Chain, tensioner, chain guard

Which chain?

The SPEEDHUB’s sprockets take a 1/2” × 3/32” 8, 9 or 10-speed derailleur chain. An 8-speed chain is the best choice: it stretches less than 9 and 10-speed chains, so it wears sprocket and chainring less.

1/2” × 1/8” chains (single-speed, BMX and hub-gear chains) do fit the sprocket, but despite their width they are weaker and wear faster, so we do not recommend them — and they do not work with Rohloff chain tensioners.

Chain height 8.5 mm max.

With a 13, 14 or 15-tooth sprocket — threaded or splined, and on the narrow 8540S carrier too — the chain may be no more than 8.5 mm high. A taller chain touches the hub shell: it scuffs it, can even damage it, and causes drag and noise in every gear. Good modern derailleur chains generally meet this; BMX, single-speed and hub-gear chains often do not.

Any 1/2” × 3/32” derailleur chainring will do. On chainline and the minimum ratio, see Chainline and gearing.

Do you need a chain tensioner?

The SPEEDHUB works with one chainring and one sprocket, and a chain can only be shortened two links (25.4 mm) at a time — so on most frames the chain is a few millimetres too long or too short. A slack chain comes off while riding, and the drive suddenly freewheels.

You need a chain tensioner if:

• the frame has vertical dropouts and the chain cannot be tensioned by moving the wheel or with an eccentric bottom bracket;
• the bike has rear suspension — the distance between bottom bracket and rear axle changes as it compresses.

The Rohloff chain tensioner takes up 10 links (20 teeth) and works on any single-speed or hub-gear bike, provided there is at least 24 mm between the outside of the dropout and the centre of the sprocket. A tensioner needs a front chain guide too, as chain slap in extreme situations can throw the chain off the ring. For hard downhill use there is the DH chain tensioner (Art. no. 8245), with a shorter arm fixed to the hanger so it cannot rotate. Setting up: Chain tensioner and chain guide.

Chain guards

In principle any chain guard on the market works, but it has to be chosen and fitted to the frame. The turning hub shell and carrier must touch nothing.

The Hebie Chainglider type 350 is made for the SPEEDHUB: it works with 15, 16 or 17-tooth sprockets and 38, 42 or 44-tooth chainrings. It is not approved with 13 and 14-tooth splined sprockets or with the Splined Carrier L with lock ring. When fitting it and re-tensioning the chain, make sure it rubs nowhere: dirt embedding in the soft plastic forms a hard, abrasive surface over time. Marks this leaves on the hub shell, up to 1 mm deep, are only cosmetic — but do not turn the sprocket round then, as the damaged surface can let oil leak.