Small 29er build advice?

[eyedrop]

Coming from mostly road bike background but take out the XC bike only a couple times a month, so lingo and knowledge is rough:

Local LBS owner is buying a 2019 Marin Rift Zone 3 and is stripping the groupset off and wanting to sell the group to me at a "good deal" for my XC 29er build. Said he will get back to me on the groupset quote but he always seems to hook it up as I do computer repair for him at good discounts...

Anyways, Im looking at potentially buying a chinese carbon 29er frame. I'm 5'2" and currently ride a 26" 15.5" 2010 Trek Top Fuel that Im very comfortable on. But technology has moved on, and this old 26er is thrashed. So looking at getting a new bike.

Since Im very small, I was eyeing the Kona Hei Hei or the Niner RKT RDO. Turn key bikes have eye watering but doable prices. But maybe chinese carbon is cheaper and 98% as good?

My requirements are dropper post, Modern 29er XC geometry, XC leaning. Full Suspension. Good value for money....

Stack and reach measurements on road bike are:
reach: 376mm
stack: 505mm

[TheRich]

Of the two, I'd try a medium Kona, just for the extra reach, standover is the same for small and medium, so no loss there. That long front center is what makes a modern MTB safer and more confidence inspiring. The shorter chainstays don't hurt either, that's what keeps a longer (front center) bike from handling like a bus.

The Niner is just an old design based on old assumptions.

[eyedrop]

Is there such thing as an XC frame anymore? Seems like the racier trail , enduro, and XC geometries are blurring... I just want to go as fast as possible all day while doing lots of loose climbing and technical handling skills.

[TheRich]

Is there such thing as an XC frame anymore? Seems like the racier trail , enduro, and XC geometries are blurring... I just want to go as fast as possible all day while doing lots of loose climbing and technical handling skills.

As far as geometry goes the differences are definitely shrinking. Short travel bikes, and even hardtails, are closing the distance between themselves and the longer travel bikes as they become more confidence inspiring (and the fact that most people are overbiked).

[eyedrop]

What do you think of the Dengfu FM026 29er frame? I may do a Chinese carbon build if I can find a modern design that will make the 29 wheels handle good, especially since I'm looking at S and XS frames...

[Lelandjt]

At your height I'd strongly recommend 27.5 wheels. Any difference in rolling resistance will be made up for in weight and acceleration and the handling will be so much better.

[eyedrop]

At your height I'd strongly recommend 27.5 wheels. Any difference in rolling resistance will be made up for in weight and acceleration and the handling will be so much better.

From what I understand, small 29ers with modern geometry no longer handle like tanks like they did circa ~ 2012. To what degree it's marketing hype, I'm honestly not sure.

[TheRich]

At your height I'd strongly recommend 27.5 wheels. Any difference in rolling resistance will be made up for in weight and acceleration and the handling will be so much better.

From what I understand, small 29ers with modern geometry no longer handle like tanks like they did circa ~ 2012. To what degree it's marketing hype, I'm honestly not sure.

Wheelsize doesn't matter, frame geometry does.

Rolling resistance trumps all, since you're rolling all.the.time, you get that advantage all.the.time. Marginal differences in weight are inconsequential when compared to rolling resistance.

If you can fit on a 29er, get a 29er.

[TheRich]

What do you think of the Dengfu FM026 29er frame? I may do a Chinese carbon build if I can find a modern design that will make the 29 wheels handle good, especially since I'm looking at S and XS frames...

I don't have a Kona, never had a Kona, but I really like that Kona. In the 15.5 size, the FM026 is shorter (reach) than the Kona (assuming you sneak up to the medium, since the standover doesn't change from the Small). Without any big body position changes, the Kona is going to put your weight in a really good place for cornering and with a dropper post is going to be as close to endo-proof as you can get, plus you'll be in a great pedaling position with a short stem. When seated, you're going to be ready to put down the hurt, drop the saddle and you're ready to tear it up.

