Another Beast Build

[blown240]

My buddy's beast arrived today via Fedex. The plan is to build an off road trail bike, nothing too serious, but still fun. Eventual plan is to have hand brakes, multiple gears, and 40lbs or less...

Out of the box the damage wasnt too bad. Here is the worst of it:

The bearings were totally dry and wayyyy to tight. We totally disassembled it, packed and adjusted the bearings, and put it back together.

Stock weight is 48.4 lbs.

So, on with the mods:

First order of business was the gearing. Since its going to be an off road bike, we wanted it to be able to climb. We put a 23tooth gear on the back, and a 36 on the front. We used a set of cheapie cranks and a gear I had laying around. I didnt have short enough chain ring bolts for a single ring, so I put 2 rings the same size on. That will change soon. We also ditched the chain guard. With this gearing its easy to pedal, but you run out of gear on flat cement, on hills though, its pretty good. Multiple gears are definitely needed.

Weight after the gear/crank change 46.4 lbs. We saved over 2 pounds just changing cranks and gears.

Heres some pics:

Next was some different bars and taking off the kick stand. I had a stem that fit, and some bars and bar ends. They are all steel, but will be good for now:

weight after bar swap 45.0lbs. Total weight saved so far is 3.4 pounds

And finally here is something I did as a joke... Fat training wheels!!

I am still trying to decide if I'm going to order one of these bad boys, its pretty cool...

 

[HRJG]

I lost 9 pounds off of mine, by swapping tires and tubes! Details of my 3-speed Beast build here: http://grinderswheels.blogspot.com/2013/08/silk-purse-from-sows-ear-dept-saga-of.html

 

[blown240]

Saving that much weight on just tires and tubes is crazy!

 

[HRJG]

I know! I replaced the stock tires with a Surly Ectomorph on the back, and a Larry on the front (used, off of Craigslist), and used Surly tubes. The stock tires weighed in at 6.5lbs apiece, and the tubes were 1.5 lbs each, on my digital scale!

 

[blown240]

My buddy likes his beast so much that he ordered 2 more for his boys. I went ahead and ordered one too...

I have big plans for mine... 190mm rear spacing, so I can run 9 or 10 speed, hopefully disc brakes, and maybe a front gear as small as a 22. I want it to be off road capable even for climbing. I think a 11-34 or 11-42 cassette would be very usable. I actually have a set of disc brake hubs that would be perfect for widening, but they are 32 hole and im not sure I want to hassle with lacing a 32 hole hub into a 36 hole rim...

 

[blown240]

My beast will be here Friday, but in the meantime I made some custom cranks tonight.

I started with a set of cranks from a cruiser I had. Aluminum arms with a stamped steel chainring. Using a hole saw, I cut the chainring off so that only the inner 1 1/2 inches was left. Then I took a cog, and drilled it so that I could bolt a 22t chainring to it. Next I ground the teeth off of the cog so that it was basically round. I then welded the cog to the cutdown stamped chainring. This allowed me to bolt the 22t ring where the large ring would be on a standard MTB crankset.

Im going to use a 16t cog in the back. This will give me roughly the same gearing as the 32/23 my buddy has on his. He loves it. Plus the 22 front with an 11t cog will give me the original ratio.

Will these cranks last? Who knows, but they were fun to make and saved me 1lb 6.2oz. The new cog is half the weight of the old one, plus it will let me cut the chain shorter.


Here are some pics:

 

[LukeTheJoker]

Nice work! Hopefully it lasts well for you!

Luke.

 

[blown240]

My Beast should be here tuesday. Im going the route of a real mountain bike with it. I got a set of Devist8r tires, a carbon fiber handlebar, a stem adapter, and a new stem for it. I also pickup up a used cassette hub that I plan to widen to 190mm. If there is room once I build the wheel, I am going to run an 11-42 8 speed cassette.

Here are a couple pics:

Here is the new tire next to a standard 26x2.1 tire:

 

[LukeTheJoker]

Any plans on how you are going to widen that freewheel hub? I have widened steel ones before, but that looks to be aluminium, might make it a bit harder, then again everything is possible with the right tools!

