hamster

I'm thinking along the lines of a 44/28 double. The idea is basically to make a monster climber at the expense of reduced top speed. I currently have a 50/34 with a BB30 bottom bracket. I can't use triples and I already have 32 in the rear.

And who can recommend a good but reasonably inexpensive crankset? (I understand that it might be a contradiction in terms.)

Commodus

The VO TA/Herse knockoff would work for you, you'd have to go searching for rings though.

https://store.velo-orange.com/index.p...kset-mkii.html

rhm

The problem I'd have with this scheme is that most MTB cranksets are 175 mm which I consider crazy long. I've been using much shorter cranks, and it works for me. Of course, this is mostly a matter of what you're used to, and if you're used to riding 175's already, this might not be an issue. If you have any knee problems, though, the 175's are a likely cause of that.

Commodus

The new ones all come in 170s. ^^

Yo Spiff

I put a MTB crankset on my recently assembled Schwinn Crosscut, and a 9 speed rear cassette with a large cog of 32t. It was geared WAY too low, even for monster hills. Shifting was poor and to get a suitable gear for city riding I had to use the outer ring, resulting in more problems caused by major cross chaining. I changed it out for an 8 speed 12-26t and it's perfect now. Still geared very low, but shifts nicely. I did the Easter Hill Country tour with it recently and the range was perfect.

unterhausen

you can often get deals on a 170mm mtb crank because there is no market for them.

anotherbrian

I'll be riding the Devil Mountain Double tomorrow with an MTB crank (42/32/22) on my recumbent. Normally I use a standard road triple on the bike, but I've been having achey knees since the beginning of the year, and I don't want any temptation to push too hard. I've done a few test rides with the cranks and spin out the gearing at ~26mph, and can even climb a lot of hills in the big ring :-), but that's going to be the trade-off to do the ride.

I'm using a ~8 year old set of Raceface XC cranks as they worked fine with my existing Shimano external BB.

Rowan

The BB30 is your issue here.

Other than that, I have been running MTB cranks (square taper, Hollowtech II, etc) for years on road/randonnee/touring bikes. I used to run 22-32-44, but opt now for 26-36-48, which might be better suited to the OP's needs ... if it's available in BB30. Shimano Deore is a highly serviceable and cost-effective model.

Another alternative to improve lo gear is a cassette with a 36T big cog. We have one on the tandem with a 26T ring and it works well.

Shimano cranks are availble from 165 to 175, but some effort to find on-line is needed. Wiggle and Chainreactioncycles have been my best sources. All my bikes bar one I think currently run 170mm

rodar y rodar

I`m curious as to why a triple can`t be used. Just because of the weird BB shell? I might be misunderstanding things, but I was under the impression that a few different adaptors were available to use regular BBs in those shells, though apparently, once installed, they can`t (or shouldn`t ) be removed.

As to RHM`s arm length issue, remember that 74/110 triples are pretty easy to find down to 165. That allows a granny as low as 24t (rumor says), and usually come with a 46 big ring, larger rings available. Also, Shimano XT cranksets come in 165, but big $$. I imagine you already knew that, but just in case!

hamster

I have electronic shifting, so I can't go 36T in the rear without physical modifications to the RD. (Technically I'm not even supposed to run a 32T there.) I can't use a triple for the same reason.

Velo Orange crank from the link above is looking good, except it's 30/46. They have 28t rings but not 44t rings. I don't see anyone else making 44t rings in that weird BCD. 44t seems to be a problem in general. Looked through Shimano, SRAM and FSA lines. I may have missed something but I didn't see any MTB double cranks with the outer ring bigger than 42t.

42/11 is 100 rpm @ 30.0 mph. 44/11 is 100 rpm @ 31.4 mph. I suppose I could live with 42t outer. I rarely if ever pedal above 30 mph.

I've seen adapters from BB30 to Shimano. It's not ideal but it would be an option if I can't find a BB30 crankset that fits.

Rowan

What I using on my current touring bike (use the dropdown option selection to see what is available in 170/175 and ring combinations):

https://www.wiggle.com/shimano-deore-...h-chain-guard/

For chainring only with 4-bolt configuration:

https://www.wiggle.com/shimano-fc-m51...inring-silver/

I'll also pop in the 9sp reference here:

https://www.wiggle.com/shimano-fc-m59...iple-chainset/

And yes, I know you run 10sp, but the wisdom here:

https://sheldonbrown.com/speeds.html

if you scroll down once or twice to "Chains" is that 10sp chains will work with 9sp rings (not optimally, but you're already considering a dodgy fix).

Even though you're thinking of only two rings out of the three on the crank, there are two other factors to account for -- if the front derailleur will move properly across the rings because the spindle spacing will be different, and the Q-factor which might affect your comfort on the bike.

hamster

I see a SRAM X9 crankset, BB30, 2x10 42/28 on eBay for $140 OBO. Is there any reason why that wouldn't work for me?

