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The 29Gnarr - Geniu...
 

[Closed] The 29Gnarr - Genius or insanity?

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[#3810792]

[img] [/img]

The back wheel is on backwards and driven by an Alfine chainring up in the triangle, and a chain, all on the wrong side. The cranks drive the Alfine from the normal side via a short chain. So the disk brake mount has had to switch sides.

In a nutshell: putting all the gearing gubbins in the middle of the bike.

Wow!


 
Posted : 26/03/2012 6:46 pm
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Genius! All the gear changing benefits of the Alfine without the rotating weight.


 
Posted : 26/03/2012 6:54 pm
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if you look realy hard there is someone their without a stupid hat and without a beard kids just have the hats they dont count]


 
Posted : 26/03/2012 6:57 pm
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I'm not sure the weight gain of all the 'gubbins' will outweigh the benefits of having a better centre of gravity. The rotating mass thing's a bit of a red herring IMO. But it's an excellent attempt and I applaud their efforts.


 
Posted : 26/03/2012 7:01 pm
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[img] [/img]


 
Posted : 26/03/2012 7:04 pm
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Genius! All the gear changing benefits of the Alfine without the rotating weight.

But there is no effective rotating weight; the hub is in the centre of the wheel, it's big knobbly tyres that increase rotating weight.
Nicolai put their gearbox in this position to decrease [i]sprung[/i] weight(?); having a big heavy hub on a suspended rear wheel affects handling, so putting it into the centre of the bike re-establishes front/rear balance, and the same thing is probably what is intended with this bike, having the weight somewhere around the c/g.
My take on it, anyway, I could easily be wrong, but it seems right.


 
Posted : 26/03/2012 7:05 pm
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more about weight balance for me rather than rotating.

rode an alfine shod bike once and it was strange. manualled nice, bunny hopped lack a sack of crap.


 
Posted : 26/03/2012 7:11 pm
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Countzero +1 IMO


 
Posted : 26/03/2012 7:15 pm
 Sam
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Agree with CZ on all counts - lots of extra weight for no benefit. Nice execution of a wrongheaded idea though!


 
Posted : 26/03/2012 7:16 pm
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Ted has put it here so's the weight is away from the back wheel for when its being jumped/tricked etc, makes sense when you talk to him, and he was still fabbing it at 4am on Friday morning, you've got too applaud someone like that who puts his ideas into practice.

and of course the real new niche of the show was statement mustaches 😉


 
Posted : 26/03/2012 7:18 pm
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Ive got some sketches of this idea from a few years ago !!
The difference is that I had the disk fitted to the alfine, belt drive and mine was a 26''. I was going to have it built by Descendence bike but turned out be too complex. Wish I had. Looks lovely!


 
Posted : 26/03/2012 7:24 pm
 Sam
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Fair enough Steve - that makes more sense - didn't realise that was the intended application.


 
Posted : 27/03/2012 8:00 am
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Ted ****ing rocks


 
Posted : 27/03/2012 8:11 am
 ndg
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I wasn't convinced by the 29Gnar, very heavy engineering to support the alfine, although I liked the concept. The bike for his Mum (white and yellow behind) was beautifully detailed though, as was the frame he had for his girlfriend (I think).


 
Posted : 27/03/2012 8:20 am
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Well I assume a production bike would accommodate the Alfine in the frame without all the hinge and bracket bits. Does it ride/pedal well though?


 
Posted : 27/03/2012 8:30 am
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Why not just mount the hub in an oversize / custom BB shell & drive it directly ? Would need a beefed up interface for the "crank" bearings but that could be overcome...I think... 🙂

10/10 though, I'm in aw of folk like him. Will 100% make the effort to go to the show next year.


 
Posted : 27/03/2012 8:38 am
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too much torque at the cranks for an internal geared bottom bracket.
I imagine the cost/ weight of one that was strong enough would be prohibitive.


 
Posted : 27/03/2012 8:44 am
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He made his own rear hub for that bike from scratch with lathes and drills - no cnc - disc mounts both sides. Ted really does rule. The other bike on his stand was a beautifully detailed, clean-lined town bike he made for his mum. 2 bikes - one extreme to the other. Talented guy.


 
Posted : 27/03/2012 8:53 am
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I listened to Ted talking about some of the detail of the bike behind in that picture. Some of it was genius. Top bloke and a true engineer.


 
Posted : 27/03/2012 8:56 am
 ton
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looks terrible really tho dont it?


 
Posted : 27/03/2012 8:58 am
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and it's now 7 inches higher than the hub.


 
Posted : 27/03/2012 9:12 am
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Would an EBB be a better way to tension the chainring-Alfine chain, and have a fixed Alfine rather than a sliding bracket?


 
Posted : 27/03/2012 9:37 am
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I thought he had engineered a very clever and involved solution for a problem that only sort of exists.

For that I applaud him and his bike! 😀
Up with this sort of thing.


 
Posted : 27/03/2012 9:38 am
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To be honest, it's been done many times before. Google Rohloff hub as gearbox to see plenty of examples. Typically with FS bikes, where the hub tends to be hidden or better integrated into the frame.

I don't think it works with simple Ti tube profiles, personally. And I have an Alfine bike.


 
Posted : 27/03/2012 9:43 am
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I love stuff like this, in any discipline. It's exploring the potentiality of a bike design rather than saying this is the way to do it. It's not mainstream and does not profess to be. Good work chap.