Luke.

 

[blown240]

My buddy has a very nice TIG welder and one of his employees used to work for fab tech. I'll either have him weld it, or worst car I'll braze it. Though I've never braced aluminum. Not even sure it's possible actually.

 

[LukeTheJoker]

Your mate with the TIG should be able to do it no worries.

Luke.

 

[blown240]

I got my beast yesterday. Once I greased everything I put it together. So far I have removed the kick stand and chain guard, installed my cranks and 16t cog, a carbon bar, a stem adapter and stem, a nice leather seat I had, and some Devist8r tires. I havent had a chance to weigh it yet.

Here are some pics:

Here is the new tire next to the old:

And here is what happened when I tried to blow the cheap grips off with an air compressor:

POP!!

The only real damage out of the box was that the fork was partially stripped by the keyed washer. Looks like they forced it on and then it spun:

Also, I tried to use some 26x2.5 tubes in the new tires because they were much lighter, but this is what happened. Does anyone know how to avoid this? Ive read many threads about using regular tubes:

At this point its rideable, but when coasting the rear hub wants to grab a bit and makes the cog click back and forth. Its probably just an adjustment, but I'm planning on swapping hubs anyway...

Next plans are to remove the stickers, drill the rims, and start working on some hand brakes.

 

[LukeTheJoker]

Keep it up, love watching this build, and be very interested to see how light you can get it!

Luke.

 

[blown240]

Just got back from my first ride. Just local, several miles, through a few parts, across a playground, etc.

The 22/16 gearing is fine for a single speed, but it spins out on flat, and could definitely be lower for sand. Rear hub is really messed up, it needs an overhaul, its pedal or brake, almost no coast...

AND with 12psi in the tires it really wants to steer itself. Not sure if that a fat bike thing, or a geometry thing.

But all in all, I LOVE IT!!!

 

[blown240]

I just finished rebuilding the coaster brake, it works great now. The grease that was in it was super sticky and really thick. I cleaned it all out and put some nice new grease in it.

I also took the stickers off...

Current weight is 40.4 pounds.

 

[Bill in Houston]

nice work!

do you ever drop the chain when pedaling hard? mine came off with the original gearing and the new 32x23 when i really mash and tilt the bike. with the original it seemed to drop in front or back. Now it only drops in back. Trying to figure out how to keep it on. My chain is quite tight, so i don't think that's it. Unless it is possible to make it too tight...

 

[rickpaulos]

nice work!
Unless it is possible to make it too tight...

yes!

On cheap bikes the sprockets often don't turn in a perfect circle. Watch the chain and see if goes tight , then loose as you turn the pedals. Adjust the chain at a tight point. The chain should not be under any tension. Just short of that.

Also look to see if you sprocket is straight and look for any bent teeth on the sprocket or cog.

Lube the chain well with chain lube. That makes a huge difference in smoothness, quietness and not jumping off.

 

[blown240]

I had a couple dropped chains at first, but I realized that my chain was just a little too loose. I moved the wheel back just a little and have had no issues yet. I did see that the cranks I made had a slight wobble in the chainring, but this was solved with an auto body hammer and the edge of my vise!

 

[Bill in Houston]

great, thank you for the advice.

 

[blown240]

I had a couple ideas for a rear suspension design for the beast. I wanted something that could use as much of the stock frame as possible. I came up with a design that doesn't need a pivot by the rear axle. To see if it worked, I busted out my boys erector set.

This is what I came up with:

Here it is in the "extended" posisition:

And "compressed":

The rear triangle is very similar to the design of my Yeti. The Yeti has a carbon flex point in the seat stay, I think this may be because of the amount of travel the Yeti has 5.75". But I feel that the steel beast frame would have enough flex naturally to not need a flex joint. In the erector set model, I didnt need a flex.

Here is the Yeti:

And as I side note I picked up this front brake setup for $35.
$20 for the caliper and lever and $15 for the rotor. All used, but functional: