changing double over to compact.

[captain slow]

ive been accepted to ride the fred whitton challenge this year but need to change my current double chainset ,53 39, to a compact,50 34.apart from the chainrings what will i have to change over.my running gear is 105 and the rear cassette is 11 25.will i need new cranks, rear derailleur. cheers.

[gbnz]

Aside from the chain rings, the crankset, as I'd assume the BCD will be different

I didn't have to change anything else when converting a 52/42 into a 50/34

[Brucey]

only a tiny increase in overall 'capacity' so you would be unlucky if the rear mech didn't cope, so yes just chainset then I guess.

cheers

[robc02]

ive been accepted to ride the fred whitton challenge this year but need to change my current double chainset ,53 39, to a compact,50 34.apart from the chainrings what will i have to change over.my running gear is 105 and the rear cassette is 11 25.will i need new cranks, rear derailleur. cheers.

Will you be able to get up Hardknott and Wrynose passes on 34 x 25?

[Brucey]

I ride my bike for two main reasons;

1) enjoyment

and sometimes

2) a challenge.

I have attempted both Wrynose and Hardknott on bigger gears than the ones the OP has started with and, although I did it, TBH one of the usual qualites was completely absent and the other was present to excess.

Everybody has a different width masochistic streak I guess. Mine wasn't wide enough that day...

cheers

[robc02]

I ride my bike for two main reasons;

1) enjoyment

and sometimes

2) a challenge.

I have attempted both Wrynose and Hardknott on bigger gears than the ones the OP has started with and, although I did it, TBH one of the usual qualites was completely absent and the other was present to excess.

Everybody has a different width masochistic streak I guess. Mine wasn't wide enough that day...

cheers

I suppose the question should have been:

Would you want to climb Hardknott and Wrynose passes on 34 x 25 - as part of 112 mile sportive event? ---- Especially if you are interested in enjoyment or speed. If pain is the main object then maybe its a great idea.

[Brucey]

Fred Whitton challenge it was not; but that day myself and my chums did the thick end of 100 miles on the road and carried our roadbikes over black sail pass. -Just for fun, like yer do....

It is not every ride of such length that is punctuated by a hike over a medium sized mountain; it turned out that parts of the Ennerdale track would be 'quite good for pinch-flats' too... which would not have been so bad, had we posessed more than two functional tubes and one patch between us. Needless to say, the guilty party had brought nothing, and had robbed everyone else's tubes, patches etc. without telling them the previous evening... IIRC we resorted to 'home made' patches, lovingly (or was it desperately...?) crafted from a dissected inner tube. That, and swearing. Quite a lot of that....

But yes, the gearing could have been better, but it might have been the least of our problems as it turned out....

cheers

[cycloret]

Several of my road bikes have MTB RDs. One has a compact giving a high of 119.5 and low of 26.3 using 50/34 and 11/34. It's a 10 speed Mars cassette from SJS Cycles. The Mars cassettes have gone a lot up in price since I bought one. Warning the latest 10 speed STI shifters may not work with MTB RDs. It's probably easier and cheaper to be with 9 speed or less.
http://www.sjscycles.co.uk/mars-shimano ... prod13495/

Some of my bikes I've fitted Stronglight Impact Triples with road RDs, 46/35/24 and 12/27 giving a high of 100.7 and low of 23.4.

[Mick F]

Your present setup has a 53/11 top gear?
128"

Rather high, I think. People are shocked even by my 53/12 @ 117"

No wonder you want to cut back to 50/11. I'm sure you'll be better off, but even that is very high @ 120"

[Ayesha]

Build an ALPINE.

[Ayesha]

That was the first attempt. So I took a photo.
It was 32/22 with an 11-25 9 spd cassette.

Now its a 36/22 with a 12-27 9 spd.

21 to 79 inch range.

Hardknott is an "Inconvenient incline".

[Steve Kish]

I did this change a while ago and had to shorten the chain and take the front mech south a bit.

My prayers are with you for 34 x 25 up some of the FW climbs!

[karlt]

There comes a point where the gearing you need is so low that whilst it'll get you up, it'll be barely faster than walking anyway. At that point, it's really a matter of personal preference, and what sort of cleats you're wearing

[Ayesha]

When I had a Garmin and a silly high geared bike, walking up a 25% gradient was 2.2 mph.

On a 21" gear, its 35 rpm at 280 Watts.

Seeings as I'm having to exert the same power to get all the mass up the hill at the same speed, riding feels more comfortable due to not having the stretch on my Achilles.

FWIW, for a person who walks at an 90 strides per minute ( 45 cadence ) pace at 5 kmh, a 23" gear is the equivalent on flat ground.
Walking is approx 100 kCals per mile on the flat, while riding a bike is 10 kCals per mile at 5 kmh ( 3.2 mph ). A few pedalstrokes and a hell of a lot of freewheeling.

Seems strange there was 5000 years between the invention of the wheel and the 'hobby horse'.

The bicycle. The most significant invention ever, second only to the flushing lavatory.

More strange, the ancient Egyptians made flying model birds, but didn't think of the bicycle.
Was it so difficult to make a model horse with one wheel to substitute its front legs and another wheel to substitute its rear legs ???

[BigG]

When I had a Garmin and a silly high geared bike, walking up a 25% gradient was 2.2 mph.

This is quite a good speed for walking up a 25% gradient pushing a bike. Following a recent serious operation that left me very weak, I re-geared my bike down to the lowest gear I could get commercially, 14.2" (20/38). This gives a speed of 2.5 mph at a comfortable climbing cadence of 60. This is one gear (14% using your figure and 25% using my own estimate of 2 mph when walking up the same hill) faster than walking, definitely more comfortable and probably more efficient. IMO it is better to have a gear range that is too low than one that is too high. Spinning out at the top end is only a minor nuisance - after all, what are freewheels for? Running out of gears at the low end is a much bigger problem resulting in walking and losing much more time. The readership of this forum, and probably the whole world of cyclists, seems divided between those who see cycling as a challange and those who see it as a relaxation. I am definitely in this latter group and have been for many more years than when in my younger days I was in the former.