Weight Weenies

i won a hotdog eating contest at a bmx nationals once--

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Well, this topic turned unpleasant quickly.

Moderators????

I apologise if I offended, I was actually trying to save you some future embarrasment.
I have deleted my own post as in retrospect it could be seen as provoking argument. That was not my intention.

Lets get back on BMX weight weenyism

I remember seeing a carbon fiber stunt BMX that was actually a lot more impact resistant than any existing alloy frame. It was pretty heavy though because of the high wall thickness.

Here's my old Diamond Back BMX from my BMX racing days in the 80's. This shot is just me playing around.
Pretty sure it was around 8kg from memory! I was a WW even then!!

Reviving an old thread...

My son just picked up sponsorship from a company that makes a sub-2-pound frame. The frame will be over a pound lighter than the Intense Junior XL he is currently riding... and with a 1/2 inch longer top tube.

Check out the SL frame at D3 BMX. http://www.d3bmx.com/index.php/d3-frames/

Frame should be here next week. I ordered it raw and plan to polish it. One weight weenie experiment I am trying is using a TRP CX-9 cyclocross mini v-brake paired with a TRP RL-950 carbon lever. Other ww parts are an older American Classic titanium square taper bottom bracket, Answer Alumilite mini SL crankset, Answer Scythe mini SL carbon fork, Redline microline 1"x40mm stem, UNI mini seat/post, Nokon brake cable, KMC x10sl chain.

For the moment, I'll continue to run his current wheelset. But I have plans for a lighter front wheel using a road front hub and fewer spokes. I don't understand why a bike built for a 63 pound kid needs 36 spokes per wheel. I'll likely use an 18 spoke front hub, radially laced to the 36 hole rim and skip holes. Finding a 20x1 rim with fewer than 32 spoke holes has been nearly impossible. I may reduce the number of spokes on the rear wheel, but there aren't many hubs lighter than the Profile mini rear hub we are currently using. I have three 28-hole sewup rims, but have found that the reduced overall diameter of the completed wheel/tire is more detrimental than the few grams required of a standard clincher setup... at least at his size. I'll save the sewups for my little one once he starts riding on the track. Maybe next year....

I'll post photos once everything is in hand and ready to build.

Well, the frame was delayed somewhat due to the manufacturer being injured. It arrived today slightly overweight. I was expecting around 850 grams and it weighs 940. However, it is still more than 450 grams lighter than my son's current frame which is smaller. The frame is completely raw, per my request. So once it is cleaned up and polished I think it will be a little bit lighter. But I doubt I'll be able to get it under 900 grams.

More to come...

Ted,

Have you considered having the frame bead blasted? It should lighten it up a bit and increase the surface hardness. Looks pretty cool, too. Older Ventana MTB frames are a good example.

I considered it, but I'm on a budget (as always). $20.00 of supplies and about 6 hours of elbow grease and the frame is gleaming. It's not finished yet, but a couple more hours of work and it will be like a mirror.

I should have the polishing finished today. Build will probably be tomorrow or Monday. I've decided to strip and polish the cranks and stem as well so it could take a little longer. Here is the build list for now. I'll be building some new wheels in the coming weeks. I forgot to weight a few parts before installation. The only parts I don't have in hand are the new pedals. Some of the parts on this build could be lighter, but are sponsor supplied items so we are sticking with them.

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 w/PowerCordz
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)

Old bike = 14.72 pounds complete.
New bike = 11.8 pounds complete.







Bars are likely to change and still waiting for new pedals. New wheel parts are ordered so these wheels will be changed for a lighter set soon.

Looks great, love the industrial stealthness. Pedals: does he stay clipped in 100% of the time that would allow him to run something like quad Ti eggbeaters?

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Yes. He'll be running the new Crank Brothers Egg Beater 11 as soon as we get them in.