ebsenopower BBSHD Chainring

The ebsenopower ring answers that with a modest offset of about 8 mm. Offset, sometimes called dish, is how far the tooth plane sits from the ring's mounting face. Deep-offset rings, 12 mm to 20 mm and more, are generally built to pull the chain inboard on standard frames. A shallower 8 mm dish keeps the teeth further out, closer to where a fat bike's cassette wants the chain.

Offset figures are measured from each maker's own reference, so an 8 mm ring from one brand and an 8 mm ring from another may not land in exactly the same place. The number tells you the family; your tape measure tells you the fit.

Those are working ranges, and hub design shifts them a little. What matters is that the ring's teeth line up with the middle of your cassette once everything is bolted on.

The ring comes in four sizes, all even tooth counts, and weighs 200 g in the configuration shown. That is light for a part that carries the full output of a 1000W motor, which is the trade aluminium always makes: low weight in exchange for faster wear than steel.

Slow and loaded is where heat comes from. The motor windings and controller warm fastest when the crank turns slowly under high current, and on a long soft-ground push that heat soak can trigger the controller's thermal cut-back. A smaller ring keeps crank speed up for the same wheel speed, so current drops and the motor stays in a happier range.

Here is how the four sizes compare on a 2.3 m fat bike wheel at 90 rpm.

• 32T: beach and snow riding, towing, steep singletrack.
• 34T–36T: all-round fat bike trail riding with road links.
• 38T: mostly hardpack with some soft sections and faster road stretches.

The internal nylon primary gear benefits too. It takes its worst loads at low speed and high torque, so a lower gear spreads that load more gently; wear signs are listed in the nylon gear guide.

Chainline is the distance from the frame's centreline to the middle of the ring's teeth. Measure it with the stock ring fitted, then compare it with the centre of your cassette. If the stock ring already sits close to the cassette centre, keep the offset change small. If the chain angles sharply inward in the small cogs, you need the ring further out.

1. Measure seat tube width and halve it to find the frame centre.
2. Measure from the outside of the seat tube to the ring's teeth and add half the tube width.
3. Do the same at the rear, from the frame centre to the middle cog.
4. Compare the two numbers; aim to match them within a few millimetres.

On a fat bike, the 8 mm ring tends to suit frames where deeper-offset rings pull the chain too far in. On a standard 68–73 mm bottom bracket, it may do the opposite and leave the chain outboard. That is where rings like mGYDY's 12 mm offset or CHAOZHU's 20.5 mm offset ring earn their place.

Tyre clearance is the other fat bike check. A chain running too far inboard can touch a 4.5-inch tyre in the largest cogs. For 100 mm and 120 mm bottom brackets, spacers and the full chainline math, work from the BBSHD fat bike guide.

Write your measurements down before ordering. They also tell you which size of spacer, if any, you might need later.

Tools first: a crank puller that matches your crank arms, hex and Torx keys, a torque wrench, medium-strength threadlocker, a chain tool and a fresh quick link. If the crank or the motor's lockring has to come off, the install guide handles both jobs.

1. Remove the drive-side crank arm with the puller.
2. Remove the stock ring's fixing bolts and slide it off the output.
3. Clean the mounting faces and fit the new ring with threadlocker on each bolt.
4. Torque in a star pattern and refit the crank.
5. Shorten the chain for the smaller ring and check chainline in every cog.

Going from the stock 46T to a 34T ring removes roughly three inner-plus-outer link pairs, using the rule of one link pair per four teeth. A chain left too long on a small ring slaps and drops over rough ground.

There is no chain guard, so a clutch derailleur and a correctly sized chain carry the retention job. A gear sensor that cuts motor power during shifts also saves chains and teeth on steep climbs.

• Need a deeper offset for a standard frame: the mGYDY 12 mm offset ring.
• Want narrow-wide teeth in 32T: the Glintique 32T ring.
• Want more speed than 38T gives: a 40T–42T ring such as EfforPrac's.