I’m currently running 1 x 9 with an 11/ 34 cassette. Is there any point going to 1 x 10 with a 11/ 36 or should I just get a 11/36 9 speed cassette?

They don’t make 11-36 9 speed cassettes, only a Deore 12-36.

If you really,really do need an 11 -36 you can always replace the 12t and use your 11 t sprocket from your current 11-34 instead.

Yeah, but the deore-spec 12-36 is as heavy as a planet. Sure I’ve got one somewhere if anyone wants it, they can have it for the price of postage, which will be one million pounds.

He is not wrong – get a 22 front and you even save weight and cheaper than chaing all your drive train
17.83 [ 22 32 and 9 speed] gear inches* v 17.29 gear inches[ 10 speed and 24 36]

I guess if you really want to then you could but for me it is costly change for only very marginal gains

* 16.78 gear inches if you do 22 34 which is available in lighter than Deore @ 9 speed

@ junkyard..I take it the 17.83 gear inches you mentioned are for a 2 x 9 set-up ( 22 32 rings ). I don’t have the lugs on my crank or Renthal chainring for a 2 x set-up. I’ve currently a 32 ring and a Sram pg990 with 11 34 ( I think ) cassette. I was thinking of changing to a 34 front and a whatever 36 rear. Do you know what my options are re. cassette?

Whilst there’s virtually nothing in it 32-34 is a marginally easier gear than 34-36. So going 1×10 will cost you a teeny bit of bottom end.

@ junkyard..I take it the 17.83 gear inches you mentioned are for a 2 x 9 set-up ( 22 32 rings ).

Yes

I don’t have the lugs on my crank or Renthal chainring for a 2 x set-up.

AH

I’ve currently a 32 ring and a Sram pg990 with 11 34 ( I think ) cassette.

24.56 gear inches

I was thinking of changing to a 34 front and a whatever 36 rear.

24.65 gear inches

You will not notice any difference IMHO

Do you know what my options are re. cassette?

No I am 9 speed. I would just stick with it personally and run a 34 if you want.The lighter stuff Sram and Xt XTR comes in 11-34 [ and probably 12-34]
You need a new shifter, chain ,rings and mech to gain basically the same range with 10 clicks instead of 9
80.67 gear inches 34-11 [ 10 speeed]
75.93 gear inches 32-11 [ 9 speed]
I guess that is where your extra gear is ie 9-10 and not an easier first/lower gears

Thanks, The easier first wasn’t a deal sealer for me as I don’t like to ( read can’t ( ex-smoker )) spin for too long as I always end up changing down and mashing…so might as well run a 34. I was looking to build up a bike for my son using parts he already has but he runs single-speed atm. If it was worthwhile I would have given him my 1×9 set-up and gone 1×10 myself. I might as well set his up 1×9 also..Any deals about??

Going 1×10 also means you can get a clutch type rear mech.