Compact vs Double - explain please!

[Yellow Saddle]

I'm old enough to remember when a standard double was 52/42, and 42 was the smallest ring which would fit on the spider!!!!!

I rode that for most of my life and my knees are perfect. I still have one Suntour SuperbPRO crank with that config in a box somewhere.

 

[Poacher]

It is a myth that high gearing damages the knees. If the gear you are using is too high your thighs will refuse to push the pedals round long before your knees give up. Walking up stairs - which most of us do many times a day - puts far more strain on the knees than riding a bike where your body weight is supported. Runners, footballers, rugby players and dancers put far more strain on the knees and all the other joints than cyclists do and they seem to manage ok. All my racing was done in the days when 42x23 was the lowest you got and my knees are ok.

Yeah, only one of my answers was truthful, the one about 5 speed blocks. Knees are actually fine, despite me being massively overweight and an ex rugby forward.
Remember kids, as @Smokin Joe says, cycling is a low impact sport, and you can still enjoy it well into your anecdotage.

 

[mjr]

Yeah, only one of my answers was truthful, the one about 5 speed blocks. Knees are actually fine, despite me being massively overweight and an ex rugby forward.

I've 52/42 on one bike now and I think I had it on the one I rode most so far. My knees are knackered for entirely unrelated reasons

 

[youngoldbloke]

I rode that for most of my life and my knees are perfect. I still have one Suntour SuperbPRO crank with that config in a box somewhere.

Is that just the crank or the whole chainset?

 

[Citius]

I'll see @Smokin Joe 's 42x23 and raise him 42x21 - that was my lowest gear back in the early 90s

I remember turning up for a winter club run once having just fitted 39x23 to my training bike - I was terrified that someone would notice my 'poncy' gearing. Most of our rides back then headed up into the Chilterns, so not exactly flat.

 

[Ness]

Congrats on perpetuating the general confusion on this issue. Like I said before on another thread, a double chainset is defined by its BCD, not by the tooth-count of the chainrings fitted to it. Remove the rings from a compact double chainset and it would still be a compact double chainset. Remove the rings from a standard double and it would still be a standard double. The definition would not change simply because it had no rings.

One of my bikes has 50/38 - does that make it a three-quarter compact double, or maybe a six-eighths double? Or maybe it's just a compact double with a 50 and a 38 on it.

How about reading my post properly?
I said they are "referred to as..."
The original posts were asking about "layman's terms" and "commonly referred to".

Are you saying that if you went into a shop and asked for a bike with a compact chainset, they'd give you a condescending lecture about how the number of teeth doesn't make it a compact? Or would they show you bikes with 50/34?

 

[Profpointy]

I've 52/42 on one bike now and I think I had it on the one I rode most so far. My knees are knackered for entirely unrelated reasons

excessive piety ?

 

[Yellow Saddle]

Is that just the crank or the whole chainset?

Both cranks, but no sets of chains.

 

[Smokin Joe]

I'll see @Smokin Joe 's 42x23 and raise him 42x21 - that was my lowest gear back in the early 90s

I remember turning up for a winter club run once having just fitted 39x23 to my training bike - I was terrified that someone would notice my 'poncy' gearing. Most of our rides back then headed up into the Chilterns, so not exactly flat.

How about 52/42 and a 13-17 straight through block? Did that a few times, you could get away with it in Essex.

 

[youngoldbloke]

Both cranks, but no sets of chains.

You see - I still don't know whether you've just got 2 cranks or the cranks and chainrings - that's the problem with using 'crank'

 

[Yellow Saddle]

You see - I still don't know whether you've just got 2 cranks or the cranks and chainrings - that's the problem with using 'crank'

I have both cranks, the left and the right one.

Edit: And the chainrings attached to them.

 

[RichardB]

Although not many of us will have ridden an Ordinary Bicycle, the concept of gear inches (i.e. the equivalent size of wheel on an Ordinary) is a useful measurement, at least for me, as it factors in the size of the wheel, which simply stating the gear ratio does not. So a 60" gear on a Brompton is the same in terms of speed and effort as a 60" gear on a road bike, even though the chainring, cassette and wheel sizes might be dfferent. I suppose that gear development is more logical measurement (the actual distance a turn of the pedals will take you, as opposed to the size of a theoretical wheel that doesn't exist), but it doesn't mean much to me. In the same way, I ought to think in terms of litres/100 km in fuel consumption, given that we buy fuel in litres, but good old mpg is familiar and useful.

 

[mjr]

I don't know about you, but I think of fuel in £/100mi and generally it's

 

[RichardB]

I don't know about you, but I think of fuel in £/100mi and generally it's

... too much.

 

[mjr]

... too much.

Still nothing like as much as it ought to be! Roll on the transport revolution!