Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: MacB on 16 March, 2010, 10:24:58 pm
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If you were considering getting a custom frame that you wanted to be able to run as fixed, SS, hub gear or derailler, what's the best option for chain tensioning and why? This would be rim rather than disc/hub brakes.
I'm only aware of, rear derailler, chain tensioner, horizontal dropouts, track ends, sliding dropouts, magic gears and eccentric bottom brackets. In this instance I'm discounting the idea of filing out a bit of a vertical dropout ;D
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Chain tensioner or rear dérailleur won't work with fixed.
semi-horizontal dropouts.
Little to go wrong, will work for any of the gear options.
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A nice long pair of old fashioned forward facing dropouts as brazed into my old CB Dalesman frame circa 1980 sumfink
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Chain tensioner or rear dérailleur won't work with fixed.
semi-horizontal dropouts.
Little to go wrong, will work for any of the gear options.
Thanks, I do know what works with what I'm just crap at expressing it properly. I just don't know the full pros and cons of each. I suppose the main decision is tension via dropouts or tension via BB. I like the simplicity of vertical dropouts but have no experience of EBB's.
The frame would be titanium if that matters
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A nice long pair of old fashioned forward facing dropouts as brazed into my old CB Dalesman frame circa 1980 sumfink
Just what i was about to put.
I have a frame with some nice forward facing, sort of horizontal drop outs. It was a geared bike originally that i converted to fixed.
It would have been very simple to convert it to gears aswell.
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A nice long pair of old fashioned forward facing dropouts as brazed into my old CB Dalesman frame circa 1980 sumfink
Just what i was about to put.
+1
I have a frame with some nice forward facing, sort of horizontal drop outs.
[semantic pedant]
I tend to use Sheldon's terminology (http://sheldonbrown.com/fixed-conversion.html#vertical). It accords with traditional UK usage, where dropouts were (and remain) a useful innovation compared with the older rear-facing fork ends.
[/semantic pedant]
It was a geared bike originally that i converted to fixed.
It would have been very simple to convert it to gears aswell.
+1 :)
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rear-facing fork ends ? do you mean track ends ?
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rear-facing fork ends ? do you mean track ends ?
Not exactly. Track ends are an example, specifically a very good quality one. Some cheap bikes came with the ends of the chainstays squashed flat and rearwards facing slots cut into them for the axle. Mrs N.'s 1976 Moulton Midi has simple steel plates brazed into the chainstays, that I would hesitate to call track ends, because they are too insubstantial to survive the stresses of track usage. There may be other variations - I'm no cycling historian.
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"Horizontal" dropouts are angled so that the brake blocks remain pretty much aligned with the rim no matter where in the dropout the axle sits. Forward facing horizontal dropouts are rarely actually horizontal.
Track ends require brake block position adjustments if the axle is moved significantly (flipping a fixed/single-speed wheel for a different sprocket size for example).
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Aye, Greenbank's right. Track ends are basically for poseurs who want you to know that their bike was designed as a single-speed/fixed wheel bike. If you're likely to be taking the wheel out on a regular basis, they're actually a bit of a faff. Especially with mudguards.
If it adds to your range of options, you could look at the sort of dropouts that I have on my Mercian (http://www.paulcomp.com/dropouts.html).
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I would go for long horizontal dropouts with integral gear hanger, eg:
(http://farm3.static.flickr.com/2469/3829383807_8b3c53b288.jpg)
(http://farm4.static.flickr.com/3032/2766861066_d54b226f24.jpg)
(http://farm4.static.flickr.com/3186/3414477968_dd384b0769.jpg)
It's simple; can be used with fixed, SS, hub gear or derailler.
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EBBs have a reputation for seizing solid if not religiously maintained, so I'd also go for horizontal dropouts. You don't need long ones. The exception is if you're running a rear disc brake, when the EBB is best. On-One Inbreds with track ends have a slotted disc caliper mount instead, but that's more faff than an EBB and they are disc-only - there are no V-brake bosses.
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If it were an option then I would be looking at sliding dropouts.
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Er, just to confuse things...
I think eccentric BBs are fab - because everything is so neat and there's no faff with brakes or 'guard positions.
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Another vote for EBB. Makes changing the rear wheel easier as well. Also a must for Rohloff users - the torque arm can be a real pain otherwise.
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Wow, thanks folks, info there I was unaware of, looks like I can strike track ends off the list. So that narrows it down to EBB versus longish horizontal dropouts versus sliding dropouts. It will be v or canti brakes so I do like an option that would mean pads didn't need adjusting. Sliding drops would mean pad adjustments unless the slide was angled, or am I being confused?
