BMX Weight Weenie - D3 Custom

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xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

Here is the D3 SL I just built for my son. It's a Jr XL with a 19" top tube. At 11.8 pounds (5.35kg) complete it is nearly three pounds lighter than his previous bike which was a smaller size. This bike was discussed in the Cycle Chat forum but I thought it deserved its own thread for those interested.

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Some of the parts could be lighter, but are sponsor supplied items so won't change. Bars are likely to change as are chain tensioners. New pedals are on the way. I'm building a new, lighter wheelset once I have the parts in hand. I'm considering stripping and polishing the crankarms, but that is a project for another weekend. Parts and weights are listed below. I forgot to weigh a few of the smaller parts but the important stuff is there.

Frame: D3 SL (Junior XL) 2.07lb/939g
Fork: Answer Scythe SL, 1" carbon steerer, uncut 370g
Crank: Answer Alumilite SX Mini 155mm w/Answer Alumilite Chainring 1 piece, 34t 406g
Headset: Cane Creek 40, 1" threadless 99g
Stem: Redline Mini 1"x40mm, w/Ti Hardware 111g
Bars: Answer Expert Carbon 322g
Grips: ODI Ruffian Mini Lock-On 110g
Seat Clamp: Profile 25.4mm, Tuned 16g
Seat/Post: Uni Mini, cut down 94g
Brake: TRP CX9 and ti hardware 167g
Lever: TRP RL950 carbon 41g
Brake Cable: Nokon
Bottom Bracket: American Classic Titanium, 110mm, sq-taper (vintage) w/Extralite alloy bolts 140g
Rims: Alienation Ankle Biter
Hubs: Profile Mini
Cog: Profile Alloy 14t
Spokes: Straight Gage Titanium
Nipples: Alloy
Tires/Tubes: Kenda
Front Wheel w/tire & tube 1100g
Rear Wheel w/tire, tube, and cog 1160g
Chain: KMC X10SL
Number Plate: Crit Custom
Pedals: Crank Brothers Egg Beater 11
Chain tensioners: Sinz 69g
Misc: Carbon spacers as necessary on steer tube (gotta leave a little room to grow)

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by Weenie


HillRPete
Posts: 2292
Joined: Tue Apr 12, 2011 8:08 am
Location: Pedal Square

by HillRPete

Nice but have you considered asking Jure Berk to do a stem/bar combo?

(Hi Daddy)

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

Actually, we have discussed a frame project for the future. But it is just an idea for now.

dmohara
Posts: 35
Joined: Wed Apr 06, 2011 8:58 pm

by dmohara

Lucky kid!

Nice job.

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

Thanks. He earned it. He's a great kid. Does well in school. Never gets into any trouble. He always displays good sportsmanship. And he is a talented rider.

legsrburnin
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Joined: Sun Feb 25, 2007 1:26 pm
Location: Australia

by legsrburnin

This is excellent!!

Weight Weenie the kid while he's young!! Get him hooked early!! :D

Well done on a great build!
Lefty heaven

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

I'm a firm believer in the power-to-weight ratio being as high as possible. I can't understand why a 165 pound adult can ride a 10 pound bike, but a 65 pound kid has to ride a bike that weighs twice as much.

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

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Last edited by xnavalav8r on Tue Aug 04, 2015 5:42 pm, edited 1 time in total.

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fa63
Posts: 2253
Joined: Mon Feb 19, 2007 7:26 am
Location: Atlanta, GA, US

by fa63

:thumbup:

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

I'm a little excited. The final parts came in today for the wheel build (sort of). The rear rim was missing from the order. But I just finished building the front wheel. It is 240 grams lighter than the previous wheel... which was already considered a light wheel. Final weight for the new wheel is 485 grams (vs 725g for the previous wheel). That's a 33% weight reduction!

Build includes the following:
Alienation AnkleBiter 20x1 1/8 Rim (36h) - 305g (advertised 325g)
Bike Hub Store SL Hub (18h) - 68g (advertised 66g)
Sapim CX Ray Spokes (18) - 63g
Alloy Nipples (18) - 5g (advertised 5.6g or .309g ea)
Zipp Bolt-on Steel Track Skewer - 33g (advertised 31g)
Rim Strip - 10g

I'll build the rear wheel when the rim comes in and post the specs for that as well.

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xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

Down to 11.2 pounds now with the new front wheel and the Egg Beater 11 pedals. The rear hub and rim haven't arrived yet, but should drop off at least another half pounds. Switching to a larger chainring and rear cog added a few grams back. I'm hoping for 10.5 pounds when all is said and done.

By the way, my attempt at switching to short ti spindles in the pedals failed. Anyone else ever have trouble getting the original needle bearing out of Crank Brothers pedals. I don't want to destroy it as the pedals are brand new. It seems a shame to have to ruin new bearings and replace them before the first use.

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

I've got another project brewing... think classic sewups meets modern bmx technology.

xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

I received the rim for the rear wheel today. Here are some photos before final tensioning and truing the wheel.

Final weight is 727 grams. That is 104 grams lighter than the old rear wheel. Much less weight saving than I anticipated.

So that's 1211 grams for the pair. 344 grams lighter than the pair they are replacing. That's 3/4 of a pound of rotating weight removed.

Build list is as follows:
Alienation AnkleBiter 20x1 1/8" rim. 28-hole
Alienation Royal Rear Hub. 28-hole. (Essentially an American Classic 205 hub spaced for BMX and with a BMX freehub body.
Sapim CX-Ray spokes... 14 x 2-cross on the drive side. 7 radially laced on the non-drive side
21 Alloy nipples
Dura Ace 14t Ti Cog
Alloy spacers

Interestingly, this freehub body can accommodate three 10-speed cogs and spacers. I am considering installing 13, 14, 15 tooth cogs and using a chain tensioning device to allow for quick gear changes without have to move the wheel and reset the brakes. Here is the tensioner I am considering. http://labs.yesspro.com/products/etr-b

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I'll likely change the current steel bolts to titanium to shave a couple more grams. But this is light as I can get it.

I will post an updated photo of the bike with revised weight tomorrow. I may not reach the sub-10.5 pound goal.

johnsonj718
Posts: 32
Joined: Wed Mar 21, 2012 10:45 pm

by johnsonj718

I don't know much about BMX but I do know that 11.8lbs is light! Unique stuff, I dig it!

by Weenie


xnavalav8r
Posts: 2643
Joined: Mon Jan 21, 2008 12:09 pm

by xnavalav8r

Thanks. I think 10.5 pounds is as light as I can get it without offending any of my son's sponsors and violating his sponsorship agreements. There are lighter tires and grips out there for sure. I could probably have found a lighter rear hub. But I'll be satisfied with this build as it is... which is about 4 pounds lighter than the bike he was riding despite being a slightly larger frame.

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