Lost with drivetrain options...

[scaley187]

Hey all, so I wanted to see if there was anyone out there that could clarify for me the options for setting up trials drivetrains from the BB/Cranks to the rear hub and chainrings.

I ask this because I have seen that there what appear to be numerous options from the standard road cassette with a tight derailleur, to front crank freewheels with fixed rear hubs to freewheel rear hubs? I'm lost. So what I'm wondering is if anyone could tell me the different ways to configure, part groups that would work well (who/what), and pros/cons?

I'm now building a trials specific bike from scratch and am looking at my options. It is easy to get lost! Seriously, any help would be greatly appreciated! :D

[Specialeded]

The best means to any new thing is to research.....
The Search button is your best friend.

Now with that being said what type of riding is the build for?

Competition?
Natrual?
Urban/Street?
Do you have horizontal or Vertical drop outs?
Do you even want gears?
Are you Weight Conscious?

I could come up with a lot different setups off the top of my head with various different parts and ways to do stuff but a little more description on what you want would be help full.

[scaley187]

Yeah, sorry I guess I should have been more specific - I guess that is what happens when you write a post late at night. So, let me back up. I'm building up my first trials specific frame for mostly Urban use (Brisa stock with vertical dropouts) and have done a lot of searching on the net so far about different drive train options.

What I have gathered is that people tend to have something like the following 3 setups for trials:

1.) Regular trials front crank, small road cassette (12-19ish) on a cassette hub, and then a light but strong road derailleur.

2.) Regular trials front crank, single speed hub in the back with a 19? tooth rear freewheel and a chain tensioner (looks like its usually in the rear).

3.) Trials crank with freewheel on the FRONT chainrings??? (here is where I get confused) and then a fixed gear hub in the back.

So what I've been wondering it which situation would I want for mostly urban riding but potentially some natural as well. I am about 190 lbs and so I think lighter wouldn't hurt. My commuter is a fixey so I don't give a damn about having gears if they aren't necessary in trials (so long as I get the gear ratio correct). :)

Anyway, I hope that clears up what I was asking. If there is one preferred option I'd like to hear people's suggestions and which parts groups you may recommend looking into. I'm definitely not rich but want to evaluate my options. Thanks and Cheers!!!

[bouncingbabyboy]

This is where everyone will probably jump in and disagree:

What I have is a White Industry tirals specific freewheel mounted on the cranks and a fixed BT wheel with a Chris King 15 tooth cog in the back. I have the tryall cranks because that is what I could afford. I think Tensile would be the one to go. I have a god speed chain tensioner but the Surly is probably a better one to go with.

Why? Because the front freewheel gives you more ground clearance than a 22 tooth chain ring which is the smallest you can run with a bolt pattern. You could just thread a fixed cog on the cranks, but the BT hub has a very wide spacing between the flanges for a strong wheel. You could run a single speed hub but the BT gives you a little more wiggle room to get the chain line straight. I like a spring tensioner because it is dynamic but honestly none of the springs are tight enough so you could just as well run a fixed tensioner. Don't run without one. It will either be to tight or you will be putting to much stress on the freewheel.

The one thing you didn't mention was the bottom bracket. A 128 will give you the widest stance and there by the best control and ballance. I run a 118 becuase it gives me a better chain line. FSA is lighter than Truvative but either will work and the Truvative is cheaper.

[eastside]

I agree with that. But you can also run a 18t thread on cog (instaead of the White Ind.) on a front free wheel crankset. This will give you the clearance you need and allow you to run a cassette hub. I have Echo cranks, 18T thread on cog and a Chris King rear hub with a 15T cog (and a bunch of spacers). I also use the Godspeed tensioner. It's inexpensive and gets the job done! Prior to this set up I also ran a 18T White Ind. front freewheel and a 15T cog on a fixed hub. Worked fine. For a street/ trials rig IMO it would be better to have a standard cassette hub instead on a front freewheel just because with a FF the chain will go hay wire spinning around 100 MPH while cruising in the city and you pants get caught....Hhhhhhh....Thats a long sentence.

[bouncingbabyboy]

And a king hub is $400+ where as I think I paid that for my wheel set front and rear. Shimano comes apart. BT, solid like rock.

[scaley187]

First let me say thanks for the post. I had read about the tensile cranks and they seemed like a good way to go but I had also seen the zoo and echo freewheel cranks on a lot of prebuilt trials bikes but it makes sense that a FF would allow more clearance.

I followed everything above but what are BT hubs? I haven't bumped into that name. Also what do you think about some of the prebuilt Echo wheels that people like webcyclery.com have. If I get it all right then a good option might be to go with a tensile FF crank and a fixed rear (possibly Echo) wheel?

Cheers, S-

[ONE EYE]

BT is a bike company that is from Poland.

They make high quality parts, and frames.

You can't go wrong with any BT parts.

