Proposed campaign: inapproriate gears

[Tigerbiten]

I agree it the range you need.
Top gear for a starter bike should be 4:1, on a nominal 27" wheel this is a 108" gear. good for just over 30 mph downhill or on the flat with a good tail wind.
Bottom gear around 0.9:1, on a nominal 27" wheel this is around the mid 20's.
Total range is 4.5x which I think is ideal.
The question is how do you get this range.
Do you go for a double at the front and have a wider step between the gears.
Or do you go for a wide triple and have smaller steps between the gears.

In an ideal world if I was building a DF bike I'd go for a wide triple, 48-36-24.
Then a close space block on the back, 12-13-14-15-16-18-20-23-27.
16 unique gears, the top 9 gears are close spaced for high speed work, the bottom 7 gears give you the range to climb silly steep stuff.
Most of the time you'll probably be on the middle ring with the top (+20 mph) and granny (-7mph) rings used as needed.

[CJ]

CJ. Do you know your long-term average cadence?

I'm not sufficiently interested in my cadence to measure it often, and certainly never integrated it over the long-term, never had the means too either, not being into cycling as a sport at all, but I did buy a rear wheel fitting kit for one of my bike computers and as it came with a crank sensor I fitted it, and occasionally looked at the cadence display. Mostly it seemed to be showing a number in the 80s or 90s. Uphill that would drop to the 70s or even the 60s, rarely the 50s. Although I'm sure my cadence would also drop that low when I wasn't trying at all, like when I've slowed down to talk to someone walking up the hill, or am just giving the pedals an occasional poke as I coast along looking for a particular address or the best spot to photograph a view.

On the other hand, when I am out of my comfort zone, hanging onto the back of a bunch of stronger riders (for as far as I can get before having to fight the wind by myself!) I will pedal as fast as 120 rpm. And not because I've run out of gears. On the most memorable occasion that I found myself pedalling that fast I had plenty higher gears but no more push: the only way I could generate enough power to keep up was to turn that push around faster!

So I don't really know what my cadence would integrate out to over the long term, but imagine it'll depend upon how hilly and how hard the ride is. And I'm assuming that freewheeling time doesn't count, when I reckon that on a hilly ride with slower people it'll be below 80, but on a flat ride with people who are too fast for me it'll be over 90.

[Tigerbiten]

I used to be like Mike F and had a low cadence (~60-70 rpm) on my DF bike.
Now on my recumbent trike, I know what speed I do in what gear.
If I plug all my sizes into Sheldon brown's gear calc, wheel 44-406, chainrings 38-53, sprockets 21-8.4, Rohloff IHG, I can then look at what cadence gives me what speed in each gear.
My average cadence looks to be around 90 rpm and I change up a gear at around 100 rpm and drop one at around 80 rpm.
The only time I now drop below 80 rpm is when I need to drop my power output on hills because I'm overheating badly.

[Mick F]

Thanks CJ.

I know mine because I had a Garmin with a speed/cadence unit. By uploading the unit into my computer as rides diary, I can tell you every pedal stroke and wheel turn of every ride from 2007 to 2013. Also I had the HR monitor.

I've since sold all that, and now all I do is log where I've been. It's actually a relief. It's given me a sort of freedom. It was as though I had a Big Brother watching me all the time.

I don't know, but I would guess that my average cadence has fallen since I had a constant cadence readout showing on the screen.
I'm more relaxed now. Garmin Edge plus all the fittings makes you tense and competitive.

Cadence?
Who cares?
Not me any more, I like the gearing I have and use it to the full - but in a relaxed way.

[Mark1978]

An example http://www.halfords.com/webapp/wcs/stor ... 65710#tab1

A Boardman bike at Halfords, granted the top model with 11 speed Ultegra. But Halfords is a shop where you'd expect people relatively new to cycling to go.

Yet it has a standard double 53/39 with a 11-25 cassette.

[Bicycler]

How about an entry level bike: http://www.halfords.com/webapp/wcs/stor ... 65710#tab2

I can't see any reason why entry-level bikes can't come with triples as standard. Much better that some have gears they never use than many not having the gears they need

[Mark1978]

Yeah 52/39 with 12/26, madness for an entry level bike. I can only assume the standard double chainsets are cheaper?

[Bicycler]

Undoubtedly. There can't be too much difference though, they seem to manage to fit triples to even the cheapest BSO MTBs and it's safe to assume every corner is cut to get bikes down to £70. I assume there's a marketing aspect too, having a triple just doesn't fit the macho roadie image they're trying to sell.

[Mick F]

There was a fashion on bikes to have a 52/36 double, in fact it was the first Stronglight 99 setup I bought for my Mercian in 1986.
I varied the back end a bit, but a 13-28 freewheel was about the most versatile I used. I did my first JOGLE with that system fully loaded with four panniers.

Eventually, I bought a 53t for the outer coz I wanted a 53/13 top gear, and I bought a 40t for the inner as I didn't need the lower gears that the 36t gave me. I had a large collection of freewheel cogs. Smallest big cog I used was a 24t. Smallest small was limited to 13t.

