Explanation of Gearing please

[fee]

I was wondering if anyone could help, I have read that if you are struggling with your gearing then change them to make it easier to climb. I take it that most bikes come with standard gears that are best suited to most riders, but if the gearing is to high or low for you then you need to change them. I am new to this sort of thing so would like an explanation as to how to discovering the gearing, is it as easy as counting the teeth, and also which gears are best suited to climbing, what gears sets make it easier to climb with or give you more speed. Hope someone can help me with this and not think that I am an idiot for not getting this. Just want to make my life easier climbing.

Cheersl.

 

[gavintc]

As a newcomer to the sport it can seem like a black art. However, once you have worked out the basics it is really quite simple. The 'gearing' refers to the ability to change the distance you travel with each turn of the pedals. To travel a long distance, you will need a large front ring and a small rear ring. Imagine that you have a ring at the front with 48 teeth and a ring at the back with 12 teeth. If you turned the pedal through a complete revolution, this would turn the back wheel 4 times. (48 divided by 12 = 4). This gearing is suited for going downhill. With the same bike, imagine that the smallest front ring has 30 teeth and at the back you have 25 teeth. Turning the pedal through a complete revolution will turn the back wheel once and a little bit (30 divided by 25 = 1.2).

So turning to real world bikes. A 'standard' road bike would probably be sold with a 53 ring and a 39 ring at the front and at the back it would have a cassette with a range between 12 and 25. The lowest gear (for climbing) would be 39 - 25.

If you have this and are finding it hard to climb the hills. You could change the front chainset to either a compact with 50 / 34 or fit a triple (3 cogs) with a range between 30 - 52. The triple would offer you the lowest gears.

A cheaper alternative is to look for a cassette which has more teeth on the biggest cog. If you have a road bike and Shimano, it will possibly be 27 teeth, but fitting a new rear derailleur will allow even more teeth to be fitted.

It is quite confusing, but the basics apply. I hope this had helped a little. Good luck

 

[accountantpete]

Two things knacker you out - either too high a cadence (ie pedal revolutions) or pushing too big a gear (ie smaller sprockets at the back) so as Gavin says you can adapt whatever gearing you have to come up with something in the middle that is just right.

After that it is down to the power to weight ratio - ie strengthen those legs ( you don't need to lose weight I'm sure).

 

[fee]

What would be the best exercises to strengthen my legs for climbing. As I do have a weak left calf from a football injury. I do need to lose some weight but hope that will come with the increase in exercise that I am doing. I have read that every extra kilo uses 5 kw of power.

 

[gavintc]

In my opinion, miles and experience are great factors in getting better hill legs. Living in Hull, you do have some options. There are some excellent flatish rides without tackling the more challenging rides of the Wolds. The Wolds are also fairly short and sharp and if you choose your route, you should be able to keep the gradient down to manageable slopes. Weight loss is an important factor, but don't expect to lose masses overnight. It is a slow process and often a boring process getting the waist line in proportion.

Personally, I found doing leg raises in the gym was a good way to strengthen my legs. But, gyms can be expensive and if you have a bike, I would suggest just get out on the flatter roads and spin out an hour or so each day. All the best.

 

[JNR]

I saw a feature during the TdF and a Team Sky mechanic said the whole tour use 54/39 rings at the front. Is that just because they are fitter and stronger and grew out of the 50/34 on my bike?

 

[accountantpete]

What would be the best exercises to strengthen my legs for climbing. As I do have a weak left calf from a football injury. I do need to lose some weight but hope that will come with the increase in exercise that I am doing. I have read that every extra kilo uses 5 kw of power.

Pick a short hill and do some interval training running up it.

How are you pedalling - pushing the pedals or turning the cranks?

 

[accountantpete]

I saw a feature during the TdF and a Team Sky mechanic said the whole tour use 54/39 rings at the front. Is that just because they are fitter and stronger and grew out of the 50/34 on my bike?

It depends on the nature of any stage.

The norm is 52/39 but bigger riders will use up to 55 on the front - smaller riders use smaller chain rings but pedal at a higher cadence to compensate.

 

[battered]

I do need to lose some weight... I have read that every extra kilo uses 5 kw of power.

I doubt it. A man generates about 1kW flat out, this is about 1and1/3 BHP. A moped is restricted to 3BHP, so if you think that 3 BHP will get a 100 kg moped and 70kg rider to 30 mph reasonably quickly, you can see 5 BHP is a lot of power. My car is about 80 BHP, it's no road burner but it tows a tonne of metal about (1000kg) without trouble.

 

[mgarl10024]

Hi fee,

The way gearing was explained to me was that we all have an ideal 'cadence' - the speed at which we turn the pedals. I think that most people are between 60-90rpm (happy to be corrected). At this ideal cadence, we are being most efficient.

Gears allow you to maintain that cadence when the terrain varies. On a hill, select a low gear that means more turns of the pedal for a given distance - this will allow you to climb the hill whilst still keeping the same cadence. On a flat/downhill, select a higher gear that means less turns of the pedal for a given distance - therefore allowing you to increase your speed whilst still keeping the same cadence.

For hills (I'm pretty sure I read it here) that a good tactic is to treat them like unfurling a carpet - slow at the start, build it up in the middle, and go for it at the last bit.

Hope that helps,

MG

 

[tyred]

I think Sheldon gives a good explanation of what gearing is all about in this article - gear theory