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

[Mike Muz]

As part of my work I also enjoy thinking way outside the box. Let me throw this one to the people with more knowledge and experience of bike and riding 29ers: What is it that makes the 29.0 inch wheel the perfect size for obtaining the benefits of larger wheels, and bottom bracket height)? Surely if 29ers give much better speed, why not go to 30" wheels to get even more of the same benefits? I don't doubt that people's experiences with 29ers are very real, but it strikes me that the marketing people have simply plucked the number 29 out of thin air.

And if even short riders can handle riding 29ers, wouldn't/shouldn't super tall riders like me be able to handle 30-31" wheeled MTBs? How cool would that be ...

29ers came about in much the same way as 26ers, using what was available at the time. 29" is the same size as 700c and at the start these rim were used in lieu of any purpose built jobs. * In the late 90's Wes Williets (or maybe Don Walker) was convinced that the bigger wheel size had benefits and set about trying to get the first 29er tyre made, eventually with the help of Gary Fisher WTB produced a tyre and set the ball rolling. 29er have been around for quiite a while now and it might be a surprise to some to know that they were not born out of an evil corporate emperors new clothes type initiative.



*I've not looked checked this for this post but its along these lines, the main players are correct though.

Indeed, like my 2002 Fisher

 

[kaiser]

Re:

36er for those interested, I saw one at SSWC and it did look a lot of fun but indeed a bit of a handful.

[youtube]https://www.youtube.com/watch?v=fYt6IqaHk_Q[/youtube]

 

[kaiser]

Re:

And FWIW Kirk Pacenti has been convinced of the merits of 650B and has been making rims for years.

 

[Mike Muz]

Re: Re:

36er for those interested, I saw one at SSWC and it did look a lot of fun but indeed a bit of a handful.

[youtube]https://www.youtube.com/watch?v=fYt6IqaHk_Q[/youtube]

I have to say, I do like that frame design. Pity they can't be done in 26" frame size. Seatposts just don't come long enough
And if the seat tube was longer, it would need bracing, which would spoil the looks IMO.

Mike

 

[GrahamJohnWallace]

29ers came about in much the same way as 26ers, using what was available at the time. 29" is the same size as 700c and at the start these rim were used in lieu of any purpose built jobs. * In the late 90's Wes Williets (or maybe Don Walker) was convinced that the bigger wheel size had benefits and set about trying to get the first 29er tyre made, eventually with the help of Gary Fisher WTB produced a tyre and set the ball rolling. 29er have been around for quiite a while now and it might be a surprise to some to know that they were not born out of an evil corporate emperors new clothes type initiative.

*I've not looked checked this for this post but its along these lines, the main players are correct though.

This, written by Joe Breeze for the 2011 San Francisco Airport MTB history exhibition, alludes to the English/Finnish connection.

There is a concept in Chaos Theory known as the 'Butterfly Effect'.

" The name of the effect, coined by Edward Lorenz, is derived from the theoretical example of the details of a hurricane (exact time of formation, exact path taken) being influenced by minor perturbations equating to the flapping of the wings of a distant butterfly several weeks earlier."

What if Geoff Apps had not exported a few hundred Finnish 700x47c Hakkapeliitta snow tyres to Gary Fisher and Charlie Kelly in the early 1980s?

Maybe without those tyres we wouldn't have 29ers today?

This is how the logic goes:

*If Geoff Apps had not exported the tyres then Bruce Gordon would not have been able to build bikes using them.

*When the tyres ran out in 1988, Gordon would not have had copies made so he could carry on producing his 700c 'Rock 'n' Road' bikes.

*And Wes Williams could not have made his bikes using the Bruce Gordon Hakkapeliitta copies.

*Gary fisher would have been less likely to be persuaded to fund the development of the NanoRaptor tyre by Williams, if he did not have prior experience of using large diameter Hakkapeliitta tyres suplied by Apps.

And Fisher may not have spent so much time and money developing 29er bikes if if he had not had the positive racing experiences whilst using Hakkapeliittas in the 1980s.

 

[kaiser]

Re:

Wes Willets = Wes Williams, and Don Walker was totally wrong it was Bruce Gordon I was thinking of.

