Gear Review: Compact Cranks

[EuanB]

Two weeks ago I used needing to get new rings as a reason to change to
compact cranks. I'd been mulling it over for about a year or so 'cause
I've got a pretty high cadence and prefer for my cadence to go up a notch
when climing a hill rather than fall. Don't ask me if it's the right
thing to do, it feels right for me.

The consequence of a high cadence (normal for me is 100) is that my 53 /
12 almost never got used. It's so shiny I could use it as a mirror to
shave with.

Living in the SE suburbs and commuting to the city I don't see many
hills, I do however go up Blackburn Road to Burwood on occaision and the
those hills on a fully laden bike take a bit of effort to get up. While
I can get up them OK lower gears would let me spin.

So there you have it, that was my reasoning for getting compact cranks.
Threw it at BSC and essentially had the whole drive train replaced. New
chain, new 12-25 cassette, new bottom bracket, new cranks and a new 50/34
combo. Oh I got the gear cables replaced as well which has lent new
snappiness to the changing (thanks Bleve).

The first couple of weeks saw me doing my usual routes and there was an
immediate difference. I never came out of the top ring and the gears I
was habitually using were nearer the middle of the cassette. it felt
very nice. How would I do on hills though?

Yesterday I found out. I set off from Bike Life for the Olinda Ride and
am really pleased to say that Suzie came along as well. Tough ride for
her at the moment but you only get stronger by putting yourself out
there. Unfortunately she flatted in the first two kms so we were pretty
much on our own for the rest of the ride, that worked out well too

So anyway we get to the Basin and Suzie peels off to Boronia for coffee
and paper. Time to see if I'd spent my money well.

I don't do hills. It's not that I don't like them but with 300km just
getting to and from work I don't go looking for more riding that often
(that's changing) and this was my first time doing the 1/20 and the Wall.
I can't put it any more succinctly than this: I purred up those hills.
At times my cadence was up around 115, HR sitting on 160 with the speedo
tipping 25, it wasn't `easy' but it was sustainable. I could have gone
on just about all day on that hill.

Two weeks in I believe compact cranks are the right choice for me. I
don't have massive leg strength by I do have cardio fitness and high
cadence plays to my strengths. Maybe not the right choice for everyone
but I'm happy.

Now I've got that off my chest hopefully I can quit boring the **** out
of Suzie ;-)

 

[Resound]

Two weeks ago I used needing to get new rings as a reason to change to
compact cranks.

<snip handy review>

Now I've got that off my chest hopefully I can quit boring the **** out
of Suzie ;-)

I've been tempted to go to the little cranks for a while. I can't really justify bike bits purchases right now, but that definitely puts another tick in the box next to wanting a set of 165s. Thanks for that

 

[flyingdutch]

coolio. apologies for 'losing you'.
wasnt aware you had flatted until much, much later

saw you as I came back down the hill btween Olinda and Sassafras and you were indeed looking remarkably relaxed and 'purring'

cheers
FD

 

[EuanB]

coolio. apologies for 'losing you'.
wasnt aware you had flatted until much, much later

saw you as I came back down the hill btween Olinda and Sassafras and you were indeed looking remarkably relaxed and 'purring'

No worries on that Dutchy, it all worked out good. The important thing is that the kids and the teachers were still there. It was a bitter sweet moment, it warms that heart to see the appreciation of the kids, parents and the principal but it really sucks they're in that position in the first place.

First time I've done that ride, won't be the last!

 

[SuzieB]

coolio. apologies for 'losing you'.
wasnt aware you had flatted until much, much later

saw you as I came back down the hill btween Olinda and Sassafras and you were indeed looking remarkably relaxed and 'purring'

cheers
FD

I have to say that when I turned up and saw all that male flesh I nearly put the bike back in the car! I do think things happen for a reason sometimes and I think flatting might have been the best thing for me as you guys are fast and I don't think I'm ready for that pace! As it was Euan and I had a lovely ride to The Basin together - it's a great route and I was happy to leave him to test himself on the hills while I hit the coffee shop (does Boronia Subway count as a coffee shop?!?!). It's given me a great incentive to get back on the diet as I think most of my problem with the ride was not so much fitness but carrying extra weight. I will do that ride with you all by the end of the year.

It's nice to see Euan enjoying his riding. I can't help but think that me getting into cycling has been a good thing for Euan as well. It also means he doesn't have to argue when he wants to buy new bike bits!

