Bottle/bag bosses

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AndyTheBikeGuy
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Bottle/bag bosses

Post by AndyTheBikeGuy » Fri May 22, 2020 12:36 pm

I'm currently designing a custom titanium frame and I'm nearly there with the geometry so I'm starting to think about where to include bottle/bag mounts and would appreciate the hive mind's thoughts. Are there any I should think about scrapping or add any more? Not sure if putting too many in has any ill-effects other than aesthetics?

My current plan is to have the following all made standard cage mount distance apart (subject to it all being possible and fitting):

3 bosses on the seattube for water/direct mount bag
3 bosses on top of the down tube for water/direct mount bag
3 or 4 bosses on the underside of the top tube for a custom direct mount bag
2 bosses on the top of the top tube
2 bosses on the bottom of the down tube (by the BB)

Optional:

2 bosses near the axle end of each seatstay for water bottle mounts for longer rides - I've tried googling but I couldn't find a frame with these, but I'm sure I've seen them before, anyone know the frame I'm thinking of?
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Bearbonesnorm
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Re: Bottle/bag bosses

Post by Bearbonesnorm » Fri May 22, 2020 12:38 pm

2 bosses near the axle end of each seatstay for water bottle mounts for longer rides - I've tried googling but I couldn't find a frame with these, but I'm sure I've seen them before, anyone know the frame I'm thinking of?
Moots I think.
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sean_iow
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Re: Bottle/bag bosses

Post by sean_iow » Fri May 22, 2020 12:46 pm

Nick Skarajew had some on his Curve prototype on the 2019 TD

You can find a pic in this lot

https://bikepacking.com/bikes/tour-divide-rigs-2019/

Managed to get the image

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AndyTheBikeGuy
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Re: Bottle/bag bosses

Post by AndyTheBikeGuy » Fri May 22, 2020 12:52 pm

Brill, thanks gents
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jameso
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Re: Bottle/bag bosses

Post by jameso » Fri May 22, 2020 12:56 pm

Jones bikes also have I think 4 on the end of the seat stay for bottles, racks and guards.
Not sure if putting too many in has any ill-effects other than aesthetics?
If you're set on a custom bolt-in bag vs using more strap-fitting options, just bear in mind how a Ti frame needs the M5 bosses welded in so every boss can be a fail point - the guys making them know what they're doing though and none of the locations you mention are unusual or risky. If you're using plain-gauge tubes it'll be fine. I might be wary of the seat stay location if the frame uses a slim or thin-wall seat stay? Only as the mount is a bigger part/weld in relation to a slim stay. Crud Catcher bosses seemed to be the area that causes the most issues as the tube's more stressed in tension there.

One thing I wouldn't underestimate is how flexy some Ti tube specs can be, more so when loaded up. That flex can be good but it can get a bit much on a loaded bike and it's also what stresses weld edges. Check they're not suggesting smaller OD tubes than might be ideal for you and your intended use (I had an under-build Ti frame from a US builder and realised how subjective frame stiffness can be).

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TheBrownDog
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Re: Bottle/bag bosses

Post by TheBrownDog » Fri May 22, 2020 1:49 pm

One thing I wouldn't underestimate is how flexy some Ti tube specs can be, more so when loaded up. That flex can be good but it can get a bit much on a ............
Double Plus what James says here. Teetanium is a lovely thing but don't go thinking it works like steel.
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ScotRoutes
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Re: Bottle/bag bosses

Post by ScotRoutes » Fri May 22, 2020 2:03 pm

Just a couple of points;

Presumably you'll need custom made bags for the frame mounted ones as there is no standard for dimensions (or is there)?

Do those seatstay bags not get in the way when pedalling? I have heel rub on frames in that general area and it's often a problem with panniers too.


FWIW my custom Ti hardtail has 2-bolt seattube and downtube mounts inside the frame triangle an a 3-bolt "Anything" mount under the downtube.

