I'm being indecisive over the set up of my newish SIR9. With the steep head angle, despite 100mm forks, I found it a bit twitchy at slow speed with an 80mm stem and 660mm bars. I changed to an (incredibly unfashionable) 110mm stem but that felt pretty sluggish when I test rode it the other night.

Any experience/advice? Should I:- get used to the twitchyness, get used to the sluggishness, get wider bars, get an in-between length stem, get a life, what?

Cheers

Sell the Niner, and get a UK friendly bike?

the bike's 6'4 friendly, which is more important 🙂

100mm on my Air9

but 80mm on my Scandal as it's got a longer top tube for same 'size' frame
Large-Large but Scandel Large is more Niner XL

wider bars will have a similar effect in some ways to a shorter stem.

I use 660mm bars (I think) on both too
You got swept or straight bars?

Whys a Niner not UK friendly?

Before doing anything too rash, try a 90 and/or a 100mm stem perhaps?

Hear what you're saying about the SIR bonesetter, but I just checked the geometry, it's listed head angle is the same as the Inbred 29er, Singular Swift, Gary Fisher Rig, and several others… Was yours really that twitchy?

Lactic, which forks are you running?

Sorry about that 😳

My Niner's (RIP & SIR) were both twitchy, especially when pointing downward.

I fitted a w-i-d-e bars (29") and a 50mm stem

This may sound crazy, and bar/stem set-ups are hugely personal, but most twitchiness went after that.

I guess I just prefer slacker angles, which is why they both went

Why's a 29er 6'4" friendly other than in proportional looks?

So.. it's too fast on 80mm stem, too slow at 110mm so… you can see what I'm going to suggest here 🙂 How about 90 or 100mm?

The bar width seems unlikely to be an issue – neither narrow or overly wide.

Bar width changes your length on the bike
so a change in stem my feel to short or long a change in bar width can be used to counter that change if required
It also changes steering feel, try holding your bars just either side of the stem and ride, it will feel different. Moments/torque

Thanks for replies chaps. The forks are 100mm rebas.
Twitchy/ sluggish is all very subjective, and I reckon I could get used to either. Just keen to try and find the sweet spot to get the best out of the bike.

I thought wider bars made the steering easier but slower?

easier and slower yes, but also effectively shortens you too
i.e. you get closer to your bars, putting more weight over the front
just bare it in mind if you changing stuff and your bike top tube feels too long

if you go with a longer stem you might want to narrow your bars a bit
or go for a swept bar instead of straight to bring your length back in a touch

I am running 80mm with big renthal bars on a sir9 It's loads of fun but it is too short and a bit twitchy. I found 100mm spot on but that stem in on another bike now.

The niners are lively bikes. I found if you have wide bars and a strong stance and some balls, you have an incredibly good ride.

I ran 80mm and Titec Flat trackers on Large EMD, I am 6'1".

Felt sweeeet as to me 🙂

Got some huge old thing on my SIR 9, must be 110 – 120 ish, should really be in a museum, but it's all that was laying around.

It's a large frame, I'm 6' 2" and It's got (scary) Mary Bars on, which while not looking wide aren't that narrow! Maybe narrow(ish) bars counteract the long stem …… ??

Rides fine for me 🙂