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Discussion Starter · #1 ·
Hi! I just have finished my work on custom titanium 2XL fatbike and will be happy to hear your opinion!)) So, tires are Vee 2XL 5.05" on 100mm Surly Clown Shoe rims. The frame has offset to achieve good clearances and to make it possible to use all range of the cassette. By the way the cassette is 11sp 11-42 and the crankset is Race Face Turbine direct mount 32T. Tire-chain clearance is 13mm on the biggest rear chainring and front chainring turned outwards. Tire-stays clearances are not less than 15mm. Chainstay length is 455mm (I can post the frame geo if there will be any interest).Dropouts on the frame and fork for throu axles were made in house on CNC milling machine. The plate on the drive side is also made on this machine)) Gold-blue welds are special made as a gift for the customer))) The whole bike with the rack weights 15.1kg. So, I'll be waiting for your opinion))
 

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Rocking on a Rocky
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Looks good. Hope you like it.
 

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fat guy on a little bike
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wow, that bike must be HUGE! it makes the vee 2XL look normal sized...:eek:

more details on the customer? is he 7 feet tall?? :confused:
 

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Discussion Starter · #5 ·
wow, that bike must be HUGE! it makes the vee 2XL look normal sized...:eek:
more details on the customer? is he 7 feet tall?? :confused:
He is not so tall, nearly 6-6.1feet. But this bike is quite comfortable for me with my 6.4))) ETT is 600mm, seat tube is 440mm (for better seatpost amortization) and standover nearly 770mm (good enough for deep snow)
 

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Bike is beautiful. Nice work and thank you for sharing your pictures.


Sent from my iPad using Tapatalk
 

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Harmonius Wrench
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Interesting solution to the chain stay/bottom bracket area. I assume that non-drive side chainstay terminates at the plate style drive side chain stay/BB junction? That is what it looks like.

I also assume the rear wheel was built to accommodate this offset frame to help clear the cassette/chain from the tire? I think that is a very good idea with this tire and rim combination.
 

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Please more pics of the bb/chainstay/yoke.

Very interesting solution with the asymmetrical setup and what looks like the left bend straight through to the plate.

I guess all the momentum from pedaling really only pushes to one side so asymmetrical bb kinda makes sense. Still very few bikes are built with that.

How's the flex? Also how much offset is in the rear wheel?
 

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Very nice work!
 

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Discussion Starter · #16 ·
Interesting solution to the chain stay/bottom bracket area. I assume that non-drive side chainstay terminates at the plate style drive side chain stay/BB junction? That is what it looks like.

I also assume the rear wheel was built to accommodate this offset frame to help clear the cassette/chain from the tire? I think that is a very good idea with this tire and rim combination.
Yes, you are absolutely right! Here some photos, they can help you to understand the design)) The plate is CNC machined with our small logo engraving)))
DSC_0797.jpg DSC_0817.jpg DSC_0847.jpg DSC_0865.jpg DSC_0848.jpg
 

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Discussion Starter · #17 ·
I will ask my designer for his calculations and diagrams and will show you strength and stiffness. It's too hard to fill the frame flex with such a great and low pressure tires)) But I know, that this solution is much stiff than standard two plate construction. Offset is 15mm, but 10mm will be good enough too)) Chain-tire clearance is too big with the outward mounted chainring.
 

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Discussion Starter · #19 ·
Please more pics of the bb/chainstay/yoke.

How's the flex?
So, my designer gave me few diagrams. So, what we can see here... 2016-12-29_16-58-04.jpg
The first picture is а total loading scheme, the load on pedals is 250Nm
2016-12-29_18-07-09.jpg
This picture shows us the loading diagram of classic chainstays which made from tubes. By the way, this is impossible on 5+ fat with ultra short 450-455mm chainstays))
2016-12-29_17-28-27.jpg
This is our constuction... Yes, the lateral stiffness of the bb area is less, but due to hi vertical stiffness of the right plate the total stiffness of the construction will be very close to classic scheme. I hope, you understand what I'm talking about)))
2016-12-29_17-24-52.jpg
So, the maximum movement in our design is 14.4mm while in classic design is 14.1mm - it's really not so big difference)))
 

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Thanks for pics and explanation!
Yea the width of the bb kinda limits the "classical" chainstay when going for 5"+ tires. Nice of you to provide so detailed pics..

Could the yoke be shaped slightly tighter though and still leave room for the tires? It looks like it's built around the 189,5 spindle and RF turbines, and that combination gives quite an extreme q factor. In addition when flipping the chainwheel on those cranks the chain goes way outboard and it looks like it is crossing quite a bit when in first gear in the rear (biggest cog). I assume the offset built wheel is matched for that chain line, but it still looks a little funky in the pictures..

Have you considered sliding dropouts? It would make the frame even more interesting, being able to dial in the geo a little bit, perhaps being able to squeeze in the 3xl if it's ever brought into production.
 
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