I hope the other riders had a good day. Euan told me the kids and parents seemed grateful.

 

[Zebee Johnstone]

In aus.bicycle on Mon, 27 Mar 2006 11:36:27 +1100
Resound <[email protected]> wrote:
>
> I've been tempted to go to the little cranks for a while. I can't
> really justify bike bits purchases right now, but that definitely puts
> another tick in the box next to wanting a set of 165s. Thanks for that

I went to them straight up as someone with a similar case of Duck's
Disease recommended 150 cranks.

I ended up getting the 170s the bent came with cut down to 145 because
that's what they could be cut down to, and replacing them with shorter
ones would mean money and time.

I'm pretty happy with them, not that I have much to compare to. Easy
to spin, I'll know how easy when the cadence computer arrives!

Zebee

 

[Bleve]

SuzieB wrote:

> It's nice to see Euan enjoying his riding. I can't help but think that
> me getting into cycling has been a good thing for Euan as well. It also
> means he doesn't have to argue when he wants to buy new bike bits!

Tandem!

 

[EuanB]

SuzieB wrote:

> It's nice to see Euan enjoying his riding. I can't help but think that
> me getting into cycling has been a good thing for Euan as well. It also
> means he doesn't have to argue when he wants to buy new bike bits!

Tandem!

I think I'd end up being the stoker...

 

[Vincent Patrick]

Zebee Johnstone wrote:

> In aus.bicycle on Mon, 27 Mar 2006 11:36:27 +1100
> Resound <[email protected]> wrote:
>>
>> I've been tempted to go to the little cranks for a while. I can't
>> really justify bike bits purchases right now, but that definitely puts
>> another tick in the box next to wanting a set of 165s. Thanks for that
>
> I went to them straight up as someone with a similar case of Duck's
> Disease recommended 150 cranks.
>
> I ended up getting the 170s the bent came with cut down to 145 because
> that's what they could be cut down to, and replacing them with shorter
> ones would mean money and time.
>
> I'm pretty happy with them, not that I have much to compare to. Easy
> to spin, I'll know how easy when the cadence computer arrives!
>
> Zebee

Keep in mind that I don't know what I am talking about here, but I would
guess the short cranks could be making hills more difficult for you to
climb if you don't have low enough gears.

Cheers,

Vince

 

[Zebee Johnstone]

In aus.bicycle on Mon, 27 Mar 2006 22:35:01 +0800
Vincent Patrick <[email protected]> wrote:
>
> Keep in mind that I don't know what I am talking about here, but I would
> guess the short cranks could be making hills more difficult for you to
> climb if you don't have low enough gears.

Hills are about spin aren't they?

My low gear is low enough that I can turn the pedals at a standstill
Well not quite that low, it's a 30-34 which is what, about 21 gear
inches?

I am wary about mashing big gears, tales of blown knees on bents are
cautionary at least.

Zebee

 

[EuanB]

Zebee Johnstone wrote:

> In aus.bicycle on Mon, 27 Mar 2006 11:36:27 +1100
> Resound <[email protected]> wrote:
>>
>> I've been tempted to go to the little cranks for a while. I can't
>> really justify bike bits purchases right now, but that definitely puts
>> another tick in the box next to wanting a set of 165s. Thanks for that
>
> I went to them straight up as someone with a similar case of Duck's
> Disease recommended 150 cranks.
>
> I ended up getting the 170s the bent came with cut down to 145 because
> that's what they could be cut down to, and replacing them with shorter
> ones would mean money and time.
>
> I'm pretty happy with them, not that I have much to compare to. Easy
> to spin, I'll know how easy when the cadence computer arrives!
>
> Zebee

Keep in mind that I don't know what I am talking about here, but I would
guess the short cranks could be making hills more difficult for you to
climb if you don't have low enough gears.

Cheers,

Vince

I think there's a confusion of terminology here. When I'm talking about compact cranks, I'm talking about the fixture pattern.

Normal cranks need 130mm diameter for the bolt pattern which precludes small chain rings on the front. Compact cranks use a 110mm diameter bolt pattern which allows me to use a 50/34 double ring as opposed to the usual 53/39.

The actual length of the cranks is about the same (5mm shorter than my old ones).

 

[sinus]

I think there's a confusion of terminology here. When I'm talking about compact cranks, I'm talking about the fixture pattern.

