two or three chainrings for xc/am?

rickbst170

Hi all,

New to the forum but I know a bit about bikes (from 6 years ago). My stepdad used to own a bike shop but when he sold it and I moved away I stopped riding. I'm going to build a bike.

I've come across a giant reign frame (05-07 shape) and will start with that. Most people I intend to ride with either ride hardtail xc bikes (one group of mates) or jump bikes and moto X (different group of mates). I used to do xc and road, but want to try jumping and AM/DH. I don't want to get dropped top far behind the xc lot, but also want to build something which can focus on AM/DH if that's where I end up spending most of my time.

Should I go for a 24/36/bash or 34/32/42? I used to pump an ok cadence speed on a 53 on road but struggled when I road a 56, and now I'm 6 years older, have smoked for a decade and haven't been on a bike for 6 years. I have no idea what my current fitness is like but I have an e cigarette, willpower and eagerness on my side.

Opinions please

Also, is there much preference these days between shimano, sram, race face etc?

Cheers
Rick

fizik

I'd go double unless you were planning on racing xc - which it sounds like you are not. Also a chain tensioner may help, something cheap like a blackspire stinger dualie would keep your chain in place! 24/36 would be ok, or even 22/32 if you need lower gearing, assuming you are running 9 speed? Once you get fitter challenge yourself and drop the granny ring!

rickbst170

Thanks mate. Thats what I was thinking hut good to hear someone verify it. Not planning on racing. When I was 15 I remember turning up to races in lycra, skinny legs and about 6 stone, looking at the DH guys and wishing I had baggy shorts and could catch big air, not spandex and a hard tail. Grown up a bit now and have a stepson to take riding, and he wants to jump/play rather than shave his legs and go fast up hill so no need for a big ring anymore.

Any preference as to brands?

Also, when did 10 speed arrive?! Do you need a 10 speed hub? And mech? Or just change the limit screws accordingly I guess. Is it still something like 11-32 but with an extra one in or do you get a really big or really small one? Sorry. Being lazy and haven't searched. Will do if needs be.

Ta
Rick

declan1

rickbst170 wrote:

Thanks mate. Thats what I was thinking hut good to hear someone verify it. Not planning on racing. When I was 15 I remember turning up to races in lycra, skinny legs and about 6 stone, looking at the DH guys and wishing I had baggy shorts and could catch big air, not spandex and a hard tail. Grown up a bit now and have a stepson to take riding, and he wants to jump/play rather than shave his legs and go fast up hill so no need for a big ring anymore.

Any preference as to brands?

Also, when did 10 speed arrive?! Do you need a 10 speed hub? And mech? Or just change the limit screws accordingly I guess. Is it still something like 11-32 but with an extra one in or do you get a really big or really small one? Sorry. Being lazy and haven't searched. Will do if needs be.

Ta
Rick

10 speed has been around for years now. Shimano, for example, needs a new rear mech for 10 speed as the cable pull ratio is slightly different. You can get cassettes with 42 teeth now but that's for single front rings. The cassette on my mountain bike is an 11-36. Usually hubs are 8/9/10 speed so you should be ok with that.

rickbst170

Ok, spot on. Front mechs still the same for 1/2/3 rings and 8/9/10 cassette? Cheers. Rick.

declan1

rickbst170 wrote:

Ok, spot on. Front mechs still the same for 1/2/3 rings and 8/9/10 cassette? Cheers. Rick.

You don't need a front mech for 1 front ring A triple front mech will work on a double chainset (not as well as a double one) but not vice-versa. The cage of the front mech gets narrower with the narrower chains but if you have a 9 speed mech I don't see why it shouldn't work as the difference isn't that great.

rickbst170

declan1 wrote:

You don't need a front mech for 1 front ring

Oh yeah :oops:

shhhhh. It's late, I'm tired.

Thanks for the info. Top tips. Can't wait to get the frame and some parts and get started!

Rick

The Rookie

fizik wrote:

Also a chain tensioner may help, something cheap like a blackspire stinger dualie would keep your chain in place!

That's a guide not a tensioner.

declan1

rickbst170 wrote:

declan1 wrote:

You don't need a front mech for 1 front ring

Oh yeah :oops:

shhhhh. It's late, I'm tired.

Thanks for the info. Top tips. Can't wait to get the frame and some parts and get started!

Rick

No problem - don't forget to post pictures when you've got it built up!

