Gear inches reduction

[DanZac]

I'm not sure if this should be here or in components so if this is not the best place then could one of the mods please move.
However I've been doing multi day camping tours, mainly in the south (Hampshire based area) on a 50\39\30 triple with 12\27 quite happily for the last few years.
This year though I've got the time to up the anti and do a month long home, lejog and back home triangle. As such I'm thinking of dropping down to 48\38\26 to make life a bit easier on the old knees.
So the question is will I actually notice the change, which only equates to a drop of about 3" or would I be better of fitting a large rear cassette or both. I quite like the close steps on the 12/27 cassette so I'm not sure if a wider ratio cassette is the best option.
Any opinions or thoughts or better ideas from any of you experts would be gladly received.

 

[raleighnut]

I'd change the crank (to keep the 'tight' spacing on the cassette)

 

[Rohloff_Brompton_Rider]

I disagree, cassettes can go pretty wide these days and a tooth increase is more inches gained when on the rear.

 

[DanZac]

Agree with you @just_fixed but as the range at the back gets wider so do the gaps between gears and as a bit of a weakling I tend to spin quite a fast cadance and chop and change the gears to maintain it instead of trying to power it out.
I think that I really want the whole lot a bit lower for long term ease which changing the front will do as well as giving a lower crawler gear. But will the small drop be noticable?

 

[Rohloff_Brompton_Rider]

Agree with you @just_fixed but as the range at the back gets wider so do the gaps between gears and as a bit of a weakling I tend to spin quite a fast cadance and chop and change the gears to maintain it instead of trying to power it out.
I think that I really want the whole lot a bit lower for long term ease which changing the front will do as well as giving a lower crawler gear. But will the small drop be noticable?

But IIRC the crossover gears would cover this, but it does mean more gear changes.

There are cassettes that have 90% close range and a large last sprocket for hill climbing.

 

[DanZac]

Very valid point I hadn't really considerd the crossovers. More food for thought, time to get my head back into the tables to see what i could get with just a casette change.

 

[Ajax Bay]

You don't need to change all the chainwheels to get the advantage you seek. I would just change the small chainwheel to a 28t to give you an extra 7% when you need it. You could go for a 26t (see bit on inner to middle delta below). I don't agree with @User9609 - you will notice it and continue so to do.
I'm on a 52-42-30 with the same cassette as you (12-27) and it's worked well so far. However, I am doing Mille Pennines (1000km) Audax in 4 weeks which includes the Lake District's Hardknott and Wrynose passes (after 100 miles of first day) and Rosedale Chimney on the North York Moors (after 100 miles of the third day): these all have 1:4 sections. So I have procured and shall be swapping out my 30t for a 28t. The FD will cope with the shift up from 28 to 42t (16 difference is the absolute maximum; and for your FD the change to the 39 would be 11, 3 teeth easier than mine, or if you go for a 26, a change of 13).
You can change the cassette as well (as has been mooted above) but the available cassettes seem to force a 11t on you, and that's really unnecessary and redundant for the type of riding I do and you plan (you lose some of the valuable closeness the cassette offers, and @just_fixed double shifting doesn't really make up for it). Best of luck with the end-to-end and back via home triangle btw - would be interested in your route if you want to share).

There are cassettes that have 90% close range and a large last sprocket for hill climbing.

Perhaps @just_fixed could suggest one compatible with a road RD. With a chainwheel difference of 20 already (22 with a 28t I've suggested) the 12-27 already puts him on the edge of RD capacity (we don't know what RD model the OP's running but 37 is normal capacity for GS).

 

[Rohloff_Brompton_Rider]

You don't need to change all the chainwheels to get the advantage you seek. I would just change the small chainwheel to a 28t to give you an extra 7% when you need it. You could go for a 26t (see bit on inner to middle delta below). I don't agree with @User9609 - you will notice it and continue so to do.
I'm on a 52-42-30 with the same cassette as you (12-27) and it's worked well so far. However, I am doing Mille Pennines (1000km) Audax in 4 weeks which includes the Lake District's Hardknott and Wrynose passes (after 100 miles of first day) and Rosedale Chimney on the North York Moors (after 100 miles of the third day): these all have 1:4 sections. So I have procured and shall be swapping out my 30t for a 28t. The FD will cope with the shift up from 28 to 42t (16 difference is the absolute maximum; and for your FD the change to the 39 would be 11, 3 teeth easier than mine, or if you go for a 26, a change of 13).
You can change the cassette as well (as has been mooted above) but the available cassettes seem to force a 11t on you, and that's really unnecessary and redundant for the type of riding I do and you plan (you lose some of the valuable closeness the cassette offers, and @just_fixed double shifting doesn't really make up for it). Best of luck with the end-to-end and back via home triangle btw - would be interested in your route if you want to share).

