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Anybody injected foam inside the handlebars?

Verskis

Monkey
May 14, 2010
458
8
Tampere, Finland
The Spank Vibrocore bars got me googling about injecting foam inside the handlebars. Seems like it is well used trick to reduce engine vibrations on motorcycle handlebars, but has anybody done it on their DH bike?
Does it make any difference in reducing arm pump?
I think Spank's theory about arm pump being caused by low amplitude high frequency vibration rather than big hits might hold some truth, because I get roughly similar amount of arm pump on long mellow but fast trails as I get on some rougher trails.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,921
borcester rhymes
I think you'd find better success in ditching the lock-ons for rubber grips, or some brand that has mostly rubber with a plastic fixture. WTB 4-front and RavX are both mostly rubber.

Not buying the stiffest bar ever made is also a good solution.
 

marshalolson

Turbo Monkey
May 25, 2006
1,770
519
esi foam grips cured all hand-pump related issues for me.

but if you tried, i would assume silicon foam would be the best call to experiment with.
 

rollertoaster

Monkey
Aug 7, 2007
730
179
Douglassville , PA
I also love the esi grips. However I am going to try the vibrocore bars when they are available, because I bent another set of blacklabels, and I'm just not sure about carbon bars on the big bike.
 

metalMTB

Monkey
Sep 14, 2005
699
3
Richmond, VA
i agree with Sandwhich. I finally ditched my odi rogue lock-ons which I used for years and went back to the old school oury slip-ons. MUCH, MUCH better. I use alcohol and grip glue on the inside and once the alcohol dries the glue keeps them from slipping. They are so much better at absorbing the vibrations. I think the hard plastic inside the lock-ons is definitely a negative. Sure lock-ons are convenient, but comfort and superior vibration damping is better. I use the bmx version instead of the mountain version. They are a half inch longer and you can just trim the flange off if you don't like it or just trim it so the shifter or lever doesn't interfer. I like the flange personally so I trim it as minimally as possible without interfering with the controls.
 

StiHacka

Compensating for something
Jan 4, 2013
21,560
12,504
In hell. Welcome!
I love the Oury slip-ons, but they do not protect the handlebar from accidental damage (or your body from coring) when you crash unless you use some plugs, the bar just cuts through the soft rubber. I just had to deal with a case of a chipped carbon bar.
 

jasride

Turbo Monkey
Sep 23, 2006
1,069
5
PA
Dooood, that's like a 300 gram weight penalty, the difference between podium on the world cup and last place in cat 3.

Fo Shizz.... I take them out for my race run and replace with foam inserts, then put on my cape. Podium finish every weekend. ridewithweights.com
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,921
borcester rhymes
rubber directly on alloy/carbon has less vibrations than rubber on plastic on alloy/carbon?
no, thick rubber passes less vibrations than thin rubber. the rubber coating on a ruffian is like 2mm. A solid rubber grip might be 10mm. If you can find one that splits the difference, you win.

http://www.wtb.com/pages/grips these show the wtb 4fronts I like. They aren't nearly as robust as the lock-ons, but they never slipped on me and they're super comfortable. They have a nylon "skeleton" instead of a plastic core.

I've also used these: http://ravx.com/products/density-x-lock/ which have a plastic core on only one side. They were decent and have a better, all metal lock on clamp.

I also tried the ergon GA1 grip or whatever, which was basically a plastic tube sprayed with rubberized paint, no trace of vibration damping rubber to be found. They were the worst i've ever used. ODI intense lock-ons were pretty good, lots of rubber on those.

Of course, getting rid of my 2010 boxxer and hope brakes solved 95% of my arm pump issues, and then grip choice mattered so much less.
 

Bikael Molton

goofy for life
Jun 9, 2003
4,010
1,146
El Lay
it's bogus for motorcycles imho.

onroad bike - handlebar weights
offroad bike - quality aluminum bars rather than OEM steel cheese
 

Verskis

Monkey
May 14, 2010
458
8
Tampere, Finland
You can already shut up about the lock-on vs. regular grips, I ride both styles and do not notice a big difference. The grip thickness makes much more difference to hand comfort, too thin and my hands get cramps, too thick and I don't have enough strength to grip the bars. But this thread is not about grips, it's about DIY vibrocore bars. So nobody has tried it?
 

BigBoi

Monkey
Oct 31, 2011
310
50
Long Island, NY
The Vibrocore bars are dope. I finally ditched my Renthals after 3 years and got 2 DH days last weekend on my new Vibrocores.
Not sure if it's because the bar isn't as stiff as the old or from the foam inside, but I didn't get the finger lock as bad as I usually do on braking bumps, fast open sections, etc.

How were you planning on doing it? What material?
 
