Combining Front and Rear Brake Controls?
#1
Combining Front and Rear Brake Controls?
I tried searching for this but couldn't find a thing. Is there a way to combine the rear and front brakes and have it controlled by just the hand or foot lever?
#4
Why would you want to do that?
If I was considering buying a motorcycle and it had "linked" brakes, that would be a deal breaker. I want to be able to control and modulate the front and rear brakes separately.
However, if someone had a handicap, I could see the benefit. But braking force would have to be balanced with a proportioning valve, or through ABS, to prevent the rear wheel from locking up too easily.
If I was considering buying a motorcycle and it had "linked" brakes, that would be a deal breaker. I want to be able to control and modulate the front and rear brakes separately.
However, if someone had a handicap, I could see the benefit. But braking force would have to be balanced with a proportioning valve, or through ABS, to prevent the rear wheel from locking up too easily.
Last edited by VTRsurfer; 05-06-2011 at 05:00 PM.
#5
#6
I'm not looking to sell my bike so I'm not worried about that, besides it would be reversible when that time comes.
My ankle was smashed up pretty good and I am finding it more difficult to use the foot brake. I'm just checking my options before giving up on riding the Chicken. I really don't want to go to a cruiser but that's going to be my only other option if I can't figure something else out.
Thanks for the replies.
My ankle was smashed up pretty good and I am finding it more difficult to use the foot brake. I'm just checking my options before giving up on riding the Chicken. I really don't want to go to a cruiser but that's going to be my only other option if I can't figure something else out.
Thanks for the replies.
#10
They used a master cylinder with appropriate size to work all three calipers. It will probably need to be bigger (more fluid to move and more brake piston area). Then their trick - a proportioning valve is used in the line to the rear caliper. The reason for the valve is to adjust the amount of pressure to the rear caliper to keep it from locking up under hard braking. They could adjust it for the track corner combinations too. The proportioning valve they used was a Chrysler truck part. No idea what though, we didn't need it since the weight of the Wing allowed the brakes to work fine by simply replacing the master cylinder with the biggest one Grimeca had at the time.
The only issue with this link brake set up is that you can not trail brake with only the rear wheel or brake exclusively with the rear brake.
If you need either of them you need to do a thumb brake or forget about linking them. Unless you want to hang another caliper back there for that exclusive purpose.
#11
Yes, Dr. John Wittner, who ran a National Endurance Champion MotoGuzzi LeMans back in the mid-80 (and also laid the groundwork for a lot of the changes in Guzzi's sport models well into the 90 as a consultant) gave me the information. We were doing a sidecar set up for a paraplegic and I knew Wittner ran a linked brake on the Endurance Guzzi with all braking at the hand lever. So I called him and got the lowdown.
They used a master cylinder with appropriate size to work all three calipers. It will probably need to be bigger (more fluid to move and more brake piston area). Then their trick - a proportioning valve is used in the line to the rear caliper. The reason for the valve is to adjust the amount of pressure to the rear caliper to keep it from locking up under hard braking. They could adjust it for the track corner combinations too. The proportioning valve they used was a Chrysler truck part. No idea what though, we didn't need it since the weight of the Wing allowed the brakes to work fine by simply replacing the master cylinder with the biggest one Grimeca had at the time.
The only issue with this link brake set up is that you can not trail brake with only the rear wheel or brake exclusively with the rear brake.
If you need either of them you need to do a thumb brake or forget about linking them. Unless you want to hang another caliper back there for that exclusive purpose.
They used a master cylinder with appropriate size to work all three calipers. It will probably need to be bigger (more fluid to move and more brake piston area). Then their trick - a proportioning valve is used in the line to the rear caliper. The reason for the valve is to adjust the amount of pressure to the rear caliper to keep it from locking up under hard braking. They could adjust it for the track corner combinations too. The proportioning valve they used was a Chrysler truck part. No idea what though, we didn't need it since the weight of the Wing allowed the brakes to work fine by simply replacing the master cylinder with the biggest one Grimeca had at the time.
The only issue with this link brake set up is that you can not trail brake with only the rear wheel or brake exclusively with the rear brake.
If you need either of them you need to do a thumb brake or forget about linking them. Unless you want to hang another caliper back there for that exclusive purpose.
But the rear brake can quite easily be made to operate "independant" of the front...
Have the front M/C operate the front calipers, and a slave cylinder for the rear brake, with a checkvalve... That means that you actuate the rear brake by the front M/C or the footpedal... The mechanical checkvalve closes of the cylinder that isn't operating, making sure you aren't putting undue pressure on the reservoair and seals... And by adjusting the slave cylinders mechanic advantage, you have the same feature as the adjustment valve...
Actually, I would like to fiddle with it, just for kicks... But I already have to many idea's and to little time...
#12
Thanks again all.
#16
Just so I understand. The vfr system operates off the hand lever but also goes off the foot pedal for varying the pressure or is it solely off the hand?
#17
I'm not sure exactly how the VFR system works, but to the best of my knowledge, most linked systems have the right foot brake lever operating the rear brake and one front rotor. The other front rotor operates off the handlebar lever. It's mainly designed for inexperienced riders who rely too much on the rear brake, or are afraid of using too much front brake. At least that's how I look at it.