Normal cranks need 135mm BCD
Those Japanese and American ones need 130mm BCD

fortunately 110mm has become a standard for compacts

 

[SEGFTG]

I don't do hills. It's not that I don't like them but with 300km just
getting to and from work I don't go looking for more riding that often
(that's changing) and this was my first time doing the 1/20 and the Wall.
I can't put it any more succinctly than this: I purred up those hills.
At times my cadence was up around 115, HR sitting on 160 with the speedo
tipping 25, it wasn't `easy' but it was sustainable. I could have gone
on just about all day on that hill.


Did i suggest a ride in the hills to you!!??
You might be towing me with a performance like that.
The more i hear about compact cranks the more i like...and want.
Will have to wait till management recovers from a new wheelset purchase before i start lobbying for another upgrade.

 

[Bleve]

Zebee Johnstone wrote:
> In aus.bicycle on Mon, 27 Mar 2006 22:35:01 +0800
> Vincent Patrick <[email protected]> wrote:
> >
> > Keep in mind that I don't know what I am talking about here, but I would
> > guess the short cranks could be making hills more difficult for you to
> > climb if you don't have low enough gears.
>
> Hills are about spin aren't they?

There's two things at play - chainring diameters (which is what a
compact crank lets you alter) and crank length, which is a very
different beasty.

Longer cranks mean more leverage (they're just levers!), which
effectively multiplies your torque for a given input of power - same as
changing gear, *except* there's a physiological change - your legs have
to move further or less when you start playing with crank length.
Changing gear does not have this requirement.

The use of a smaller chainring (compact crank) means you get lower gear
ratios, more like a MTB than a roady double. This is just like having
a larger gear on the back wheel. No effect on cadence save for the
different gear ranges available.

If you want a practical extreme example, we rode a 105mm (!) crank in a
'bent race last summer, I could spin it at 267rpm for about 15 seconds,
the best I can spin on a 172.5mm crank is about 205rpm for the same
time (and a lot of bouncing!). That's against a minimal load, just
enough to stop overspinning. I was crippled on the 105mm crank though,
I simply couldn't accelerate it out of corners (the damn thing was 32kg
too .... which didn't help).

As a gross generalisation, crank length is best determined by leg
length, and kept mostly independant to gear selection. Some trackies
will fiddle with crank length though for different events, YMMV.

> My low gear is low enough that I can turn the pedals at a standstill
> Well not quite that low, it's a 30-34 which is what, about 21 gear
> inches?

Depends, how big are your wheels?

 

[Rory Williams]

I
Will have to wait till management recovers from a new wheelset purchase before i start lobbying for another upgrade.

The odd thing is, there isn't anything new about a 110 BDC chainwheel set up.

I've got 110 BDC chainwheels on four of our working bikes (road, dirt road, tandem and a ladies hybrid) and another three sets as spares. I went to a

I think I have three shimano (all triples) , two Sakae (doubles) a Sugino (T) and a Richey Logic (T- but actually a Sugino).

110BDC was the early default on MTBs and then became a standard for touring bikes. I have don't think I have paid more than $40 for a set second hand.

All of the Sakaes came out of hard rubbish collections - I think the last was of an old Repco superlight. It was set up 50/40 but the chainwheels are steel.

If your not fussy about having a perfect groupset there would be ways of scrounging a compact set at moderate expense

RoryW

 

[Zebee Johnstone]

In aus.bicycle on 27 Mar 2006 16:02:24 -0800
Bleve <[email protected]> wrote:
>
> Zebee Johnstone wrote:
> As a gross generalisation, crank length is best determined by leg
> length, and kept mostly independant to gear selection. Some trackies
> will fiddle with crank length though for different events, YMMV.

Yeah, the leg length was why I got it - I'm 5 foot 2 on a good day....
>
>> My low gear is low enough that I can turn the pedals at a standstill
>> Well not quite that low, it's a 30-34 which is what, about 21 gear
>> inches?
>
> Depends, how big are your wheels?

The back one's 26 with 1.25 tyres. So I plugged the numbers into
Sheldon Brown's calculator. And yeah, the wheel size is needed

The gearing's low enough, what surprised me about the calculations was
how much of the big ring's not really needed. I suppose if you are
spending a lot of time in an area flat or downhill (I wish!) then
using the big ring a lot makes sense. I sit in the middle ring and
only use the big one if there's a lot of downhill, mainly trying to
get up speed for the next uphill.