Hmmm, EBB really appeals, neat and tidy, ticks all the boxes. But, following a bit of reading up, and Rogers post, I'm concerned re reliability and longevity. If they need a lot of TLC then maybe I'm not a good partner for them.
Horizontal drops, I've got them on two bikes already, stick with what I know, don't go getting all fangled and modern on myself. Though I do use chaintugs(I think they're called) on both sides.
I will continue to read and ponder, will consult in detail with frame builder when final decision is made. I think I'm getting close now, I can't see more than another 20 mind changes ahead of me ;D....thanks for the help again.....Al
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I'm not sure whether it's an issue for OP, but how easy is it to reverse the rear wheel to change sprockets with an EBB? My experience with a tandem EBB would put me off trying to do it during a ride, and maybe even during a longer trip.
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If it adds to your range of options, you could look at the sort of dropouts that I have on my Mercian (http://www.paulcomp.com/dropouts.html).
Very pretty, but how exactly does the axle drop out of those fork ends?
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Pedant :P
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Self-confessed pedant.
However, I fail to see how these "dropouts" differ from track ends and was looking for some explanation that I might have missed.
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Your term 'fork ends' isn't very useful since the forks are at the other end of the bicycle. They are called forks because they look like a fork. The rear end of the bike with it's triangles doesn't.
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Your term 'fork ends' isn't very useful since the forks are at the other end of the bicycle. They are called forks because they look like a fork. The rear end of the bike with it's triangles doesn't.
When I was young the ones at the front were called front forks.
If you take a bit of time to study the original Rover safety cycle, I think you might discover why the rear end was deemed to have forks as well.
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If you're likely to be taking the wheel out on a regular basis, they're actually a bit of a faff. Especially with mudguards.
No, no, no
They're really not. If you run a stouter tyre it's actually a lot easier to remove the wheel with track ends than with forward-facing dropouts. Since I do, that's why I use them.
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If you're likely to be taking the wheel out on a regular basis, they're actually a bit of a faff. Especially with mudguards.
No, no, no
They're really not. If you run a stouter tyre it's actually a lot easier to remove the wheel with track ends than with forward-facing dropouts. Since I do, that's why I use them.
Isn't that a function of frame geometry? I cannot imagine having a problem with my venerable hack using anything less than 40mm tyres - after all it worked fine with 27" wheels.
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Yes
I really meant 32 or 35 mm tyres on bikes meant for 700C wheels.
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Presumably a custom frame builder would handle that if requested.
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Possibly. You might end up with vast clearances though, possibly limiting the type of brake you can use. Either way, it would need specific consideration at the time the frame was planned and wouldn't work with off-the-peg ones.
Given that there's really no issue with taking a wheel out backwards, and in practice little or no adjustment on brake position needed for different sprockets, I'd stick with track ends myself.
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But wouldn't track ends with a derailleur be a bit awkward when removing the wheel?
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But wouldn't track ends with a derailleur be a bit awkward when removing the wheel?
You will not use the D-word in the presence of Mal Volio!
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Can I resurrect this, have had a change of heart, yet again ;D
Having helped a friend install, nad tried the bike, some Avid BB7 mechanical disc brakes...I've become a fan, especially where a general commuting bike is concerned. This was on vertical dropouts though and I'd still like the frame to be suitable for SS/Hub gears as well as deraillers.
I've seen reference to setups where the disc brake moves along with the wheel, is that right, and what are they called? Or should I stick with vertical and EBB or chain tesnioner?
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See bottom of page for Bob Jacksons version (http://www.bobjacksoncycles.co.uk/rohloff-hubs.php)
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I've seen reference to setups where the disc brake moves along with the wheel, is that right, and what are they called? Or should I stick with vertical and EBB or chain tesnioner?
Sliding dropouts. I have them on my Orange P7, and they're fab! :thumbsup:
(http://farm4.static.flickr.com/3010/2981905031_14eaf39f52.jpg)
(Bigger picture here (http://farm4.static.flickr.com/3010/2981905031_14eaf39f52_b.jpg))
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Thanks folks, fraind I'm still a bit confused, am I getting this right?
The dropouts are vertical but the entire dropouts can be slid forward or back via two bolts on each side?
I see that the rotor for the disc brakes will follow the wheel but wouldn't the caliper itself remain in situ on the stay?
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No, cause the caliper mount is on the sliding part of the dropout, so they stay in the same relation.
