New S&M raceforks for 20mm hubs

[SaMAlex]

I dont know much about racing BMX's but I do know the big boys go real fast. The stresses involved are gnarly and even "light bikes" need to be able to hold up to the job. I just lifted these pics and story from the S&M site.



Yesterday we posted a photo of some prototype forks with new style drop-outs, on our S&M Facebooger. Some of you got your panties in a bunch real quick, but here's some info to pick that wedgie from yo ass. These are 20mm "Through Axle" dropouts made for the newer race hubs. The current forks suitable for these hubs are basically shit. So we opted that we get some American quality in that game. Keep checking back for updates on these bad boys.


We wanted to make a burlier race fork for the new 20mm race hubs, after seeing this vid.

http://www.youtube.com/watch?feature=player_embedded&v=ZvAATM108gw

[Dark Diggler]

Just need suspension and a tapered steerer now

[Peter J]

Looks like the stem came off the forks on that vid  

The 20mm idea is a bloody good one (I know that others have done it) with a larger bore more rotational stresses can be displaced, there would be a fraction of additional energy displaced with the additional surface area contact but this would be counter acted by the reduction in heat transfer and also reduced rolling resistance on the bearings I think (would have to run the numbers) the kinetic energy used would also be less providing that everything has been “true” and there is no rotational motion or as a simple engineer like me knows it as……wobbly wheel  

I also think that we’d need to consider another factor with the large bore axel………….I think it looks cool as fcuk  

[SaMAlex]

Looks like the stem came off the forks on that vid  

From what I've read, the steer tube of the forks snapped (I think they might have been ally!), meaning the top of the forks came away with the stem and the legs of the forks went the other way 

[Dannywhac]

An alloy steerer? K'in 'ell. So it looks like it went around the star fangled area then.

[SaMAlex]

An alloy steerer? K'in 'ell. So it looks like it went around the star fangled area then.

"The current forks suitable for these hubs are basically shit."


Sure sounds like it! No point having a nice solid 20mm "Through Axle" if the fork legs dont stay on 

[Peter J]

Just watched the Vid from answer explaining what went wrong and the steer tube did snap  

[SaMAlex]

Just watched the Vid from answer explaining what went wrong and the steer tube did snap  

Ooh, Ive not seen that. Link?

[Dannywhac]

I've just watched that as well - it's here:

http://www.youtube.com/watch?annotation_id=annotation_800801&v=_koaE2qaCpw&src_vid=ZvAATM108gw&feature=iv

So it was the compression cap + spacers......now embarassed for being all 90's and calling it the 'star-fangled area'

[SaMAlex]

So it was the compression cap + spacers

I'd say that its not really to do with using spacers (although I do think you should always run the stem right down and use a stem & bars to give you the height you want). Its more from having the thread inside the fork going below the stem. If people didnt use spacers on those forks, then they removed the problem because the stem would be lower than the threads.

Its pretty crazy to have a thin, light steer tube and then cut a thread into the inside of it. Esp as the "solution" is then to screw a big lump of ally in there. Why not make the tube thicker in the first place, and/or have a separate insert with the threads on it? (glued or welded in)

All S&M forks have a threaded insert welded into the top of the forks. I dont like it cos it makes it harder to get a cable down there, but Im in a minority, for sure

When the first clamp on stem/ forks were coming out, Hoffman bikes had the exact same problem with the top of their Super forks snapping off.

[Dannywhac]

I remember the Hoffers fork problems. You're right - they might have well just perforated the top of the steerer. Can't see that the lump of ally will sort a lot either - the steerer's still gonna strees around those there threads.

Oooh yeah, and cheeky pm coming your way

[SaMAlex]

they might have well just perforated the top of the steerer.

      Exactly!

[stidds]

S&M could have saved so much time and just bought loads of Odyssey Xtro forks and re-stickered them.. 

[SaMAlex]

S&M could have saved so much time and just bought loads of Odyssey Xtro forks and re-stickered them.. 

As said: "The current forks suitable for these hubs are basically shit."   

[HEYWOOD BMX]

  Sinz,Redline and ABD already have 20mm through-axle hubs on the market.The premise is that it increases power transfer.Not too convinced myself as modern forks are already stiff enough and the only front axle I`ve ever broken was a Shitmano DXR.A thru- axle on the rear is understandable maybe but wouldn`t larger cone nuts and bigger bearings solve this "problem"?

 

[Dark Diggler]

The forks in that video are a using a std 10mm axle and the forks are Answer Dagger carbon/alloy.
A 20mm thru axle is overkill on decent cromo forks, pointless. I get it on the new rear frame dropout/axles for racing because its stiffer than 10mm axles/bolts when sprinting

[rooski]

Looks like bike companys makin new standards and chasin sales again

20mm axles are not needed on cromo bmx race forks,why go from 10mm,which works well, to double that

99% of racers wont benefit from this standard,supercross maybe.

[motomagII]

should my new set bombshells require 20mm axles with my fat arse riding it lol
yea i agree cant see the point at all to be honest

[rooski]

should my new set bombshells require 20mm axles with my fat arse riding it lol
yea i agree cant see the point at all to be honest

Think you will be Ok as long as you fit them carefully

The dropouts look a bit skinny on them though,make sure theres some washers on there, so they dont spread when you tighten em Greg

[oldtired]

i thought s&m already did a frame/fork  with round dropouts, for the 20mm through hubs , ?  W.T.F i think

[SaMAlex]

i thought s&m already did a frame/fork  with round dropouts, for the 20mm through hubs , ?  W.T.F i think

The W.T.F. forks do have the enclosed dropouts but they are for 10mm bolts (eg, profile hubs).

I have a set of Pitchforks with enclosed dropouts that I use with a WTP front hub. I LOVE it!
I have an irrational fear of my front wheel falling out, I always have had!

[oldtired]

 

[elevensies]

mmm.....

not sure im buying into the through axle, ok for bouncy forks, not sure about 20'', there should be less flex in there already,

im ususlly totally wrong though