Front Sprocket Nut On My Centennial

Stationary Traveller · Mar 23, 2026 at 10:46 AM

I finally got around to replacing the chain and sprockets yesterday but what a job that was. The front sprocket nut was practically welded on, I actually have a slightly curved breaker bar as a result of my failed efforts, I had to resort to asking for the help of my missus and stepson to give me a hand to get the bigger undone, with a a length of steel tubing on my breaker bar while I stood in the rear brake, not ideal I know but it finally loosened with a distinctly audible crack. Whoever had tightened that up previously must’ve been somewhat mechanically unsympathetic. What a beast of a job

TRIPLE X · Mar 23, 2026 at 1:13 PM

Stationary Traveller said: ↑

I finally got around to replacing the chain and sprockets yesterday but what a job that was. The front sprocket nut was practically welded on, I actually have a slightly curved breaker bar as a result of my failed efforts, I had to resort to asking for the help of my missus and stepson to give me a hand to get the bigger undone, with a a length of steel tubing on my breaker bar while I stood in the rear brake, not ideal I know but it finally loosened with a distinctly audible crack. Whoever had tightened that up previously must’ve been somewhat mechanically unsympathetic. What a beast of a job

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I have also found the front sprocket nut sometimes takes a lot of effort to remove. It can be more difficult than the single sided swingarm rear wheel nut even though it requires less torque at 132Nm (rear wheel nut is 146Nm). And it lets go suddenly so best to wear some heavy gloves to avoid grazed knuckles if you are using a breaker bar. Well done for persevering.

joe mc donald · Mar 23, 2026 at 2:14 PM

Been there done that. THATS WHY I GO TO THE DEALER THESE DAYS

Stationary Traveller · Mar 23, 2026 at 4:57 PM

Yes, the rear nut on the sprocket side let go more easily but was still a team effort for me and the missus but the steel tube wasn’t needed. I’m now awaiting delivery of new rear sprocket bolts as some of the originals stripped their threads at 22 lb/ft so I don’t know what sort of cheese they were made from ?
Incidentally the tab washer for the front sprocket had been folded up all round the nut absolutely flat, took a while to prise that out.
As I’ve worked on the bike since taking ownership of it I’ve found all sorts of signs of bodging which I’ve put right. I enjoy working on my bikes, it’s kind of therapeutic but today, I can feel aches and pains from yesterday’s battle.

Pegscraper · Mar 23, 2026 at 6:04 PM

Milwaukee 18v impact driver, makes light work of anything on the bike and bolts on the SUV at 400+nm. Not as cheap as a piece of tubing though!
Last time I changed the front sprocket on the ZZR, which was TIGHT, I positioned the bike with the brake lever directly over the ground anchor and ratchet strapped it down enough to lock the wheel and leave both hands free to tackle the nut.