April 11th, 2006
Is it 69 or 96?
It seems no-one in the bike world can agree on the name of 26/29er hybrids, they’re variously called 69er or 96ers. The one thing they do all have in common* is a 29″ front wheel and a 26″ rear. To me that makes ‘em all 96ers.
They bring to mind all those junkyard bikes we’d build as kids, with whatever wheels and forks we could lay our hands on, sticking 24″ front wheels and forks into Raleigh Choppers for an even more rakish look.
But my initial thoughts on this bastardised hydra are:
- The claims that 29er rear wheels are easier to pedal for a given gearing development than a 26er are being tossed aside. Bad.
- 29er steering is seen by some as an issue, (though 29ers do steer better than people think), and it’s still an issue. Bad.
- The front of the bike is still waaay up there in the air. Bad.
- It’s not uncommon for the 96er to have front suspension too. Isn’t the 29er front wheel supposed to remove the need for suspension? Illogical, or an admission that the 29er isn’t so hot.
- Rear wheels tend to ride over stuff you’ve cleared with the front anyway, so 26″ at the rear is not an issue for tracking/overcoming obstacles. Good.
- The comfort advantages of a 29er at the rear are lost. Bad.
- 29er tyres offer a larger contact patch, so offer more grip. This is lost with the 26er rear. Bad.
- Better grip at the front. Good.
I’m wondering now about a “proper” 69er. By which I mean a 26″ wheel at the front 29″ wheel at the back.
- No 29er steering issues at the front. Good.
- The bars can be kept low without the need for silly short headtube (eek) or inverted stem. This means better standover. Good.
- Not so efficient as a 29er at the front, no smoothly rolling over stuff. Bad.
- The whole range of front suspension now becomes available. Good.
- 29er at the rear gives the comfort benefits of smoother rolling without the weight of suspension. Good.
- 29er grip at the rear. Good.
- 26er grip at the front. Bad.
Intuition right now tells me that maybe, just maybe, we need to tip current 96er logic on it’s head. More thinking is required, and I reserve the right to change my mind, or even be swayed.
But this is where the importance of names comes in. Once this idea is out in the mainstream we can use the 69er to exclusively mean bikes with a 26er front/29er rear, and 96er exclusively for bikes with a 29er front/26er rear.
Now, who’s got the address of Gary Fishers patent attorney? I have an invention to file.
*Someone might have done it the other way round, but my half-arsed web searches have failed to reveal any deviation from this standard.
![[Valid RSS]](http://32sixteen.com/wp-content/themes/three_column/images/valid-rss.png "Validate my RSS feed")
del.icio.us
April 11th, 2006 at 6:59 pm
years back I had one of those Cannondales with the 24 inch wheel in the back and a 26 inch wheel in the front
have been wanting to make a project bike with an old mountain frame
a 26 incher in the back
and
a 29er in the front
I have everything other than the spare disc brakes
well…
I do not really have a spare front wheel
okay
I don’t have squat more than an idea
patent pending
April 11th, 2006 at 7:46 pm
I’ve just built and test ridden a 69er. It was rubbish.
http://www.simonbarnes.net/tmp/69er.jpg
April 11th, 2006 at 8:43 pm
LOL at Simon, but that’s hardly a 29er fat tyre on the back is it?
April 12th, 2006 at 1:23 am
“The one thing they do all have in common* is a 29″ front wheel and a 26″ rear. To me that makes ‘em all 96ers.”
Ah, but 96er doesn’t carry the sexual currency that 69er does, now, does it? At least, not in the states.
April 13th, 2006 at 8:22 am
Well that’s another reason to adopt a true 69er - it addresses these guys sexual inadequacies :)
April 13th, 2006 at 11:46 am
Just to confuse matters….
I’ve got a 60er (26 front 20 rear) on the full susp kiddy seat bike. The small back wheel allows a low c of g kid seat plus clearance for 5″ of suspension. Apart from draggy rutted grass fields, you really can’t notice any of the supposed issues with rolling resistance and the tiny back wheel. But is it just masses of suspension travel masking the problem??
April 16th, 2006 at 9:25 pm
Yeah, I saw that. The evidence from Dave Harris suggests that suspension can compensate.
It was certainly the reasoning of Issigonis and Moulton when designing the Mini.
Paradoxically Boulanger, who had a design brief to build a car that could drive across a ploughed field without breaking a tray of eggs, used big wheels and lots of suspension in his design for the 2CV.
April 19th, 2006 at 8:29 pm
[…] Gary Fisher watch out. Simon and Nick have a cunning plan. Quite why the bearded old hippy didn’t think of it first I don’t know. Clear demonstration of Britain leading innovation. Nick has the arguments. From: Tyrrell Subject: Virus Warning - Please Read Warning! There is a dangerous virus going around. It is called WORK. […]
April 20th, 2006 at 12:14 pm
I disagree mstly with 2 points.
