I am building a new fs bike and know very little, so this has/will be a bit of a learning curve.

I have a triple 42/32/24 crankset and need a 10 speed cassette, options being 11-32 11-34 and 11-36.
As I see it all three will give me the same top end gear but the higher the second figure, will give me a lower lower gearing but with the penalty of a larger ratio difference.

So in the words of Harry hill which is best.

Do I need the lower gearing given that I have a granny ring.
All opinions welcome.

Thanks.

As I see it all three will give me the same top end gear

Correct.

Do I need the lower gearing given that I have a granny ring.

It depends on so many things. How fit are you? How heavy is the bike? Is it a 29er? What sort of riding do you do and what sort of trails do you ride?

The safest option is 11-36 as it covers everything. A lot of folks use a 2×10 setup with a 36 cassette.

What were you previously riding?

Advice above is spot on. It’s a very personal thing. One other thing to consider is that some people really like small steps between each gear. This is often why road riders will have close ratio cassettes.

Me personally, I’m not that sensitive. I ride heavy bikes at a sociable pace in places with though technical climbs. I like to treat each climb as a challanged. Therefore, for me, the 11-36 would be a no brainer.

Unless you can get a different size much cheaper or you’re really counting grams I can’t see the point in having an 11-32.

As above, very personal.
What do you currently ride and how is that geared?

I’d normally suggest that 11-32 is perfect for a triple up front

If you run a double up front then go for 11-34 if the front granny ring is a 24 or higher. Otherwise stick with 11-32 unless you’re really bad on hills. If its a heavy full-sus then go 34 as well

11-36 is only really if you want to go 1x – and even then its best to put a 34 or 36 up front. It can be pretty heavy in comparison to an 11-32.

That’s only my guideline tho…up to you really!

Thanks to all who have answered so far.
The bike I am building is a five, I am trying to keep it as light as possible bar the forks which are rockshox 150 sektors DP coils.
Everything so far drivetrain and gearwise is xt, not sure how much it will weigh when finished but hopefully should be average.

I currently ride a voodoo hoodo HT which halfords state as weighing 14 kg,
Which has a 44/32/22 Alvio triple and nine speed cassette. Not sure of the cassettes ratios as the bike is not with me and cannot find info on the net.

I’m not too keen on hills and see them as a necessary evil but still don’t like being beat.
I was following someone last week around swinley and at every climb they just stayed in the saddle and span like the clappers, where as I was always out of my seat trying to power up.
Although I think this Is more to do with better organisation on his part as I am always getting caught out in the wrong gear.

I guess I need to find out what lowest gear ratio is on my current bike and go from there.

I was following someone last week around swinley and at every climb they just stayed in the saddle and span like the clappers, where as I was always out of my seat trying to power up.

Were you in your lowest gear?

Like many things, climbing technique is preference to a large extent. Some folks like to stay seated and spin up the hill in a low gear. Others prefer to climb standing. Neither is right or wrong, though I’m sure that someone will be along to say otherwise! 😀

So you buy a frame ,fork and crankset and now decide to ask for advice on which cassette? 😯

I was following someone last week around swinley and at every climb they just stayed in the saddle and span like the clappers, where as I was always out of my seat trying to power up.

Depends how long your riding for too – what you do on an hour ride is different to a 4 hour ride. Swinley hasn’t major elevation changes, so allows more flexibility in riding style too.

A quick Google search will reveal Alivio 9spd cassettes come in 11-32 or 11-34. No right or wrong answer to cassette size, it very much depends on local trails, riding style, bike weight, rider fitness etc.

I am trying to keep it as light as possible bar the forks which are rockshox 150 sektors DP coils.

A bit pointless then… 🙄

I was still in the middle ring, in a low gear.
Like I said I am constantly caught out in to high a gear and then have to try to push hard to build just enough speed to be able to unload the peddles to knock it down a gear or two.

But then I will still go down just enough to be able to make it up standing.

When commuting on my hack i will stay seated and spin but then hills are normally long and gradual and you see them coming a mile off.

b r

I bought the forks as I decided they were the best new forks in my budget.
If I was super lean I may be super OCD about the weight of my bike paying through the nose to shave off a few grams.
But the best way for me to knock weight off my ride would be to stop filling my face with pies and I could knock stones off it for free.

I don’t see the point of a 15 stone man worrying about a few gramms here and there on my build.
I am just trying to build a good bike on my limited funds and wisdom.

I used to run for an hour (7 miles) every other day up until a knee injury last year and bought a bike to try and keep some fitness, I have put on quite a bit of weight which will have to go, and have just started running again but I really enjoy riding a bike and getting out in the woods.

chip
My advice is that you need to ride a bit more on your current bike to understand your gears and your capabilities/fitness better.If you’re not selecting the right gear with 27 then 30 will only confuse you more,hence the added confusion over which cassette.If you keep riding you will get fitter.
Uphill offroad seated is best IMHO as you get better traction but if you do decide to get out of the seat then you should change up a gear or two anyway.
Unless you do lots of road downhills then I would ditch the big front ring and get a bashguard with just a double upfront and an 11-34 cassette,you will be fine and have less gears to worry about.You can always change back if you want to but you won’t. Spinning with a granny and a 34 will get you up the longest climbs in the Scottish mountain routes but your heart and lungs will probably give out sooner.A 36 would only hasten the process.
Personally I would go 1×10 with 11-34 or maybe 11-36 if I had concerns about my fitness but that might be a bit disconcerting for you at this time.

Thanks nick,
I will give your points serious consideration as I have the hardtail for riding out of the front door to the local woods where the big ring is handy for there and back.
As the five would be overkill, Quite frankly my rigid would be enough for this.

The five will be for putting in the car and taking places more suitable so you could be right in what you say about the large ring being surplus to requirement.

Chip – it sounds like you need to get used to shifting to a lower gear before you need it! It takes a little bit of practice, but once you’re used to it, it becomes second nature.

And I have a triple on my main (4″ full suspension) bike. Every year, I consider removing the big ring. Then I use it a few times, linking some singletrack by road, on a rails to trails, or something else like that and I’m glad that I have it! I’d say leave it on the Five for a few months, and see if you use it at all. If not, take it off.

Chip. Ive got a Five and my current set up is 2×10 with 11-34 cassette. I changed from 11-36 when it needed replacing and I do sometimes wish i had kept the 11-36 but then the granny ring is always in reserve if needed. I didtched the big ring as i hardly ever used it and i dont miss it even tho i ride on the road to link up the trails. I much prefer to have a bash and chain device. Im considering getting rid of the granny ring too as its very rarely used. If i was you id stick with the triple set up for now with 11-36 casette and see how things go. You can always change your set up when parts need replacing, which by then you’ll be fitter and know what set up will suit you better