Just built a 29'er. Will I ever ride on 26" wheels again?

[02gf74]

Recently published?

Surely this goes back to newton.

Rearrange p = f / a

So the patch is the same for same weight and same air pressure.

 

[PurpleFrog]

Re: Re:

Really? Mondraker bikes are selling as well as anything with their forward geometry and they are widely "acclaimed" to be really ugly.

"Acclaimed" is correct: the Mondrakers look like the bicycle version of the Dropship from Aliens. This is a great look to sell MTBs.

 

[GrahamJohnWallace]

Recently published?

Surely this goes back to newton.

Rearrange p = f / a

So the patch is the same for same weight and same air pressure.

The research that I referred to is this allegedly real world research that has been widely distributed by Bike Radar.
http://www.bikeradar.com/gear/article/b ... ths-29245/

Judging by the lack of detail, his is no doubt a journalists summary of the research. More pseudoscience for the purposes of cycle industry marketing than anything meaningful.

The article is full of generalisations and. inconsistencies. How much faster do "29er mountain bikes roll"? a lot or an insignificant amount? And does a rolling road reproduce real world trail conditions? etc.

Here is a quote from it:
"Larger diameter wheels roll faster than smaller ones: Yep, it's now been confirmed in the lab – 29er mountain bikes roll faster than 26ers. Wheel Energy say the effect here is similar to that of tire width, in that larger-diameter tires exhibit less casing deflection and thus less energy loss. In the case of 29ers, there's the additional factor of the 29in wheels' lower angle of attack for anything other than a perfectly smooth ground surface".

"The longer effective lever requires less energy to overcome whatever tire bulge exists at the contact patch so more forward momentum is maintained. In addition, Wheel Energy's analyses of tire contact patch have confirmed that 29in tires don't have a bigger footprint than otherwise identical 26in ones. While the total area is the same, the shape of the patch is longer and narrower on 29ers, though".

 

[PurpleFrog]

Recently published?

Surely this goes back to newton.

Rearrange p = f / a

So the patch is the same for same weight and same air pressure.

The research that I referred to is this allegedly real world research that has been widely distributed by Bike Radar.
http://www.bikeradar.com/gear/article/b ... ths-29245/

Judging by the lack of detail, his is no doubt a journalists summary of the research. More pseudoscience for the purposes of cycle industry marketing than anything meaningful.

The article is full of generalisations and. inconsistencies. How much faster do "29er mountain bikes roll"? a lot or an insignificant amount? And does a rolling road reproduce real world trail conditions? etc.

Here is a quote from it:
"Larger diameter wheels roll faster than smaller ones: Yep, it's now been confirmed in the lab – 29er mountain bikes roll faster than 26ers. Wheel Energy say the effect here is similar to that of tire width, in that larger-diameter tires exhibit less casing deflection and thus less energy loss. In the case of 29ers, there's the additional factor of the 29in wheels' lower angle of attack for anything other than a perfectly smooth ground surface".

"The longer effective lever requires less energy to overcome whatever tire bulge exists at the contact patch so more forward momentum is maintained. In addition, Wheel Energy's analyses of tire contact patch have confirmed that 29in tires don't have a bigger footprint than otherwise identical 26in ones. While the total area is the same, the shape of the patch is longer and narrower on 29ers, though".

Wheel Energy's tests may well be junk - roll tests, which do measure real world RR, diverge significantly from the rolling drum tests WE use.

And, as usual, Bike Radar is cretinous. Theory says that a 29er should roll better than a 26 - but it also says that the **size** of the difference, simply measured at a single wheel, is pathetically small. It's the size of the difference that BR needed to report and, of course, did not.

 

[GrahamJohnWallace]

http://www.bikeradar.com/gear/article/b ... ths-29245/
"Larger diameter wheels roll faster than smaller ones: Yep, it's now been confirmed in the lab – 29er mountain bikes roll faster than 26ers....

And, as usual, Bike Radar is cretinous. Theory says that a 29er should roll better than a 26 - but it also says that the **size** of the difference, simply measured at a single wheel, is pathetically small. It's the size of the difference that BR needed to report and, of course, did not.

We need to be careful with terminology here. "Larger diameter wheels roll faster than smaller ones" as used by Bike Radar implies that you will always go faster with 29" wheels. Which would mean that 29er wheels would be dominant mountain bike racing.

The term "roll smoother" or "roll better" implies that they absorb more vibration and so feel smoother, and whilst this may in certain circumstances allow a bike to go faster, in other circumstances may slow it down due to increases in rolling resistance or pedaling induced
'bobbing' of the tyres.

It is this roll better/roll smoother sensation that I am finding some evidence for. We are talking about a roughly 10% smoother ride from a 29er when compared to a 26er with the same width of tyres. This is due to the 10% larger air volume of the 29" tyres.

An interesting thing that I observe whilst messing around with different wheel sizes is that smaller tyres look much flatter than bigger diameter ones set at the identical pressure and carrying the same load. Therefore, it appears that you can have a 10% more softly sprung 29er tyre that is paradoxically less likely to bottom out against the rim than 26" one.

And whilst the lower 'contact patch to air volume ratio' of the 29er, predicts a slight benefit of this nature, the observed effects in real tyres appear to be significantly larger.

 

[JamesM]

Re:

It's an undisputed fact that 26ers are more fun to ride than 29ers and if you consider that 'time flies when your having fun', whilst the 29er may get you where you are going sooner the 26er will seemingly get you there earlier. However, when you arrive on the 26 you'll be further into the future so more people will point at your tiny wheels and laugh and if you get a puncture your chances of being able to buy a new inner tube will also have been greatly reduced, and that sucks!!!

 

[Mike Muz]

Re: Re:

It's an undisputed fact that 26ers are more fun to ride than 29ers and if you consider that 'time flies when your having fun', whilst the 29er may get you where you are going sooner the 26er will seemingly get you there earlier. However, when you arrive on the 26 you'll be further into the future so more people will point at your tiny wheels and laugh and if you get a puncture your chances of being able to buy a new inner tube will also have been greatly reduced, and that sucks!!!

Either A) Carry a spare , or B) Run tubeless.

Of course , it's also quicker to find the puncture in a likkle tube than a BIG 29er tube, should both be tubed up, so to speak

Mike

 

[PurpleFrog]

We need to be careful with terminology here.

We would if the article was worth discussing; as usual for BR it isn't...

 

[kleinalpine]

Re:

I decided to give this 29er thing a go , 10 rides in and I've sold my bike to go 650b . Shocking ride characteristics on a 29er. If you like riding wagon wheels that don't turn then give it a shot.

 

[Mike Muz]

Re: Re:

I decided to give this 29er thing a go , 10 rides in and I've sold my bike to go 650b . Shocking ride characteristics on a 29er. If you like riding wagon wheels that don't turn then give it a shot.

I can see where you've gone wrong there mate.

Marshmallow doesn't have the shock absorbency the marketing people would have you believe, the biscuit strengthening just crumbles and the chocolate melts just loooking at brake pads/the Sun

Mike