 
Posted : 27/03/2012 10:04 am
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Looks good imo, would like to see a closer look at in person. Couple more pics over on [url= http://bikemagic.com/gear/bespoked-bristol-2012-curtis-engima-29-gnar-qoroz-mawis-and-more.html ]bike magic[/url] I see


 
Posted : 27/03/2012 10:06 am
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The back wheel is on backwards and driven by an Alfine chainring up in the triangle, and a chain, all on the wrong side. The cranks drive the Alfine from the normal side via a short chain. So the disk brake mount has had to switch sides.

Forgive me for possibly being a bit clueless on this, but wouldn't it have been a shitload less faffing about to just put the crank on the other side?


 
Posted : 27/03/2012 10:07 am
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Forgive me for possibly being a bit clueless on this, but wouldn't it have been a shitload less faffing about to just put the crank on the other side?

Only if you don't mind your pedals unscrewing 🙂


 
Posted : 27/03/2012 10:11 am
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Its nothing new though is it?

Nicolai G-Boxx (the original was based on a (ohloff Speedhub) has the drive on the left, and the chain on the right.
The Zerode has a Alfine hub mounted above the BB (with more conventional chain on the right)
The Pinion is even available for hardtails...

Don't get me wrong, I think frame mounted gear-boxes are great, centreing the weight etc. And basing it on exisiting mass-produced equpiment will keep costs down. BUT, the Alfine (and original Rohloff-based G-Boxx) were designed for hub use so use epicyclic gears, so its not perfect.

Pinion is by far the best idea as its designed specifically for a purpose. And its cheaper then the G-Boxx. (still bloomin' pricey though)


 
Posted : 27/03/2012 10:15 am
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Forgive me for possibly being a bit clueless on this, but wouldn't it have been a shitload less faffing about to just put the crank on the other side?

Only if you don't mind your pedals unscrewing

Tandem cranks?


 
Posted : 27/03/2012 10:16 am
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Nicolai G-Boxx (the original was based on a (ohloff Speedhub) has the drive on the left, and the chain on the right.

Riding alongside someone with a Nicolai gearbox bike is odd, because the left-hand chain keeps moving when they freewheel; always seems really strange.


 
Posted : 27/03/2012 10:18 am
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In fact, why did Ted make his own hub? Why not use a fixed hub, and benefit from the freewheel integrated into the Alfine (like the G-Boxx)?


 
Posted : 27/03/2012 10:19 am
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In fact, why did Ted make his own hub?

Because he can? 🙂

I think the hub is fixed; the description I read seemed to be saying it effectively had a 6-bolt disk mount on each side. Sure that a fixed-disk hub would have worked the same though? Maybe there's potentially more force through the sprocket because of the gearing, so it needed a bolt-on sprocket?


 
Posted : 27/03/2012 10:22 am
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Dear god! WTF is wrong with you people? Would you like a shit-load of pointless, unsightly gubbins bunging up your frame, getting in the way, and being ground away by peak district mud?

Or ... OR.... how about this revolutionary concept....

[img] [/img]

I know its going out on a limb, but I reckon it just might work 😉


 
Posted : 27/03/2012 10:25 am
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You mean a slightly different bit of unsightly gubbins, in a more vulnerable location? 🙂


 
Posted : 27/03/2012 10:28 am
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being ground away by peak district mud

ah, 'cos derraileurs don't just hang off the side of the bike, hitting rocks, getting ground up with gritstone grinding paste. But fully-sealed hub gears, especially ones mounted up in the frame are just daft for those conditions?

😉


 
Posted : 27/03/2012 10:29 am
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Look where all that gubbins is though. Directly in line with all the crap being sprayed off the back tyre. Can you imagine what a peak district winter would do to that lot?

You can tell its been designed by someone who lives in a place where it never rains 🙂


 
Posted : 27/03/2012 10:31 am
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mudguards? And besides, why should it be worse when its on the frame compared to in the wheel? Stop being a naysayer and pissing on new ideas.

Back to my orignal thougts. Nicolai rear hub is suitably mental:

[img] [/img]


 
Posted : 27/03/2012 10:34 am
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So add a full set of mudguards to that lot?

This bikes sure going to be a looker 😯


 
Posted : 27/03/2012 10:40 am
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that does indeed look like a solution in search of a problem. Also not very aesthetically pleasing...

BUT good on him for trying it out - you never know might lead to a breakthough


 
Posted : 27/03/2012 10:40 am
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It does seem like a mildly complicated answer to a problem that doesn't really exist. Got an Alfine'd bike and whilst it might feel slightly different I can't say it holds me back - but I use it as a wheels on the ground mud plugger and I'm a big enough lad to muscle it around. The faff of tensioning 2 chains and extra components to wear does not seem worth the hassle.

You long baggies wearers are also surely going to catch the hem in that upper chain/sprocket interface?


 
Posted : 27/03/2012 10:46 am
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This is one of my old bikes... ideas deserve to be tried.

[img] [/img]


 
Posted : 27/03/2012 10:49 am
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does an alfine hub really weigh more than a XT cassette, hub and derailleur?


 
Posted : 27/03/2012 10:50 am
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Getting the gears to fit into an EBB or similar would be genius .Using a cassette system so it can be slide out to service it


 
Posted : 27/03/2012 11:02 am
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does an alfine hub really weigh more than a XT cassette, hub and derailleur?

yes, claimed weight is 1590g, tested weight is 1700g+ (that's the 11spd - 8spd more). XT components come to around 1000g.


 
Posted : 27/03/2012 11:06 am
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