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Sinister Bandwagon
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Discussion Starter · #1 ·
I am on the mission to find out what would be lightest possible build for a park/dirt bike I am going to building one up for my nephew to get into continue his biking and upgrade him from hardrock. I want light build since the kid isn't more then 100lbs an has a hard enough time with the hardrock, so I'd like build him a sub 30lbs bike preferible with gears. I was looking into crabon frames but I can't find any jumping ones, so I was thinking perhaps a blk mrkt mob with gears hand build up wheels and some kind of qr jumping fork air perhaps....not sure need some help with components
 

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Meh.
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Aluminum frame like an STP will be lighter than a Mob. It'll weigh under 5 pounds. And the geo is pretty good.

You could go with something like a Reba dual air for the fork.

XC tires with small closely spaced knobs. Ultralite tubes.

Bars, Answer Protapers or Deitys

Rest of the build depends on the budget... It's very hard to tell you without a budget.

To go low budget... XT or Ultegra cassette, x7 rear derailleur and cassette, XT or SLX cranks, Chopped aluminum post, some old roadie saddle, one of the e13 guides with a steel backplate.

Or... XTR cranks, x0 derailleur and shifter, Dura Ace or XTR cassette, Syntace Superforce or Point1 stem, new e13 lg1 guide.

Wheels... again, depends on budget. Since he's light, you can probably get away with RhynoLites and some DT Swiss butted spokes. If you've got the money... 721s, alloy nipples, Sapim CX-ray spokes. Hubs... Most of the cheapo hubs will hold up fine, but will be heavier.
 

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Sinister Bandwagon
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301 Posts
Discussion Starter · #3 ·
XSL_WiLL said:
Aluminum frame like an STP will be lighter than a Mob. It'll weigh under 5 pounds. And the geo is pretty good.

You could go with something like a Reba dual air for the fork.

XC tires with small closely spaced knobs. Ultralite tubes.

Bars, Answer Protapers or Deitys

Rest of the build depends on the budget... It's very hard to tell you without a budget.

To go low budget... XT or Ultegra cassette, x7 rear derailleur and cassette, XT or SLX cranks, Chopped aluminum post, some old roadie saddle, one of the e13 guides with a steel backplate.

Or... XTR cranks, x0 derailleur and shifter, Dura Ace or XTR cassette, Syntace Superforce or Point1 stem, new e13 lg1 guide.

Wheels... again, depends on budget. Since he's light, you can probably get away with RhynoLites and some DT Swiss butted spokes. If you've got the money... 721s, alloy nipples, Sapim CX-ray spokes. Hubs... Most of the cheapo hubs will hold up fine, but will be heavier.
Thanks for a place to start.

Yeah I was thinking of the STP I have had friends crack them before, though I think with his weight he should be fine on one.

Fork I was thinking a used fox float qr or the X fusions the blk mkrt team runs seem to be nice.

I think for gears I may spend a lil more on, cranks XT or saints, deffently get some e.13 on there.

As for wheels debatible either mavic 321 with some hub built not sure or get a complete set up like the deetraks.

I want to keep it under 3k so I think I can get a pretty good built.
 

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Meh.
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Saints will be a good chunk heavier. Get either the XTs or the SLX with the pedal insert. Or even the Hones with the pedal insert.

The Reba will be comparable in weight to the Fox. I prefer Rockshox for the ease of service and maintenance. And they seem to be less creaky.

321s aren't terribly good rims for this application. Pass. The Deetraks are okay, but probably overkill. They use 325 rims which are pretty strong, but also pretty heavy. And the hubs are mediocre. I'm not a huge fan of the straight pull spokes either.

Brakes... Avid Elixir Rs are cheap, relatively light, and work very well.

MG1s are light pedals. So are the Odyssey Twisted PCs or the JC PCs.
 

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mtbr remember
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I will mention, for $3k, your nephew will have a nicer bike than I have. How old is he? Can he appreciate a $3000.00 bicycle? Or will it just be "another toy" to throw around, then get ditched when he gets his driver's license?
 

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i 2nd the buy/build him a 20'' bmxer and when he grows some and is hooked on the sport then go all out on a 26er build
 

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mtbr remember
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Implying bmx bikes are for children and 26" is for adults is completely off base.
The kid would probably have a blast on a nice 20" though, no doubt about it. But if he gets into it deep enough, he'll probably stay 20". Unless like mentioned, he wants gears.
 

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Seriously, use the one with gears for the trails. Use a 20" bmx for park/DJ. He wont be able to handle or lift it well in the air and will get frustrated. 26" wheels are much harder for us smaller people. Gears are not needed in DJing! The DJ forks will be too rigid for his weight to be of any use really so stick with rigids. I think you can cut the springs, etc. But seems more complicated then needed. The 20" is much more fun for me anyway. I'm small and can do a lot more on a small bike. A heavy bike doesnt go up far in the air for me, BMX's fly!
 

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you can build a sub 30lbs MOB with no problem but what is he looking to do with it? A 20" is an option. and at his weight you can build a real light bmx a Eastern Grim Reaper 2 frame is only 4lbs and a great start or a VOLUME First Blood frame if build right those bikes can be in the low 20s range . there is also the 24" option like a Doberman Pinscher which can be run single speed or geared 24" or 26" wheels. If it is a park and dirt jump bike then you don't want gears, street, park and dj bikes with gears = broken derailuers and derrailuer hangers.
 

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mtbr remember
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tell Aaron Chase that... or Lenosky... or...

But yeah, I agree to a certain point.

My BMX is just over 21#. I honestly would not want to go any lighter than that.
 

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BikeSATORI said:
tell Aaron Chase that... or Lenosky... or...

But yeah, I agree to a certain point.

My BMX is just over 21#. I honestly would not want to go any lighter than that.
I see your point about Aaron or Jeff but they are extremely skilled riders thus very smooth. Also they have sponsors that replace their parts when they break. To the normal human riding serious park or urban a der. is just something to get in the way.
Example The Brooklyn Banks Street jam this past Sat. not one person on a 24 or 26 was riding geared. Carter the owner of Black Market and Adam Hauk Blk Mkrt team rider were riding single speed and lots of guys were running full rigid.
Also most skate parks won't let bikes in with deraileurs. Plus a 20" or a 24" is much more manuerverable in skate parks.

21lbs very nice. What are you running?
 

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sittingduck said:
I've seen some really sweet 24" mtb setups under 25 lbs. You're talking about some decent $$$ though. $1,000 used, or around 2,000 new.
are you talking geared or ss?
 
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