How to Flip a worn Cog

I bought a new SRAM 7 speed cassette a mere year ago, and already the most used cog 15T is clicking.

I change chains when they stretch 1/8" to 1/4" and I'm loathe to buy another new cassette, so I'm wondering if I can flip the worn cogs.

Maybe I can get another few month's pedaling out of this one.

I can surely tap out the 3 cassette pins/rivets that hold the bigger cogs in situ, flip the worn cog, and tap the pins back in.

Question: Which way out do I drive the pins? Tap from the outer side or the inner side?

The inner side has what looks like a hammered down "head" on them. Do I grind off the "heads" and tap out from that side?

Is it worth all that faff for a few quids?

Not to you Sir, but to others; definitely

Do you want one? Shimano type. For postage?

Re:

I changed a cog on one of these the other day. I found it was screwed together. The head need a tiny allen key.

SP

Re: Re:

Splatter Paint":1u8gjl9v said:

I changed a cog on one of these the other day. I found it was screwed together. The head need a tiny allen key.

SP

Click to expand...

Yes nice, I read about those more modern types, but the SRAM 7 speed is the old-fashioned riveted pin form. I bought it new from chainreaction in Ireland.

I'll try grinding the head down and tap outwards, that makes sense; tapping on the other end doesn't move anything.

The History Man":27s8k4an said:

Do you want one? Shimano type. For postage?

Click to expand...

Very kind Sir. PM imminent...

Re:

You'd have to play around with the splines on just about any brand of cassette these days, its just not worth the hassle. Unless you go for some of the more obscure brands that made individual cogs available, such as mavic or regina but then that limits you a bit too.

Thank you for your responses.

Taken aback by their passivity, I +had+ to get stuck in.

To answer my own question:

Which way do you tap the pins out?

Answer: From the side which has the rounded pin heads, after rubbing all three off with some emery folded on a bathroom tile. Tap out the pins with a concrete-nail from the same side. Only took a minute or two.

Can you flip just one cog?

Answer: Not on my cassette, because as Mr. Cheese pointed out, the odd-sized splines prevent them aligning.

So you bin it then?

Answer: Yikes No! That's the yuppie approach.
The answer is to simply flip all the pinned cogs. Align them by threading each in turn, and spacers, onto a nail through one set of holes, then press in the pins.

The smallest two cogs cannot be flipped because they compose the lock ring.

My cassette is reassembled ready to re-fit.

Because what little rampage there is on the cogs is now flipped, I anticipate minor shifting stiffness, but at least I'll have almost all new strain bearing surfaces, so should give a few more month's click-free riding.

Sram cassettes have impressed me more than Shimano, but this Sram 15T cog needing replacement (flipping) +after only a year+ marks them down in my book. I average 300-400km a week, clean and lubricate the drive chain weekly.

Perhaps this thread will help others extract more life from their cogs.

Sadly the only 7 i have is quite worn. I'm assuming iy won't be worth the postage to you especially now. Good job!