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Fat Bike Conversion??

24029 Views 10 Replies 5 Participants Last post by  ReverendPDP
Hello Gang. Newbie here lurking in the background. I'm thinking of putting the widest possible tires on an older Mongoose Tech 4 frame. Currently it has 26x2.1 WTB Velociraptors on it. How can I tell what tires will fit? I'm thinking of either a 26x2.8 or if I can a 26x3.0.
Also, will converting from a 2.1 to say a 2.8 or 3.0 give me that much better performance in sand to warrant the expense?
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First thing, you can put a fat front on any bike so you are ok up there.

Now the rear. We need a pic to see what you have.
bighit said:
First thing, you can put a fat front on any bike so you are ok up there.
That depends on the fork. Some forks won't fit past a 2.5 tire.
you can fit a fat specific fork like a pugsley to any bike is what i think BH meant,alot of folk fit them to bikes giving a semi fatbike up front,
3" or 2.7" tyres- usually downhill tyres fit alot of frames and yes it would be better than a regular 2.3" tyre...but everyone who trys it then rides a bike with at least a 50mm rim and an endomorph tyre agree there way better,
so maybe you have to bite the bullit and buy a fatbike set up if your planning on alot of sand riding, maybe the next best thing would be a 29er with speedway cycles 50mm una rims and 2.5 tyres...but proberly cost you the same in parts to buy as a fatbike,
what i can say is if you ride a pugsley in sand with tyres punped up to 20-25 psi it isnt much cope....however lower them to 10 psi or even lower and the bike just floats most soft stuff :thumbsup: ,riding these bikes becomes addictive :D
If sand is all you need maybe the tommisea bike is for you.
Fork measurement

Measuring the width of the fork where the rear tire is now, I get 3 inches. I'm assuming then that a 3 in. tire is out of the question unless I change that fork. But how about a 2.8 inch tire? Will it be too tight for comfort? I'm also assuming that the fatter tires will have the same height as the existing tires. I say this because from the top of the tire to a cross bracket in the front of the fork I have about 1.5 inches. Hope this makes sense.
Few more questions...

Is it acceptable to have 2 different size tires on? Say a 3.0 up front and a 2.8 in the back?(Sorry again for newbie questions). Will this affect performance?

Also, what kind of tread should these tires have? Can you recommend a few options that I can take to my bike shop?

To answer the above question, although my main riding will not be on sand, I am planning a 4 day trip where it will be exclusively sand... sugar sand to be precise.
have a look at the Continental 2.5 Diesel tyre, folding bead, so very light for size,alot lighter than a Downhill tyre,
you maybe better with a set of these if just for a 4 day ride,can proberly lower the pressures of them to about 20 psi as long as not slamming into rocks
The fattest tyre I've yet seen although only a 2.4 width wise is the rubber queen, it can be ran real low and give a huge foot print on a DH rim if required.

A 1/2 fat, 4" tyre front with a 2.5 on the rear to keep rolling speed acceptable could be the way forward, like my 69er.

Max width with a standard On-One £50 steel fork is approx 3.4", 3"'s useable, a 3" DH tyre on a cheap EX325 26" rim would improve sand on a budget.

But nothing is going to compare if your riding on a beach to a real 4"x4" Fat bike.
is this the bike,

you can use the zoom and see there is not much room. new bike time.
bighit said:
is this the bike,

you can use the zoom and see there is not much room. new bike time.
This is not the bike, although they are similar. Mine might have been its predecessor. It is a flat black bike with white forks. It also has decals that read, "dirtech engineering," "4 bar link," and "Mozo" shocks. I bought it back around 2006, and if I remeber it MSRP'ed at around $800... if that means anything.
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