Author Topic: fitting bottle cage mounts / rivnuts (Read 2861 times)

Manotea · « **on:** 09 May, 2018, 12:25:01 pm »

I've got my eye on a very nice newly refurbished Reynolds 531 framed bike on eBay. Only problem is it has no bottle mounts.

I don't care for strap-on jobs so would look to use Rivnuts for a permanent solution.

Looks simple on YouTube (!)...

Anybody tried it?

Any recommendations for shops in London/SE who would do it for me at a reasonable cost?

Brucey · « **Reply #1 on:** 09 May, 2018, 12:33:26 pm »

folk do this (including manufacturers) but I have no idea why; it weakens the frame and makes a good place for corrosion to start.

Presumably you are buying this frame because it is not made of gas pipe and you want it to last. Well gas pipe is the only material I would happily put these things in and even then I would expect it not to last as long.

531 tubes are often about 0.5mm wall thickness at the mid-point and you wouldn't buy one with, oooh, I dunno, two cracks in the middle of the main tubes, so why would you deliberately add such features yourself....?

cheers

mzjo · « **Reply #2 on:** 09 May, 2018, 12:38:53 pm »

I thought that this was the procedure for aluminium frames. Silver-soldered bosses would be more usual for a decent steel frame (or band-on if the tubes are too thin to stand heating)

LittleWheelsandBig · « **Reply #3 on:** 09 May, 2018, 12:44:35 pm »

To be fair, drilled holes are used to stop cracks propagating. I wouldn't have huge concerns with riv-nuts in well-finished holes. Cannondale has put plenty of them into thin-walled Al frames with little resultant cracking.

cygnet · « **Reply #4 on:** 09 May, 2018, 12:48:26 pm »

You could try asking a frame-builder

e.g. Saffron, Talbot or Hartley cycles

edit: just realised you said London/SE not SE London, but still.

Manotea · « **Reply #5 on:** 09 May, 2018, 12:58:44 pm »

Huh huh, sounds like the tube thickness makes it a problematic, as apart from other considerations will make it difficult to ensure a solid fit.

The frame itself is newly restored so a bit criminal to apply a torch to secure the fittings. Damn.

bikepacker · « **Reply #6 on:** 09 May, 2018, 01:17:06 pm »

I have two bikes where rivnuts are used to fit bottle cages. On my old Galaxy frame Francis Thurmer added a third bottle cage with them about 15 years ago and never had a problem. With my Mercian frame I fitted a second bottle cage with them myself. It was an easy job and again no problem.

Aren't most bottle cage fitting on aluminium frames done with rivnuts?

Polar Bear · « **Reply #7 on:** 09 May, 2018, 01:18:52 pm »

This reminds me that Teh Unicorn could do with a similar piece of surgery.

Watching with interest.

Torslanda · « **Reply #8 on:** 09 May, 2018, 01:37:40 pm »

Presumably you want the bottle cage to be inside the triangle?

So, in effect, you're going to take a drill to a curved surface, with limited access and no means of jigging the whole thing so it can be drilled accurately? Not to mention that most cordless drills are too long to fit inside the frame triangle, rendering the upper hole an absolute bastard to cut...

If you don't want the clips then look at Zefal's bands which, I believe, use the bolt securing the cage to draw the band tight. Or pay a frame builder to do the job properly.

LittleWheelsandBig · « **Reply #9 on:** 09 May, 2018, 01:44:05 pm »

Jigs are rare but exist. Scroll down.
http://www.jastein.com/Html/Tools_for_Frames_Forks.htm

jsabine · « **Reply #10 on:** 09 May, 2018, 01:52:11 pm »

As do right-angle drills.

nobby · « **Reply #11 on:** 09 May, 2018, 01:55:03 pm »

I've fitted several Rivnuts to an aluminium frame using a home made tool as found on YouTube.
The key is to not oversize the hole even a little. I drilled undersize and reamed out gently for a good fit until I discovered that I had an imperial drill that was the exact equivalent to the metric size needed.
Before electric drills we used hand drills. I have a few and one allows access to tight spaces by removing its handle.

robgul · « **Reply #12 on:** 09 May, 2018, 05:36:45 pm »

I've fitted rivnut bosses to probably 8 or 9 frames - incl about 5 that were 531 or 501 - without issue (I have the specific compression tool)

One tip : stick a bit of masking tape where you want to drill and mark the place for hole - tap a centre punch on the mark to give the drill a chance to start and not slip on the tube.

Rob

Brucey · « **Reply #13 on:** 09 May, 2018, 06:12:57 pm »

the minimum stress concentration factor (SCF) you will generate by simply drilling a hole is about three, i.e. the local stresses in the tube will be magnified by a factor of three. The maximum is a lot more than that; very often the edge of the hole is all raggy underneath and this is a perfect spot to start cracks off; in fact it could be said that it is cracked already.

The effects of drilling holes are worst in parts of tubes that see high bending loads (as well as high torsion), so worse than bottle bosses are things like brake cable or dynamo wire holes in the front of the top tube and the down tube. I have lost count of the number of frames with such features that I have seen break.

