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Half Fat

11K views 37 replies 28 participants last post by  Co-opski 
#1 ·
Firstly is it OK to ask about 'Half Fat' on here?

I'm considering putting a fat front end on my Swift.

Was planning to use the rigid fork on a 26" wheel and I think I can fit a 3" tyre in there.

Is 3" fat enough?

Will that combination affect the handling too much?

Or should I get a dedicated fork? If so any recomendations?

Thanks
 
#3 · (Edited)
Don't waste your money on a 3" tyre unless you have one lying around. The volume of a 3" is much less than that of a proper fat tyre of around 4". If you look at the area of the cross section you'll see why.

Tyre 3" =1.5x1.5x ∏ = 2.25x∏
Tyre 4" = 2x2x∏ = 4x∏

ie the 4" tyre cross section is 77% larger than the 3"

If you calculate the volume of the toroid, you'll have an even bigger difference.

You may be able to squeeze a fat tyre into your Swift fork if you use a narrow rim. A Black Floyd on a 40mm rim is 82mm, and a Larry slightly more, so if you can get hold of a rim that size you may be able to fit in to your existing fork.

The best option?

Buy a Pugsley 100mm fork.
Build a wheel with a 80mm rim obtainable from Classic Cycle in Germany (only €50) and you'll need a 36 hole hub.
Don't waste money on a rim strip - too heavy - duct tape does the job.

All this will sell easily on eBay if you don't like it

Then you've got the front end of your fat bike sorted. A few rides and you'll be ordering a frame too. :)

Shame Singular don't do a fatty.

Edit: Volume of a torus (ie tyre)
 
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#5 ·
I've got the parts on the way to put a Fat Front on my SS 29er. I went for a fork and wheel. The idea is to go half fat now as an interim solution until I have the scratch for a full fat. All the parts will transfer to a future build.

So far this winter I've been riding a lot with my fat bike buddies. I can usually ride about 80% of what they can on my 29er. The parts that usually suck the worst are the loose downhill sections where my skinny front digs in and/or washes out. I expect the fat front will help a lot there. It won't help for climbing (obviously) and will probably only marginally improve overall float.

I'll report back once I've got the parts and battle tested the setup for a few weeks.
 
#7 ·
Half fat Swift you say?

DSC_6286

As you have already surmised, going all the way fat is a much better way to go. If you're on a Gen I Swift, an Enabler fork[what I'm using] steepens the head angle to 73*. Yes. You read that right. You can feel it as you ride, but not to the degree you'd think. The big ass tire that you're mounting up does a fantastic job of slowing it all down again, so you still end up with a nice riding, sharper cornering mountain bike.
 
#9 ·
I got bored and had an extra 26" Maverick wheel kicking around so I took my Trek 69er SS and fattened it up. Added a 2.4" Maxxis Ardent to the rear, that's the most it will take, and it's great in the mud and hard pack frozen dirt we've got in the Northeast. Don't know how it will do in the snow, but we'll see. Clearance around the fork isn't an issue, but then again it was an AM rim, not a fat rim.

http://www.shutterfly.com/lightbox/view.sfly?fid=ca25df1f9161742cbcfd7207a7b1fe91
 
#18 ·
I've been getting in a lot of winter riding this year. For the most part my SS 29er has been getting the job done, but I won't lie, I have the itch for a fatty. I decided to throw on a fat front on my bike for the rest of this season, with the intention of moving it to a full fat next year.

I've been out for a few rides and am getting a feel for the new setup. This is my impression so far.

The handling is a bit odd due to the shorter fork and slightly smaller wheel. The head angle ends up being somewhere around 73 deg. The big wheel slows the handling down, but there are some auto-steer quirks that took a little getting used to. If I was going half fat long term a longer fork (e.g. Enabler) would have been a better option, but I went with a moonlander fork because it fits better with my future build plans. Overall the bike does feel different, but once I got used to it it was okay.

Going uphill the fat front doesn't help much. Obviously. It helps a little keeping the front end planted and tracking straight, but that is about it.

Going downhill the difference is night and day. Sections I was digging in or washing out are now point and shoot. All smiles! Definitely bomber in comparison to the skinny front.

On the level the front does help steamroll and brake trail for the rear. And perhaps the best benefit is it helps a lot with stability and control. Situations that used to require finesse are now much easier.

Overall I like it! And I'm looking forward to a fully for next season!
 

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#22 ·
My Swift was built with a half-fat option in mind.

I built it with Enabler forks and a 135mm non-fat front wheel now ... ready for a fat-front to just drop in as required.

That hasn't happened yet tho' - in part as the Swift is still being finished off, but mostly as I think I'll go straight to full fat now anyway ...

:rolleyes:
 
#23 ·
so curiously enough this bike island frame happens to be designed around a 450mm AC fork, Rare nowadays. I had a bunch of parts in the parts bins including a lovely white Pugsly fork so i decided to drop a couple hundred on the frame and build up a half fat SS bike. The rear wheel is a WTB i19 Tubeless rim laced to a x7 hub, the front wheel is actually off my pugs for the moment but im going to build up a sweet fat front wheel with a marge lite rim and maybe a husker du tire. inital impressions are this thing is gonna be a blast but ive got to get it out for some more rides soon. (like 20 min from now)

 
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