Cassette ratios

[smiggs1967]

Did you do this using 50 x 11?

Yes mate, not sure if it's good bad or indifferent......I know I was knackered at the end :-)

 

[gavintc]

Gear ratios are not that difficult to understand. If you consider that whatever your pedals do is transferred to the back wheel. A 50 cog at the front and a 12 at the back means that for a turn of the pedals, your back wheel will go round 50/12 times = just over 4 revolutions. If you have a 34 cog at the front and 27 at the back, a turn of the pedal results in 34/27 = just over 1 revolution. Simples.

 

[smiggs1967]

Gear ratios are not that difficult to understand. If you consider that whatever your pedals do is transferred to the back wheel. A 50 cog at the front and a 12 at the back means that for a turn of the pedals, your back wheel will go round 50/12 times = just over 4 revolutions. If you have a 34 cog at the front and 27 at the back, a turn of the pedal results in 34/27 = just over 1 revolution. Simples.

Cheers mate, a lot clearer now

 

[smiggs1967]

This is not a one size fits all thing, some spin and some push big gears, so take any advice on this as a starting point and see what works for you. I would ease that onto one of the bigger cogs at the back, 14 or 15 and spin a bit more.

You're not the first to tell me that. I was in a Sportive recently and a club cyclist overtook me and gave the exact same advice. Cheers mate

 

[Nigelnaturist]

Also depends on what you've got up front. I'm not entirely sure how it works, but a standard (53t) big ring will give you considerably more oomph than a compact (50t).

7" more on a 53x11 compared with a 50x11 tyre size dependent or 34.02mph compared with 32.14mph @90rpm, hardly considerable, and a 50th ring is not by definition a compact.
@T.M.H.N.E.T you can certainly get 53th rings on a 110mm B.C.D. compact chainset (be it double or triple), so a new chainset might not be needed, though its easier to bend the the rings the bigger they go.

 

[slowmotion]

^^^^^ @Nigelnaturist speaks the truth.
http://www.spacycles.co.uk/products.php?plid=m2b2s149p296

BTW, Spa Cycles are a good source for a lot of chainrings.

 

[jiberjaber]

I had a similar issue when I was buying a new bike about what cassette to have on the back so I used an online gear calculator to see what my existing bike gave me and then compare that with the options I had for the new bike. Worth putting your existing set up in to one of those and seeing what other numbers return, either in terms of speed @ rpm, gear-inches or ratios.

It doesn't mater too much which you look at, its about comparing the current 'feel' with what the options might give you. If you spin your peddles vrs grind it will feel different to the grind instead of spin approach. Do you know what sort of cadence you ride with at the moment, is it 60, 70, 80, 90, 100?

If you did 18mph on 50x11 that would be about 50 RPM (probably closer to been known as grinding)
You might actually get the same speed with feeling less pain at the end on a slightly lower gear and a higher cadence?

http://sheldonbrown.com/gears/
http://www.bikecalc.com/speed_at_cadence

 

[DWiggy]

Damn riding in 53/11 would just kill me even on the flat! The fastest I've manage on a relatively flat ride (10 miles with 350feet of climbing) I managed an average of 22mph and was quite chuffed with that.
I'm running 50/34 -11/28 and was probably in the middle of the cassette at the back, big ring up front for most of that ride spinning 90-100rpm

 

[smiggs1967]

I had a similar issue when I was buying a new bike about what cassette to have on the back so I used an online gear calculator to see what my existing bike gave me and then compare that with the options I had for the new bike. Worth putting your existing set up in to one of those and seeing what other numbers return, either in terms of speed @ rpm, gear-inches or ratios.

It doesn't mater too much which you look at, its about comparing the current 'feel' with what the options might give you. If you spin your peddles vrs grind it will feel different to the grind instead of spin approach. Do you know what sort of cadence you ride with at the moment, is it 60, 70, 80, 90, 100?

View attachment 60155

If you did 18mph on 50x11 that would be about 50 RPM (probably closer to been known as grinding)
You might actually get the same speed with feeling less pain at the end on a slightly lower gear and a higher cadence?

http://sheldonbrown.com/gears/
http://www.bikecalc.com/speed_at_cadence

Really helpful mate, cheers

 

[smiggs1967]

Damn riding in 53/11 would just kill me even on the flat! The fastest I've manage on a relatively flat ride (10 miles with 350feet of climbing) I managed an average of 22mph and was quite chuffed with that.
I'm running 50/34 -11/28 and was probably in the middle of the cassette at the back, big ring up front for most of that ride spinning 90-100rpm

It seems clear now that I am staying in the smallest cog too much and not spinning enough. I have extremely large legs and have paid to my strengths a little too much. I have been a head down and push the fastest gear as much as I can without considering more revolutions on a larger cog. Cheers mate

 

[T4tomo]

Yes, putting it in a higher gear doesn't necessarily make you go faster. 50-11 is normally reserved for downhill.

Don't bother withn the hassle or expense of trying to get a 53 ring on the front, again it won't make you go any faster.