Having said that, the frame is always likely to break at the worst stress concentration first. In welded aluminium frames this is nearly always at the weld beads even if the frame has lots of nutserts in it. Thus in such frames (and others with inherently high stress concentrations at the joints and plain gauge tubes) putting in a few nutserts arguably doesn't do that much harm; the frame is probably going to break somewhere else first anyway.

Note that it is difficult to make good comparisons between framesets unless you have a fair amount of information. For example a frameset with a '531 ST' tubeset might have completely different tubes in it depending on when it was made and who made it. So you could at one point buy a '531ST' frameset (with nutserts in the down tube and seat tube) from Dawes or a '531 ST' frameset from Raleigh's lightweight unit (no nutserts!) and the weight difference was over 1 lb. That some of the tubes were utterly different would be evidenced by the seat pin dia, up to 1.0mm difference.

The Dawes frames were made using lugs that had the sloppiest fit imaginable, (so there was an insufficient fill of spelter internally, making the lug to all the work) and they tended to break at the lower head lug first anyway.

BTW braze-ons are better but only if they are done well; in the worst case the braze-on will be a high area of residual stress (which may greatly exceed the typical service stresses), together with a stress concentration and a nasty brittle microstructure.

You can mount bottle cages in all kinds of ways; under the saddle, to the handlebars (very retro...) band-on bottle cages, you name it.

cheers

Jurek · « **Reply #14 on:** 09 May, 2018, 08:07:39 pm »

Corridori in Epsom have a riv-nut tool and were happy to flex it on a dodgy riv-nut in my warranty replaced Van Nic frame.
Mind you, that was in the days when the inimitable Paul Smith (OTP) was part of that outfit....

arabella · « **Reply #15 on:** 09 May, 2018, 08:15:37 pm »

any particular reason you don't want to use a band-on bottle cage, or do they no longer exist? in which case I may have problemas when I finally get around to turning my intended replacement fixie into a fixie/longer distance steed thus requiring a drinking option.

Manotea · « **Reply #16 on:** 09 May, 2018, 10:04:37 pm »

Quote from: arabella on 09 May, 2018, 08:15:37 pm

any particular reason you don't want to use a band-on bottle cage, or do they no longer exist? in which case I may have problems when I finally get around to turning my intended replacement fixie into a fixie/longer distance steed thus requiring a drinking option.

There are plenty of band on options around however on the one hand, whilst contemporous with the frame they would rather mar the appearence of a beautiful restoration (my main concern, such is vanity). The other consideration is that should a band on fitting slip on a fixed wheel bike and get tangled up with the rotating cranks, then a sequence of very bad things will happen very quickly. DAMHIKT.

I use a bar mount on my Airnimal which rather lacks an (accessible on the move) frame mount, which works well enough but its a big compromise. On the Airnimal though TINA.

Gattopardo · « **Reply #17 on:** 09 May, 2018, 10:38:06 pm »

https://www.machinemart.co.uk/p/tool-connection-nut-riveter-40-nut-rivets/?da=1&TC=GS-040212979&gclid=EAIaIQobChMI7e_hgcv52gIVL7ftCh2CjQI0EAQYAyABEgImBPD_BwE

Brucey · « **Reply #18 on:** 10 May, 2018, 11:12:59 am »

if you put a strip of rubber (eg old inner tube) beneath the bands in a band-on fitting, they are much less likely to move and it of course protects the paint.

Also, if you are worried specifically that a bottle cage might slip down a seat tube, this can be prevented by first putting a few turns of (say PVC) tape tightly around the seat tube to make a bolster (i.e. so that the diameter is locally increased). The last couple of turns of tape are taken up the tube slightly so that the lower band fitting goes over them, (holding the tape in position so the end cannot unwind). Thus the lower band cannot slip over the tape bolster if it is only a little loose; it needs to be rattling about wholesale before this is possible.

cheers

mrcharly-YHT · « **Reply #19 on:** 10 May, 2018, 11:54:05 am »

Band on used to be the only way on really old bikes, surely?

Top tip - when using a bit of rubber tube as suggested by brucey, when you've worked out the exact position, put some double-sided tape on the frame under the inner tube. It then won't slip while putting on the band.

Efrogwr · « **Reply #20 on:** 10 May, 2018, 02:32:48 pm »

Self-amalgamating tape is good, too. It doesn't lose its grip like PVC tape.

Paul · « **Reply #21 on:** 10 May, 2018, 09:50:45 pm »

I put one of these onto a frame with no cage mounts. It's alright, but doesn't look great.

Somnolent · « **Reply #22 on:** 10 May, 2018, 10:03:56 pm »

My experience of band-on mounts on the down tube is that they tend to rotate around the tube. This is usually with a full bottle in the holder and as result of hittng a pothole. Much less chance of this happening with it on the seat tube (which I prefer anyway, unless that position taken up with a classic frame pump)

Paul · « **Reply #23 on:** 10 May, 2018, 10:16:32 pm »

The one linked to above hasn't moved a mm in 2 years of almost daily use. Full bottles. Some potholes. But it's not pretty.

hubner · « **Reply #24 on:** 12 May, 2018, 09:52:07 am »

It's not the original paint, does it matter if the new paint gets a bit scratched? Where as drilling holes would permanently alter the frame.

And anyway band on bottle cages were normal before the 80s.