All city nature boy brake cables
05-22-17, 08:05 PM
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All city nature boy brake cables
I'm switching to sram tt500 levers so I need to drill my handlebars and route the cables and housing internally. I want to use a grommet to make the holes on the bars look neat but I don't know what size the cables are 4mm?
5mm? 6mm? All city doesn't show it and neither do any of the distributers. Any help would be greatly appreciated.
5mm? 6mm? All city doesn't show it and neither do any of the distributers. Any help would be greatly appreciated.
05-22-17, 09:00 PM
#2
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You want toninstall tt brake levers on the drop bars?
...or what habdlebars do you plan to use?
...or what habdlebars do you plan to use?
05-23-17, 04:02 AM
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I wouldn't be too hot on the idea of drilling an aluminium bar for internal routing in general.
I would be even less hot on the idea to drill them for grommets in particular.
It takes a 7 mm hole to mount a grommet with a 5 mm center.
How much material are you comfortable to lose from your bar circumference?
A bar breaking is almost guaranteed a nasty accident.
Besides, I'm struggling to see how you'd be able to use a round hole for internal routing on a bar. The cable would need to exit at a fairly shallow angle, meaning you'd need either an oval grommet or a fairly oversized round hole. Again losing more material from your bar circumference.
Brakes cable housings are generally 5 mm.
I would be even less hot on the idea to drill them for grommets in particular.
It takes a 7 mm hole to mount a grommet with a 5 mm center.
How much material are you comfortable to lose from your bar circumference?
A bar breaking is almost guaranteed a nasty accident.
Besides, I'm struggling to see how you'd be able to use a round hole for internal routing on a bar. The cable would need to exit at a fairly shallow angle, meaning you'd need either an oval grommet or a fairly oversized round hole. Again losing more material from your bar circumference.
Brakes cable housings are generally 5 mm.
05-23-17, 07:34 AM
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No, you don't. You really don't want to drill handlebars.
The cable for the tt shifters are supposed to be routed on the outside of the bar and taped over. See instructions here.
What you are proposing will weaken the handlebars so much as to make them dangerous to ride. You will have to drill them in four places: near the shifter and near the stem on each side. A hole in a drawn part is a "stress concentrator". This means that in addition to the fact that you have less metal to support your weight on the bar, all of the stress in the bar gets concentrated around the holes. So you end up with a catastrophic fatigue failure while riding.
Even if the bar could handle it, you are adding 4 bends to you shifter cables. They may, at best, wear out faster. At worst, you'll get crappier shifting.
Why do something that is 1) not per design usage/installation, 2) is highly dangerous, and 3) won't work as well?
The cable for the tt shifters are supposed to be routed on the outside of the bar and taped over. See instructions here.
What you are proposing will weaken the handlebars so much as to make them dangerous to ride. You will have to drill them in four places: near the shifter and near the stem on each side. A hole in a drawn part is a "stress concentrator". This means that in addition to the fact that you have less metal to support your weight on the bar, all of the stress in the bar gets concentrated around the holes. So you end up with a catastrophic fatigue failure while riding.
Even if the bar could handle it, you are adding 4 bends to you shifter cables. They may, at best, wear out faster. At worst, you'll get crappier shifting.
Why do something that is 1) not per design usage/installation, 2) is highly dangerous, and 3) won't work as well?
Last edited by WizardOfBoz; 05-23-17 at 07:48 AM.
05-23-17, 08:47 AM
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05-23-17, 09:53 AM
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No, you don't. You really don't want to drill handlebars.
The cable for the tt shifters are supposed to be routed on the outside of the bar and taped over. See instructions
What you are proposing will weaken the handlebars so much as to make them dangerous to ride. You will have to drill them in four places: near the shifter and near the stem on each side. A hole in a drawn part is a "stress concentrator". This means that in addition to the fact that you have less metal to support your weight on the bar, all of the stress in the bar gets concentrated around the holes. So you end up with a catastrophic fatigue failure while riding.
Even if the bar could handle it, you are adding 4 bends to you shifter cables. They may, at best, wear out faster. At worst, you'll get crappier shifting.
Why do something that is 1) not per design usage/installation, 2) is highly dangerous, and 3) won't work as well?
The cable for the tt shifters are supposed to be routed on the outside of the bar and taped over. See instructions
What you are proposing will weaken the handlebars so much as to make them dangerous to ride. You will have to drill them in four places: near the shifter and near the stem on each side. A hole in a drawn part is a "stress concentrator". This means that in addition to the fact that you have less metal to support your weight on the bar, all of the stress in the bar gets concentrated around the holes. So you end up with a catastrophic fatigue failure while riding.
Even if the bar could handle it, you are adding 4 bends to you shifter cables. They may, at best, wear out faster. At worst, you'll get crappier shifting.
Why do something that is 1) not per design usage/installation, 2) is highly dangerous, and 3) won't work as well?
05-23-17, 04:08 PM
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The lever allows for individual adjustment of each cable. I'm really happy with it.
Last edited by habilis; 05-23-17 at 04:25 PM.
05-23-17, 05:47 PM
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I've run bullhorn bars, and I've NEVER drilled a bar.
05-23-17, 07:43 PM
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Recall that folks didn't even consider an undrilled aluminum stem or bar safe until Cinelli introduced in 1960 and 1963, respectively.
05-24-17, 02:27 AM
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Thing is, we can't tell.
I have base bars that are drilled. And contoured. A dimple in the bar before drilling lets you get away with a smaller hole and still let the cable exit at a nice and shallow angle.
But since they were bought that way, from a brand supplier, presumably some thought, and maybe even some testing, has gone into ensuring that the bar will actually hold up in this configuration.
Easiest fix is simply to use a slightly thicker tube to retain enough strength despite being drilled.
You OTOH are starting with a bar made w/o any thought of being drilled.
Maybe there is enough margin for it to survive.
Maybe there isn't.
And a bar failing while JRA is only marginally less scary than a fork failing.
Why not look for a Base bar instead?
They're very similar to bullhorns and can be bought drilled for internal routing.
05-24-17, 06:38 AM
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There are plenty of reasonably priced bullhorn bars that are pre-drilled, to be safe I'd get some of those...
05-24-17, 06:52 AM
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If I were the OP, I'd take the money I saved drilling my own bars, and invest it in a very good helmet.
05-24-17, 07:36 AM
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dabac's thinking is spot on. To be sure that your bar is suitable for modification, you'd have 1) Do engineering analysis to see if there's enough metal to be possible, and 2) buy several dozen identical bars, drill them, and then test them to failure in a fatigue testing machine.
Life's too short to make it shorter, intentionally. Buy a pre-drilled bar that the mfr has tested. Good luck.
Life's too short to make it shorter, intentionally. Buy a pre-drilled bar that the mfr has tested. Good luck.
