[teamkranzelbike]

I am in the process of building a downhill race bike for a very agressive 90# jr. expert. Being a big, very hard on parts kind of guy, I have never been too concerned with weight. this is a different case.
due to sponsorship obligations the frame, fork, and brakes are already chosen. can anyone help with good choices on durable lighter weight components for the rest of the build? price is no object, but we would like to steer clear of carbon if at all possible.the frame is coming with a ti spring, and I have a set of custom made ti springs being made for the fork, both willl lighten the load about 1 1/2-2 pounds.

 

[dexter]

mavic 823 or d521's o n hadleys with db spokes.
new xt or saint cranks
sram xo drivetrain
e13 guide
thomson stem post
flite ti gel seat
sic bars or ec70dh bars

 

[DHS]

mavic 823 or d521's o n hadleys with db spokes.
new xt or saint cranks
sram xo drivetrain
e13 guide
thomson stem post
flite ti gel seat
sic bars or ec70dh bars

raceface cranks will fit more things, maybe some middleburns. i've always wanted some
no gel seat for me, but i'd stay with everything else there.
Hadleys all the way

 

[buildyourown]

Depending on the bike, you can save some weight with the chainguide.
I'm currently running an e13 with a custom alum plate. You don't really need a bashguard on a race bike. You can get away with an 1/8"-3/16" piece of aluminum.

Also, I'd really be surprised if you can save 1.5 pounds by going to Ti fork springs. I bet stock boxxer springs only weigh about 1.5-2#

 

[teamkranzelbike]

Depending on the bike, you can save some weight with the chainguide.
I'm currently running an e13 with a custom alum plate. You don't really need a bashguard on a race bike. You can get away with an 1/8"-3/16" piece of aluminum.

Also, I'd really be surprised if you can save 1.5 pounds by going to Ti fork springs. I bet stock boxxer springs only weigh about 1.5-2#

yea, going with the e13 and probably an aluminum ring, the fork springs will save bout a 1/2-3/4 pound and the shock spring bout another 3/4. wont know for sure till the fork springs are finished. already decided on dbl butt spokes, been using them a while and they are more reliable and lighter than straight gage. not too sure about the cranks, been considering xtr's but trying to shy from shimano. may go with a set of race face x types. considering the rider weight and cost possibly an the all mt. set (atlas?)with single ring.

 

[Kornphlake]

For a kid weighing 90# I'd think you could get away with a lot of XCish components. Last I heared (and I may be way off) Rhynolite XL's are lighter than 521's, you might be able to get away with something like 519's or whatever the all mountain wheelset is called. I think you'd be fine with some atlas cranks, although I don't know if they're any lighter than say XT. I'd think you could get off easily with single ply maxxis tires and stans too, you should be able to save quite a bit of weight there as a rider that light certainly doesn't need heavy tires.

 

[narlus]

since it's a light rider, try using 6" rotors rather than 8" (or 150mm vs 203mm, if you've got those type of brakes).

you also might be able to get away w/ non-DH cranks.

 

[DHRracer]

Just out of curiosity what frame and fork is it going to be?Also who's doing the fork springs?

 

[punkassean]

There is no reason to get away from Shimano components, especially cranks. Good luck finding lighter and stronger stuff. I'd suggest looking for the M950 XTR cranks and BB or the new XT's if not that then Middleburn with a Ti ISIS bb is your best bet. PM BrianHCM#1 about those if you are interested.

For rims, go with F519's (Now called XM719) as some have suggested, they are 460gm each and are very strong. I personally would go with alloy nipples but most would disagree. DT alpine spokes are also the best choice.

There is also nothing wrong with carbon, especially for a 90# rider. Easton's 225gm carbon DH bar is plenty strong for even full size adults. But light alloy bars are only 25-30 grams more. For a shifter go XT, it's lighter than XTR by about 10 grams.

I won't argue an e.13 guide and even the makrolon (or whatever) basher is not heavy. But a custom carbon or alloy one would be nice I guess. Don't skimp on the chainring, look for an older XTR or something similar. Most DH rings are waaaay beefier than they need to be.

Does he ride clips or flats? If flats go for most any magnesium pedals or Shimano DX's and for clips go Crank Brother's Mallet or Time platforms.

If you can find Ti hardware for the bike get it but some bolts are hard to come by.

For the seat I recommend WTB, either the Rocket V stealth Ti or the new Shadow V that saddle is super light and way more comfy than a Flite. Thomson post's can't be beat, get the "Masterpiece" version it is about 35-40 grams lighter and should be fine for a 90# kid. Thomson stems are awesom too, don't bother with the DH version, the regular style is available in a 35 & 50mm length and is plenty strong.

the last thing is tires/tubes, go "ghetto tubeless", it's the lightest no fuss way...