 

[GrahamJohnWallace]

Re: Re:

Hmmm. Very interesting but 'leaning as hard as i can' seems to me not very scientific.
What you really need to do is to spill some paint on the floor, pump all the tyres up to a useable 30psi, then carefully put the bike on the paint to show up the real world footprint.
And where are fat bikes in the equation? I think they are around 29" when fitted with their massive tyres. They are run at far lower pressures though, so put around 8psi in those.
Finally, it looks like you need a longer chain, sunshine.

Mike

The maths for of the area of any tyre footprint is to take the weight (in say lbs) on a wheel and divide it by the Pounds per Square Inch(PSI) of the internal air pressure .
For example: 100lbs weight at 10PSI would give a contact patch of 10 square inches. This would be the same whatever the tyre size.

So the idea that bigger diameter wheels run at the same pressure have larger contact areas and more traction than small wheels, is a myth.

All tyres with the same air pressure will all have the same contact area, regardless of tyre width or wheel radius. So a Fatbike at 20PSI will have the same contact area as any other bike using 20PSI. Though the Fatbike contact patch will be wider and shorter than that of a standard mountain bike.

It is this ratio of constant contact area to varying tyre circumference and total volume of air, that produces the variations in contact patch to rim distance shown in my earlier photographs.

 

[PurpleFrog]

Something no one has mentioned is that adult bmx bikes are 20-24 inch - with the smaller wheel size being the one favoured for agility. Wheel size is a trade-off: if go bigger, you lose agility - there's no free lunch to be had.

As for super fat with terrific volume, the problem is that tyre technology is limited and the life of an mtb tyre is hard (especially with wookie on top of the bike.) So you reach a point where a high volume tyre needs extra reinforcement, and this decreases carcass suppleness, which increases rolling resistance. Which is fat bikes are not uber bikes.

However, the technology is advancing all the time; the Almotion semi-slicks I've been raving about take my Zkr up to 650b outer diameters and are insanely low rolling resistance. It's quite possible that one day the White Coats at Schwalbe or Conti will come up with a tough, low RR 4" wide tyre. At which point it will be back to 26. Or even down to 24.

 

[JamesM]

Re: Re:

Hmmm. Very interesting but 'leaning as hard as i can' seems to me not very scientific.
What you really need to do is to spill some paint on the floor, pump all the tyres up to a useable 30psi, then carefully put the bike on the paint to show up the real world footprint.
And where are fat bikes in the equation? I think they are around 29" when fitted with their massive tyres. They are run at far lower pressures though, so put around 8psi in those.
Finally, it looks like you need a longer chain, sunshine.

Mike

The maths for of the area of any tyre footprint is to take the weight (in say lbs) on a wheel and divide it by the Pounds per Square Inch(PSI) of the internal air pressure .
For example: 100lbs weight at 10PSI would give a contact patch of 10 square inches. This would be the same whatever the tyre size.

So the idea that bigger diameter wheels run at the same pressure have larger contact areas and more traction than small wheels, is a myth.

All tyres with the same air pressure will all have the same contact area, regardless of tyre width or wheel radius. So a Fatbike at 20PSI will have the same contact area as any other bike using 20PSI. Though the Fatbike contact patch will be wider and shorter than that of a standard mountain bike.

It is this ratio of constant contact area to varying tyre circumference and total volume of air, that produces the variations in contact patch to rim distance shown in my earlier photographs.

How about the fact that the tyre will sink a little way into the soft ground? Not all of the contact patch may be load bearing and so a tire with a larger diameter and hence a flatter arc may contact more of the soft ground?

 

[PurpleFrog]

Re: Re:

How about the fact that the tyre will sink a little way into the soft ground? Not all of the contact patch may be load bearing and so a tire with a larger diameter and hence a flatter arc may contact more of the soft ground?

Why would digging in stop a part of the cp from being load bearing? If it's in contact, it will bear load.

Also, a large diameter tyre with the same cp will probably dig in more not less - the cross section is narrower, so it's a more effective "drilling" tool. This would be good or bad depending on a lot of stuff..