Cycling UK Forum

Is a 10-speed 'mountain bike' cassette (Shimano Deore XT M771 - 10 Speed Mountain Bike Cassette - 11-32t ) the same as one sold as a 'road' cassette...i.e. Tiagra 11-32? Are they the same dimensionally?

I have a 10s 105 triple setup with a mountain 10 cassette - 11 to 36 - on an Ultegra hub.
I use a 9sp mountain rear changer which indexes fine. If you use a modern 10sp MTN rear mech it doesn't index with the 10sp road shifter.
Other than that I think the MTN cassette will be ok but I think it won't fit a 10sp DURA- ACE - someone should be along shortly to clarify this.

I also use a 9-sp RD with a 10-sp cassette.....thanks to advice on here a while back.

Just wondering whether MTB & Road cassette are the same dimensions. Seems like some 'MTB' 32 & 36 cassettes are actually lighter than their 'road' equivalents.....considerably so in some cases. I'm not a weight weenie but if I can save 100gms on the cassette, I will do.

AFAIK all Shimano 10 speed cassettes fit any 10 speed freehub. (also fit 8 & 9 hubs as well).
I did have a 10 speed cassette that came with a thin spacer which I think was an Ultegra.
Currently running 11/34 SLX cassette on Ultegra hub with a Deore 9 speed RD on one bike.
Not sure whats on my other cycles.

The difference is going to be in ratios available, and the MTB one will most likely be a heavier material, but the fit is the same.

What about the top-end ones...XTR or XX (Sram). No difference in how they operate? I can't think of anything but wanted to check before buying....used of course, I ain't made of money!

for a few years some shimano 10s racing parts were different from other 10s road and 10s MTB. They designed a variation on their 'old' freehub body spline such that the major diameter of the spline was enlarged on most of the sprockets, and the minor diameter of the spline was retained. This was to allow freehub bodies to be made from something softer, either Aluminium or Ti, without the dreadful 'biting' wear you usually see between the cassette and the freehub body.

This arrangement was on Dura Ace 10s, Ultegra 10s and even 105 10s, as well as several shimano wheelsets. The 'special cassettes' will also fit onto standard steel freehub bodies but the 'special freehub bodies' will only accept the special cassettes. So anyway it remains the case that any shimano 10s cassette will fit onto a standard (8/9/10s) steel freehub body.

The weight difference between cassettes is usually because the lighter weight ones have an aluminium spider (or 'carrier') for some of the sprockets. Occasionally some of the sprockets are Ti or aluminium instead of steel; these wear faster so are not an unmitigated blessing. In 9s they made 'all titanium' cassettes in Dura Ace and Ultegra, but they seem to have not bothered (so much or at all) in 10s.

A minus side to the 'carrier' type cassettes is that the sprockets can't be swapped about or respaced; they are riveted to the carrier. However there is otherwise little or no difference in use if you choose a 'carrier' type cassette; it works the same but is just lighter.

cheers

Thanks for that comprehensive answer.

BTW your instinct -that £ per g buying a lightweight cassette is a good way to save weight- is correct. However, buying a more expensive cassette (or indeed any consumable part) is something that you pay for again and again; each replacement costs more. So over the life of the bike you might spend more £ per g than you might expect, whereas other lightweight parts are more like true 'one off' costs.

Then again some folk manage to run their cassettes with very many chains, by changing the chain before it wears the cassette badly. Mileages of 20000 miles (or more) per cassette are possible this way. For them, the cassette is less of a consumable and more of a one-off cost.

cheers

Yes, totally agree.

I 'like' (inappropriate word) climbing hills so a big cassette is a must for me. Combine that with a long cage RD and a bit more chain and the weight adds up. Thanks to you and others on here that offered advice, I've gone the 10-sp cassette, 9-sp RD route. Currently running a 36 on the back, and have been for a few years now.
I just treated myself to some Absolute Black rings, dropping the front cogs down to 30/46 so I can go 32 on the back and have the same gearing for lighter weight. Checking out available cassettes, I find the top end MTB cassettes are actually lighter than available road cassettes by quite a bit.
I don't go mad on 'lightweight' wheels....Fulcrum 3's are good enough for me, but throw on a dinner plate 36 cassette weighing 1lb and it ain't light(ish) anymore.
My bike, set up for comfort and weight, is about 8Kgs, so not WW, but I can grind up most hills. I set it up for the Fred Whitton, and never changed it back! (That's with peddles and bottle cages, but not the well-equipped little tool bag on the saddle or 1.5 kg of water).
What difference does 100gms lighter at the cassette make? Don't know, just the placebo effect probably.
Check me out on Strava (same name). I gained 700,000ft+ over 8500 miles last year. I rarely use the 36 cog, but nice to know it's there! Same (cheapo 2nd hand) cassette the last 3 years too, and I don't change the chain as often as I should.