“The claims that 29er rear wheels are easier to pedal for a given gearing development than a 26er are being tossed aside. Bad.”
It’s just a claim. Gearing is changed, you don’t all at once go 10% faster, just pedal slower with the same gear ratio.
“The front of the bike is still waaay up there in the air. Bad.”
While it’s true, why do most 26″ bikes come with riser bars? Looks to me that for most they’re actually too low. with riser bars you can’t properly move your hands inwards. With a flipped riser bars, suppose the front end was way too tall for you, that is actually a were agreeable aero or climbing position. I use a flipped Mary bar on one bike, it rocks.
Overall, I agree that is you MUST mix 26″ and 29″ wheels in one bike, a large one in the back is best. The argument that you need a (bad) longer chainstay length to fit it is rubbish, as 26″ bikes in all sizes all get the same CSL. For short riders almost a third their body, for tall ones just over a 5th.
People complain about weaker (especially rear) 29″ wheels, and it’s true. However, add 20g for 4 extra spokes, and the difference is more than overcome. And why, if you have long chainstays anyways, not beef up the rear hub? 135mm has never been consider “wide”. DH bikes like them wider, so why not for 29″? Wider flange spacing makes for a stiffer more durable wheel, and it costs nothing but a couple grams.
Since 60-70% of the weight leans on the rear wheel, 80-90% when climbing, for rolling resistance that’s the best place to stick the larger one, which rolls better. Unfortunately the fastest 29″ tires are not on par with the ultimately fastest 26″ ones yet, due to different technology used. This will change within a year, the last reason for a small rear wheel gone.
Carver claims the 26″ rear wheel makes for more snappy acceleration that a true 29″ bike. If you do the math, it makes for a 150g weight reduction. With a 10kg bike and 65kg racer boy rider, worth 1/500th or 0.2%. Pretty huge, obviously, especially if you consider that rotation mass only gets up to twice as heavy under fierce acceleration. The weight savings can’t make up for the rolling resistance loss, but Carver claims it makes a difference, as do some reviewers. I wonder if they could tell the 150g difference in a blind drag race, rear wheel all boxed in, but weight difference still coming from the rear wheel only.
I rode my 29″ bike (2.35″ schwalbe slicks) with 3.5 litres (3.5kg, 8lb) of water in the rear tube, to see how much a difference that would be. Surprise : I actually felt it, but riders that rode next to me didn’t notice a difference in my acceleration. And then to think that the 26 vs 29″ rear wheel debate is just about 1/24th of the weight I added. 1/12th if looking at 26/26 vs 29/29.
My heartrates and speeds were the same as always, I just spent a bit more metres out of the saddle after a traffic light. It handled a bit funny, all that water sloshing around with speed changes.
But considering the weight I added, similar to doubling my wheelsize to 58″, the effect of weight was neglegible.
One reason to use a small rear wheel I could see is if you spend lots of time hanging behind your seat on downhills, using the rear wheel as toilet paper. 29″ will allow for less freedom of movement, especially if you’re short. Then, a 29″er has such a better endo factor, that you may just ride everything down, bum on or above the seat where it belongs.
It’s fun to put a rigid 29″ front in a 26″ hardtail (I did it before I got my 29/29″ fix, and liked it to 26/26 rigid), but UTTERLY POINTLESS as a concept for a new XC bike. The few reasons that are valid for such a setup, are not used in marketing.
April 20th, 2006 at 1:10 pm
LMFAO at the water filled tube.
April 20th, 2006 at 1:24 pm
Those claims about wheels rolling further per pedal revolution aren’t mine, indeed I’ve stated my opinion that they are nonsense in the past.
With low front ends those of us who like flat bars can build a low front end. Those who prefer a taller front can add risers. Keeping the front end reasonably low is presumably why 29ers such as the Rig have such short headtubes. And those most definitely are bad. Using a reasonable length headtube and inverting risers is a bad idea because:
1) risers aren’t designed to take the loads in that direction, and
2) for schure it looks like something the Germans would do.
Endo Factor is not a result of wheel size, it’s purely a case of how far behind the front tyre contact patch your centre-of-gravity sits. The only way a 29er can be less likely to endo is by putting you further behind that point. Don’t be misled by believing everything Jobst Brandt writes about braking forces, he has basic flaws in his writings that should have been picked up by a proper peer review.
Oh, and filling your tyres with water - that’s just taking it waaay too seriously :-)
May 2nd, 2006 at 1:49 pm
Others are picking up on the debate.
March 2nd, 2007 at 1:35 pm
[…] to a 69er (26″ front/29″ rear) Brant at On-One has weighed in along the same lines as I posted a long long time ago. From a physics point of view, this theory here would make no odds if it was a 29er front, 26in […]