not a great deal of room on my tallboy, 700ml bottles take a wiggle to get out

how secure are the arundel side loaders

I use the Specialized side loaders in my Tallboy, which are available in left and right handed. I’ve had no problems so far. You can get them from Evans.

Lezyne ones work well, not carbon though.

I use one on my Cannondale Scalpel and it has been great with Camelbak Podium Bottles. Two sets of holes as well, so you can position it lower. Make sure you get the right side. I THINK down tube mounting means you need a left hand one for a right hand opening, but not sure. Check the description carefully!

cheers, ill give one a try,

I use Lezyne Carbon, absolutely fine. Never dropped a bottle.
You need to be careful with bottles regardless of cage, some are a bit thinner than others and more prone to falling out.

anyone seen an Arundel “other side loader” in Matte? can only find gloss and normally my google-fu is good