The XTR M970 9 speed cassette is the latest design in the XTR cassette range and replaces the previous XTR M950 cassette.

The M970 has no less than three spiders that hold the 6 largest cogs in pairs. The 4 largest cogs are titanium to get the weight down. The 5 smallest cogs are steel.

The previous M950 cassette was prone to failure because the spider did not provide sufficient support for some of the larger titanium sprockets which would then crack.

What does it weigh?

The XTR M970 9 speed cassette weights are as follows:

Is there anything lighter?

Yes for the 11-32 and 11-34 ratios.

There are basically four lighter options available in the 11-32 size:

Recon aluminium cassettes - 144g

The good:

• lightest 11-32t cassette available - almost 80g lighter than XTR;
• cheapest option lighter than XTR.

The bad:

• these are a bit of a joke for offroad use as the aluminium sprockets will wear out fast;
• shifting performance even from new is reported as sub-standard;

Recon titanium cassettes - 167-175g

The good:

• definately lighter than XTR by almost 60g;
• cheaper than SRAM PG-999.

The bad;

• more expensive than XTR;
• riders have reported poor shifting performance and faster wear than XTR. Apparently the gears are made of thinner ti than the XTR's which may contribute to their faster wear;
• only have the 4 biggest gears are on carriers (cf. XTR where the 6 biggest cogs are on alloy carriers). Those separate thin 16t and 18t ti gears will chew into aluminium freehubs;

Omniracer OM129TA cassette - 160g

The good:

• 61g lighter than XTR;

The bad:

• aluminium cassette with Ti nitride ceramic finish, despite fancy coating will wear faster than ti or steel when used offroad;
• more expensive than XTR - around $230;

SRAM PG-999 cassettes - 175g

The good:

• 46g lighter than XTR;
• all steel except for aluminium 32t cog so should have same or better wear than XTR ti cogs;

The bad:

• expensive - around $300;
• can't replace a few worn cogs like you can with XTR;

What gear ratios are available?

How does this compare to XTR 10 speed?

9-speed / 10-speed 11-32T ratios compared:

9-speed / 10-speed 11-34T ratios compared:

9-speed 11-34T / 10-speed 11-36T ratios compared:

9-speed 12-34T / 10-speed 12-36T ratios compared:

What's so good about the XTR M970 9 speed cassette?

A few things make this cassette a standout:

• it's light;
• you can order the individual parts to replace what may have worn out.

Just replace the worn out bits

The 4th largest sprocket on the cluster is the smallest one made of titanium. It generally gets a fair bit of use and being titanium it wears a little quicker than the smaller steel cogs and the larger titanium ones. But, the beauty of the new XTR design is that you can replace these cogs in pairs because they are available as genuine Shimano parts:

If you're entire cluster is worn out, then its much cheaper to just buy a new one, but if one a few gears are worn out, then around $40 will get you a replacement and you might get another season out of the cassette.