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[Closed] 26 -> 29 Tarmac Speed Question

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[#4440273]

Right I understand there will be many variables so I am not looking for scientific evidence, just an opinion from anyone that has made the change.

My situation;
A lot of my riding for the foreseeable future will be 50% tarmac 50% woods/tow paths etc, due to my location. I will still be going on the odd trip to trail centres as its my favourite part of MTBing.

I current own a pretty lightweight 26" carbon FS, probably about 25lbs. I have a monorail/advantage tyre combo, so fairly low profile.

Now to my question (if your still with me), will there be any perceivable speed increase in a change to a slightly lighter 29er hardtail, with lowprofile tyres, somelike like SB8 front and back?

Thanks in advance, any opinions taken on board.


 
Posted : 08/10/2012 10:06 pm
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Buy a disc cx bike....16.4567392635% faster-FACT.


 
Posted : 08/10/2012 10:08 pm
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I should've included that im not interested in a CX bike, my fault, forgiveness please.


 
Posted : 08/10/2012 10:09 pm
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A lack of interest in cx...unforgivable.
How about a 29er with really skinny tyres and dropbars?


 
Posted : 08/10/2012 10:11 pm
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Can you lock the FS out when pedaling?

If no then there will be an efficiency increase going hard tail I would imagine. I would also say the bigger 29 wheel would hold its momentum better making it easier for you to maintain a speed on the flat black stuff.


 
Posted : 08/10/2012 10:13 pm
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Sorry Rorschach maybe one day, only room for one bike at the mo.

Yeah the front and rear remain locked for any tarmac sections.


 
Posted : 08/10/2012 10:19 pm
 mboy
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From 26--->29 on road, like for like there will be a small advantage in rolling resistance. But it will be small.

Biggest advantage will come from the tyre tread patterns, or lack thereof. You'd be better off spending £50 on a decent set of the baldest tyres you can get away with still being able to ride offroad too, for your current MTB, than you would chopping it in and buying a 29er and losing a load of money in the deal.

That said, if you want a 29er anyway, don't let anyone stop you!


 
Posted : 08/10/2012 10:35 pm
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Well mboy, i'm in two minds. On the one hand, cheap and probably nearly as effective, on the other hand, shiny shiny.


 
Posted : 08/10/2012 10:43 pm
 mboy
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Ok then, well seeing as I work in a bike shop...

"You obviously need a new bike sir, and it sounds like you need a 29er. And you don't want that cheap tat over there, look over here at the Carbon Fibre XTR loveliness of this one, a mere snip at £4k!"

Or words to that effect... 😉


 
Posted : 08/10/2012 10:46 pm
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On Tarmac, assuming the same tyres, wheel size doesn't matter. Recumbents, Moultons etc have much smaller wheels, yet are faster than conventional racing bikes.


 
Posted : 08/10/2012 10:51 pm
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I went from a Boardman 26er to a Cannondale 29er and I am faster over everything on the 29er, with no noticeable downsides. All this stuff about higher inertia in the wheels, less maneuverability and all the other 29er downsides stuff you read is all either nonsense or not noticeable to the vast majority of us, and bigger wheels will always roll better than smaller ones. If you want a one bike for everything, then I would advocate the larger wheel. I'm not dissing 26ers, I'm not a better rider on the 29er and my riding mates on 26ers are all still better riders than me, but I am quicker than before for sure.


 
Posted : 09/10/2012 8:16 am
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yup everything else being equal bar wheel size

speed would be a function of input effort not wheel size.

you may accelerate a bit slower though

are you spinning out 44:11 on the flats - if you are it will make your gearing a little taller and your spin out will be faster.


 
Posted : 09/10/2012 8:20 am
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Just get a 29'er and stop thinking of excuses not to have one


 
Posted : 09/10/2012 8:24 am
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Same input effort applied to a larger wheel will result in a higher speed assuming gearing is the same. But importantly they roll over things better which is more likely the reason for the increase in speed that I've noticed. Lower rolling resistance.


 
Posted : 09/10/2012 10:59 am
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Recumbents, Moultons etc have much smaller wheels, yet are faster than conventional racing bikes.

I though it was the reduced frontal area that gave recumbents an advantage ?

Anyway, [half remembered fact] didn't someone have a go at racing a small wheeled Moulton type bike once and it got banned because it was faster than traditional bikes ? [/half remembered fact]
Strangely enough, I don't think it was Graham Obree either.


 
Posted : 09/10/2012 11:09 am
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My local riding is 50/50 on and off road and the biggest difference I've noticed since getting a 29er ht is there's less compromise between the Tyres, they roll well on road like semi nobbly 26 Tyres but still work well in the slop off road..
On my 26er I always wanted either better mud Tyres off road or slicker Tyres on road.
I'm not finding this on the 29er which seems happy to do either..


 
Posted : 09/10/2012 11:18 am
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Rolling resistance - no idea, probably very little in it.

However I found with my 29er that I just couldn't pedal it over about 30km/h on the flat as the wind resistance was like hitting a brick wall. On my 26er with similar spec and tyres, I can get it to about 36km/h. This and the fact that 29 er tyres get so heavy when full of mud made my 29er quite a bit slower than my 26er for the sort of riding I thought it would be good for (bridleways, byways and road sections).


 
Posted : 09/10/2012 12:00 pm
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Interesting - for me it was the opposite! I swapped from a lightweight carbon FS 26 to HT 29 earlier this year for MTBO + trailquest competitions - ie I was considering the same things - on/off road speed etc. 29 HT has been everything I hoped for - way quicker on the roads, especially on climbs (ie locked out FS still had flex in the rear triangle + I can now run slicker tyres on the 29er) + better off road on the majority of terrain.

If you're riding style at trail centres involves pumping the bike to get some air whenever you can though, then stick with the 26 FS - as you'll lose much of that with a 29 HT - if you're a ground lover, get the 29er + it'll smooth out the trail.

Tyre wise, at the Polaris I ran a Schwalbe Sam back + Ralph front - ie more road orientated - I've now put Ralph on back, Maxxis Beaver front for an MTBO this w/e - woodland trails, fire road climbs, little bit of tarmac. Both have been good combos - hope that helps a bit!


 
Posted : 09/10/2012 12:46 pm
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Worth just getting a pair of 29er wheels and fitting some roadie/cx-ish tyres on - they'll fit on a normal 26er (assuming disk brakes of course!).


 
Posted : 09/10/2012 1:24 pm
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Worth just getting a pair of 29er wheels and fitting some roadie/cx-ish tyres on - they'll fit on a normal 26er (assuming disk brakes of course!).

+1, the cheepest/fastest option.

If you're riding style at trail centres involves pumping the bike to get some air whenever you can though, then stick with the 26 FS - as you'll lose much of that with a 29 HT - if you're a ground lover, get the 29er + it'll smooth out the trail.

-1, The difference between 26" and 29ers isn't that much, compared to the jump from 20"-26" anyway. And it depends how you ride trail centers, unless you're doign Bubba Scrubs over every jump the inertia of the wheels is pretty irelavent to riding/jumping in a straight line. My only downside is the 29er feels slower (it's not, it's very definately faster, just less perception of speed) so you have to pedal harder and go even faster again to get the same "whoooaaaaa this is quick" buzz (or buy a BMX and take it down a trail center, small wheels + brakes for decorative effect only = epic riding buzz).


 
Posted : 09/10/2012 2:58 pm
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robowns - Member
I should've included that im not interested in a CX bike, my fault, forgiveness please.

forgiveness granted - cxers are for indecisive/fence-sitter type people. 🙂


 
Posted : 09/10/2012 3:09 pm