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No, cause the caliper mount is on the sliding part of the dropout, so they stay in the same relation.
aha, that makes sense....ta
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Just recalled that Jacksons said that they didn't like using EBBs because it changed the effective seat tube angle and upset the geometry. I'm not sure that's significant, myself, especially when you factor in the change to wheelbase of the sliding dropouts.
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I'd read similar on a US forum, some people claimed they could feel the difference in pedalling when they moved the EBB. I don't know myself but would rather keep the fangled stuff all in one place so sliding dropouts make more sense for me.
I did have concerns about the attachment of the brake caliper being strong enough, but some reading up has allayed those fears. There also seems to be a lot of framebuilders offering this option.
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Dunno if this has been mentioned, but the White Industries ENO hub is great for running vertical drops as SS/fixed (I have one), there also appears to be a gizmo for running disc brakes.
http://www.whiteind.com/rearhubs/singlespeedhubs.html (http://www.whiteind.com/rearhubs/singlespeedhubs.html)
Hmmm, actually it seems disc version is SS only.
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I think Clarion's already answered your question WRT brake mounting, but there are some good pictures on this thread (http://forums.mtbr.com/showthread.php?t=464412) of some rather nice sliding dropouts...
;D
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Ooh yes, Black Cat (http://www.blackcatbicycles.com/), very nice.
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Just recalled that Jacksons said that they didn't like using EBBs because it changed the effective seat tube angle and upset the geometry. I'm not sure that's significant, myself, especially when you factor in the change to wheelbase of the sliding dropouts.
My main concern when I had a Rohloff fitted Mercian was that as the EBB moved forwards to take up the chain slack it also moved up or down, thus changing the pedal to saddle distance. If it was near the front or rear dead centre the vertical movement could be more than the horizontal movement needed.
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No, cause the caliper mount is on the sliding part of the dropout, so they stay in the same relation.
It does however mean that you can't put the disc caliper above the chainstay, so fitting a rack becomes more difficult.
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No, cause the caliper mount is on the sliding part of the dropout, so they stay in the same relation.
It does however mean that you can't put the disc caliper above the chainstay, so fitting a rack becomes more difficult.
I thought you could get disc specific racks to solve this?
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No, cause the caliper mount is on the sliding part of the dropout, so they stay in the same relation.
It does however mean that you can't put the disc caliper above the chainstay, so fitting a rack becomes more difficult.
I thought you could get disc specific racks to solve this?
You thought right (http://www.chainreactioncycles.com/Models.aspx?ModelID=32816).
As disc brakes become more common on road bikes, the choice of racks can only improve, too, I'd have thought...
ETA: As we're talking about a custom frame, I imagine that it would be possible to get stand-offs added to the frame to allow the fitting of a standard rack without fouling the brake caliper. Probably not the cheapest solution, but almost certainly the neatest...
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One other question, looking at various images would I be right in thinking it's possible to fit sliding dropouts, quite easily, to a frame with track ends?
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No
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Just recalled that Jacksons said that they didn't like using EBBs because it changed the effective seat tube angle and upset the geometry. I'm not sure that's significant, myself, especially when you factor in the change to wheelbase of the sliding dropouts.
It's never bothered me, I suspect there's more variation in different combinations of shorts and shoes.
If you wanted to minimise the movement Phil Woods make a half link eccentric with a quarter of an inch adjustment rather than half an inch.
I've found hub gears pretty forgiving. I used to tension the chain on my Rohloff every other week, now I do it when it looks like it might fall off. I think I could do away with a chain tensioner altogether and just add or remove half a link. I've just got a new frame and kept with the EBB, though a clamp type rather than Thorns set screw type. I just like the simplicity. One advantage of slot dropouts is the ability to easily change them. Different hubs and gearing systems could have their own dropout changed with a couple of bolts.
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Well, I've had a good look at the links and info supplied and am definitely being seduced by the idea of sliding dropouts. I've not found much in the way of serious technical discussion on them. Beyond things like cheap ones are rubbish and the benchmark has been set by Paragon but more and more frame builders are offering as an option.
So far it seems to be positive, giving you a frame that can do all the gearing options and gives more brake options. As usual still got some questions, though I have finally gotten my head round how they work :-[
As long as you get a decent brand/model/option are there any issues with slippage, creaking, or failure around them?
As long as the cassette, and rotor, are the same, could you just swap wheelsets between racy and robust, obviously within any frame limitations?
I'm thinking versatility here, I can almost envisage a frame where I could run a triple up front. Then a choice of 9 speed cassette, fixed, single speed or hub gear at the back. As long as the chainline for the middle ring was ok with the non-derailler options.
Any views or links on this gratefully absorbed ;D