Stix Zadinia

Has anyone done this, or is it something usual to try it?

I've been giving a bit of thought for a while about getting a 29r mtb, but the small cranksets that come stock in these bikes (especially mid-and-higher end bikes) make me think those stock parts are not best suited for what I would use the bike (Not any hills or trails of any kind mind you, I'm rather interested in putting up a -machine aside- very fast and light commuter, for flat terrain use.

I'm already slowly putting up a road bike together, but I'd still like the option of having a second ride, with a nice fork (VERY resistant/durable and with good effective travel) and an overall mtb sturdy feel, for heavier duty rides (jumping up and down the curbs, go fast over broken pavement, etc). I basically broke/bent a stock Suntour fork on my previous mtb after only 1 year, so I'd like to go with either a RockShock or a Fox this time, I think.

In particular I've been looking on the LBS at a Specialized Carve 29, and I'm wondering if it's feasible to replace some -or all- of the stock group with a road group.



Thanks much for you opinions

CraigB

I'm not sure what you hope to gain from going with a road group. Brakes/shifters aren't interchangeable due to fork/frame and handlebar designs, and unless you go with a smaller cassette, many road RDs won't handle the wide-range cogs that come standard on a mountain bike.

Maybe the route to go would be to get a mtn bike frame, buy only those road components that make sense (standard or compact crank, road cassette, road derailleurs) and mtn bike components for the rest.

Or buy a 'cross bike.

wphamilton

As far as I know, a mtb cassette is drop-in replaceable by a road-bike cassette, the main consideration being the range of the dr, which shouldn't be a problem going to smaller cogs. Putting a standard road crankset (larger chainring) on might be problematic though because of clearance with the chainstay. Maybe you can compromise with a 48 ring and tighter cassette.

fietsbob

The wide rear tire clearances require a certain shape of chainstay,

which thereafter can interfere with chainrings past a certain size,

given the tiny high gear cogs on cassettes now a days , big front chainrings hardly matter .

But the companies sell stuff like the racers use , and market it as such.

Touring with full panniers , the opposite is somewhat common MTB crank on a road /Cross/Hybrid.

for the low gear ratios to get stuff over the passes..

likebike23

Is this kind of what you're talking about? https://www.bikesdirect.com/products/...y/zilla_xx.htm. I'm not sure if you want a flat bar bike with lower road gearing or a heavy duty drop bar bike. Do you want a single speed like the specialized carve, only with higher gearing? The carve comes with a rigid fork, do you want to install a suspension fork?

umazuki

Be warned, if you do this and Shimano or SRAM find out, their secret police will come and throw you in Bike Prison. They take mountain and road groupsets seriously. People think, I can put Deore on my road bike! But then, they don't think about the consequences.

*: I'm just kidding do whatever you want there are no rules just make sure things fit. Although from what you describe, just throwing slicks on a hardtail 29er with standard gearing should work for you pretty well.

dynaryder

Depends. Some modern higher-end groupsets are designed to interact only with each other. If you go with 9spd or older parts,you shouldn't have many issues.

puckett129

When I was in college I bought a new Cannondale F-400 mountain bike and had the shop put RSX brifters, travel agents, and slicks on it and loved that thing. When I moved to NYC I used it for commuting and it was perfect. It was stolen from my home during a burglary. In retrospect (or if I was doing the same thing now) I would use a cross frame or buy a purpose built urban style bike.

Stix Zadinia

I swapped the stock 42/34/24 triple crankset on my previous mtb for a a 53-39 road crank, and it didn't work too well with the shifting, but I think it was mostly because of negligence on the part of the local shops to change the chain (no matter how much I told them, they wouldn't do it). The frame had good clearance for the crank, though. The stock cassette was a 11-32, 8 speed one, but I think I swapped it (along with the shifters) for a 9 speed setup at some point.

My main reason to do this is to have higher shifts available, and the Carve ('Crave' for 2014) bikes with suspension forks have tiny ring options for non-trail use. The bike I've been looking at is this, I like the components, but the chain rings are only 36/22:

https://www.specialized.com/us/en/bik...ve/carveexpert

Maybe I could just try and find some road rings that would fit into that spider?

^ I think this might be less of a joke that we ought to make of it


THat's what I have been thinking..

Retro Grouch 

If that's what you think would rock your boat, I say go for it. Couple of issues:

1. 2-piece external bearing cranks are frame specific. If your bike has a 72 mm bottom bracket (and a 29er will) you will need a crank and bottom bracket combination that will fit the 72 mm bottom bracket shell. 2-piece road cranksets fit 68 mm bottom brackets.

