Changing a front sprocket for dummies

Changing a front sprocket for dummies

Author
Discussion

sc0tt

Original Poster:

18,032 posts

200 months

Thursday 24th April 2014
quotequote all
Dern has very kindly sent me a -1 tooth front sprocket for my r1 because obviously it is lacking in the acceleration department.

How does one go about changing it?

Will it fit my Standard chain?

v60marko

1,048 posts

178 months

Thursday 24th April 2014
quotequote all
Bike on paddock stand, in neutral. Get a plank of wood. Stick it through your wheel / swing arm so the wheel can't turn. Loosen front sprocket bolt. Now slacken off your chain adjusters so the chain can come off the sprocket. Remove and replace sprocket. Chain back on, tension it up again. Still using the piece of wood, torque the front sprocket to manufacturers torque spec. Job jobbed!

Current chain should be fine if your only dropping 1 tooth, but the back wheel will be a little further forward than it was before, meaning a shorter wheelbase.

sc0tt

Original Poster:

18,032 posts

200 months

Thursday 24th April 2014
quotequote all
v60marko said:
meaning a shorter wheelbase.
And what does that bit mean?

Prof Prolapse

16,160 posts

189 months

Thursday 24th April 2014
quotequote all
sc0tt said:
Dern has very kindly sent me a -1 tooth front sprocket for my r1 because obviously it is lacking in the acceleration department.

How does one go about changing it?

Will it fit my Standard chain?
Yes it will fit. I also don't believe you need to break the chain to fit.

I'd stick it in gear with the chain taught, then use a breaker bar on the front sprocket bolt (it will be threadlocked) to get it moving.

Then loosen all slack for chain, remove spindle bolt if necessary to slide the wheel forward. Then you can remove the old sprocket and put a new one on.

You'll need threadlock to put it back on. You'll also need Lithium grease if you take out the spindle.

Then realign your rear wheel and reset the chainslack as usual.




v60marko

1,048 posts

178 months

Thursday 24th April 2014
quotequote all
Sorry mate I got it the wrong way round, if you keep the same chain and drop a tooth the wheel is going to be slightly further back. It'll just change the handling characteristics but the difference will be minimal, nowt to worry about.

SAS Tom

3,398 posts

173 months

Thursday 24th April 2014
quotequote all
It means the wheels are closer together. This will translate into the bike turning in quicker. Chances are it'll be so small you won't notice it though.

Prof Prolapse

16,160 posts

189 months

Thursday 24th April 2014
quotequote all
Is this actually a real thing?

It will be less of a difference than if you adjust your chain when it stretches slightly with age. I've never heard of people chucking new chains away because they've stretched and the wheelbase is now 10mm longer?


Wildfire

9,774 posts

251 months

Thursday 24th April 2014
quotequote all
Don't forget to get the right torque settings for the sprocket.

So I take it you'll hoisting the front on rides out now? wink

theshrew

6,008 posts

183 months

Thursday 24th April 2014
quotequote all
Prof Prolapse said:
Is this actually a real thing?

It will be less of a difference than if you adjust your chain when it stretches slightly with age. I've never heard of people chucking new chains away because they've stretched and the wheelbase is now 10mm longer?
Yes it is.

TBF you probably wont even feel it.


sc0tt

Original Poster:

18,032 posts

200 months

Thursday 24th April 2014
quotequote all
Wildfire said:
Don't forget to get the right torque settings for the sprocket.

So I take it you'll hoisting the front on rides out now? wink
Sounds simple.

I'll ask my mechanic I think. Peeeeeete hehe

I jest.

I'd like to, we will see.

Biker's Nemesis

38,534 posts

207 months

Thursday 24th April 2014
quotequote all
You don't need thread lock for the front sprocket it has a locking tab which you will need to bend back before you put a socket on to remove the nut.

Do not hammer the locking tab flat when you take it off. Don't forget to bend the tabs back when refitting

dai1983

2,902 posts

148 months

Thursday 24th April 2014
quotequote all
May also need to get a new tab washer for the sprocket nut.

Instead of wood I used an assistant holding the rear brake on while I torque it up. An impact gun is useful for undoing it and...




Welding the nut back on FTW!!!!

Biker's Nemesis

38,534 posts

207 months

Thursday 24th April 2014
quotequote all
You want 15-49 sprockets on for wheelies

sc0tt

Original Poster:

18,032 posts

200 months

Thursday 24th April 2014
quotequote all
Good lord. This sounds complicated.

I'm assuming it's worth it. Or is it likely to make the bike just try to rear its head everywhere?

Biker's Nemesis

38,534 posts

207 months

Thursday 24th April 2014
quotequote all
sc0tt said:
Good lord. This sounds complicated.

I'm assuming it's worth it. Or is it likely to make the bike just try to rear its head everywhere?
With that gearing on mine it will go vertical at an indicated 170 in 6th (speedo is out) off small crests

bass gt3

10,186 posts

232 months

Thursday 24th April 2014
quotequote all
Easiest way is before you loosen the rear wheel, take a 3/8ths extension bar and place it between the chain and front sprocket. Now with the socket needed to loosen the main nut, turn the sprocket anticlockwise so the bar is carried between the chain and sprocket. It will bind up the chain and sprocket so you can loosen the nut. Then undo the rear wheel and change the sprocket.
Tightening the front sprocket is the same procedure but put the bar on the bottom side and let it carry into the sprocket. Hey presto, easy peasy no assisstants needed.

sc0tt

Original Poster:

18,032 posts

200 months

Thursday 24th April 2014
quotequote all
Biker's Nemesis said:
You want 15-49 sprockets on for wheelies
I can't do wheelies.

Prof Prolapse

16,160 posts

189 months

Thursday 24th April 2014
quotequote all
theshrew said:
Yes it is.

TBF you probably wont even feel it.
I understand how adjusting my chain works, I just can't see how anyone could notice the wheel base length difference, that's my point.

bass gt3

10,186 posts

232 months

Thursday 24th April 2014
quotequote all
sc0tt said:
I can't do wheelies.
You will with 15/49 biggrin

Biker's Nemesis

38,534 posts

207 months

Thursday 24th April 2014
quotequote all
Can someone do it for him.

Scott, what do you do for a living