Gearing set-up on new bike

RyanW

The abominable Bikeman
Location
Ashford, Kent
I am getting a Spec allez elite in a few days, i was told they would happily change the standard cassette out for one more suited to my riding. On my current 21speed sora set up i never use the smallest front cog and spend alot of my time in the highest gear of the bike, with a fairly high cadence.

Would you say the standard 18speed (compact) on the allez is going to be ok of should i get the front cassette swapped out to something with more teeth? he mentioned 37 or something, but means little to me

regards
 

gavintc

Guru
Location
Southsea
I think you are confusing the chainset (the front rings) with the cassette that is fitted to the rear wheel. I would presume that the bike will come with a standard 12-25 cassette and this should be good enough for most of your riding. If you struggle on the hills and find that you run of our gears a lot, you could consider fitting a 12-27 cassette.

The best way to imagine the gearing is to think of what happens when you turn a pedal through a complete revolution. If your bike for example had a front ring of 48 teeth and you were in the 12 teeth rear ring. The pedal would turn the back wheel 4 times. 48/12 = 4. Using this concept you should be able to imagine that a standard compact will have a 50 tooth ring and 34 tooth ring at the front. For climbing, you would be in the 34 tooth ring at the front and the biggest ring at the back. A ring of 27 teeth is getting pretty close to 34 teeth, so you see that turning the pedal will turn the back wheel once and then a little bit more - 7 teeth remaining to turn making it about one and a quarter turns of the back wheel.

So in summary, I would stick with the standard kit of 12-25, unless you need to drop the gearing to a 12-27 for steep hills.
 

515mm

Well-Known Member
Location
Carmarthenshire
I changed to a 27tooth rear cog and it really helped. It may not sound like much of an improvement over a 25 but it really worked.

If you prefer a closer ratio you could consider a 14-27 cassette. The gaps between gears are much smaller than a 12-27. This is useful if you haven't developed a great deal of leg strength yet. You will lose a little high end speed due to the easier 14 tooth top gear, but if you're doing 30mph+ it's more beneficial to concentrate on steering the bike!

If you find you run out of gears on the flat 'cos you're too fast - don't worry about low gearing for the hills!:ohmy:
 
OP
RyanW

RyanW

The abominable Bikeman
Location
Ashford, Kent
Hey,

yeah sorry i did mean crankset, the point is im looking to gain some higher gears, not lower ones as i am currently using the highest gear on my current setup and could really use more.
 

potsy

Rambler
Location
My Armchair
depends on the gearing you have now Ryan,the lbs are probably talking about swapping the smaller chainring to a slightly bigger one but if you're using the big ring all the time now it won't make a lot of difference,unless your current gearing is lower.
 

PpPete

Guru
Location
Chandler's Ford
RyanW said:
Hey,

yeah sorry i did mean crankset, the point is im looking to gain some higher gears, not lower ones as i am currently using the highest gear on my current setup and could really use more.
You are obviously very strong!

Simplest is to change the cassette from a 12-25 to a 11-23

As Potsy says changing the inner ring of the compact crankset isn't going help you with higher gears.

If the stock compact crankset (with the smaller cassette above) still isnt a high enough gear for you then you'll probably be after something closer to a non-compact double. If the mech can be mounted high enough maybe a 53-39 ?

Obviously with these changes you are going to sacrifice some hill-climbing ability but it sounds like you are not over-worried by that?
 

gavintc

Guru
Location
Southsea
RyanW said:
Hey,

yeah sorry i did mean crankset, the point is im looking to gain some higher gears, not lower ones as i am currently using the highest gear on my current setup and could really use more.
Then you either need to get racing or learn how to use your gears properly. The top gear is very hard to push over at a decent cadence on the flat. Indeed, I was out training tonight, and was pushing about 45 kph at peaks on the flat. I think my chain was on the mid cog on the cassette.

I have a compact on my best bike as I use it for sportives. I think I only use the 50 - 12 on downhills.
 
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