The Park DH-1 Dummy Hub makes cleaning and transporting bikes much easier. It's designed to keep your chain under tension to enable pedalling forwards or backwards and to allow rear derailleur movement with the rear wheel removed. This is useful for a number of reasons.
When cleaning a bike on a stand it's much easier to remove the rear wheel first. You can get to the brake arch to scrub out and inspect the pads – impossible with the wheel in place – and properly scrubbing the drivetrain down is harder and takes longer with the wheel on the bike. Also, access to the inside face of the rear derailleur is much easier with the wheel out of the way.
But removing the wheel drops the chain, making turning the cranks likely to damage the chainstay, and you'll also end up jamming the chain into the chainrings. Enter the dummy hub, also known as a sleeping hub.
This fits into the rear dropout just as a cassette block does, lifting the chain back into the line it would follow over the cassette. The chain can then run back and forth when you turn the cranks without it jamming due to lack of tension. Unlike other dummy hub designs that are fixed in place at the 'highest' gear position, the Park DH-1 allows the derailleur to shift through its full range – opening it up and letting you get in there with scrubbing brush/sponge/cloth.
You can also slide the black plastic wheel off the blue alloy spindle and onto a 12mm thru-axle, to do exactly the same thing; 12mm thru-axles are increasingly common on road bikes with disc brakes and cyclo-cross bikes, so it's a nice future-proof feature.
Also, if you are sending your bike someplace – be it in the boot of a car, or in a cardboard box or high-end soft bag or plastic crate for airline travel – you really should be using a Dummy Hub to help protect the rear mech and prevent the chain from flapping about.
Some bike cases require the removal of the rear derailleur and there's no other option, due to the tight fit. But if you can get the frame in without removing the mech, it means you won't risk cross-threading it while jetlagged in a dingy hotel room somewhere hilly. It's always a good idea to shift the mech all the way inboard, and this is where the DH-1 design is great – you can do so with the chain held taut. And it's only adding 80g to your luggage.
While you need the wheel and cassette on the bike when you're setting up the front or rear mech, if you're dealing with another issue around the derailleur hanger, crankset, front mech or suchlike, and it's easier if you remove the wheel, the DH-1 will be handy for keeping the chain taut and pedalable.
Also, if you're a stickler for keeping your drivetrain as clean as possible, lubing the chain and leaving it set up on the DH-1 as opposed to the cassette will keep things a bit cleaner.
It's a simple idea beautifully executed by Park. It's compatible with most current road bikes and many future ones using the 142x12mm standard thru-axle. And it's small enough and light enough to fit in a toolbox or case for a trip.
No, it's probably not at the 'essential' end of the Bike Tool To Buy Next scale, but when you get one you'll wonder why you waited so long.
Makes cleaning and transporting bikes much easier, by allowing shifting and pedalling with the back wheel off
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Make and model: Park Tool DH-1 Dummy Hub
Size tested: n/a
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?
It makes cleaning a bike on a workstand much easier, and helps protect the rear mech when shipping bikes around the place.
Park say: "Also called a sleeping hub, the DH-1 slides into rear dropouts and replaces the rear wheel for chain cleaning and transport. The DH-1 works with all derailleur and 1/8" chain. The unique design allows the bike to be shifted and works with open dropout and thru-axle frames up to 12mm."
Tell us some more about the technical aspects of the product?
It's made of metal and plastic. It's round.
Apart from the fact that the anodising wears off, it's fine.
It does exactly what it's supposed to.
The anodising wore off in a few places after months and months of heavy use.
Given it's so good at its job and likely to be a tool you'll pass on to your kids, for £20 it's pretty awesome value.
Tell us how the product performed overall when used for its designed purpose
Tell us what you particularly liked about the product
The vibe. The whole thing. It just works.
Tell us what you particularly disliked about the product
Nothing. Except they should have made it from solid blue aluminium so it didn't show signs of wear.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your score
Anyone who cleans or ships bikes around the place should own one.
Age: 42 Height: 183cm Weight: 71KG
I usually ride: Charge Juicer My best bike is:
I've been riding for: Over 20 years I ride: A few times a week I would class myself as: Expert
I regularly do the following types of riding: club rides, general fitness riding, fixed/singlespeed, mountain biking, singlespeed and Dutch bike pootling