Saddle bag size?

[PikeyPriest]

I’m new to cycling and just covered my first 120 miles (cumulative). I’m looking to go further afield to keep the rides interesting so need to carry supplies. Currently I haven’t taken anything, but I don’t want to get stuck 7+miles away!

I’ve ordered a spare tube and will pick up the other essentials I’ve read about, but what I don’t know is how big a saddle bag I need to contain these things. Is 350cc big enough?

Weight does not matter as it is a £200 Halfords bike that weighs near 14kg. I plan to buy a road bike next year if I’m cycling regularly and enjoying it.

 

[UTmaniac]

Mini pump
Puncture repair kit
Hex key for thru axles
Spare tube if planning to be out for 40+ miles
Mobile
Zip bag with ~12+ jelly babies per hour after first hour
British Cycling card with £5 wrapped around it

All in rear pockets of cycling jersey, just like last Sunday's ~63 miler, first "Gran Fondo" since August iirc. Didn't need tube, but took it after puncture on way back from Southwick last month.

I keep thinking about a saddle bag since starting these longer rides three years ago, but it never happens. But then I typically do 20-40 mile rides with maybe the odd longer one each month.

When I did my only century to date in May 2018, i put everything including an extra 2l of water in a rucksack, which isn't a good move when doing ~9000 feet of climbing... Had to take climbs very steady due to ventilation issues and the extra weight didn't help!

 

[SPG]

Bike Tool
Spare Tube
2 C02 Canistors
Zip Ties
Laytex Gloves.
Repair Kit
Emergency Cash

Sod carrying all that in my pockets, pockets are for flap jacks

 

[arknor]

imo you will need a bigger one than you expect once you start putting munchies or whatever inside it


I think mine was "medium"
and with an innertube, multitool, zipties, repair kit, small first aid kit and whatever else is in there it's pretty much full.

barely get my mobile phone and a snickers in there