97th choice

The Rookie wrote:

fizik wrote:

Also a chain tensioner may help, something cheap like a blackspire stinger dualie would keep your chain in place!

That's a guide not a tensioner.

People have started doing this just to bug you.

rickbst170

declan1 wrote:

No problem - don't forget to post pictures when you've got it built up!

Will do. Frame is a bit tatty (stone chips and scratches from when it was shipped overseas by last owner in poor packaging) but mechanically sound. Might get it powder coated at some point. I'll grease/replace bearings and servicr the shock, then build her up over time. I know it costs more long term to build from scratch but at least I'll have a bike with everything I want, not a compromise. If I buy a working complete bike and try to change bits later it will never happen. The missus will spend everything before I ever get my hands on it for upgrades!

declan1

rickbst170 wrote:

declan1 wrote:

No problem - don't forget to post pictures when you've got it built up!

Will do. Frame is a bit tatty (stone chips and scratches from when it was shipped overseas by last owner in poor packaging) but mechanically sound. Might get it powder coated at some point. I'll grease/replace bearings and servicr the shock, then build her up over time. I know it costs more long term to build from scratch but at least I'll have a bike with everything I want, not a compromise. If I buy a working complete bike and try to change bits later it will never happen. The missus will spend everything before I ever get my hands on it for upgrades!

Exactly

JMcP92

I ran a triple on my AM bike, then dropped it outer ring to a double as it was never used. Then compromised to a 1x10 with a 32t front ring, really don't need a double. The only time you miss out is on fast firetrack or on road, beyond that a 1x10 is plenty. Or 1x11 if you've the money

bennett_346

The Rookie wrote:

fizik wrote:

Also a chain tensioner may help, something cheap like a blackspire stinger dualie would keep your chain in place!

That's a guide not a tensioner.

It's a tensioner, even Blackspire call it a tensioner:

http://www.blackspire.com/site_assets/w ... _guide.pdf

STINGER CHAIN TENSIONER INSTALLATION INSTRUCTIONS
PLEASE READ!!
Thank you for choosing Blackspire. We pride ourselves in manufacturing best performing
chainguides on the market today

rickbst170

Right. Been reading up and I think shimano only do a 3 ring shifter which you just limit if going 2x10. Based on that and based on my lack of knowledge as to what I need (current fitness and rate of improvement etc) I think I'll go triple to start with, then drop the big ring if I don't use it. As far as I can tell, 3 rings weighs more by a tiny amount, 2 rings is cooler, but other than the weight gain and uncoolness of three rings, more is better. You don't lose much gear ratio by going 2x10, but you do lose something. Why, if only for a 10g weight saving and to look awesome?

declan1

rickbst170 wrote:

Right. Been reading up and I think shimano only do a 3 ring shifter which you just limit if going 2x10. Based on that and based on my lack of knowledge as to what I need (current fitness and rate of improvement etc) I think I'll go triple to start with, then drop the big ring if I don't use it. As far as I can tell, 3 rings weighs more by a tiny amount, 2 rings is cooler, but other than the weight gain and uncoolness of three rings, more is better. You don't lose much gear ratio by going 2x10, but you do lose something. Why, if only for a 10g weight saving and to look awesome?

Another reason to go with a double at the front is the reduced q-factor.

rickbst170

Q factor?

cooldad

Width of cranks. It's a roadie thing.

rickbst170

Q factor being measurement between bb and pedal, lower Q factor = less twist = better drive efficiency and lower knee injury risk, right? Not sure it'll make a great difference to me at an ameture level, but interesting stuff.

cooldad

Unless you sit and pedal long distances it's a bit irrelevant.

Most mountain biking includes a lot of movement and standing.

But I am more amateur than most, so most of what I say is irrelevant to serious MTBers.

rickbst170

Lol cheers cooldad. Still not sure what I'll end up buying, price will be the deciding factor. But at least I'm getting an idea of what I'm looking for. Think I'm going 3 x 10, newish disc calipers, probably shimano throughout. Will drop to a double in time if it makes sense to. Easier to go triple and cut back than start double and find myself short of options on a long climb/fast section. Next topic will be riser bars or flat, and stem lenth/angle but I think I'll need to sit on a few bikes in a shop for that

declan1

It's definitely less of an issue on mountain bikes as you're standing up and moving around a lot more than on a road bike. I get knee pain after a long ride on my mountain bike however (triple crank) as the q-factor is quite a bit wider than on my road bike. Just worth thinking about!

rickbst170

Noted Declan. Thanks.