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Verdict: 
Perfect inexpensive small saddlebag
Weight: 
131g
BTwin Comp 0.4L Seat Post Bike Bag
10 10

This BTwin seat pack is great. Simple and swappable and just the right size for the things you'd normally put in it. I wholeheartedly recommend it.

At a penny under eight quid you're probably not expecting the earth, but the Comp 0.4l Seat Post Bike Bag (another snappy name, chaps) has everything you need. It's a semi-rigid construction with a good quality zip that goes all the way round. There are reflective patches on all sides, and a light loop too. Inside there's enough space for a tube, levers, a tool and a puncture kit.

The best thing about this pack though is the mount. It's sprung, so you just push the two halves in, slip it between the rails and let go. It's stayed put on every ride on a range of bikes, and it doesn't catch my thighs. And if it doesn't catch mine, yours are probably safe.

Taking it off takes about one second, so switching it between bikes is the simplest thing ever and you can take it off when doing repairs on the side of the road too, which is more of a bonus than you might imagine. The design means it'll fit any round-railed saddle. If you have special needs with regards to your rails, you're out of luck. Otherwise, happy days. The first time I fitted it, I fitted it the wrong way round - the mount is sort of counter-intuitive. Once you've worked that out though, it works perfectly on every saddle I've tried, which is a few.

There's literally nothing not to like about it. The mount (hard plastic) has pulled away from the semi rigid case a little bit, so you can see underneath the middle of it, but the rivets holding the two bits together are still tight as new, and it doesn't look in any danger of failing; it's no different from a bunch of other seatpacks I've used in that regard.

Given that it has a 2-year guarantee the worst case scenario is that you have to buy a new one 2 years down the line, so that's an outlay of £4 a year. For the money, I simply can't find fault with it.

Go and buy one. I would say buy two, but it's so easy to swap that there's just no need.

Verdict

Perfect small budget saddlebag

road.cc test report

Make and model: BTwin Comp 0.4L Seat Post Bike Bag

Size tested: Black

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Capacity: 0.4L.

Ease of use: 1 compartment. Attaches to saddle rail. Reflectors.

Low weight / lightweight: 120 g.

Guarantee : 2 Years

Rate the product for performance:
 
10/10
Rate the product for durability:
 
8/10
Rate the product for weight, if applicable:
 
8/10
Rate the product for value:
 
10/10

Tell us how the product performed overall when used for its designed purpose

Without fault.

Tell us what you particularly liked about the product

Great mount, easy to swap between bikes, just the right size.

Tell us what you particularly disliked about the product

Nothing.

Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Rate the product for quality of construction:
 
8/10

Overall rating: 10/10

About the tester

Age: 41  Height: 190cm  Weight: 102kg

I usually ride: whatever I'm testing...  My best bike is: Genesis Equilibrium 853

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Experienced

I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track

 

Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.

17 comments

Avatar
mudrush [11 posts] 1 year ago
0 likes

im more interested in what seatpost that is!

Avatar
armb [87 posts] 1 year ago
0 likes

> I would say buy two, but it's so easy to swap that there's just no need.

I'm tempted to get more bags so bikes with different tyre sizes can have right size tube in a bag at all times. Still needs to be easily swappable so it can be removed when the bike is locked up.

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Ashbyrich [1 post] 1 year ago
0 likes

can u buy an additional mount?

Avatar
jova54 [644 posts] 1 year ago
0 likes
Ashbyrich wrote:

can u buy an additional mount?

Looking at the pictures, and reading the text, it looks like the bag and mount are all-in-one. The mount has a spring loaded section which you squeeze in and then it just clips to the seat rails.
Looks just the job.

Avatar
dave atkinson [6148 posts] 1 year ago
0 likes

the bag and mount are one piece, riveted together. you just pull the whole thing off

Quote:

im more interested in what seatpost that is!

it's one of these:

http://ridefullgas.com/spn-precision-speed-metal-titanium-seat-post-31-6mm/

Avatar
nowasps [379 posts] 1 year ago
0 likes

It looks like the saddle is positioned in the extreme backward position... Won't there be issues squeezing it in, if your saddle is further forward?

(I have a nice Lezyne one, that I can't use for this reason)

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Zermattjohn [193 posts] 1 year ago
0 likes

Any chance of a photo from beneath the saddle? You say you put the bag on the wrong way first so a view of how it sits correctly would help. This looks a decent bit of kit, a bit more sturdy than those velcro-fastened ones Continental sell (though they do come with an inner and some (very flimsy) levers).

Avatar
I love my bike [108 posts] 1 year ago
0 likes

There is a 0.2l version (much more suited to road use, still with room for tube, levers & mini-tool), which would have more clearance, but it's best to try it on your bike/saddle before buying.

