Author Topic: Road Crank of MTB Flex? (Read 3627 times)

jinder · « **on:** February 12, 2005, 06:41:43 am »

Just a quick question... have any of you seen a road bike crank with 53 teeth ring on a MTB Proflex before? I am not about to do it.. but my friend is...what are you comments?

Thanks!

Matno · « **Reply #1 on:** February 12, 2005, 08:50:26 am »

I'm not sure I understand the point of that. A lot of people don't even use their big ring (44t) as it is! In fact, even on my road bike, I use the smaller ring more often than the 53t. And I'm more of a masher than a spinner...

As for whether or not it will work, it depends on the model of proflex. A problem you'll run into is that the front derailleur will also have to be a road derailleur (I think) to match the larger arc of the bigger ring. And it will have to be mounted higher, which won't work on EVO frames because of the short derailleur mounting post. Also, he may run into clearance problems with the swingarm, although that's less likely to be an issue.

If he still wants a granny ring, he may not be able to position the front derailleur to allow the chain to pass through it in both rings. In addition, the rear derailleur capacity may be maxed out, thus limiting the overall gear spread (the sum of the difference of the largest and smallest front rings, and the largest and smallest rear cogs).

jinder · « **Reply #2 on:** February 12, 2005, 09:28:54 am »

Yes, same as I was thinking....

ReBeL · « **Reply #3 on:** February 12, 2005, 10:24:20 am »

Well I would like to clear things up about the road crank on an 856.

I would like to have 2 cranks/crank arm assemblies to interchange between road & mtb use. I would use a BB with the same type of drive so cranks would be interchangeable. The derailleur would also have to move up or down the tube to correspond to the crank in use. These spots would be marked to facilitate “change over”. I live about 20 kilometers from work and plan on riding along the train tracks that are about 3 blocks away from work. The tracks run between the city I live in and the city I work in. The distance between the two is country side. It would be insane to try this area on a road bike and the main road is way to busy to bike on, it would be suicide. The open distance is great for endurance & speed training. Not to mention just plane old better than driving.

I will keep you posted on the success or failure of this experiment. Besides…ReBeL is my name & I just have to try to be different! LoL

ReBeL Rick

jinder · « **Reply #4 on:** February 12, 2005, 10:31:39 am »

Matno · « **Reply #5 on:** February 12, 2005, 11:21:11 am »

Quote

I would like to have 2 cranks/crank arm assemblies to interchange between road & mtb use. I would use a BB with the same type of drive so cranks would be interchangeable. The derailleur would also have to move up or down the tube to correspond to the crank in use.

You ARE a Rebel...

Three concerns:
1) constantly switching the cranks is not only hard to do, it's probably pretty hard on your cranks. Those interfaces are difficult to get tight, and difficult to pull apart, which makes me think there would be a lot of stress on the interface resulting in very premature wear and a loose fit.
2) Adjusting a derailleur - even the front one - is not as easy as one would like to think (although if you pull this off, I imagine you're going to get very good at it). Small variations in angle, tension, and chainring spacing can create aggravating shifting conditions.
3) (The most important thing) This is going to take a lot of effort and time each time you switch. I'd hate to think that something like this would eat a big chunk of your riding time!

Recommendation: The gear range on a normal mountain bike is pretty wide. Get a rear cog with 11 teeth and an XTR front ring (46t rather than the standard 44), and I think you'll be happy. Rather than investing in an extra set of cranks, get an extra set of wheels so you can quickly swap from knobby tires to slick. That's the easiest way to see the biggest difference in riding on and off road, IMHO.

kiwi · « **Reply #6 on:** February 12, 2005, 01:19:56 pm »

nice idea and if you want to do it i hope it works.....one warning tho,the bend in the seat tube may make it impossible for you to move the deralieur up,not to mention the brake cable port,check before you layout the cash,i think 48 is pushing it.....

StoereVent · « **Reply #7 on:** February 12, 2005, 11:24:55 pm »

Wouldn't the difference in chain length between the two setups cause a problem?

jeroen.

jinder · « **Reply #8 on:** February 13, 2005, 01:53:28 am »

Yes.... he would have to replace the chain aswell. I think he would be much happier with a Road bike for his road trips.

ReBeL · « **Reply #9 on:** February 13, 2005, 05:59:23 am »

Well the 20 kilometer trip may have 3 kilometers on the road…the rest of the trip would be on a trail that runs along train tracks. It’s a mix of loose gravel with hard pack. A road bike is not able to ride in this area.

Road bikes also use a short cage rear derailleur…I’m hoping that with a long cage derailleur, a chain with a couple extra links and the ability of the derailleur to pull forward a little bit that this will work with the larger crank. If not I will need to come up with a method of taking up the slack when running the mtb crank.

To take up the extra slack in the front shifting cable I am considering the possibility of a small turnbuckle similar to what is found on ski boots….its all ideas in my head for now and trying it is half the fun….all input is greatly appreciated & needed to make this work...where there is a will there is a way!!!

ReBeL

Matno · « **Reply #10 on:** February 13, 2005, 11:40:16 am »

Ever thought of getting a cyclocross bike? Basically a road bike with more tire clearance for bigger tires. Sounds like exactly what you would need. I rode trails that sound like yours when I lived in Germany, and the slightly bigger than road tires worked beautifully (approx 35mm tires, to be exact). They come in knobby (well, knobbier) models specifically for off-roading, but still ride a lot like a regular road bike on the road.

Not that I'm trying to discourage your project. I'm just the kind of guy who hates using bike roof racks that require you to remove the front wheel, because they waste too much time...

jinder · « **Reply #11 on:** February 13, 2005, 11:42:52 am »

Matno · « **Reply #12 on:** February 13, 2005, 11:44:58 am »

Okay, now I'm drooling... That bike even makes the ugly "celeste" green tires look cool somehow!

jinder · « **Reply #13 on:** February 13, 2005, 11:53:23 am »

I love those Green tyres.... Michelins I guess

Dennis · « **Reply #14 on:** February 13, 2005, 01:54:14 pm »

OR better yet, a carbon cross bike:

I agree with everyone else, get a 'cross bike, its the perfect thing for you.

[smiley=groucho.gif]

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Author Topic: Road Crank of MTB Flex? (Read 3627 times)