As far as the price goes, most people are happier when they get what they want. I'm SO done with getting something and wishing it was something else, it changes the entire ownership experience when you start with exactly what you want.

[Lelandjt]

At your height I'd strongly recommend 27.5 wheels. Any difference in rolling resistance will be made up for in weight and acceleration and the handling will be so much better.

From what I understand, small 29ers with modern geometry no longer handle like tanks like they did circa ~ 2012. To what degree it's marketing hype, I'm honestly not sure.

I think anyone who is under 5'5" and is a good enough bike handler to feel differences will prefer the handling of 27.5" wheels to 29. Long top tube, steep seat tube, short stem, slack head angle, 44mm fork offset help both wheel sizes but physics still exists. A bigger, heavier gyroscope can be felt by someone so short. At my shop we sell plenty of both wheel sizes and have plenty of demo bikes for prospective buyers to try. No one that short has ever bought a new 29 from us and the size small 29ers are always the last demo bikes to sell at the end of the season. I suspect the buyers of those bikes can't resist the deep discount. If you can, try before you buy.

[TheRich]

I think anyone who is under 5'5" and is a good enough bike handler to feel differences will prefer the handling of 27.5" wheels to 29. Long top tube, steep seat tube, short stem, slack head angle, 44mm fork offset help both wheel sizes but physics still exists. A bigger, heavier gyroscope can be felt by someone so short. At my shop we sell plenty of both wheel sizes and have plenty of demo bikes for prospective buyers to try. No one that short has ever bought a new 29 from us and the size small 29ers are always the last demo bikes to sell at the end of the season. I suspect the buyers of those bikes can't resist the deep discount. If you can, try before you buy.

I have a 5'4" friend that (also) rides a Trek Stache, which has 32" diameter tires. She finds it faster and more confidence inspiring than her old (normal) 29er.

All that matters is the fit. As long as your grips aren't up in the sky due to the stack, the wheelsize is transparent. Bikes are so light and the speeds are so low that comparisions to cars and motorcycles simply don't apply. Any marginal increase in effort, which becomes transparent over time and familiarity, is also an increase in stability and as we've seen with recent developments, having a stable platform is more important than raw agility. Riding agressively on dirt requires a stable platform that gives you the confidence to actually manipulate the bike. Otherwise we'd still be riding bikes with steep HTAs and short reaches, which can be ridden agressively, it's just really scary to do so because everything is on a razor's edge.

I'll also say that most of the riding public knows next to nothing about actually riding a mountain bike, and they really don't want to learn either. That's what they want to do, so that's fine, but it leads them to blame their equipment instead of their lack of confidence in general...and that lack of confidence leads them to be even less confident on an unfamiliar bike.

[eyedrop]

Just stradled a small Kona hei hei alloy 29er and the top tube was too high to the point that I couldn't bounce the bike between my legs. 750mm standover. Straddled the small Kona Satori at 730mm. Felt a little tight but doable. Tried a 27.5 trek top fuel at 730mm and it felt a little shorter than the Satori despite quoted measurements about the same. If I do an RC 900 clone build, I get the feeling it might be a touch too big for me.

That niner RKT RDO is looking real sweet at just 696mm standover. I wish the chainstay was shorter and more slack on head angle, more progressive geo, but maybe beggars can't be choosers?

Having a hard time finding standover Info on these Chinese builds... I'm right on that line of being able to fit it seems...

[Lelandjt]

Does standover actually matter though? Will there ever be a time on the trail when you say, "This bike has too little standover clearance and it's affecting me negatively"?
The only thing I can think of is it might limit how much you can lean the bike between your legs.

[TheRich]

Lack of stand over is just something you have to deal with when you're short. Bikes aren't designed for you, or for tall people...just the way it is.

[Dilberto88]

What do you think of the Dengfu FM026 29er frame? I may do a Chinese carbon build if I can find a modern design that will make the 29 wheels handle good, especially since I'm looking at S and XS frames...

EBay currently has a small Pivot Mach 429SL race bike for auction in USA