P.S. Forget eBay. Jenson USA has them for $95+tax/shipping (though without a bottom bracket, my understanding is that I don't need to replace mine.)

P.P.S. Ordered one. We'll see how it works out.

fietsbob

VO has their own idea.. a 46, 30, .. And the White VBC..
you pick the ring size..

decent set up Middle chainring for the 'big' one, and then the 3rd one

Chainguard disc goes on where the Biggest ring Aint.

been there done that 30 years ago ..

trescojones

used triples few times both triple and with a reduced number of chainrings(granny+middle), ., so that i can ride up 20% sustained slopes more easily. I used a suntour xc pro and specialized, 5 bolt cranksets. I think 2 rings on the inner of a triple set would work I got them to have a q factor of about 147mm the same as my campag record CT. I used a 102mm BB. The problem i found at first was that a standard 22 or 24 granny was too much of a change in tension to be able to use all the gears with a short cage road rear derailleur, a med to long is needed to have enough slack/reserve to do this. I certainly didnt regret it though and 30 40 50Ttriples have always been a part of campags lineup and seem to be compatible in shimano without issues from what i understand.
The other issue at times was getting sufficient clearance with some BB crank combinations to stop the inner face of the crankset rubbing on the BB face. I had to file down the spacialized a little but the suntour didnt have this problem. Perhaps a 105mm would have been a good solution. I used a 42 outer with a 12-27 and found it just a bit small at times, 44 would be better but with 11 i would think is ok. Ta specialities seem to make rings for absolutely everything used to be availible from sheldon,peter white etc

hamster

Well, I got the crank. It's pretty heavy, heavier than I expected (I thought X9 was supposed to be a high end group?) 753 g including arms, rings and the spindle (my original road FSA SL-K Light crankset weighs 572 g.) But installation was straightforward. Tapped out old crank with a block of wood and a hammer, kept the original bearings in place (not sure if there's anything wrong with that - all I know is that, once they are out, it takes a $50 tool which I don't want to buy to put them back in), pressed the new crank in place by hand. Had to add some spacers, other than that, smooth sailing to this point.

Now the unexpected roadblock is that my original setup has the chain line of 43.5 mm, and the crank is designed for the chain line of 49 mm. Which means that FD sits 5.5 mm too close to the frame and it's impossible to tune.

Checked with two bike mechanics, no luck. There seems to be a custom FD clamp adapter made by K-Edge that resolves this problem. Trying to find out if anyone carries it around here...

P.S. does not look like it. Ordered it online. In the mean time, new crank goes out, old crank goes back in.

ThermionicScott 

/stocks up on square-taper parts.

fietsbob

Touring bikes do just that.. after all do you need higher than a 44:11..

k edge is in Idaho, they ship.

bmike

TA Carmina on my IF. Double or triple. I run double. 30-46 or 30-48. Or 34-50.
Just moved to a 9spd bar end. Came from campy 10 speed. Aside from my hub deciding to die the day I get everything rebuilt, all good.

I have the x9 or similar on my Fargo. 28-44 with a 10spd rear that goes to 36. Really like it. Although for randonneuring I would probably go no lower than 28f and 32 or 34r.

rodar y rodar

Aw, man- that sucks! You can`t get different spindles for those, I take it? I guess you can`t return it after mounting, but hope you find a tighter FD or something.

EDIT: Unless you already have fat tubing, maybe you could use a derailler with clamp for OS mounted over a plastic plug with OD of OS an seat tube and offcentered hole with ID of regular ST, rotated like a cam? Not likely, but maybe worth a try.

hamster

Will do a road test later today.

rodar y rodar

Good deal, fingers crossed for you. What did you do different from the first attempt?

hamster

Special front derailleur clamp: https://www.amazon.com/K-Edge-Braze--...dge+derailleur

hamster

It works!

Shifting works correctly, like before.

The low end is very comfortable. Haven't tried it on any really steep hills, but the increase in cadence at any given speed in the lowest gear is noticeable. The sweet spot is right around 8% grade, where I go from having to work at/above FTP to spin 80 rpm, to somewhere around 85% of FTP to do the same.

Tested the high end (42/11), managed to apply power while spinning at 125 rpm briefly, going downhill at 38 mph. Wouldn't want to do that often, but it's doable.

On flats, I'm riding in the big ring and in the middle of the cassette (42/15 or 42/17).

I'll have more coherent feelings after a longer ride or two, but this setup feels workable so far. I got a vague feeling that I'm more sensitive to gaps between rings now (particularly to the gap between 28 and 32 at the top of the cassette). It would probably be nice to have 44T instead of 42T in front, but I couldn't find anyone who made 44T rings with that BCD. Will try again.

Bekologist

Like this? just got back from a 120 mile overnighter with considerable off road.



48 big ring.

Glad to hear you got it sorted out , K-edge makes some great stuff.

alexaschwanden

My trek 520 touring bike has a mtb crank and gears from a 1995 trek 9900 oclv carbon pro issue mtb.