And cursing loudly and inventively when some insensitive clod in a car
pulls in front of me and does 3kmh for long enough for me to have to
slow right down, then takes off. grrrrrr


Zebee

 

[Euan]

SEGFTG wrote:
> I don't do hills. It's not that I don't like them but with 300km just
> getting to and from work I don't go looking for more riding that often
> (that's changing) and this was my first time doing the 1/20 and the
> Wall.
> I can't put it any more succinctly than this: I purred up those hills.
> At times my cadence was up around 115, HR sitting on 160 with the
> speedo
> tipping 25, it wasn't `easy' but it was sustainable. I could have gone
> on just about all day on that hill.
>
>
> Did i suggest a ride in the hills to you!!??
> You might be towing me with a performance like that.
> The more i hear about compact cranks the more i like...and want.
> Will have to wait till management recovers from a new wheelset purchase
> before i start lobbying for another upgrade.
>
>

Heh heh, on occasion I got up to 25. Most of the time I was hovering
around about the twenty mark. There's a couple of lulls where you can
really get some extra speed up.

I might be wrong but I think a higher cadence makes you more reactive to
the landscape. Seems that way to me anyway.
--
Cheers | ~~ __@
Euan | ~~ _-\<,
Melbourne, Australia | ~ (*)/ (*)

 

[TimC]

On 2006-03-28, Euan (aka Bruce)
was almost, but not quite, entirely unlike tea:
> SEGFTG wrote:
>> At times my cadence was up around 115, HR sitting on 160 with the
>> speedo
>> tipping 25, it wasn't `easy' but it was sustainable. I could have gone
>> on just about all day on that hill.
>>
>> Did i suggest a ride in the hills to you!!??
>> You might be towing me with a performance like that.
>> The more i hear about compact cranks the more i like...and want.
>> Will have to wait till management recovers from a new wheelset purchase
>> before i start lobbying for another upgrade.
>
> Heh heh, on occasion I got up to 25. Most of the time I was hovering
> around about the twenty mark. There's a couple of lulls where you can
> really get some extra speed up.

Did you find the false flat up the 1:20? If you are riding by
yourself, you might not notice that you are gradually putting in less
effort to spin the same. Until someone passes you doing 35km/h. It
still looks uphill, but becomes much easier.

As it was, I was riding with craigster, I think (I didn't notice it
was him until later, so I don't know whether it was him with me before
then). I started changing up gears, and got up to about 28km/h (was
doing ~22km/h up most of 1:20), but then a group of 4 flew past. It
was a struggle to catch up, but then we stayed with them for a while.

Then eventually, the uphill illusion gives way, and it starts looking
like it's tipping down, and yet you can't go any faster. And then you
start going slower. Then it tips up again.

--
TimC
According to the latest official figures, 43% of all statistics
are totally worthless.

 

[Euan]

TimC wrote:
> On 2006-03-28, Euan (aka Bruce)
> was almost, but not quite, entirely unlike tea:
>
>>SEGFTG wrote:
>>
>>>At times my cadence was up around 115, HR sitting on 160 with the
>>>speedo
>>>tipping 25, it wasn't `easy' but it was sustainable. I could have gone
>>>on just about all day on that hill.
>>>
>>>Did i suggest a ride in the hills to you!!??
>>>You might be towing me with a performance like that.
>>>The more i hear about compact cranks the more i like...and want.
>>>Will have to wait till management recovers from a new wheelset purchase
>>>before i start lobbying for another upgrade.
>>
>>Heh heh, on occasion I got up to 25. Most of the time I was hovering
>>around about the twenty mark. There's a couple of lulls where you can
>>really get some extra speed up.
>
>
> Did you find the false flat up the 1:20? If you are riding by
> yourself, you might not notice that you are gradually putting in less
> effort to spin the same. Until someone passes you doing 35km/h. It
> still looks uphill, but becomes much easier.

Hmm, must have missed that. First time up that hill and as you say I
was on my own.
--
Cheers | ~~ __@
Euan | ~~ _-\<,
Melbourne, Australia | ~ (*)/ (*)

 

[flyingdutch]

Hmm, must have missed that. First time up that hill and as you say I
was on my own.

'about' 2/3rds of the way up, for about a km IIRC.
Just after water tank on right...