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  • Castelli Undersaddle Mini Bag
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CastelliUndersaddle Mini Bag
Sale 35% Off$16.22 $24.95

Item # CST00AH

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Item # CST00AH

Be prepared.

You probably won't notice Castelli's Undersaddle Mini most of the time, but at some point, what you put inside of it will probably be the difference between you calling your spouse to come pick you up on the side of the road or just changing your tube and getting on with your ride. It's called the Mini Bag for a reason, so pack your ride essentials and leave the unnecessary stuff at home. Noticing the bag under your saddle wouldn't be such a bad thing either — it's made out of sleek, water-resistant material with Castelli's signature clean lines and classic style, and it's even sealed with a water-resistant zipper to keep your stuff safe during a shower.  Reflective accents help keep you visible to motorists any time of the day, and the bag attaches cleanly and securely to your saddle with a hook-and-loop strap.

Tech Specs
Tech Specs
1 main
water resistant zipper
5 x 13 X 5 cm
Recommended Use
Manufacturer Warranty
30 days

Reviews & Community


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Basic; well-made; all you really need.

  • Familiarity: I've put it through the wringer

I've mostly used the smallest-sized Arundel bags, favoring their simplicity (no seat post attachment, minimal size, styling, and thoughtful add-ons like the leather patch that mitigates wear on main contact point). But they're not waterproof, the straps fray prematurely, and the fabric zipper loops tend to fall off. This bag's attachment operates on the same principal: just a strap that loops through the saddle rails and around the bottom of the bag, where it is then affixed securely with Velcro. It is slightly larger then the Arundel--although a spare road tube, CO2 cartridge/inflator head, and lever is still a pretty tight fit. It is far more water resistant--even waterproof. It seems more durable and well-made overall, too, although time will tell. The only drawback is that the straps are quite stiff, making them a tad more challenging to thread through the rails. No big deal at all.

Great Minimalist Seatpack

  • Familiarity: I've used it several times

Really Nice seat bag if you are going for a minimalist approach. Enough for 2 c02's lever, inflator, tube and multi tool. The pack uses waterproof material and is constructed with the quality you would expect from castelli.

best in class

  • Familiarity: I've put it through the wringer

just the right size for CO2, tube, patches, small tool and a lever. seems water tight and looks good as well. other bags i've had are too big (fizik) or just bad (rapha).

Great little bag

  • Familiarity: I've used it once or twice and have initial impressions

Seems like a very durable material, includes a nice thick velcro strap that allows me to really snug the bag up against my seat and it's a perfect size that easily fits: a tube w/80mm valve, 2 CO2 cartridges, small CO2 inflator, multi-tool, tire lever and a small amount of room for a few bucks. This is replacing an Arundel Uno that I found to be of poor quality in terms of both material and closure strength.

good for its size

  • Familiarity: I've put it through the wringer

won't fit a pump but will fit enough patches, co2s, or tubes. solid little guy

Great looking and compact

    Fit a tube, multitool patch kit and levers. Will need a CO2 or keep packing the pump in my jersey

    Great looking and compact