Horizontal Dropouts For Stock?

[Matt_Thibeau]

I know that some stocks called "mod stocks" have horizontal dropouts, but why do alot of stocks have virtical dropouts anyways? No one runs gears anymore.. and tentioners suck. So what is the point why dont ALL trials frames have BMX style dropouts?

[Luke Rainbird]

I know that some stocks called "mod stocks" have horizontal dropouts, but why do alot of stocks have virtical dropouts anyways? No one runs gears anymore.. and tentioners suck. So what is the point why dont ALL trials frames have BMX style dropouts?

Because some people do still run gears, others still want to run a full width (135mm) hub and there's not many horizontal stock spaced frames about

I honestly don't see the issue with tensioners? Horizontal seem to give tight/loose spots in most cases and you still see some people with horizontal d/o running a tensioner too anyway!

[Muel]

I used to think the same, but have changed my mins recently, I've got a fixed tensioner, and I'm constantly fiddling with it. A good sprung tensioner removes the hassle of adjusting the chain tension manually.

[spartan]

Yeah but that said snail cams and good bolts will lock you chain tight with no hassle whatsoever.

I spend way more time adjusting my echo tensions then i do my snail cams on my monty.

Horizontal dropouts on a stock frame would be nice, just to have the option you know, this whole modstock thing is f**king stupid IMO,

Ian

[Jason222]

Having had a modstock frame, I think they're pretty bogus. Horizontal 26" bikes should all have 135 spacing, like the newer koxx frames do. My next frame probably will be something like the hydroxx, if not a hydroxx . Sprung tensioners can be an excellent thing as well, I'm running a custom one, and it works amazingly.

Edited August 15, 2008 by Jason222

[Ash-Kennard]

i like vertical because its all ive ever used and i always see people having to play with their mods for chain tension and shit

[psycholist]

With vertical dropouts you've got the exact chainstay length specced in your frame's geometry rather than having to deal with a change every time you replace the chain (And gradual changes as you tension it). Snail cams seem to be a lot of trouble to adjust compared to a sprung tensioner or even the fixed one on my Echo stock hub (Which takes all of 10 seconds to adjust every 2 or 3 hard cycles), alignment of the brakes will need to be adjusted as you move the wheel around and running a disk will usually involve a bit of messing around unless you have a sliding disk mount. To be honest I'm a lot more curious as to why people are willing to endure horizontal dropouts ...

[JonMack]

I run horizontal dropouts on my dual disc bike and don't need to play with calliper alignment at all. Also if you use snail cams for about 10 seconds you will realise they're just as easy to tension a chain with. The amount of times my friend has to stop riding to sort out his 74k because it's not giving him enough tension puts me off ever running one, I'd much rather have horizontals.

Have you ever used snail cams, psycholist?

[AdamR28]

I run horizontal dropouts on my dual disc bike and don't need to play with calliper alignment at all. Also if you use snail cams for about 10 seconds you will realise they're just as easy to tension a chain with. I'd much rather have horizontals.

[Deonn h]

I run horizontal dropouts on my dual disc bike and don't need to play with calliper alignment at all. Also if you use snail cams for about 10 seconds you will realise they're just as easy to tension a chain with. The amount of times my friend has to stop riding to sort out his 74k because it's not giving him enough tension puts me off ever running one, I'd much rather have horizontals.

Have you ever used snail cams, psycholist?

Ive never had to evan touch my 74k tensioner since i put it on

[psycholist]

I haven't owned a bike with them, but I've tensioned enough horizontal dropout bikes with and without chain tugs of various descriptions to never want to endure them on my own bike. You haven't addressed the other comments though - namely the change in chainstay length inherent in adjusting chain tension by moving the wheel and the readjustment of brake pads to maintain alignment with the rim (I'm presuming you have a moving disk caliper or the brake pads don't catch the whole disk depending on where the wheel is in its adjustment range). The 74 kingz tensioners are pretty poor as evidenced by the sheer number of threads on this forum filled with bodges to make them actually work, so it's a bad comparison. Modified derailleurs and better designed tensioners work fine, while making it easier to take the wheel off, maintain correct chainstay length and keep the chain tensioned...

Edited August 15, 2008 by psycholist

[AdamR28]

You haven't addressed the other comments though - namely the change in chainstay length inherent in adjusting chain tension by moving the wheel and the readjustment of brake pads to maintain alignment with the rim (I'm presuming you have a moving disk caliper or the brake pads don't catch the whole disk depending on where the wheel is in its adjustment range).

With respect to this, the resolution on a set of Try-All snail cams is around 0.4mm (less than 0.3mm in the case of Monty, and infinite if you use smooth cams), so it makes very little difference to the geo of the bike. Once the chain has settled in (2 or 3 clicks max) you very rarely need to adjust it, maybe one click a month. I am very sensitive to changes in geometry, setup etc and I cannot notice this amount of change.

To ensure correct brake setup you just add one click/the same amount of tension to each cam (left and right) when you re-tension the chain and the wheel/rotor is still aligned as previously.

[basher]

snail cams are homosexual!