 

[teamkranzelbike]

Just out of curiosity what frame and fork is it going to be?Also who's doing the fork springs?

Kona is supplying an 05 Stab Supreme frame and the fork will be a Marzocchi 888. The brakes will be hayes, most likley el caminos. his uncle works for a huge industrial supply company and is using one of his contacts at a spring manufacturer to make a set of custom ti springs. they are going to be expensive, but the money saved from not having to purchase a frame, fork, and brakes leaves a lot for custom and higher end stuff. This is a good example and a big thanks to sponsorhouse. IT REALLY WORKS!! That and the shop sponsorship will build this rig probably, for the value of the frame.

 

[Echo]

If money is no object, doesn't E13 make a "race only" superlight version of their chainguide?

 

[DHS]

oh yea, the carbon guide plate, and cut down bash guard. SAWEEEEeeeet

 

[brake_and_bleed]

yeah, mrp carbon,
slr carbon seat, 173 grammes or something, the one with the ti rails and just a carbon platform, if your made of money that is!!
carbon post,
middleburn cranks with an xc bb... xc tubes
just watch the weight of those tyres!!

 

[BMXman]

so why does a 90# person need a 888...why not a 66 or something lighter...and yes I would just buy the thinner bashguard that evil offers....also rhyno-lite rims should be more than strong enough for someone so light. If he rides flats I would recommend wellgo mag pedals...I don't think there is a lighter flat pedal for the money....D

 

[leprechaun]

an XT crankset is as light as older 950-952 series XTR was and the new XT has more crank arm room for the swingarm.and the BB is designed with e type or a guide in mind for a centered chainline.
i'm 125lbs and have my bike to 39lns with the following mods
-721 rims-xc rims will be too narrow for the front tire to get a good contact patch. Ryno's are as light and wider,but not as strong
-thin bashring
-take a LX cass and remove the screws and ditch the 2 largest cogs.It will now be as light as Dura Ace! put some spacers where the cogs were.
-Hadley hubs
-Easton ea 70 alu bar,std dia.
-Thomson stem and post
-Maxxis 2.5's with stans
-WTB Rocket V,or Flite seat
-FSA orbit extreme HS,deep cups and aluminum super light for a strong hs.
-Try some 185 mm rotorswith avid adapters
-Shimano 545 peds or some mag platforms
- one X Firm spring in the fork or find a spring out of a single spring type fork like an old Foes one

 

[Spunger]

I agree fork wise, go with a single crown 5-6" fork. Save's a decent amount of weight there vs using a dual crown fork. I'd sell that 888 on ridemonkey and use the money from it to get a 66 from zocchi. I doubt even with soft springs he'll get that 888 to go it's full travel unless he smacks something really hard.

Ti hardware/springs if using a coil shock. If the frame will accept an air shock that'd drop some decent weight there as well.

Wheels I'd go with the EX721's. For that weight of a rider, even if he destroy's things, these are some of the best weight to strength rims out there. Use single ply tires with tubeless setup and you're on some pretty light weight wheels.

XT stuff as it doesn't weigh much more than XTR and is still easy to replace/work on and shifts crisp, no need to shell out money for XTR, just stick with XT.

Cranks.......middleburns. I think that might be the lightest combo. Truvativ holzfellers aren't too heafty but the middleburns are gonna be as light and strong. Chainguide E13 or custom drilled MRP (dunno how easy the custom MRP would be to come by).

Bars carbon of some type OR some EA70/Protapers. Add's only a few grams and costs half as much. Stem Thomson, headset Pig DH pro. Good strong front end there. Plus weight wise it's less than others + cost.

Other than that just build it and go!

 

[leprechaun]

-Dude when are you guys going to figure out that the 66 weighs 7.25 lbs and the 888 with flat crowns also weighs 7.25 lbs????????????????
-There are some lighter forks out there but he is getting hooked up with zoke.
-Even if a kid is only 90lbs if he is fast and a fork is set up right he should get full travel!! Good luck showing up Schweitzer with some 6" fork in the jrx class
-I would go 170 mm over 200 for the mauverability though.

 

[punkassean]

The Stab Supreme is a great bike, but the WB and specifically the rear-end is really long. He might have some trouble man-handling that thing. But then again he's only 90# so he might have trouble man-handling most any DH bike. He might be better off on a 7" Stinky frame with a floater from Brake Therapy. Just a thought...

Krispy's suggestions are really good. I agree that one fork spring should be enough.