The web adress is www.btbike.com

Check it out.

I run a old style/traditional crank set, meaning 22T chain ring, a rear King hub with a 19T cog. Also on most traditional crank sets you can go as low as a 20T chain ring, most come with a 22T though.


I ride mostly street, and I don't find that I need more clearance for street moves.

Though the FFW set up is nice because it's so small and compact, probably helps alot more for natural.

My 2 cents.

Matt.

[scaley187]

Whoa!!!!! It's like a whole new world of parts! Very nice! Just when I thought I'd seen most of the companies making trials stuff! Thanks for the info.

[Specialeded]

I had wrote out about 15 lines of knowledge, then realized I wasn't logged in when trying to post<stupid noob.
So you get whats left to give....
Anyway, you don't need a king hub but they are nice, a Cass hub on the rear is IMO a great setup for ease of use, part availability and setting up your chain line. Also if you want to run gears you have the option.

Also above posts have mentioned what tooth they are running front and rear, but that does you all well until you want to set up your own and realize shit even with a Tensioner (a product used to keep the chain from falling off) there is a ton of slack. What to do? experiment with different different setups. For a good starting point on a single speed a 2:1 is generally the rule of thumb(ex. 32front 16rear) to start out with and adjust from there but for trials it is almost closer to a 1:1 (22front 22rear) for optimal performance for the intended riding. More than likely the gear ratio you want will not be the one that provides the best chain tension so there will be compromise somewhere.

[goose]

There aren't any good 19T BMX freewheels. So you're gonna be stuck looking for a ratio close to 22/19, but keep in mind a longer/shorter crank will make a difference in the feel also.

[scaley187]

So what I've got laying around is an 8 speed cassette on a shimano hub and a shimano 105 that I was thinking about running in the back. Do you seen any issue going this route and then just getting a crank that could run a front freewheel if I wanted to upgrade the rear hub in the future?

[ONE EYE]

^^^ sounds like a good idea for a starter bike.

Your going in the right direction.

Matt.

[goose]

if you have it, then start with it. You may find that after a couple hard rides pedal kicking, the shimano freehub body will cease to work. It'll cost about 30 bucks buy a replacement freehub body, and then it'll die again after another couple hard rides. This is what happens to many people who try to ride trials on cheap, XC hubs.

[AgrAde]

if you have it, then start with it. You may find that after a couple hard rides pedal kicking, the shimano freehub body will cease to work. It'll cost about 30 bucks buy a replacement freehub body, and then it'll die again after another couple hard rides. This is what happens to many people who try to ride trials on cheap, XC hubs.

well, sorta. as a beginner/sport level rider a shimano freehub lasted me out a good 8-12 months. i'm confident i could rip one apart in a ride nowadays but when i was beginner they lasted ok.

ride it until it dies then upgrade.

[ONE EYE]

well, sorta. as a beginner/sport level rider a shimano freehub lasted me out a good 8-12 months. i'm confident i could rip one apart in a ride nowadays but when i was beginner they lasted ok.

ride it until it dies then upgrade.

Word.

[goose]

well, sorta. as a beginner/sport level rider a shimano freehub lasted me out a good 8-12 months. i'm confident i could rip one apart in a ride nowadays but when i was beginner they lasted ok.

ride it until it dies then upgrade.
Ya, ride until it dies, as long as you're not attempting anything dangerous. In my own beginner experience, they were pooo. Sure it depends on how heavy/strong you are, and how hard you're trying to learn to pedal kick:) But, I'm playing devil's advocate here!!! For rocking/pivoting/hoping/wheelie droping everything, they were fine, as soon as I started pedal kicking drops and gaps... CRUNCH.
If you hear a weird crunchy noise, and all of a sudden the chain rotates backwards AND forwards, congratulations, you've sheared the pawls off a shimano freehub!!! Time to go out and get something stronger. ACS Claw at minimum, king at maximum. I figure that you can spend as little as 100 bucks on a surly+ACS, then at the other end of the spectra, it's 400ish for a full heavy duty King.

[beedo]

Ya, ride until it dies, as long as you're not attempting anything dangerous. In my own beginner experience, they were pooo. Sure it depends on how heavy/strong you are, and how hard you're trying to learn to pedal kick:) But, I'm playing devil's advocate here!!! For rocking/pivoting/hoping/wheelie droping everything, they were fine, as soon as I started pedal kicking drops and gaps... CRUNCH.
If you hear a weird crunchy noise, and all of a sudden the chain rotates backwards AND forwards, congratulations, you've sheared the pawls off a shimano freehub!!! Time to go out and get something stronger. ACS Claw at minimum, king at maximum. I figure that you can spend as little as 100 bucks on a surly+ACS, then at the other end of the spectra, it's 400ish for a full heavy duty King.

