12sp Cassette on older Shimano hub - yay or nay??

No go. To get 12s to fit, Shimano invented MicroSpline. 11 is your max on HyperGlide, as per older XT.

Balls! Thanks for saving me the hassle though.....

I think that there are other 12speed cassettes that will fit though?

Yes you can fit a 12 speed cassette to a 11 speed freehub

You need a Sram SX or NX 12 speed cassette, these still use Shimano's hyperglide freehub

You can also use Brand X 12 speed cassette's (looks like a Shimano cassette) and loads of other brands 12 speed cassette's just not Shimano's

The Sram ones are 11-50 the Brand X are 11-50 and 11-52

Shimano 12 speed road cassette's are hyperglide so work fine on a 11 speed freehub, the ratios are closer together but you wont get a large gear like a 50T

https://uk.redbrain.shop/p/00710845818011?utm_source=google&utm_medium=css_organic

https://www.highonbikes.com/products/brand-x-12-speed-mountain-bike-cassette-hg-fitting

https://www.merlincycles.com/sram-sx-pg-1210-mtb-cassette-12-speed-280318.html

Shimano roadie stuff will fit, I’ve got

https://www.merlincycles.com/shimano-105-r7100-cassette-12-speed-271625.html

Interesting.... So, would the above basket work? I'm not sure on what chain length to go for.

Thanks for the replies so far.

The above will work. Check how shimano measure 12sp chain length

Also i think you may need a different tooth profile 12sp chainring?

Nah, chainrings will work with 10-11 & 12 speed chains

would the above basket work

It would but I'd make changes.

I'd go xt shifter as this makes the biggest difference to shift quality feel £31.50

https://www.merlincycles.com/shimano-xt-m8100-right-hand-gear-lever-12-speed-180711.html?utm_source=PHG&app_clickref=1100lyrX6eFw&source=PHG&utm_medium=Affiliates&utm_campaign=genieshopping

Then go for the pg1230 cassette to save quite a bit of weight over the 1210 version. £59.99

https://www.ebay.co.uk/itm/226124523526?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=qdjagiFjRCC&sssrc=4429486&ssuid=Znv27-LHRwe&var=&widget_ver=artemis&media=COPY

Then a kmc x12 chain as they work great and are very corrosion resistant £20.99

https://www.bikeparts.co.uk/products/kmc-x12-black-silver-chain-126l?currency=GBP&variant=44646717915293&utm_source=google&utm_medium=cpc&utm_campaign=Google%20Shopping&stkn=a894e8283159&gad_source=1&gclid=Cj0KCQjwudexBhDKARIsAI-GWYVn1KW6Rq-S_0zMayPfQayQEO-ZsTa_Ttfi5TuWPfdgTePHLzfEbeAaAg_mEALw_wcB

Finally an m5100 rear mech as they work perfectly and are a lot cheaper than slx for essentially no difference in functionality £33.99

https://sportandleisure.com/products/shimano-deore-m5100-11-speed-shadow-rear-derailleur?variant=44620276629761&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=Cj0KCQjwudexBhDKARIsAI-GWYVW51_KLsFsVC7bt3epPrIJjCeXLhX0Dkap1jT8HFmi_o9CdHG4ED8aArRZEALw_wcB

Cheers, XT shift is out of stock for standard bar mount. Deore mech is 11sp, rather than 12sp?

Thanks for confirmation my basket will work - good tip on the cassette though.

Don't think my mild OCD could cope with a black and silver chain! One or the other...

Basket would work.

Sunrace also do 12speed cassettes that fit on a Shimano HG (11speed/oldskool) freehub.

XT shifters ARE nicer!

Looks like I should be shopping around for XT shifter then!

Will do.

Thanks for the help all.

Deore mech is 11sp, rather than 12sp

They're the same and interchangeable. Just marketing.

Is that so?!? Well, everyday is a school day.