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K1100T
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Re: Bottle/bag bosses

Post by K1100T » Fri May 22, 2020 3:33 pm

AndyTheBikeGuy wrote:
Fri May 22, 2020 12:36 pm
2 bosses near the axle end of each seatstay for water bottle mounts for longer rides - I've tried googling but I couldn't find a frame with these, but I'm sure I've seen them before, anyone know the frame I'm thinking of?
Also the new bikepacking bike that's coming from Decathlon...

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AndyTheBikeGuy
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Re: Bottle/bag bosses

Post by AndyTheBikeGuy » Fri May 22, 2020 8:23 pm

ScotRoutes wrote:
Fri May 22, 2020 2:03 pm
Just a couple of points;

Presumably you'll need custom made bags for the frame mounted ones as there is no standard for dimensions (or is there)?
Yeah I'll have to go custom, I'm hoping to have a crack at making my own frame bags soon.
Do those seatstay bags not get in the way when pedalling? I have heel rub on frames in that general area and it's often a problem with panniers too.
I tried a bolt on set up with 750ml bottles on my Ramin 3+ and there was an inch or so of clearance so I think with some anything cages I could fit a 1l nalgene there if needed.
jameso wrote:
Fri May 22, 2020 12:56 pm
Jones bikes also have I think 4 on the end of the seat stay for bottles, racks and guards.
Not sure if putting too many in has any ill-effects other than aesthetics?
If you're set on a custom bolt-in bag vs using more strap-fitting options, just bear in mind how a Ti frame needs the M5 bosses welded in so every boss can be a fail point - the guys making them know what they're doing though and none of the locations you mention are unusual or risky. If you're using plain-gauge tubes it'll be fine. I might be wary of the seat stay location if the frame uses a slim or thin-wall seat stay? Only as the mount is a bigger part/weld in relation to a slim stay. Crud Catcher bosses seemed to be the area that causes the most issues as the tube's more stressed in tension there.

One thing I wouldn't underestimate is how flexy some Ti tube specs can be, more so when loaded up. That flex can be good but it can get a bit much on a loaded bike and it's also what stresses weld edges. Check they're not suggesting smaller OD tubes than might be ideal for you and your intended use (I had an under-build Ti frame from a US builder and realised how subjective frame stiffness can be).
Thanks for the in depth advice, it's currently spec'ed as plain gauge 0.9T tubing all over so I hope that would be strong enough to deal with two mounts on each stay? I'll speak to the designer and get their input too.
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drjon
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Re: Bottle/bag bosses

Post by drjon » Fri May 22, 2020 8:24 pm

who is building the frame?

as James alludes to, bosses near the head tube are potentially a focus of stress- for a few reasons. ti can be finicky that way, so Id want to know the builder is capable of assessing the outcome. I have a few ti frames and respect the builder enormously., he was not keen on top tube bosses for a gas tank bag for this reason.

its not that it can't be done, but it isn't a case of simply adding a boss to a tube with no other effect.

AndyTheBikeGuy
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Re: Bottle/bag bosses

Post by AndyTheBikeGuy » Fri May 22, 2020 10:05 pm

drjon wrote:
Fri May 22, 2020 8:24 pm
who is building the frame?

as James alludes to, bosses near the head tube are potentially a focus of stress- for a few reasons. ti can be finicky that way, so Id want to know the builder is capable of assessing the outcome. I have a few ti frames and respect the builder enormously., he was not keen on top tube bosses for a gas tank bag for this reason.

its not that it can't be done, but it isn't a case of simply adding a boss to a tube with no other effect.
I'm going through the Alpkit custom route so I'm confident they'll stand by their 10 year warranty. Neil may say they can't do the bosses in which case it's a moot point and I may still not go ahead with those options. Thanks for the info, I'll raise that and see what they say.
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drjon
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Re: Bottle/bag bosses

Post by drjon » Sat May 23, 2020 12:01 pm

thumbs up!

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