 

[teamkranzelbike]

he may be small, but he is a very agressive, fearless rider. he is also very fast. believe me, he will use up every inch of the 888. the stab is a big bike,not as heavy as you think. he has no trouble hefting around my old m1. I am a little concerned about the slack head angle in the turns, but the biggest problem comes when you hit those peddling section. the heavy bike wont accelerate under his light weight and scrawney legs. he has been riding a stinky and doing great, the stab is a freebie, so you cant turn it down!!

 

[punkassean]

I am aware of the weight of the Stab in fact I never mentioned the weight. I am very familiar w/Kona's entire line. I managed their largest retail dealer in the world for three years...

The Stab Supreme is a great bike and your son is obviously a great rider. You should expect the bike to be right at or just under 40lbs complete. That is about the lightest I've ever seen a Stab and it was built with a works 888, a Ti sprung Romic. Wheels were Mavic EX823's on Hadley's with tubeless Michelin's.

Good luck to the kid!

 

[DHRracer]

I would really like to find out more about who is doing your fork springs.Are you going with a single side or running them in both sides?How tall is this rider?

 

[Jm_]

There is no reason to get away from Shimano components, especially cranks. Good luck finding lighter and stronger stuff. I'd suggest looking for the M950 XTR cranks and BB or the new XT's if not that then Middleburn with a Ti ISIS bb is your best bet. PM BrianHCM#1 about those if you are interested.

For rims, go with F519's (Now called XM719) as some have suggested, they are 460gm each and are very strong. I personally would go with alloy nipples but most would disagree. DT alpine spokes are also the best choice.

There is also nothing wrong with carbon, especially for a 90# rider. Easton's 225gm carbon DH bar is plenty strong for even full size adults. But light alloy bars are only 25-30 grams more. For a shifter go XT, it's lighter than XTR by about 10 grams.

I won't argue an e.13 guide and even the makrolon (or whatever) basher is not heavy. But a custom carbon or alloy one would be nice I guess. Don't skimp on the chainring, look for an older XTR or something similar. Most DH rings are waaaay beefier than they need to be.

Does he ride clips or flats? If flats go for most any magnesium pedals or Shimano DX's and for clips go Crank Brother's Mallet or Time platforms.

If you can find Ti hardware for the bike get it but some bolts are hard to come by.

For the seat I recommend WTB, either the Rocket V stealth Ti or the new Shadow V that saddle is super light and way more comfy than a Flite. Thomson post's can't be beat, get the "Masterpiece" version it is about 35-40 grams lighter and should be fine for a 90# kid. Thomson stems are awesom too, don't bother with the DH version, the regular style is available in a 35 & 50mm length and is plenty strong.

the last thing is tires/tubes, go "ghetto tubeless", it's the lightest no fuss way...

Man, your post makes so much sense. I'd suggest virtually everything you just did, and I've used all those products to boot.

Why do people immediatly suggest the heaviest derailer on the market when he asks for the lightest? Hmm, 230gm SRAM X0 at $200, or 230g Shimano XT at $70? (bike shop prices) Wow, that's a hard decision. I don't know how heavy their new rapid fire shifters are, but their twisties have been ballooning in weight over the last few years, and aren't as lightweight as the older stuff, although if this means metal "pawls/detents" then it's well worth it.

 

[teamkranzelbike]

I am aware of the weight of the Stab in fact I never mentioned the weight. I am very familiar w/Kona's entire line. I managed their largest retail dealer in the world for three years...

The Stab Supreme is a great bike and your son is obviously a great rider. You should expect the bike to be right at or just under 40lbs complete. That is about the lightest I've ever seen a Stab and it was built with a works 888, a Ti sprung Romic. Wheels were Mavic EX823's on Hadley's with tubeless Michelin's.

Good luck to the kid!

that is what we are shooting for, between 38 and 40 pounds. we have got some great ideas. he picked up some help from sun last night, so we will be running sun rims and I will be building them on hadley hubs, and we are going to run michelin tubless as well. will let you all know in a couple weeks how we make out.
and for everone asking about the ti fork springs. they are being made as a favor by a large spring manufacturer that has nothing to do with the bicycle industry, directly. They are going to be expensive even as a favor. The guy doing them rides and is just as curious as we are as to wether it is worth making them. and no, unless you are willing to buy like a 10 grand production run, they wont make them again. they will be a one off custom. although I do know a smal spring shop in Va. Beach that can handle the production of small qtys if you can get them a print. Dont know if the engineers will let me have it or not. I know there was a lot of reserch done on this guys part on just what was required to make them.