Help! Frame battery without bottle cage screw holes

[Warwick2]

I'm helping a mate convert his wife's bike. It's half decent and worth converting, but it has no bottle cage screw holes on its step-through frame. I'm trying to avoid a rack-mounted battery, as it already has a rack.

Is there a solution that will safely allow me to mount a 13ah battery on an aluminium frame with a chunky, elliptical downtube?

 

[Bogmonster666]

Rivnuts?

 

[Warwick2]

Thanks. Being fairly (totally!) ignorant of such things, it seems an M3 rivnut can be fitted with a pop rivet gun. Would a couple of M3 bolts be beefy enough to hold a 13ah battery, holder and controller in place?

 

[saneagle]

Thanks. Being fairly (totally!) ignorant of such things, it seems an M3 rivnut can be fitted with a pop rivet gun. Would a couple of M3 bolts be beefy enough to hold a 13ah battery, holder and controller in place?

Best is M6 rivnuts, otherwise use 3 x M5.

You drill a hole so that the rivnut is a tight fit. Take a couple of steel strips and drill holes about an inch from the end. The holes should be big enough to clear the screw thread. Put the riv-nut in the hole. Place the holes on the two strips over the riv-nut and screw in the screw. Lever the two strips apart to pull up on the screw while holding the riv-nut down. Screw the screw down again and repeat until the screw won't pull up any more.

 

[StuartsProjects]

Rivnuts M3 I would not go with, bigger, bigger.

There is a hailong type battery holder that has the battery connector at the bottom of the holder which allows you to fit more and wider spaced mounting bolts.

Just using two mounting bolts seems completly daft to me, if one were to fail, then with the battery flapping about it could cause damage to the frame.

I needed to use rivnuts to fit a hailong type battery to the titanium frame of my mountain bike that I converted, I used 4 ..........................

 

[jimriley]

Rivnut kits with pliers are cheap enough
Eg https://www.ebay.co.uk/itm/374678444569?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_xay5yxrsye&sssrc=2349624&ssuid=&var=&widget_ver=artemis&media=COPY

 

[saneagle]

Rivnut kits with pliers are cheap enough
Eg https://www.ebay.co.uk/itm/374678444569?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_xay5yxrsye&sssrc=2349624&ssuid=&var=&widget_ver=artemis&media=COPY

Until you add the shipping cost.
A bit cheaper here:

86 PCS Threaded Nut Riveter Gun M3-M8 Insert Tool Riveter Rivnut Nutsert Kit UK | eBay

Size of Riveter: 27 x 9.7cm/10.6” x 3.8”. 1 x Hand Riveter. 10 x M8 Rivet Nuts. 20 x M3 Rivet Nuts. Material: Carbon Steel, Alloy Steel, Aluminium Alloy, PVC Plastic. Tool Set Includes Total Weight: 1.28kg/2.82lbs.

www.ebay.co.uk

 

[Warwick2]

Hmm, M6 rivnuts mean drilling 9mm holes into the frame. I'm not sure I'd be comfortable with that.

4 x M3 would work.

Thanks everyone for chipping in.

 

[StuartsProjects]

4 x M3 would work

Probably OK to keep the battery holder in place.

 

[matthewslack]

M3 bolts are way too small and weak for battery mounting.

Another way is to clamp around the frame instead of drilling. Make a shaped seat between the curve of the frame and the flat of the battery mount at two or three places, bolt to mount, clamp around frame with huge cable ties or plastic covered Jubilee clips. Many variations are possible.

 

[Nealh]

Minimum needs to be M5 as that is what a std rivnut screw size is.

 

[StuartsProjects]

M3 bolts are way too small and weak for battery mounting.

I disagree.

M3 bolts are way way way way ....... too small and weak for battery mounting.

 

[saneagle]

Hmm, M6 rivnuts mean drilling 9mm holes into the frame. I'm not sure I'd be comfortable with that.

4 x M3 would work.

Thanks everyone for chipping in.

The bigger the riv-nut the stronger it is and the less likely it is to crack. I have 6mm rivnuts in all my bikes. M3 would be a disaster. When you drill holes in stressed parts, the solution is counter-intuitive. The bigger the radius, the lower the stress. a small hole will crack after some time. 3mm would be nowhere near stroong enough anyway.

 

[Al Wright]

I had a similar problem, though the supplier of the kit I fitted provides an attachment for frames with out bosses for a bottle holder. The bracket shown was made from scrapped hinge from Upvc window

 

[Woosh]

Is there a solution that will safely allow me to mount a 13ah battery on an aluminium frame with a chunky, elliptical downtube?

you usually need at least two M5 x 12mm bolts. For that, you'll needs a 7mm drill bit and a couple of aluminium M5 rivnuts.
The main issue is to find a straight section on the frame to rest the battery on.
Give us a link to the model of the bike, we'll have a clearer idea of what is needed.

 

[AndyBike]

What about jubilee clips to hold on a mount that the battery can be attached to ?. Not aesthetically pleasing I know, but it would provide a firm mount.

 

[Raboa]

Wolf tooth do this, I have not used any of these:

B-RAD Everywhere Base

Wolf Tooth’s B-RAD Everywhere Base is a versatile mount that allows riders to add a bottle cage where there once was none. In addition, the Everywhere Base can function as a B-RAD base, offsetting existing water bottle cage bosses by up to 22mm to make room for frame bags, piggyback shocks, or...

www.wolftoothcomponents.com

Giant also do this

Giant Bottle Cage Adapter - Black

<span>The Giant bottle cage adapter allows you to fit bottle cages to bikes that are missing the mounting holes.</span>

www.cjperformancecycles.com

 

[Warwick2]

Right, here's a picture of the bike. The frame is very elliptical, which might be why Dawes didn't provide screw holes.

Thanks for the suggestions of alternatives. The straps would probably hold a bottle & holder in place, but may not be beefy enough for a heavy battery.

 

[Raboa]

Electric Bicycle Frame Battery Box Mount For HaiLong E-bike Coversion-Adapter | eBay

1 x Bike Battery Box Mount. Material: Aluminum alloy. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.

www.ebay.co.uk

 

[Raboa]

Bafang TSDZ2 E-bike Hailong Shark Dolphin battery bracket spacer downtube x3 | eBay

Bafang Tongsheng TSDZ2 E-bike Shark Hailong or Dolphin battery spacer bracket set for downtube mounting 3D Printed. This is my very last version of the battery base plate brackets. Set includes 3 spacers, 6 high quality cable ties washers and 3 x M5 nuts.

www.ebay.co.uk