Our site works best with JavaScript enabled.
{/layout:set} {/layout:set}

Exo-Rail Seat pack mount

Exo-Rail Dropper post compatible anti-sway seat pack mount for all-terrain bikepacking


  • - Exo-Rail Dropper post compatible anti-sway seat pack mount for all-terrain bikepacking

Dropper seat post compatible and anti-sway seat pack mount for keeping your bikepacking luggage stable and secure


  • Full Description
  • Features At A Glance
  • Customer Reviews

Our bikepacking setups rarely feel complete without our spacious seat packs in the rear to carry all our bulky stuff. Ditch the sweaty backpack and let the Exo-rail take care of your luggage. 

Exo-rail is our unique system for adding stability and dropper seat post compatibility to your seat pack for minimal sway in your bikepacking setup, all the while reducing faff with its simple slide-on, slide-off pack attachment system. Convenient, light, and sturdy – it's ideal for tackling whatever the road, the track, or the trail throws at you... 

The Exo-rail system fits to your saddle rails with minimum faff. The rail itself slots in with your saddle rails and clamps into place with the clamp and bolts provided. Once on it is unobtrusive and elegant, with no moving parts to clang around, so you can leave it on ready for when you need it.  

The Exo-rail’s shape allows for multiple attachment options, depending on your pack, your frame, and your preference. Our Koala seat packs, available in 7 litre and 13 litre capacity, now feature a slide-on, slide-off Exo-rail sleeve that is incredibly simple to use and gives your seat pack setup excellent stability. 

Will it fit my seat post?

Exo-Rail does not fit all seat posts.

It does fit 2 bolt micro-adjust seat posts with the bolts in line with the bike, including Rockshox Reverb dropper and all Alpkit seat posts. Exo-Rail does not work with single bolt seat posts or posts with side-by-side bolts. Watching the video will help you determine if your seat post head is compatible, but if you have any doubts please send us a link or a photo of your seat post so we can advise.

More images

Key features
  • Dropper post compatible seat pack mount for all-terrain bikepacking
  • Holds your seat pack rigid and reduces sway for excellent manoeuvrability and handling
  • Clamps into saddle rail for a secure, unobtrusive fit
  • Rail offer multiple attachment options
  • Included: rail, clamp, 2 x clamp bolts
  • Designed and made here in the UK
  • 3 Year Alpine Bond
Vital stats

Pack weight limit: 2.3 kg
Weight: 195 g
Dimensions: 28 x 43 cm
Rail diameter: 6 mm
Material: Steel


Supplied with M6 bolts
6mm SS304 - stainless steel 304

Origin: United Kingdom

What You Say: Customer Reviews and Comments

9 Reviews


Used this product?

Write a review
David Knowles
Brilliant Solution

What a great solution to what is probably the biggest bag problem in bikepacking. Easy to fit, although an extra pair of hands helps. Gives a really solid anchor for strapping your seat pack in place. Ace product!

Does what it says on the tin

Bolted it in last night and took 2 minutes.
Now I personally hate tail bags, they sway all over the place unless you carry the weight of a tea towel.i went back to panniers but wanted a solution to the sway.
Now I use Blackburn bags for my sins so no sleeve. Works a treat. Just pull the back piece over the rail. Rock solid. Alternatively just wrap a bungie round it.
I ride fast and also heavy and I was amazed today how rigid and I also forgot it was on the bike.
Just buy it and try it.

Top kit! Versatile! Secure!

I bought the rail because I have a bag with a sleeve that the rail can fit into. The rail is solid, really versatile, secure. It takes the faff and guess work out of bag mounting.

Exo Rail

Great product and works well. I would note, that if you have a saddle with just the one bolt (such as mine. Giant Contend 2) you will need to source a 50mm M8 to fit with the system as the bolt supplied will not work. Works great once installed correctly

Usual quality, beware the fitting!

This looks and feels like a great idea, I have the bag to fit and bought both ahead of a couple of upcoming bike-packing trips. Once on the bike everything feels sturdy. I was hopeful that I could fit to my cane creek thudbuster, but alas no, the thudbusters micro-adjust clamp interferes with the middle cast aluminium peice of the exo rail. Fits fine to my alternative seatpost, however this uses M5 bolts, smaller than the supplied extended bolts, so something to check before ordering as you will need longer bolts!!

Faff to mount

A pain to mount, but once it's on, really helps stabilize the bag. I will use it with my taper Airlok. Only good for 2.3kg but that will work for me. Using my measuring calipers, it adds 8mm to your seat height. It would be good to mention that in the instructions.

Good for gentle use

I’ve had this for a while, though only used it a few times before the trip I’m currently on in NZ. It’s lasted 3 weeks with around 3kg of stuff (sleeping bag, mat and jacket) and the rail snapped on both legs.

Until then I thought it was a good solution to the usual sway issue, though tricky to install and only good for specific seat posts.

Perhaps it comes down to steel selection, clearly no good under fatigue!

I’d recommend for road bikes or occasional gravel/trails but not up to heavy use.

David W
Great Idea But Fitting on Road Bike Problematic

Until I bought this I had no idea how many different saddle/seatpost fixing variations there are. The road bike I wanted to fix it on had a Fizik two in-line bolt fixing, however one of the bolts is fixed - therefore couldn't be used. (my fault for not checking beforehand).
My son then told me he had a spare seat post, I picked it up but it had a single bolt fixing - therefore no good!
I then bought a new seat post on-line which looked ideal - two in-line removable bolts. However ... the bolts were too short to take the extra depth of the rail and plate. No problem ... longer bolts are supplied to overcome this problem ... BUT the bolts supplied were a larger diameter than the ones needed for the seat post!
A trip to my LBS secured longer smaller diameter bolts and all was well - finally.
I think the basic design premise is based on an MTB bike. The dropper seat post on my MTB would have been a perfect fit first time.
The website does to be fair, suggests that if you have any doubts about the suitability of your current seat post, you should refer back to them .
However, perhaps some more detailed such as bolt sizes would have been useful.
The website and the video really give the impression that the basic design will fit the majority of situations, which in the case of a road bike may not be the case.
Finally - now it is fitted I think it is a great idea for a large saddle bag, I am fed up with drooping wobbly bags.

Narrow saddle rail

Exo-Rail plate (and the rails) only have circa 42.7mm spacing. My Nitto S83 seatpost and Selle Italia saddle both have a 44mm rail width which has long been the industry standard. I like the system and if the plate was wider would have fit the Nitto S83 fine. If the plate (and Exo-Rail) came in a 44mm spacing, I would buy it again without hesitation. Odd that that this narrower spacing was chosen.

Here are some similar products

Wax Cotton Koala

Exo-Rail compatible saddle bag


Camo Enduro Seat Pack

3 litre bike saddle day pack



Lightwieght handlebar harness



Exo-Rail compatible saddle bag



Lightweight handlebar harness with fibreglass batons


Camo Koala

Exo-Rail compatible saddle bag


Be the first to hear about our newest products and promotions

Join AlpCol's Espresso newsletter for that hit of Go Nice Places, Do Good Things Greatness


By adding your email you consent to our terms and conditions