[Al_Fel]

I've never had a problem with decent notched snail cams. Smooth ones can be a right pain in the arse. I've just got a Coust V2 which I am very happy with and even though I've not rode it much I haven't had a problem with chain tension. The movement of the rear wheel is minimal when tensioning the chain I really don't think you could notice it.

[psycholist]

My comment on the geometry change was about the big change when you fit a new chain/different gear - I would definitely be very surprised if you noticed individual adjustments to maintain tension alright. If the cams are in the same position both sides (And the frame is straight/cams aren't deformed etc) the disk should run straight in the caliper, but that's not what I'm talking about - I'm talking about the disk pads no longer sitting centered on the braking surface of the disk as the wheel is moved around in the dropout...

Out of curiosity, has any manufacturer tried an eccentric BB with vertical dropouts in a trials frame? It would allow for perfect rear wheel alignment and easy wheel removal, while the nature of the eccentric adjustment would keep the chainline etc. straight. It would tweak the BB rise and chainstay length/reach rather than the chainstay length though. Since there are two solutions for almost all chain tensions (Except BB fully forward or backwards) there would be a high and a low BB option for the setup... Pretty sure it'd weigh more than a tensioner or snail cams though...

Edited August 15, 2008 by psycholist

[AdamR28]

Fitting a new chain - not a problem, it's only 4 or 5 clicks from new to 3 months old. New gear ratio... all the frames with horizontal dropouts are designed to be used with only one ratio. Caliper over rotor: again the frames are for one ratio so this is not a problem.

I think eccentric BB would just cause more problems than it solves... As you said, it adjusts two geometry aspects instead of one, and would add a lot of un-necessary weight.

Edit: As Anal says, horizontal dropouts may not suit everyone though.

[Al_Fel]

Ok I personally have no problems with horizontal dropouts. I think this is because I'm not a spaz with a spanner and I like to buy decent parts. The changes in new chains/cogs are very minimal providing you keep the same gear ratio. I don't really think all frames should have horizontal dropouts because they might not suit everyone. I think its nice to have a selection of different frames for people who are decent mechanics and people who arnt so gifted.

[forteh]

I dont know why horizontal dropout frames dont have screw tensioners built in like the onza slinger prototype, far simpler and effective than snailcams

Also suprised that more stock frames arent coming with integral tensioners either, particularly with the majority of bikes designed for singlespeed. A single bolt inside the rear dropout is all thats needed to bolt it on

[psycholist]

The screw tensioners probably need to be coupled with graduations on the frame to allow the hub to be kept straight, but look like a nice solution (Road bikes from back before vertical dropouts were common used this setup, but chain tensions were nothing like on a trials bike). Probably not as quick as snail cams for wheel removal or setting tension, but you'll get more tension. Depending on the hub you run and how they finish the screw tensioner end, the axle could get damaged by the end of the screw tensioner...

I'd love to see a standard mounting point for a tensioner on trials frames (That's not the derailleur hanger). I like the setup on my Echo fixed hub though (Which needs no extra mounting point at all) - very robust and quick to adjust without getting in the way, though I haven't landed on it yet, so can't be 100% certain how touch it is ...

Edited August 15, 2008 by psycholist

[forteh]

Wouldnt agree with you on the need for graduations, set the chain side to the tension you want, nip up the bolt/screw, then set the non chain side so the wheel is straight in the frame and finally tighten the wheel up properly - job done. Of course it can take a bit of practise and fiddling to get it right but its pretty simple, also depends on how straight your wheel is

On the triton Ive used the mech hanger fixing bolt to fit the tensioner to (infront of and above the axle) and rigged up a leaf spring arrangement from a hacksaw blade and bits of aluminium/plastic. Works exceptionally well and is inboard of the chainstays which stops it being twatted like all the tensioners mounted on the mech hanger; also doesnt flap about loads when you take the wheel off

[psycholist]

The graduations are more for making sure the angle of the hub relative to a disk is constant after the wheel is moved, should stop all that nasty squealing that goes on when the caliper is off line...

[forteh]

The graduations are more for making sure the angle of the hub relative to a disk is constant after the wheel is moved, should stop all that nasty squealing that goes on when the caliper is off line...

True I hadnt considered rear disks :$

Was thinking about bmxs where theres loads of clearance between rim and pad

[AdamR28]

But again, you could just add the same amount of turns on each side?

With an M6 thread for example, 1/4 turn would be 0.25mm, this is better resolution than notched snail cams with which you're hard pushed to tell disc brake alignment from one click to the next. Surely graduations would have to be much more than 0.25mm (for example) or you couldn't see them?

[JonMack]

Ignorance is bliss

You have chosen to ignore all posts from: psycholist.

I love this forum and the f**king idiots on it.

[psycholist]

Counting turns on the adjusters or setting them to a constant datum is awkward given the bolts will be squashed into a very small rear triangle - setting initial matching positions on both sides would be annoying too. Very true on the resolution improvement from comparing graduations on the frame to counting turns though. A vernier arrangement moving with the axle to match graduations on the frame would allow the setting of a datum for wheel alignment, though it may run the risk of showing up just how badly aligned a lot of trials frames are... It's really a case of setting the wheel up to look straight with the disk aligned to this position and then just making the same tension adjustment each side to maintain alignment as the chain wears.