Understanding Chainset Specs?

[AndyRM]

I'm still not entirely sure what you're asking. A bicycle is only as sprightly up a hill, or as fast on the flat, as the engine: you.

If you're thinking of one over the other, I'd go with the Dawes as it's got a slightly better spec.

 

[mark st1]

A, will provide a lower bottom gear but no higher at the top end. If that makes it better uphill would depend on the rider and the hill.

What he said is the best way of putting it.

 

[puch]

Yes your original post was correct.

Merci.

 

[mark st1]

The Dawes is Red so has to be the right choice And as Andy said slightly better spec.

 

[puch]

I'm still not entirely sure what you're asking. A bicycle is only as sprightly up a hill, or as fast on the flat, as the engine: you.

I thought you could roughly deduce a bikes likely performance by its gear numbers. Why? Because of posts like this:

I have a Horizon which is a fine, if unexceptional, bike and I don't see why the Vantage wouldn't be fine too. It has an Ally frame which is often thought of an undesirable for a tourer but should be fine for general touring use. The lowest gear is pretty low 28 front, 32 rear; 26 front is more normal but this would make little difference IMHO.

and

Looks very good value for money and I've found the four Dawes bikes that I've owned to be solid and reliable. I'd agree that with the 28 chainring the gearing is higher than I would like for a laden tourer. Maybe you could pay extra to have this changed : it would still be a good bike for the money paritcularly compared to a Galaxy.

I know it's mainly up to the riders fitness, but the question was an, All things being equal, one.

 

[lejogger]

I thought you could roughly deduce a bikes likely performance by its gear numbers.

Unfortunately there are many more variables, such as bike/wheelset weight, tyres etc, but in very broad terms, if you're going downhill, both have the exact same biggest gear, so in theory your top speed and cruising speed will be the same.
In terms of climbing, the gearing on the first bike has an easier bottom gear, so 'in theory' you could climb a steeper hill that you could on the second... BUT both have very low easy gears in any case. It's not a reason to choose one bike over another.

The fact that the middle cog is different will not have too much of an effect. Most of the same gears will be present, you'll just have to have the chain on different cogs to achieve them.

 

[Cyclist33]

I'm still not entirely sure what you're asking. A bicycle is only as sprightly up a hill, or as fast on the flat, as the engine: you.

If you're thinking of one over the other, I'd go with the Dawes as it's got a slightly better spec.

Well only half true. Put the same engine into the two different bikes and you'll get different performance.

Anyway... those specs are for triple chainsets, typically cyclocross-style ones. There won't be any difference in nominal top speed because both have 48 teeth up top. The one that's 38/28 will be marginally higher-geared which yes, ought to mean harder to get up hills but easier to maintain speed once there. It does depend on what cassette is fitted though.

If you're trying to decide between the two, I would say go for the 48/36/26 because the slightly lower gears will help for hills and the top gear is still pretty high.

 

[puch]

Unfortunately there are many more variables, such as -----.

Cheers. That explained it.

 

[simmi]

In real basic terms the fewer teeth at the front the easier it will be to turn the crank on any given bike.

 

[SpokeyDokey]

Re the 28 and 26 front which is the real difference that you are focused on.

Let's assume that you have a 28 rear cog:

26 front x 28 back = 24.5 inches traveled for one rotation of the pedals.

28 front x 28 back = 26.3 inches traveled for one rotation of the pedals.

Not much difference in my book but maybe if you were climbing a mountain pass it would be a heck of a difference.

Or alternatively as 26.3 is 7.9% bigger than 24.5 someone may well argue that 7.9% is a big difference even if you are not climbing a mountain pass.

Both are very low gears though - although I guess someone could argue that point too.

Have a fiddle with this as the actress said to the bishop:

http://www.bikecalc.com/gear_ratios

 

[T4tomo]

In all likehood on the road, you'd never use either bottom gear as they are both so low, unless you were carrying tons of gear up a mountain pass.

 

[puch]

26 front x 28 back = 24.5 inches traveled for one rotation of the pedals.

28 front x 28 back = 26.3 inches traveled for one rotation of the pedals.

So for one million pedal rotations, the bottom set would be about 28.5 miles ahead. Quite a lead.
(I would have had the Pope say it to the actress)

 

[mark st1]

If Forest Gump rode bikes........

 

[Phoenix Lincs]

Having puffed my way up some hills yesterday, I was wondering if I should improve the gears on my bike. This is the spec for the 2013 version of my 2012 bike (not sure if they've changed anything from mine except the colour)

Bearing in mind I'm going to try and get up Box Hill and Leith Hill in August, (or at least try and get as far up as possible before I have to get off and push) I'd welcome thoughts. I'm no mechanic at all, so I'd be taking it somewhere to be done, but thought you clever lot would give me some input first.

All feedback welcome, even if just, rule #5

 

[themosquitoking]

I can manage Box hill with the same gears you have, Leith hill is tougher though i believe. There is a Tiagra 12-30 cassette available but apparently it might require a new chain.