So whats the deal with brake jack? My old stinky primo seemed to suffer bad from this malady. Now I got this Hairy Gary W/ the pivot around the bottom bracket, and I swear it seems like it doesn't jack at all. But I don't know if it's because of the pivot placement or something else. whaduya think?
I guess I don't know Jack.Brake that is
bambambam
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So whats the deal with brake jack? My old stinky primo seemed to suffer bad from this malady. Now I got this Hairy Gary W/ the pivot around the bottom bracket, and I swear it seems like it doesn't jack at all. But I don't know if it's because of the pivot placement or something else. whaduya think?
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Brake jack does not exist....
if you think brake jack doesnt exist, you havent ridden many bikes. Go ride a stinky, then go ride a turner 6-pack and come back and tell me that brake jack doesnt exist.
brake jack occurs when you are braking with your rear. It's severity depends on how hard you're braking and how much suspension is being used. Brake jack feels like the rear end tightening up. It doesnt absorb bumps as well and chatters on low freq bumps.
most 4 bar non-fsr horst designs suffer brake jack because they're essentially single pivots with respect to where the brake is. Generally frames have more brake jack when the brake mount is on the chainstay, and in fsr designs and essentially what floating brakes do is take the brake off the travel path of the chainstay and allow it to float in place keeping braking consistant and independant of the rear end activity.
brake jack occurs when you are braking with your rear. It's severity depends on how hard you're braking and how much suspension is being used. Brake jack feels like the rear end tightening up. It doesnt absorb bumps as well and chatters on low freq bumps.
most 4 bar non-fsr horst designs suffer brake jack because they're essentially single pivots with respect to where the brake is. Generally frames have more brake jack when the brake mount is on the chainstay, and in fsr designs and essentially what floating brakes do is take the brake off the travel path of the chainstay and allow it to float in place keeping braking consistant and independant of the rear end activity.
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While I agree with you regarding the Kona/brake jakc issue, i find it's not as bad as say a high/ forward pivot like a Bullit. High forward pivots exhibit the worst brake jack I've ever experienced. I have a Ginat AC & KHS Fr2000 and both do exhibit BJ, but it's less noticable than on the high forward bikes I've ridden. However nothing brakes better than an FSR or floater equipped bike.Zonk0u said:
I was justing using the two bikes as example becuase they're so similar in suspension design. The only exception being that the kona has its brake mount below the rear pivot, while the 6-pack has its' brake mount above the rear pivot... And the reason these two frames are so night and day is because of this (one gets horrible brake jack, the other gets hardly any)CRASH said:
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It's also highly dependant on the terrain you ride.
On super steep rocky stuff where you're going slow and trying to keep the bike in control (because there's no way else to do it) brake jack can cause you to easily lose rear traction, whereas an active system will keep the suspension planted and absorbing the hits.
If you're just riding at high speed through rock gardens on more level terrain, you may not notice it as much, or even at all. The harder you use the rear brake, and the nastier the terrain is, the more you'll feel it, but if you're going through nasty terrain and you try to brake in the smooth sections because that's where you get max traction, again, you may not notice it happening at all.
So, there are riders that pick up on "brake jack" a lot more than others, and for some people it's not going to be a big issue. Not saying that one kind of terrain is "better" or one person is "better", but I think it depends a lot on the terrain.
I do ride a lot of the super-steep stuff where I need the rear end to keep working. I do notice a difference between single pivots and 4-bars in that situation, but in the other situations (which compramise a much larger percentage of the time I spend riding) I don't notice it much.
On super steep rocky stuff where you're going slow and trying to keep the bike in control (because there's no way else to do it) brake jack can cause you to easily lose rear traction, whereas an active system will keep the suspension planted and absorbing the hits.
If you're just riding at high speed through rock gardens on more level terrain, you may not notice it as much, or even at all. The harder you use the rear brake, and the nastier the terrain is, the more you'll feel it, but if you're going through nasty terrain and you try to brake in the smooth sections because that's where you get max traction, again, you may not notice it happening at all.
So, there are riders that pick up on "brake jack" a lot more than others, and for some people it's not going to be a big issue. Not saying that one kind of terrain is "better" or one person is "better", but I think it depends a lot on the terrain.
I do ride a lot of the super-steep stuff where I need the rear end to keep working. I do notice a difference between single pivots and 4-bars in that situation, but in the other situations (which compramise a much larger percentage of the time I spend riding) I don't notice it much.
BB pivots: GOOD
I designed that bike years ago for Gary to get rid of brake and chainline problems that most DH bikes have. Add a floater and you can force the HG to squat with heavy braking. It must be installed differently than brake therapy instucts. Very nice for racing.......lowers the whole bike and carves loose clapped out corners well.bambambam said:
Get your Hairy Gary fix here
First is my old DH ride from back in the racing days. New parts of course, but same old frame. 42lbs. Over 60 days of Whistler on top of 3 years of local thrashing and 2 years of Pro DH racing. All on the same frame with only one repair from falling off a 10' skinny and denting the top tube (3 years ago). Yeah, steel....
Notice the 29er behind it. 16.7 chainstay on a 29er and fits the 2.55 WTB.
I cant seem to load more than 1 at a time.
First is my old DH ride from back in the racing days. New parts of course, but same old frame. 42lbs. Over 60 days of Whistler on top of 3 years of local thrashing and 2 years of Pro DH racing. All on the same frame with only one repair from falling off a 10' skinny and denting the top tube (3 years ago). Yeah, steel....
Notice the 29er behind it. 16.7 chainstay on a 29er and fits the 2.55 WTB.
I cant seem to load more than 1 at a time.
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Turner doesn't make FSR rear ends anymoreZonk0u said:
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artwork...good stuffDRTRIDR said:
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this has been posted before, but it might help some people
(scroll down for video)
http://www.konaworld.com/dope.htm
(scroll down for video)
http://www.konaworld.com/dope.htm
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Most bikes exhibit brake squat. Fabien Barel designed his floating brake arm to induce more brake squat to balance out the foward momentum braking produces.
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