Fat bike vs XC race geometry

My fat bike is a rocket ship on the climbs and I’m looking for a proper XC bike that is faster. My reasoning is that an XC race bike should be quicker right?

I’ve tried the fat bike with 29×3″ wheels and (within reason) the climbing ability is unchanged which leads me to believe it’s the geometry, maybe the riding position

The fatty is very long, low and steep but not particularly heavy. I’m 6’2″ and as a trail bike it looks too big but it just clicks on the climbs. I can stand up easily without being too far over the front and it requires about as much effort as walking upstairs. I have other bikes that are lighter and/or more nimble but they can’t climb like my fat bike.

Comparing the geometry with similar-size seat tube XC bikes the XC bikes are generally shorter, have less reach, are slightly slacker and are a bit taller. I guess this is to make them fast in a variety of situations not just uphill.

So with climbing ability as the absolute #1 priority are there any long and low XC bikes? Or is it more related to riding position and pedalling efficiency?

Or should I just forget about it 🙂

Efficiency/speed when riding uphill is simpy about power/weight.

If you get a lighter bike it will speed up by the difference in weight of you+bike.

What XC bikes have you ridden? How were they set up? How much faster is your fat bike?

The fatty is very long

I think this could be quite important. My fatbike was also my best climbing bike (by quite some way) until I got my Cotic FlareMax. The FlareMax is heavier than the fatbike and full-suss but I’m climbing faster. Perhaps more surprisingly I’m also beating times set on other bikes that should in theory climb faster (e.g. my old Solaris). I think (but it’s no more than a hunch really) that the super long reach on the FlareMax is doing something to make it climb so well. Whether it’s my position on the bike or just that it gives me more space to breathe I don’t know.

I suspect that longer chaintays also help here, which might be something else to consider.

Are you all checking your power output when comparing these times?

Fat bike will also offer presumably more grip so you don’t need as much technique over rough stuff or loose ground.

Just race the fatty.

I’ve dabbled in building light(ish) weight XC bikes and always found them more difficult/precious to ride than my fatty or 29 plus.

OP what fat bike do you have? I have a Canyon Dude and it’s fairly long, plus I’m considering a 2nd set of wheels and running 29×3 on it.

I also have a Cannondale F29 carbon so comparing the two on climbs I’m noticeably quicker on the 29er. The fat bike is more fun and a riot on descents but the 29er is quicker everywhere else.

The FlareMax is heavier than the fatbike and full-suss but I’m climbing faster

How does your FlareMax compare (dimensionally) with your ICT RP?

I’ve dabbled in building light(ish) weight XC bikes and always found them more difficult/precious to ride than my fatty or 29 plus.

Hmm have heard this from a number of sources now

OP what fat bike do you have?

It’s a Scott Big Jon…

The fat bike is more fun and a riot on descents

..which is hard work on the descents 🙂

How does your FlareMax compare (dimensionally) with your ICT RP?

I was thinking more about my Dude (which replaced the ICT), although some of my fastest climbs were still on the ICT before I got the FlareMax. All three were size large. I guess, since we’re talking about seated climbing, ETT is a useful number. So:

ICT: 630

Dude: 642

FlareMax: 658

I used a 35mm stem and 680mm bars with all three by the way.

Interesting

Is the Cotic actually longer than your ICT and Dude or is it all in the ETT?

My Scott is 650 mm which is 35 mm more than my next-best uphill bike. The bike itself is well over 2m long

Efficiency/speed when riding uphill is simpy about power/weight.

<span style=”font-size: 0.8rem;”>If you get a lighter bike it will speed up by the difference in weight of you+bike</span>

Fat bike will also offer presumably more grip so you don’t need as much technique over rough stuff or loose ground.

There’s a limit to how much technique can help you. I can get up some of the scrabbly loose climbs near me with only a few dabs on my road bike, but it’s way slower than my heavier fatbike.

There are other climbs where it’s firm but rooty, and when you’re out of the saddle on 2.4in 29er tyres, the back wheel skips out over the bumps and you dump a load of power and momentum. Low pressure tyres just grip and drive.

On some climbs, big low pressure tyres will be offer more advantage in terms of delivering power to the ground than a few pounds less in weight or better technique.

There is a balance between tyre width, grip and overall weight.   If your fat bike is not much heavier than an XC bike but grips and rolls better up hill then you may be faster.

I was using a track bike with 25c tyres on gravel and easy single track but a few months ago moved to a heavier frame with heavier and bigger (43c) tyres, all other components remained the same and the measurements were almost exactly the same with exception of 10mm lower BB on new frame.

Bike weighs 1.5 kg more but have beaten a lot of my PRs on it (most up hill or with hills in)

Is the Cotic actually longer than your ICT and Dude or is it all in the ETT?

Wheelbase;

ICT: 1156

Dude: 1134

FlareMax: 1246

So a fair bit longer overall. Canyon don’t actually give wheelbase figures for the large Dude, but the wheelbase for the medium is 1104 in the short chainstay position (which is the one I use) and the reach on the large is 30mm more than the medium.

Ok thanks again

When I owned a fatbike (regretfully had to sell it at the time due to personal circumstances) was the Mondraker Panzer hardtail, supposedly built with ‘race geometry’, compared to my times on other bikes on the same trails, it was actually the fastest, climbed very well too despite it being rather hefty! So if you can get fatty with more of a race geometry then you’ve certainly got the best of both worlds!