Question about gearing

[Jmenorton]

Hi, the bike i plan to do some touring on currently has a 46/36t chainring and 12-25t cassete, im i right in thinking this is too high for loaded touring? i will be crossing the Pyrenees at some point. Also would it be as simple as swapping the inner chainring, its a Shimano CX50 chainset with 110mm bolt spacing.
The tour wont be untill next summer, so im hoping to be fitter then.

 

[rich p]

Blimey! My Galaxy's lowest gear on my recent tour was 28 ring and 34 sprocket and I had to use it frequently in the mountains. I had 4 panniers and a tent but that sounds like a tough ask.

 

[Jmenorton]

I think i definitely need to lower it somehow, i got caught out yesterday on a new course, 40 miles 4000ft of climbing with a 20mph head wind for some of the ride and really struggled, and that was unloaded. So what are my options? Can a mountain bike double be fitted to a road/cx bike? Is there 110bcd that go low enough? Im guessing converting it to a triple would be expensive?
This is the bike http://www.rosebikes.co.uk/article/rose-pro-dx-cross-2000-4636/aid:532649

 

[TheDoctor]

34T is as low as compact inners go. I'd be tempted to go mad with the cassette.
10 speed MTB cassettes are out there - I'd get as big a one as you can find. 11-34, maybe?
You then need a decent MTB rear mech. DO NOT get a 10 speed one - the cable pull is different. Get as good a 9 speed Shimano one as you can find. Chris Juden of the CTC says this works perfectly.
Your other option is to get a triple, but a new chainset, front and rear mech, cassette, chain and set of STIs gets a bit spendy.

 

[Jmenorton]

Thanks for the ideas, so 34 front 34 rear could be doable? Would there be any issues with the shifter and the mtb rear mech?

 

[TheDoctor]

.

Thanks for the ideas, so 34 front 34 rear could be doable?

Indeed so. 1:1 isn't ideal as a lowest gear for loaded touring, you could do with something lower, but let's work with what we have. It's a damn site better than 34:25 anyhow.

Would there be any issues with the shifter and the mtb rear mech?

None at all. Other than 10 speed MTB DynaSys rear mechs, all Shimano rear mechs have the same pull ratio, so an MTB rear mech works perfectly with road shifters.

 

[billflat12]

I had this same dilemma with a ridley cx just 2 years ago with dura-ace sti,s , settled with a new adjustable flat bar 700c hybrid , 28/38/48 & 11-32 , Bike has strong shimano mtb type hubs double wall 36h rims, combined mtb trigger shifters that really brought the cost down & It,s been really comfortable, overall making it ideal for loaded tours, whole bike was less than the price of the triple duraace shifters without spoiling my ride, (great excuse for another bike too)

 

[rich p]

I had this same dilemma with a ridley cx just 2 years ago with dura-ace sti,s , settled for a flat bar fast commuter/hydrid 28/38/48 with MTB shifters and adjustable stem for loaded tours, bike cost less than the price of triple duraace shifters alone without spoiling my ride, (great excuse for another bike too)

There's a lot of truth in this. You can tour on anything.
I did my first few tours on a hardtail mtb with slicks - perfect for loaded hills and you can probably pick a decent one up secondhand cheaper than the adjustments you're thinking about.

 

[Danny]

If it was me I would fit a triple chainset for touring in mountains, but as The Doc says this could be pricey.

Whether the expense is justified depends how often you intend to do that kind of riding. If this is a one of tour you could always push your bike up any really steep bits.

 

[billflat12]

The problem i had with my mtb hardtail was frame geometry, heal clearance was a problem with panniers because of shorter chainstays.

 

[jjb]

I pedalled the Pyrenees using 34/34, terrific. I kept the luggage to 8 or 9kg and did the mountains after 2 weeks of easier days, so was in good shape relative to my normal mild chub. I don't remember ever pining for one more gear, so that's a good sign.

Back home I wouldn't switch back to the 12-25, despite its super slick shifting - for my fittness level and gentle-to-middling pace, the 34 is just the ticket, which is good because it's a lot of cash otherwise (for me), for a one-off use!

 

[Jmenorton]

Good to know jjb, when i first bought the bike i didn't know anything about gearing, my initial thought was with it being a cx bike it must have a wide range of gears,but seems cx bikes seem to favor closer spaced gearing, dont know why must be a reason among racers though. I should be plenty fit after riding to Portsmouth (from Manchester) and a bit of meandering before the Pyrenees.

 

[theloafer]

Good to know jjb, when i first bought the bike i didn't know anything about gearing, my initial thought was with it being a cx bike it must have a wide range of gears,but seems cx bikes seem to favor closer spaced gearing, dont know why must be a reason among racers though. I should be plenty fit after riding to Portsmouth (from Manchester) and a bit of meandering before the Pyrenees.

the boardman cx team has 50/34-11-32..

 

[betty swollocks]

Looked at the pic and the bike looks lovely.
Recall being very interested in their bikes when they exhibited at The Bike Show, Earls Court, acouple of years ago.
Looking more closely at this particular pic though, it is not apparent (to me at any rate) as to whether this model has luggage carrying capability ie racks for panniers........I assume you've checked this out?

 

[Jmenorton]

Its got mounts at the bottom of the seat stays, and im using a fancy seat clamp with a rack mount built in. Seems solid (i sat on it).