Gear ratio of less than 1?

[midliferider]

Advice please..
My present road bike has 3 chain rings in the front, 50-39-30 and 8 speed cassette 12-25.
I am now looking to upgrade to a carbon bike. I would like to have the lowest possible gear ratio just to help with going up the hills. I am not too worried about the speed. Most of the bikes that I looked at has similar gear ratio.
In double ring, 50-34 with 10 speed cassette 12-25, still give the same lowest gear ratio (1.20)

Is it possible to have 50-39-30 in front and 11-28 or even 11-32 in a road bike?

 

[uclown2002]

yes but someone more knowledgeable will be here soon to explain why.

 

[MikeW-71]

Yes, you can. Touring bikes run that kind of gearing a lot. Regular road bikes can do it by running an MTB rear mech.

However, if you're going to a carbon bike with some decent wheels and tyres, you'll be surprised at what you can get up with 50/34 and 11-28. All current Shimano rear mechs can take up to 30t at the back too and this should be more than enough.

When I bought my Defy Advanced 2, I wondered if the gearing would make it harder. My first bike had 12-30 at the back and the new one is 11-28. I needn't have worried, the new bike climbs way better and it feels just as "easy" as the other bike. The biggest difference is in the wheels though, even a relatively small difference there makes a big difference to the effort needed in climbing.

 

[jowwy]

Specialized roubaix triple is available at £1500.

 

[deptfordmarmoset]

I've got a carbon bike with 32 at the rear (SRAM Rival). (Slow and low on power, me.) It works out slightly above a ratio of 1 but it's close. I've also got a steel tourer (Shimano Deore) that has a sub-1 ratio*. I spin out at 4 1/2mph. Being experienced at cycling slowly, I manage to stay upright

*I think it works out as 30 at the front, 34 at the back but, as it got caught out in torrential rain this afternoon, it's so filthy I'm not going to have a proper look right now.

 

[midliferider]

Thanks.
it dies not have to be less than one. If I can find 50-39-30 in front and 12-30 in the back.
Perhaps the best bet is to buy and upgrade?

 

[MikeW-71]

If you are OK with the 30-25 on your current bike, 34-28 is the same ratio and 34-30 is slightly lower. You would not find it any harder than your current gearing, particularly if the new bike has better wheels and tyres.

EDIT: Couple of examples (Giant I know, but I know the range) though I don't know your budget.
http://www.giant-bicycles.com/en-gb/bikes/model/2014.giant.defy.4.white/14977/66547/#specifications
50/34 with 11-32, 8 speed

http://www.giant-bicycles.com/en-gb/bikes/model/2014.giant.defy.3/14977/66546/#specifications
and the same with 9 speed

Those two have a bottom ratio of 1.06

http://www.giant-bicycles.com/en-gb....defy.composite.3/14976/66541/#specifications
And that's a carbon with 50/34 and 12-30, 10 speed

 

[midliferider]

I need a carbon bike! I just need one.
I have no fixed budget but prefer something less than £2000 preferably around £1500.
I would like to reduce the ratio to a minimum of one. So my ideal bike would have 50-39-30 and 12-30.
Specialized triple sounds good.

Any suggestions for good wheels?

 

[MikeW-71]

Bikes:
Here's one:
http://www.evanscycles.com/products/scott/cr1-20-triple-2014-road-bike-ec054446

Another:
http://www.evanscycles.com/products...sl4-sport-x3-2014-road-bike-ec053040#features

And one more:
http://www.evanscycles.com/products/trek/domane-43-triple-2014-road-bike-ec041048

What bike do you have at present? If you go for a bike like the 3 I've linked to, you'll probably find their wheels are an improvement anyway.

 

[midliferider]

At present I ride B Twin Triban 3. It is my first road bike. I was not sure whether I will be able to learn to ride a road bike at my age and therefore just bought a most basic entry level bike. I really enjoy riding, now do about 40-50 mile over the weekend. I would like to upgrade my bike even though B Twin is sufficient for my current requirements. I was looking at this but realised that it has the similar gear ratio.

http://www.chainreactioncycles.com/forme-axe-edge-sport-2013/rp-prod91370

 

[PpPete]

I need a carbon bike! I just need one.
I have no fixed budget but prefer something less than £2000 preferably around £1500.
I would like to reduce the ratio to a minimum of one. So my ideal bike would have 50-39-30 and 12-30.
Specialized triple sounds good.

Any suggestions for good wheels?

Avoid anything sold by Specialized as part of a built-up bike.
Other than that it depends what kind of riding you want to do.

 

[MikeW-71]

Wheels are a very common upgrade for Triban 3s, they are likely to be relatively heavy. Any £1500 carbon bike will have better wheels anyway and if you then pop on a good set of tyres (Conti GP4000S for example) climbing will suddenly be easier even if the gearing is slightly higher. That's what I found with my new bike. You might not need that triple.

If possible get some test rides, that will tell you a lot.

 

[Sterba]

I posted this answer to a similar question recently. It might help you nderstand the effect of different sized cogs front and back

When we used to ride penny farthings a few years ago, the front wheel had to be huge because, without any gears, each time we turned the pedals round once, the wheel travelled forward the distance of its circumference. Unless it was a big wheel, you didn't travel very far. Now that we have invented gears, we still hark back to the size of those original penny farthing wheels. So, gears are measured in inches, relating to the equivalent diameter a penny farthing wheel would be. Are you still with me?

To find out what "size" a particular gear is, you count the teeth on the cog that the chain is on at the back, and divide it into the number of teeth on the chainring at the front, and then multiply it by the diameter of the wheel. As an example, if the cog at the back has 20 teeth on it, and the chainring at the front has 40 teeth on it, twenty into forty gives 2, multiplied by 26 (roughly equivalent to today's 650 wheels), giving a gearing of 56 inches. With a multi-speed derailleur, you will have a range of gears that will get you up the hill more easily when you use the larger cog at the back (because the gearing gets lower, try the maths for yourself) and, when you change up to the smaller cogs at the back, the gearing gets higher so that you can pedal downhill in a more measured way, without having to twiddle the pedals to have any effect.

Conversely, the larger the front chainring, the higher the gear, and the slower you have to pedal to cover the same ground. So, if you have a double or triple chainset at the front, as you change down to the smaller rings, you will lower the gearing and make it easier to go uphill. When you have an idle moment, work out the gearing in inches for all of the possible combinations of front and rear cogs on your own bike, and it will help you see why one gear is faster or slower, easier or harder, than another.

I hope this helps.
Sterba, 13 Oct 2013 Edit Delete Report
Top #5 Reply

 

[andrew_s]

"Gears are measured in inches" only in the English-speaking world. Everywhere else they are measured in metres - how far 1 pedal revolution takes you.
The point of using inches or metres is that wheel size is taken into account, which quoting teeth or sprocket ratios doesn't. 1:1 on a Brompton is a much lower gear than 1:1 on a road bike (and is, coincidentally, what the lowest gear on my touring bike is).

 

[mcshroom]

My bottom touring gear is a 22-32 (22 front, 32 back, <19" gear), but I can't imagine you ever needing something that low unladen.