Changing chainring

[Pedro2015]

Currenty riding a shimano 105 30/39/59 looking to move to a 53/39. Looking for a bit of extra speed on the flats with a low option for the hills.

Also currently have an 12-27 cassete going to change it for an 11-28.

Once they are changed over will it need much adjustment?

 

[fossyant]

You might need a new chainset, not just rings. Whats your climbing ability like ? You've got enough speed on the flats with the existing gears. I spot the 59 typo, do you mean a 50 ? If you can push a 50 x 12 on the flat then you are a better man than most of us. You should be able to pedal upto about 40 mph at least with that gear down hill.

 

[Smurfy]

If you can push a 50 x 12 on the flat then you are a better man than most of us. You should be able to pedal upto about 40 mph at least with that gear down hill.

Maybe he's a grinder rather than a spinner, in which case the obvious advice is to learn to spin, which I've heard from veteran grinders is rather hard to do, the temptation to lapse back into grinding being quite strong.

 

[Smurfy]

Currenty riding a shimano 105 30/39/59 looking to move to a 53/39. Looking for a bit of extra speed on the flats with a low option for the hills.

Also currently have an 12-27 cassete going to change it for an 11-28.

Once they are changed over will it need much adjustment?

Here's a comparison of the two setups. At 90 rpm you should be at almost 30mph, a speed that few could maintain for long on the flat. Changing the setup will give you approximately another 5mph at the same cadence.

http://www.gear-calculator.com/?GR=...15,17,19,21,24,27&UF=2135&TF=90&SL=2.5&UN=MPH

http://www.gear-calculator.com/?GR=...14,16,18,21,24,28&UF=2135&TF=90&SL=2.5&UN=MPH

 

[arch684]

You could just change the cassette to 11/28 giving you a low 28/30 for steep hills and 11/50 for speed.I have a flat bar road bike with 48/38/28 and a 11/28 cassette.The only time i use 11/48 is going down hill,i value my knees to much

 

[Nigelnaturist]

Currenty riding a shimano 105 30/39/59 looking to move to a 53/39. Looking for a bit of extra speed on the flats with a low option for the hills.

Also currently have an 12-27 cassete going to change it for an 11-28.

Once they are changed over will it need much adjustment?

I presume the 59 is meant to be 50, I run a 26/38/50 on the same cassette, and have a range from 25.5"-110.4" your current set up has a range of 29.4-110.4" a set up of say 30/40/52 on an 11-23 would give you a range of 34.6" to 125.3" and 125" @90rpm has as been mentioned is 33.5mph, you want to lose your inner ring and low gears, but want higher gears with a larger rear and therefore bigger gaps between the rear gears.
Your proposed gears

The setup I mentioned

Though personally I would go with a 12-23 (12-13-14-15-16-17-18-19-21-23) but I would have lower on the front.

 

[zacklaws]

Since October, I have only ridden on the inner ring to try and improve my Cadence as I am a big gear pusher. Its a 39 on my triple and a 34 on my double and I have been very suprised that I have been able to keep up on club rides, spinning like a lunatic at times with a 39 or 34 x 13 combination so as not to cross chain too much. But I find I am worn out around 40 miles and looking forward to end of March when I'm going back to my old ways, doubt I could do 200/300/400/600 Audax with a high cadence.

But it has opened my eyes that I do not need a 53 chain ring as I have recently had a 50 fitted on a new group set and was not too happy about it and I was going to fit my old 53 on it but realised I do not need it. Found a 46 x 11 was also fast on club rides and is a bigger gear than a 50 x 12 which is what a lot of riders use on their compacts

 

[fatboy123cycling]

The old adage was - Learn to pedal fast before you can ride fast - twiddle a 63 inch gear through the winter

 

[Nigelnaturist]

The old adage was - Learn to pedal fast before you can ride fast - twiddle a 63 inch gear through the winter

My average gear is 61" or there abouts.

But it has opened my eyes that I do not need a 53 chain ring as I have recently had a 50 fitted on a new group set and was not too happy about it and I was going to fit my old 53 on it but realised I do not need it. Found a 46 x 11 was also fast on club rides and is a bigger gear than a 50 x 12 which is what a lot of riders use on their compacts

46x11=110.8", 50x12=110.4", you must be quite sensitive to notice 0.4" on separate bikes
I ride virtually on my middle 38th ring most of the time and my average gear is about 61" or 38x16-17, I can spin anywhere between 85-95 higher when a little fitter than now (or maybe its temps and extra clothing), I very rarely need to come off the middle ring, other than down a slope where my speed starts to increase beyond 24-25mph, I can climb upto 15% on the 38x27 pretty easy enough, but the 26 is there if its needed, but I do use it as gears are supposed to used and not as a final resort as i am running out of gears, I will climb a steady climb on say 26x17-19 rather than 38x24-27 as I have more options and a closer group of ratios.

EDIT
@zacklaws having said that about the difference in gears, I am considering a 12-23 as I really dislike the the 17-19 gap, though not sure on the 23th rear gear, I never have to go as low as 26x23 round here and the 38x23 is only a little higher the the 38x24=42" which is my usual low gear range, but a 12-25 on an 11sp triple would be ideal on my setup, but its not likely to happen.
for reference of the above charts this is my current setup on inches.

and the 12-23 would give

I will probably go with a 12-25 for the summer, but there are many options, I could stay with what I have on the back and change to a 28/40/52 front giving a range from 27.5-114.8", but I still have the big gaps from 17-19, 21-24 and 24-27

 

[zacklaws]

46x11=110.8", 50x12=110.4", you must be quite sensitive to notice 0.4" on separate bikes

Not really, the 46 is on my cross bike and when I bought it I thought it was too small if I use it as a winter bike for the road on club rides and was going to fit a 50 so I could have a 50 x 11 instead of 46 x 11......but I looked up the ratio to see how much I would be loosing and discovered it was slightly bigger than a 50 x12 which is what a lot of club riders have, so I have left it

 

[Pedro2015]

So I'm guessing I want see much difference in changing the cassette from 12-27 to a 11-28 which was going to be my first move

 

[Nigelnaturist]

@Pedro2015 an inch or so lower on the low end and 10" on the high end with a 30/39/50 chainset, option keep the same cassette and change the front to 30/40 or 42/52 this will give a range from about 29.4" to 114.8" I did get past 40mph on that combo last Aug/Sept but then I changed it to the 26/38/50

 

[Smurfy]

So I'm guessing I want see much difference in changing the cassette from 12-27 to a 11-28 which was going to be my first move

Also bear in mind that 11T has very few teeth taking the load, and will wear more quickly.

Unless you are already a very fast rider, best advice is to up your pedalling cadence.

 

[Nigelnaturist]

@YellowTim my middle set of cogs are more likely to wear than than an 11 or 12th
I think its negligible as it wont be rotating as much for a given speed, but in all honesty, unless really expensive groupsets most cassettes are affordable, even to me a 105 cassette at £22 or so whilst a lot in terms of my income, isn't expensive and an Ultegra at less than £30 isn't overlay expensive, (both 10sp).