Perhaps @just_fixed could suggest one compatible with a road RD. With a chainwheel difference of 20 already (22 with a 28t I've suggested) the 12-27 already puts him on the edge of RD capacity (we don't know what RD model the OP's running but 37 is normal capacity for GS).

We also don't how many sprockets on the cassette do we?

 

[T4tomo]

Agree with just change the granny ring for a 26t. 26-27 should be low enough for anything.

Re a.couple of posts up, keeping a 2 wheeler upright on a 26f -30r would be tricky I reckon as that's substantially less that 1:1 gearing, and into trike territory.

My retro tourer has 50-40-30 mated to 14-28 (5spd) and you can climb a wall in 30-28, but I've not riden it fully loaded. Its noticeably lower than 34-28 on the best bike.

 

[Crackle]

I run a 49/38/26 with a 12-25 rear exactly because I like the closer ratios. It was a 30 inner and you can tell the difference in small increments despite the small percentage change on paper.

 

[the snail]

Agree with just change the granny ring for a 26t. 26-27 should be low enough for anything.

+1 Did this recently, now running 50/39/26 and 11-28, very noticable difference on the hills, and a cheap change - £10 ring from Spa cycles. On my 105 setup, 30T sprocket is probably the limit, but I wanted to keep the closer spaced gears on 11-28.

 

[numbnuts]

On my touring bike I use 22 36 48 and 11-34......hills what hills

 

[DanZac]

Many thanks for all the replies guys much appreciated and appears to have sparked some debate. Just to try and clear up a few questions:
@User @just_fixed I'm running 9 speed, (Sora STI levers and Acera rear mech) and could quite happily do away with the 12, what are the thoughts here? 13-30/32 or similar? I must confess that I haven't really looked that hard but is anything available in this range off the shelf? Not that there's anything stopping me making up a custom set apart from my inherent laziness.
@Ajax Bay and others your thoughts seem pretty close to my own, I only wish I had the legs to push 52 on the front full stop.
Route wise I'm planning on working down to LE from Basingstoke (Salisbury, Glastonbury, Taunton, Holsworthy etc.) then loosely follow Royston Wood's End to End cycle route back up, as it seems a pretty good route, coming back I was/am planning on coming down the east side, although this is looking less likely as time goes on (and I may just end up coming back down the west and cutting across at some point and down the middle.) as I'm having trouble finding what I think is a good route down that side (even the LEL route takes on some roads that I would much rather avoid) and having spent the last few years living in the Peterborough area during the week I don’t know if I can face a fortnight of howling gales. Either way I'm looking at about 2500 miles in around 30 days.

 

[mcshroom]

If you like spinning and you have a band-on front mech, then a 42-32-22 crankset will work (it's what I fit on my Dawes Horizon for camping-touring). When you are touring the top end of the gears isn't as important, but it's always nice to ride up hills rather than push up them.

I think the gear spacing is more psychological than anything else, as I use a 11-32 8sp cassette on that bike without issue, but then again I also ride single speed so I'm used to a greater cadence range.

 

[swansonj]

Agree with just change the granny ring for a 26t. 26-27 should be low enough for anything.

Re a.couple of posts up, keeping a 2 wheeler upright on a 26f -30r would be tricky I reckon as that's substantially less that 1:1 gearing, and into trike territory.

My retro tourer has 50-40-30 mated to 14-28 (5spd) and you can climb a wall in 30-28, but I've not riden it fully loaded. Its noticeably lower than 34-28 on the best bike.

Without wanting to be confrontational, I feel you are sending out some unhelpful messages. There is a view of cycling which is about fitness and machismo and "beating" hills, and the view that 26-27 or 30-28 are low enough to climb anything seems to align with that view. There's an alternative view that cycling is about enjoying yourself, anyone can do it, and hills should be as easy as possible - and on that view, even 22/24-32/34 is not as low as ideal. I have no problem with you or anyone else choosing whatever gear you want. I do have a problem with people being put off the infinite joys of cycling because they find it too hard because some twit in a bike shop sold them a bike with racing-derived gears because of some macho hang up about cycling not being supposed to be easy. (I also have a problem with the term "granny ring" but let's tackle one issue at a time...)