Thirstyman

My 1981 steel framed bike has no threaded mounts for water bottles. So I'm considering drilling and tapping the seat and down tube on a steel frame (tube walls look about 1/8" thick). Is that as bad of an idea as I'm thinking or is the frame so overbuilt that it's not a problem? Have others done this? I have attached the cages with cheap bolt-on rings but it looks like complete crap ends up working loose as they fit poorly to begin with. I have completely rebuilt this bike from the frame up with new Ultegra/SL parts so just considering upgrading this too.

rmfnla

Tubing really doesn't have enough wall thickness for tapping.

There are several rivet nuts on the market that will help; here's one:

https://www.bollhoff.com/web/usa/en/w.../index_us.html


The tools are pricey but some bike shops have them and will do the installation for you. Or, here's a link to a guy who did-it-himself:

https://www.fjr1300.info/howto/rivnut-tool.html

J T CUNNINGHAM

+ 1

Regards,
J T

tellyho

I'd get some clamps and call it a day.

Sheldon Brown

If the frame is built with straight-gauge tubing, it should be fine. I did this on my home-built tandems, no problems.

I knew a guy once who even used self-tapping sheet metal screws for this on some old beater.

I wouldn't do this on a butted frame though.

Sheldon "Taps" Brown

CdCf

Really?

Soil_Sampler

search seems to be working now.

https://ourworld.compuserve.com/homep...ng_rivnuts.htm
https://www.aircraftspruce.com/menus/to/rivnuttools.html

Dan Burkhart 

I have installed several riv-nut sets for water bottle mounts, and with the right equipment, it works out fine. The first thing to consider is whether your frame triangle is large enough to get a straight shot at drilling a hole with a conventional drill. I use a 90 degree angle drill for this.
I use the Stein drilling kit which consists of a V block with guide holes drilled in it. They are properly spaced, so after drilling the first hole, a guide pin is installed to hold the position so the second hole is properly spaced. It also insures the drill bit won't wander and mash up your frame.

well biked

I once had a framebuilder repair a frame for me, and while he was doing that I had him add a couple of water bottle bosses. I think he charged me $20 for the bosses. That being said, I've had excellent luck with Zefal Gizmo clamps. Just make sure and measure the diameter of your tubing and get the correct size for your frame. I've had them on one of my bikes for years, I think they look good and I've never had any problems with them:


https://www.nashbar.com/profile.cfm?c...%20Accessories

rmfnla

Sheet metal screws did occur to me but I thought it might be too declasse' (he did do an Ultegra/SL upgrade).

How are you doing, Sheldon?

HillRider

Use them. They are hidden by the water bottle anyway so no one will know if they are sheetmental screws or Ti cage bolts.

Thirstyman

sorry, I meant seat and down tubes (corrected above)

Thirstyman

Wow, thanks for all the great ideas. I never knew about riv-nuts. useful little devices. Ok, so now I need to determine if my 1981 Lotus Unique manufactured by Tsunoda of Japan is butted or not. Any suggestions about how I can do this?

operator

Yeah the riv-nut + drill thing is the way to go. However - do similar warnings apply as they do with tap + drill?

E.G Do not do on butted tubing etc.

Dan Burkhart 

Not a problem if you use a drilling guide, a properly sharpened drill, and lots of care and patience. Getting a nice clean round hole is the most crucial step here.

J T CUNNINGHAM

Use a smaller drill first, (after protecting the paint with masking tape & layout lines)

then ream the resulting hole to size.


Regards,
J T

mtbikn212

You could always get one of those seat mounted water bottle clamp...have seen them for 1 or 2 bottles. Might do this on my Raleigh Inferno XC Pro, the bosses on the down tube don't allow me enough room to comfortably remove & replace a water bottle while rifing (don't always want to wear the camelback around town)
Just my 2 cents
Eric

Rowan

Drilled and tapped -- done it and highly satisfactory on an older probably non-butted frame.

Drilled and self-tapping screw -- done it and highly satisfactory, even if not so salubrious.


Drilled and Rivnuts -- done it and highly satisfactory and the way many "braze-ons" are done these days. Agreed that some care needs with the hole, but more so to ensure the fit for the Rivnut is sufficiently "tight" -- in other words, don't overdrill or overream it because the bulge caused by pulling the "rivet" up will pull through the hole rather than pull up around the inside edge. Ask me how I know (oh, don't bother, you really don't need to know the details.) For a bidon cage, you will need a 5mm Rivnut.

Drilled a hole and inserted a bolt through to a Nyloc on the inside of seat tube -- Done it and highly satisfactory, even though it presents some challenges in using a ring spanner on the end of a wand. In this case, I ran out of Rivnuts and needed the job finished ASAP before leaving for Europe.

teamcompi

Up in Canada one can get a Riv-nut kit, cheap from Princess Auto, I have put bottle cages on this way a number of times. I have never done it on a good frame, just junkers.

I was looking at my Cannondale T2000 and noted they used what looks like riv-nuts, and I think those tubes are butted so maybe they would be ok? On the Cannondale one of those things loosened up so when I put them in I usually add a touch of locktite prior to tightening.

neilG

I've seen ordinary braze-on bosses just epoxied in place, so there's another option. You could probably soft-solder them too.

mike-on-da-bike

i would also go with good rivites or you could even weld two small nuts there to take screws rivets sound better i certainly would not like the job of tapping that soft metal

mike-on-da-bike

maybe a less drastic method would be just to use some bolt on brackets?

jsharr

Another reccomendation for the Zefal Gizmo.

rmfnla

The warnings to not do it on butted tubing is because butted tubing has thinner wall thickness away from the ends so there is not enough metal to actually thread.

That thinner area is what reduces the weight in a butted frame. The ends are thicker to better withstand the heat of soldering/brazing/welding.

Since the riv-nuts provide the threaded shank wall thickness is no longer an issue.

nuovorecord

Had you considered one of these gizmos that mount the bottle cages to your seat rails?

https://www.universalcycles.com/shopp...s.php?id=14861