm having a good day (torture, if I'm not) but 53x11 and 53x12 are totally unnecessary. If you are going fast enough (70+kmph) to actually spin those gears out, you're either drafting a dublin bus or wasting energy on a long descent where you might as well just tuck in and let gravity do the work. 50x12 is plenty and you get a tighter range on the back to make finding a nice climbing gear easier.

If you take it that Mark Cavendish hits about 70km/h in a bunch sprint on 53x11 and even he does not spin out. Then I can't see a case where mere mortals need that gear. In this vid he's going about 65-70km/h at about 115rpm. After being led out by one of the finest sprint trains ever.

https://www.youtube.com/watch?v=HIVsYHIT8yk

jmdsk

Would the chain length be the same for 53/39 and 50/34. Could you just swap between depending on spin

petethedrummer

jmdsk wrote: »

Would the chain length be the same for 53/39 and 50/34. Could you just swap between depending on spin

The team car will probably have a spare bike for the occasions you need the 53x11.

The Noble Nudge

Thanks lads for all the sound advice.

cycleaddict

looking for some advice as not great at this kind of stuff. Usually ride the hills comfortably on compact 50/34 with a 11-25T Cassette. I have recently changed to a standard 53/39 and was wondering if put on a 11-28T cassette would I find this similar to what I was riding on the compact or would there be a big difference. Far as I know I can't go any bigger than 28T without having to change to a longer cage.

nilhg

cycleaddict wrote: »

looking for some advice as not great at this kind of stuff. Usually ride the hills comfortably on compact 50/34 with a 11-25T Cassette. I have recently changed to a standard 53/39 and was wondering if put on a 11-28T cassette would I find this similar to what I was riding on the compact or would there be a big difference. Far as I know I can't go any bigger than 28T without having to change to a longer cage.

34/25= 1.36
39/28= 1.39

So slightly harder, the thing that might get you is the gap between the 28 and the next sprocket down but that depends on whether you are 10 or 11 speed and which exact cassette you fit

cycleaddict

Would that be a very slight difference???
Compact was a 10 speed 11-25 and the standard is an 11 speed 11-28. Thanks for help I'm getting bogged down with all of this never knew there was so many different options and some not compatible with others etc.

crosstownk

cycleaddict wrote: »

looking for some advice as not great at this kind of stuff. Usually ride the hills comfortably on compact 50/34 with a 11-25T Cassette. I have recently changed to a standard 53/39 and was wondering if put on a 11-28T cassette would I find this similar to what I was riding on the compact or would there be a big difference. Far as I know I can't go any bigger than 28T without having to change to a longer cage.

Not a massive difference in the lowest gear: 34x25T = 1.36:1. 39x28T = 1.39:1. Slightly higher ratio in the 39x28T but only by 0.03:1

jinkypolly

Dividing size of chainset with cassette size to compare different combinations is not technically correct. Using Sheldon Browns gear ratios HERE both combinations come out the same;

34/25= 2.7
39/28= 2.7

youtheman

jinkypolly wrote: »

Dividing size of chainset with cassette size to compare different combinations is not technically correct. Using Sheldon Browns gear ratios HERE both combinations come out the same;

34/25= 2.7
39/28= 2.7

Have to disagree with you there Steve. If I use the Sheldon Brown formula then I get 39/28=2.8 and 34/25=2.7, slight difference (the latter being easier). Sheldon Brown is good if you are going to vary crank length and tire size, but if you don't very these then the simple gear ration is good for comparison purposes (for me anyway).

quozl

jinkypolly wrote: »

Dividing size of chainset with cassette size to compare different combinations is not technically correct. Using Sheldon Browns gear ratios HERE both combinations come out the same;

34/25= 2.7
39/28= 2.7

You're mistaken. If everything else is the same (wheels etc) then all you need to compare is the difference in ratios between chainring and cassete sprocket to compare multiple gear options.

Sheldon Brown's calculator is only to 1 decimal place. I'd imagine it's rounding that has made the two numbers appear the same. They are only different by 2%!