I still have all the bits.

[reohn2]

How many times do I have to say it Mick,you're not the norm with a low 60's rpm cadence.The vast majority pedal in the upper 80's to mid 90's.
Their gearing therefore needs to be correspondingly lower than yours,even a top gear of 48x13 with a 90+rpm cadence gets 35mph.
Now tell me how many people get a bike upto that kind of speed on the flat?
I'll also repeat,a 1to1 gear ratio isn't low,especially if the rider is tired!

[Tigerbiten]

even a top gear of 48x13 with a 90+rpm cadence gets 35 mph.

No it doesn't'
The easy one to remember is "A 100" gear at 100 rpm is 30 mph".
So a 48x13 gear (which is a 100" gear) at 90 rpm is 30x0.9= 27 mph.
If you use 23-662 tyres, it can be as low as 26 mph.
To get 35 mph you need to be doing close to 120 rpm.

[Vantage]

even a top gear of 48x13 with a 90+rpm cadence gets 35 mph.

No it doesn't'
The easy one to remember is "A 100" gear at 100 rpm is 30 mph".
So a 48x13 gear (which is a 100" gear) at 90 rpm is 30x0.9= 27 mph.
If you use 23-662 tyres, it can be as low as 26 mph.
To get 35 mph you need to be doing close to 120 rpm.

I do believe reohn2 added a + sign to that 90rpm figure, anything over 90rpm could get you to 35mph and I doubt anyone is quoting exact speeds to the decimal point so reohn2's 35mph could very well be under or over that speed. We need to think about tyre size here too as that alters the gear inches travelled.
Another thing I'd say is that entry level bike doesn't mean entry level cyclist. Not everyone is made of money and so a Wiggo challenger might not have the option of a £2000+ bike with big ratios.
Every bike on sale should in my humble opinion be offered with a choice of gearing to suit the rider, not their wallet or purse size.

[Tigerbiten]

even a top gear of 48x13 with a 90+rpm cadence gets 35 mph.

No it doesn't'
The easy one to remember is "A 100" gear at 100 rpm is 30 mph".
So a 48x13 gear (which is a 100" gear) at 90 rpm is 30x0.9= 27 mph.
If you use 23-662 tyres, it can be as low as 26 mph.
To get 35 mph you need to be doing close to 120 rpm.

I do believe reohn2 added a + sign to that 90rpm figure, anything over 90rpm could get you to 35mph and I doubt anyone is quoting exact speeds to the decimal point so reohn2's 35mph could very well be under or over that speed. We need to think about tyre size here too as that alters the gear inches travelled.
Another thing I'd say is that entry level bike doesn't mean entry level cyclist. Not everyone is made of money and so a Wiggo challenger might not have the option of a £2000+ bike with big ratios.
Every bike on sale should in my humble opinion be offered with a choice of gearing to suit the rider, not their wallet or purse size.

I take +90 rpm as the 90-100 rpm range.
This is easily doable as I'm happy in that range.
But theres no way I'm happy pushing close to 120 rpm for any length of time.

I used to push a 102" gear (53-14) at close to 30 mph all the time, either on the flat with a good tail wind or downhill.
It makes for a fun ride when you can hit those types of speeds ........
Which is why I said earlier that to maximum top gear on a starter bike wants to be 4:1 or a 108" gear.
Bottom gear want to be in the range 1:1 and 0.8:1 or the mid 20"'s.
It's how you get that range and how close the gears are together which is the important bit.

[reohn2]

even a top gear of 48x13 with a 90+rpm cadence gets 35 mph.

No it doesn't'
The easy one to remember is "A 100" gear at 100 rpm is 30 mph".
So a 48x13 gear (which is a 100" gear) at 90 rpm is 30x0.9= 27 mph.
If you use 23-662 tyres, it can be as low as 26 mph.
To get 35 mph you need to be doing close to 120 rpm.

I get 30mph on 46x14 on 35 mm tyre.
I don't count cadence but it's quite quick,though if I had the power I could spin a lot higher on that gear.
So I reckon a 48x13 can be spun upto 35mph without too much trouble.

I'd say that's more realistic than some folks do pushing their tripes out trying to turn over a 120inch gear with any kind of realistic cadence,unless they like to pedal with a cadence like Mick or have the power a Manx Missile.
Bear in mind I'm talking about unfaired upwrongs with normal human beings on board of average
fitness

[Mick F]

How many times do I have to say it Mick,you're not the norm with a low 60's rpm cadence.The vast majority pedal in the upper 80's to mid 90's.

You don't know that.
You only think that from your experience of the cyclists you have seen.

I ride a bike like I like to ride a bike.
There are millions(?) of cyclists in this country, and many many many many millions throughout the world.
No doubt the vast majority couldn't give a toss about high cadence.

Today, I was riding home via Tavistock.
Plymouth Rd is straight, wide, and fairly flat.
I was pootling along in top gear - 53/12 - at no more than 15mph.
Easy gentle relaxed cycling.