Avatar
The _Kaner [693 posts] 1 year ago
0 likes
Ashbyrich wrote:

can u buy an additional mount?

 24 24 24

Buy two packs, drill out the 3 rivets on one and hey presto, you have a spare additional mount...oh wait a min...

Avatar
antigee [279 posts] 1 year ago
0 likes

Any chance of a photo from beneath the saddle?

I guess this is the internet  1

personally I like room for some bierre money and got a couple of Blackburns that have a nice mesh pocket that means a puncture repair doesn't cost more than it should
but then again at that price with btwin last for ever build looks very good

Avatar
matthewn5 [639 posts] 1 year ago
0 likes

I bought one of these on the strength of the review and it arrived today. It's a very nice design and the spring loaded bracket is very strong.

But I cannot get it to fit either of my bikes. On the Canyon it fouls the back of the seatpost, even when I moved the seat back 10mm. On the Bianchi there isn't enough of the level seat rails showing. It will fit on the sloping splayed section going up to the rear of the seat, but on wriggling it sprung off.

All of which is a pity and I will be sending it back with regret for a refund. Basically, unless you have a zero setback post with the seat pushed back, this won't fit.

Avatar
jova54 [644 posts] 1 year ago
0 likes
drmatthewhardy wrote:

I bought one of these on the strength of the review and it arrived today. It's a very nice design and the spring loaded bracket is very strong.

But I cannot get it to fit either of my bikes. On the Canyon it fouls the back of the seatpost, even when I moved the seat back 10mm. On the Bianchi there isn't enough of the level seat rails showing. It will fit on the sloping splayed section going up to the rear of the seat, but on wriggling it sprung off.

All of which is a pity and I will be sending it back with regret for a refund. Basically, unless you have a zero setback post with the seat pushed back, this won't fit.

Sorry you weren't able to use it but great info. I'm looking to get one but don't want to be stuck like you. Do you have any idea what the minimum exposed rail length needs to be to fit without fouling the seatpost?

Cheers  4

Avatar
PJ McNally [589 posts] 1 year ago
0 likes
armb wrote:

> I would say buy two, but it's so easy to swap that there's just no need.

I'm tempted to get more bags so bikes with different tyre sizes can have right size tube in a bag at all times. Still needs to be easily swappable so it can be removed when the bike is locked up.

+1 to that - a difficult problem to crack.

I solved this with a tool bottle for my commuter (wide tubes, Schrader valves), and a seat pack for my road bike (narrow tubes, Presta valves). Because my commuter gets left locked up outside, so a seat pack would go missing; the tool bottle lives in the bottom of my bag until it's needed, then comes out to save the day.

Also the tool bottle I use costs £2. So you can buy 4!

http://www.chainreactioncycles.com/elite-felicano-water-bottle-container...

Avatar
dave atkinson [6148 posts] 1 year ago
0 likes
jova54 wrote:
drmatthewhardy wrote:

I bought one of these on the strength of the review and it arrived today. It's a very nice design and the spring loaded bracket is very strong.

But I cannot get it to fit either of my bikes. On the Canyon it fouls the back of the seatpost, even when I moved the seat back 10mm. On the Bianchi there isn't enough of the level seat rails showing. It will fit on the sloping splayed section going up to the rear of the seat, but on wriggling it sprung off.

All of which is a pity and I will be sending it back with regret for a refund. Basically, unless you have a zero setback post with the seat pushed back, this won't fit.

Sorry you weren't able to use it but great info. I'm looking to get one but don't want to be stuck like you. Do you have any idea what the minimum exposed rail length needs to be to fit without fouling the seatpost?

Cheers  4

i did fit it to other bikes that had layback posts and i didn't have any issues. however, i do tend to run the saddle a good way back on the rails, so missed the point that it wouldn't necessarily always fit. apologies for that  3

Avatar
pirnie [198 posts] 1 year ago
0 likes

I also bought one (the 0.2 l one) on the strength of this review and I have to say so far I'm impressed. Fits everything I need in and sits very firmly on the rails. It fits fine on both my bikes, both of which have setback seatposts and saddles (ISM Adamo Prologue) pushed a long way forward. I have it on the sloping bit of the rails, and the back of the bag just touches the seatpost. Seems to hold on pretty well there.

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levermonkey [646 posts] 1 year ago
0 likes

.

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happy_otter [9 posts] 1 year ago
0 likes

Bought one last week and had to return it to the store immediately as it didn't fit my (somewhat older) saddle - the distance between the saddle rails was too narrow for the bag's mount to attach to it.