I'll second that.....I'm a beginner of only a few months now, riding about twice a week on my shimano freehub(s). After two sessions of learning to pedal punch/surge only small gaps my lx freehub started skipping. I replaced it with an xt and after one session of the same, it is skipping also. I weigh about 165lbs and I'm not super strong, so take my account into consideration when shopping. Because of my problems, I am also on an oddessey to build a good rr wheel and I'm not sure if I want to go cassette or single speed...

[scaley187]

Thanks for the information - I never even thought about the fact that the freebody would likely get trashed. So if this is the case and I've now committed myself to getting a single speed rear all I have to decide on is: front freewheel or rear....and my understanding is the front freewheel option just gives better clearance then... almost got it nailed down I guess thanks to all of your help! :)

[eturt9]

I'm not sure if I want to go cassette or single speed...

Singlespeed it, its less hassel and lighter. You do have the option of putting spacers on a cassette hub with a single speed cog, or just a singlespeed hub.

[goose]

if you're starting from scratch, FFW is good. Be warned, you'll go through chains faster with the smaller gearings. That clearance comes at a price. I was tempted to go FFW, but I think I prefer using standard mtb components, just because they're easy to find and replace. I'm very happy that you're considering singlespeed. It's definitely the way to go. I had several nagging injuries over the years from chain skips, chain breaks, and bent derailleurs. Now with a singlespeed, I'm quite happy, and have a much more reliable bike. Good luck!

[rndm*dv8n]

Cool I've been looking for a relatively inexpensive rear wheel setup (disc compatible). I just can't afford a CK. So here is what I've come up with:

Surly Singlespeed Disc rear hub, 36h
DX 32
ACS Claws freewheel, 20 or 22 tooth

And goose mentioned a surly+acs combo. I wonder if anyone has feedback on that? For myself specifically I'm looking at a rear freewheel (so I can run two chainrings up front), bolt-on (for horiz. dropouts + chain tugs), disc brake setup.

[scaley187]

Have you looked into the problems with running a rear disc on a trials bike? There are a lot of docs out there about why it isn't a good idea. Most people end up running a disc front with rear rim brakes (magura, etc). You probably know this though.

[goose]

Cool I've been looking for a relatively inexpensive rear wheel setup (disc compatible). I just can't afford a CK. So here is what I've come up with:
Surly Singlespeed Disc rear hub, 36h
DX 32
ACS Claws freewheel, 20 or 22 tooth
And goose mentioned a surly+acs combo. I wonder if anyone has feedback on that? For myself specifically I'm looking at a rear freewheel (so I can run two chainrings up front), bolt-on (for horiz. dropouts + chain tugs), disc brake setup.

let me get this straight, you want to run horiz dropouts with two chainrings up front? How much travel does your horizontal dropout have? What two chainrings are you thinking of running? It's doubtful that you'll be able to tension a 32T and a 22T with the same chain lenght and horizontal dropout length.

Horizontal dropouts with disc mounts are usually solved with slotted disc mount like this:
http://www.unrealcycles.com/uploaddir/IMG_1462_1.jpg

or this:
http://www.simtrabikes.com/hires/hrbnbdropouts.jpg

You shouldn't have a problem with an ACS, lots of trials riders use them. Run a thin lube in it, and replace it before it breaks, for example whenever you replace your chain (which should be done once a season). They're really cheap, so replace them often to stay out of the hospital and on your bike. I still have no idea how you're going to tension for two chainrings with 2ish inches of horiz dropout travel

[rndm*dv8n]

Hey, for tension I'll continue to do what I'm doing now. I run a rear derailleur. I have a fixed line on it so it's set for only one gear. I've just enough chain that I can switch between 22 and 32 tooth front chainrings, but the chain doesn't jump. Therefore the rear hub doesn't move and my disc setting is fine.
tks for the advice on the ACS. I'm pretty stoked to have discovered the Surly rear hub, with my thick dropouts and 2 chain tugs I was having trouble finding a long enough axle.

http://www.mtbkanata.ca/pp/data/661/medium/IMGP5129.jpg

[goose]

what frame is that?

[rndm*dv8n]

Hehe, it's why I'm in the beginner's section. It's a Steelhead. I do a bit of everything on it, with trials being more and more of my game. I like having two gears, not just for getting places but for some street riding too (while I get there). Though I find the head angle kinda slack for natural.

[goose]

COOL. I was thinking of getting a steelhead for FR/street. I want a steel bike, with disc mounts that hopefully can hold up to a few pedal kicks

[Free-Ride-Junkie]

Well I am picking up a Simtra and was kind of lost on drivetrain options. For now it looks like my rear wheel will have a fixed hub with a cassette on it. I will have a White Industries FW mounted on the crank, and then run a chain tensioner on the back to run it as a single speed. This allows me to change gear combinations slightly if I need to, or even throw a shifter and rear derrailleur on if I decide that I need the gears around campus...... Opinions??