2. I'm about 90% certain you won't have chainring to chainstay clearance issues. 90% isn't 100%.

3. Bigger chainrings need a differently shaped front derailleur. The arc on mountain bike front derailleurs is too small so you'll have to install it way high on the seat tube. That looks goofy and doesn't shift very well.

4. All road bike front derailleurs that I'm aware of use under the bottom bracket down pull cable routing. Most mountain bikes are top pull.

5. If you change the front derailleur, you'll have to think about the front shifting. You MIGHT be able to get it to work to your satisfaction with your existing shifter but I doubt it. If it was my bike, I think I'd use some kind of friction shifter for the front.

dynaryder

I don't think you'll find anything bigger than 48t for those. 48t with big wheels and an 11 high on your cassette is a decently tall gear.

Stix Zadinia

Thanks much for this advice! That's what I was looking for, I'm worried about compatibility issues should I basically try a road crankset on that bike.

Apparently the big wheels do make a difference? I was told so by the LBS owner; he said he had tried these bikes and small chainrings were sufficient and actually felt very fast, even on paved flat terrain.

Wilfred Laurier

according to sheldon browns gear calculator
with a 44 x 11 and 700x50c tires aka 29x2
you would be going 55 km per hour
when pedaling at 100 rpm

Retro Grouch 

How fast do you really need to pedal?

The big ring on the SWB recumbent in my avatar is a 48 and that's with a 26" rear wheel. That works out about perfectly for me. Once I get much over 20 mph I'm coasting rather than pedaling anyway. I've got short cranks (148 mm) on that bike so I lose a bit of leverage for turning a bigger gear. The 48t chainring is also a good match for the nos XTR derailleur from my junk box.

Stix Zadinia

That is interesting, thank you!

I like having some resistance on the pedals every now and then, but I'm starting to think smaller chainrings may be more forgiving on my knees.

theronin

I just did this on two hybrids which essentially have mtb frame clearances. The crank has maybe 5mm clearance tops to the chainstay. But otherwise that was really the only issue. Swap to drop bars was no problem. Tuning both derailleurs was no problem. I put on a 2x8 50/34T Claris crankset on one and a 2x9 40/34T Sora crankset on the other. Purpose for these conversions was I wanted the hybrids (his and hers - yes, hers to experiment on lol) to ride more like my road bike. End of the day, nothing compared to the road bike but still much funner to ride than the original.

tomato coupe

Out of curiosity, how did you stumble upon this thread?

theronin

I was googling "road groupset on mtb" to see how others have fared on this type of conversion.

tomato coupe

Got it, thanks.

veganbikes

The reason the question was asked so you know is that the thread was from 2013 so it is almost 10 years old and only lasted 3-4 days so it wasn't currently active and had been dormant all that time. In online forum etiquette it is generally good practice to leave old threads alone unless you have some beyond relevant information that must be shared in that thread and doesn't fit to a new one or you are the original poster (OP) and are updating the situation like say on a build thread or something.

Just to keep in mind not trying to attack you or anything.

Leisesturm

____!!! Did I really spend the last 15 minutes catching up in a zombie thread! If you're not going to attack him, stand aside. Let me at him. Grrr!!!

tomato coupe

That isn't the reason why I asked the question. It seems that a disproportionate number of zombie threads are revived by "newbies", and I'm just interested in why that happens.

sean.hwy

Topstone Shimano 105 2x convert to flatbar

I converted my drop bar topstone 2x to flat bar gravel bike.

I listed the parts I used in that thread. Shimano and microshift both make flatbar shifters that have the correct pull ratio for road/gravel shimano derailleurs front and rear.

I am not sure about sram.

veganbikes

Ok fair dinkum.

theronin

LOLL this place is really a piece of work. Yes, I necro'ed a thread. Yea, I know what necro'ing a thread even means. Nowhere in this old thread is there any confirmation of how a roadbike crankset can be an issue on a mtb/hybrid frame. Call me crazy but to me that is a key piece of information to this topic in case a "noob" is googling it and comes across it. Last time I checked, that is actually the sole purpose of a forum.

Now if the mods want old threads archived, here's another pro tip: forum software allows that. How do I know? I've owned several.

Pro tip#2: Want a thread to die? Don't respond.

Oh almost forgot: not trying to attack or anything. mmmkay?