Custom Rob English MTB

Almost a year ago I put down my deposit with Rob English for him to build me a custom twenty niner . I was intending to race in the Tour Divide in 2O13, but after spending 8 months building a whole new workshop I realised how unrealistic this was.
I still plan to race it, but it will need to be put off another year.
The bike however will still be going ahead as planned, and my place in the queue is almost here.

I'm about to start the discussions with Rob about exactly what I want. I've had a firm idea about this since day one. I want this bike to be as adaptable as possible so there are a few features you don't find on the average MTB...such as a folding frame, interchangeable front and rear wheels, custom frame bag mounts, custom aero bars etc.
It was almost sorted in my mind...but then I started to really miss my favourite MTB of all time...my Surly Pugsley.
I had the first Pugsley officially imported into the UK...many years ago and I loved every minute spent riding it...so now, my design plans may be about to change drastically. :]

I'll edit this post once I have more to tell. :]

Ooof. One to watch. I remember you posting somewhere that you were in the build queue for this, I'd assumed it was going to be a road bike.
Very much look forward to seeing progress.

subscribing, popcorn thread, in a good way

Just how fat do you intend to go?

On-one seem to thnk 4" tyres, and 70mm rims are the way to go for UK mud. I'm inclined to trust them on this.

Some Marge light rims, and some 45NRTH mud tyres would be a sweet set-up, light, grippy, and they'd only be 92mm or so wide. So a flat 49mm chainline would barely brush the tyre. Thats only 2.5mm more than shimano MTB standard. So a outer mounted chainring, and a spacer at the sprocket would get you there. With decent chainline to boot. I've spaced my NuVinci hub out 1-2mm. Not sure if its also doable on the Alfine.

A lot of 29ers are looking to the new Krampus tyres from surly. But the height of the tyre + wheel simply wont fit in a standard 29er frame. Personnally I would'nt want to lengthen stays for it.

I posted this in my thread. But the more I think about it, the more I like the idea.

83mm DH BB shell. Could be made to work well both fat and 29er.

You could always run 65mm rim + 3.8" tyre at the back, and 85mm rim, and 4.8" tyre front for max fat. That makes sense from a standard MTB viewpoint. Feck knows how it would work on a fatbike.

Surly have some sweet 4.7" mud tyres coming out.

I want interchangeable front and rear wheels too though. :]

I'm thinking no more than 4", especially with some of the great tread choice out now in the sub 4" range..
If I use the fatbike base with 1OOmm BB it means I can run any tyre size including the Krampus platform, as the stays on that are only about 3mm longer than my current twenty niner.
Longer stays have the benefit of more stability when the bike is loaded, and more comfort on a hardtail.

I want to be able to use the bike as my regular twenty niner, but also be able to run it fat front, full fat, Krampus style, or any possible combo.

I reckon if anyone can make this work, Rob can, as he's never one to shy away from some problem solving.

I seem to remember you mentioning a eccentric BB. How would that work in a 100mm BB shell?

Custom?

Should just need a longer connecting bolt between the two halves.
It'll be a niner EBB.

I want interchangeable front and rear wheels too though. :]

In that case I'd look to 65mm to 70mm rims personally. Theres no point in going wider, as you just start ruining the profile of a sub 4" mud tyre.

I have 80mm, and will upgrade to 82mm rolling darryls (My rims are a bit rubbish). But thats just a compromise between wanting 100mm rims for my winter floatation set-up, and 65mm for mud'n'rock riding.

1.5" headtube?

Super versitile.

I'm planning on keeping them fairly narrow anyway. I'll have dierent sets of wheels for different purposes, but I want to be able to switch front and rear so I can have a bailout fixed front hub incase of hub gear trouble out back. :]

I have thought about 1.5" head tube, but not settled on that yet. May stick with 1.1/8

The fat front rims that Jeff Jones sells are nice too...only 5Omm and 66Og. He's been using them for quite some time now with great success.

I
I have thought about 1.5" head tube, but not settled on that yet. May stick with 1.1/8

I had a 1.5" headtube spec'd from the start. But as I'm happy with my head tube angle with all the forks I could think of using, All of which are 1 1/8" it did'nt seem worth it.

I'll be having custom forks made too so I'm not really planning on changing them anytime soon. :]

The fat front rims that Jeff Jones sells are nice too...only 5Omm and 66Og. He's been using them for quite some time now with great success.

They look sweet. Plenty of people ran endos or larrys with 47mm trials rims for off-roading. As it clears the Maverick sus fork. If you look around the web for those running the Mav on a fatbike. You'll get an idea of the tyre profile.

like these two beautys.

I'll be having custom forks made too so I'm not really planning on changing them anytime soon. :]

For me it was the ability to run an angleset headset. But as I went with a lefty. My axle to crown doesnt change anyway. So why bother.

Anything cage mounts on the fork? I really want some anything cages.

Sorry for the thread spam fest BTW. Its a real interesting project.

I'm planning on bottle mounts on the forks...I like having my bottles there.
I'll be making full custom bags anyway. :]

I've decided you want a 83mm DH BB shell, and a 7,5mm offset 135mm rear (and forks).

• The tyre will hit the belt only if it is over say 102mm in width. Which wont be a problem for your spec.
  
• The beltline will be a perfectly straight DH 55mm.
  
• You wont need a special offset rim to achive 7.5mm of offset*.
  
• Its still 10mm less offset than your old pugs.
  
  

(*difficult to garantee this. But I'm pretty sure my front fat lefty wheel has at least this without specal rim drilling + lacing)

I think you're right in that some offset may be needed in order to run an alfine. I was just hoping I could keep things nice and central. :]

Thats based on the chainline of the alfine being fixed. I've no idea if it is TBH. If you can space the cog out by 2.5mm your down to 5mm offset.

If you run a 100mm BB shell your back up to 15 - 17.5mm offset.

I just saw a 1Omm offset cog that works on an Alfine with some 'tweaking' of the cable carrier. :]

Means no belt drive, but hey. :]

I just saw a 1Omm offset cog that works on an Alfine with some 'tweaking' of the cable carrier. :]

The Sturmey Archer one?

Cuz that aint work with no belt ;)

Apparanently the alfine chainline is 42mm, not 47.5mm. The dished sprocket brings that to 50mm.

So with a belt this is'nt going to work without offset.

I might just suck it up and go with offset?
I think a cuppa will help me decide. :]

Means no belt drive, but hey. :]

In that case 50mm rear chainline = 47mm of clearance.

So you'll need a wonky chainline to properly clear the tyre. Wearing out the chain and sprocket in no time. The idea of having interchangeble wheels, yet a faulty drivechain just doesnt fit with me (IMHO etc).

I'd get 5-10mm of offset built in.