Dooood, that's like a 300 gram weight penalty, the difference between podium on the world cup and last place in cat 3.
Bullsh1t. Assuming that rider, bike, and gear weigh 220 pounds, 300 g is a difference of 0,3% of system mass. The weight difference is down in the noise range, Podium riders certainly tend to have the lightest bikes bikes, but it ain't a weight difference of a few hundred grams that yields the win.
 

joeg

I have some obvious biases
Jul 20, 2011
198
137
Santa Cruz CA
Is this true?

"Vibrocore leverages the fact that when energy waves pass between materials of different density, they dissipate."

What I'm reading from that is that if you used shimz of different densities, could you use less than moar of them of the same density material? Somebody ought to be patenting that! Density Utilized Modulation Behavior

and this gem stands out:
"Spank also noted more unexpected results such as their riders reporting heightened sensitivity to trail input, as well as a dramatic improvement in the lifetime of the bar itself."

AND THEY BROKE LESS TOO! SELL THAT QUICK JETHRO.
 

joeg

I have some obvious biases
Jul 20, 2011
198
137
Santa Cruz CA
I can't comment on foam in bars, but we at SCB recently developed a gang of handlebars. In the process, we threw out almost $20K in carbon bar tooling because the first bar we made, we were like "lets make the strongest bar EVER!!!" - and we made this 35mm dia, 800 width, 244g DH bar. it was hella strong! But then riders starting complaining about arm pump.
So we made some lighter ones of the same shape, and got it better, but eventually we ended up making a new external and internal mold to get more flex into the bar. Still as strong as DH bars on the market, but ended up lighter at 200g, and feels much nicer. Before you say "35mm - thats your problem right there", its also the reason we have DH strength at that lightweight. 240+g in a 31.8 can be made strong and have good flex characteristics too, at least from what i've tested and tried.
Doing A-B bar stiffness testing with the same geometry bar in different stiffnesses is eye-opening. I might have a couple of the early prototypes around if anybody wants to try it themselves.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,289
5,029
Ottawa, Canada
no, thick rubber passes less vibrations than thin rubber. the rubber coating on a ruffian is like 2mm. A solid rubber grip might be 10mm. If you can find one that splits the difference, you win.

http://www.wtb.com/pages/grips these show the wtb 4fronts I like. They aren't nearly as robust as the lock-ons, but they never slipped on me and they're super comfortable. They have a nylon "skeleton" instead of a plastic core.

I've also used these: http://ravx.com/products/density-x-lock/ which have a plastic core on only one side. They were decent and have a better, all metal lock on clamp.

I also tried the ergon GA1 grip or whatever, which was basically a plastic tube sprayed with rubberized paint, no trace of vibration damping rubber to be found. They were the worst i've ever used. ODI intense lock-ons were pretty good, lots of rubber on those.

Of course, getting rid of my 2010 boxxer and hope brakes solved 95% of my arm pump issues, and then grip choice mattered so much less.
Sandwich, have you tried the Easton grips? I don't know how thick they are, but for me they have proven to be the Goldilocks grip... just right.
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,031
5,921
borcester rhymes
I have not, do they rubber all the way through? That seemed to help for me, quite a bit, but everybody's grip preferences are different. I could never use an ODI Rogue or Oury but other people love them...
 

Bikael Molton

goofy for life
Jun 9, 2003
4,010
1,146
El Lay
Expanding foam - the sign of the true imbecile home DIYer, along with using channel locks on everything.

hehe TGIF

 

Bikael Molton

goofy for life
Jun 9, 2003
4,010
1,146
El Lay
keeping the mice out of his car?

i'm always getting mice and other rodents in my TR450... might expanding foam the sh!t out of it tonight after I've drunk a sixer.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,289
5,029
Ottawa, Canada
I have not, do they rubber all the way through? That seemed to help for me, quite a bit, but everybody's grip preferences are different. I could never use an ODI Rogue or Oury but other people love them...
no, it's rubber on plastic. but the rubber is different (Easton claims it's proprietary I think), and it does not wear out fast, it is thicker in the palm area, and just generally feels really good to me. I was having pain in the tendons over my knuckles on long days in the saddle, and these grips combined with thin gloves pretty much solved that issue. Funny thing is, I only bought them because of the colour!
 

Bikael Molton

goofy for life
Jun 9, 2003
4,010
1,146
El Lay
^ some BMW dweebs put the BBs in the wheels of their touring motorcycle behemoths too.

I always thought aluminum monocoque frames could do with a bit of in-fill. I'm thinking Foes especially might sound better filled with sand a la audiophile speaker stands.
 

kickstand

Turbo Monkey
Sep 18, 2009
3,441
392
Fenton, MI
I've heard of people balancing big fat truck tires with small BBs. http://www.pirate4x4.com/forum/general-4x4-discussion/516446-airsoft-pellet-tire-balancing-including-charts-calculators.html

Maybe you should fill your frame tubes with them to help balance out any high-frequency mouse squeeks or something.
I've tried that in the past with big tires as suggested on the pirate4x4 link, my results were that it sucked ass and did not work as advertised.

How do your grips affect anti squat? It's a big concern of mine when trying to dial out vibrations.