It doesn't sound like that's what you're looking for.
You might want to PM calitoz to see if he can give you an explanation of exactly how the VFR system works.
It doesn't sound like that's what you're looking for.
You might want to PM calitoz to see if he can give you an explanation of exactly how the VFR system works.
Last edited by VTRsurfer; 05-07-2011 at 09:59 PM.
#18
I haven't played too much with it, but AFAIK, I got the basics on how it works... The VFR rear brake actuates one set of pistons on each front caliper and one in the the rear brake... The front brake actuates the other two pairs of pistons in the front, and the other one in the rear...
Ie for medium braking, it doesn't really matter if you stomp on the pedal or yank the handle, the result is the same... But if you really, really need to stop, do both... It's not ideal, but probably good enough...
Ie for medium braking, it doesn't really matter if you stomp on the pedal or yank the handle, the result is the same... But if you really, really need to stop, do both... It's not ideal, but probably good enough...
#19
I have an easy solution - don't use the rear brake. Not a big loss since you really shouldn't use it anyway. You could take the rear brake lever off my bike and I wouldn't know it for several days. The first time I would realize it was gone would be when trying to crank the rear sideways going into a turn - if that tells you anything about it's practical usefulness.
It's funny, the VFR800 guys go to lengths to de-link their brakes!
It's funny, the VFR800 guys go to lengths to de-link their brakes!
#20
Here ya go...this was just added today. It enables you to use your left thumb for the rear brake.
https://www.superhawkforum.com/forum...b-brake-25562/
https://www.superhawkforum.com/forum...b-brake-25562/
#21
I have an easy solution - don't use the rear brake. Not a big loss since you really shouldn't use it anyway. You could take the rear brake lever off my bike and I wouldn't know it for several days. The first time I would realize it was gone would be when trying to crank the rear sideways going into a turn - if that tells you anything about it's practical usefulness.
It's funny, the VFR800 guys go to lengths to de-link their brakes!
It's funny, the VFR800 guys go to lengths to de-link their brakes!
#22
I have an easy solution - don't use the rear brake. Not a big loss since you really shouldn't use it anyway. You could take the rear brake lever off my bike and I wouldn't know it for several days. The first time I would realize it was gone would be when trying to crank the rear sideways going into a turn - if that tells you anything about it's practical usefulness.
It's funny, the VFR800 guys go to lengths to de-link their brakes!
It's funny, the VFR800 guys go to lengths to de-link their brakes!
#23
Here ya go...this was just added today. It enables you to use your left thumb for the rear brake.
https://www.superhawkforum.com/forum...b-brake-25562/
https://www.superhawkforum.com/forum...b-brake-25562/
#24
On the 89 GoldWing the lines ran from the master cylinder to the right caliper, a double banjo bolt and a jumper line to the left caliper with another double banjo bolt and the long line that went up into the frame and back to the rear brake. Sounds like a lot of problem, but it was really simple. Braking was good, especially considering the weight of the Wing with side car. On a more standard street bike a proportioning valve would be good, possibly frame mounted in an accessable area to adjust on the fly or at least easily as needed for conditions. That was what the good doctor used.
The brake systems used on the VFRs I believe are the ones that use a three piston caliper. The front brake lever operated two of the pistons in each caliper on the front and one on the back. The foot pedal operates one piston per caliper on the front and two on the back. So front brake only has a bias toward the front with light rear and vice versa, with full pop going when all are anchored. I don't know about any anti-lock system if they have one.
The check valve thing with two master cylinders sounds interesting, but there still needs to be a flow from the caliper back to each one so I don't see how it would work. BUT, one of the linked brake calipers from the rear of a VFR or whatever other bike used it could be set up keeping the rear brake master cylinder to operate one or the other set of pistons while the front master cylinder worked the other ones. I know one is sealed off from the other, they don't have a complete fluid link from any one master cylinder, there are two complete independent circuits. The link is that the pedal operates part of both ends as does the hand lever. Now THAT would be easy while still maintaining a remote operating rear brake for really slipper situations. That is what I'd do if it was me. I like the idea of having a rear-brake-only for gravel, mud on the road, or grassy surfaces.
Now you have me thinking about it for the Zephyr. I kind of like the idea of some light brake drag from the rear when using the handlebar brake. I'm going to have to check into it. I'm gonna hit ebay right now to see what it would cost me.
Last edited by klx678; 05-14-2011 at 11:09 AM.
#25
I'm with Jamie on this one...back brake? whats that for?
Since starting to ride on the track I rarely ever use the back brake, the only instance I can think of is leaving a certain driveway which is gravel going downhill onto a busy flat road, don't want to the front to slide there....
So far the arguments I've seen for keeping the rear brake are controlling wheelies and making sound effects haha
Since starting to ride on the track I rarely ever use the back brake, the only instance I can think of is leaving a certain driveway which is gravel going downhill onto a busy flat road, don't want to the front to slide there....
So far the arguments I've seen for keeping the rear brake are controlling wheelies and making sound effects haha
#26
#27
BUT, one of the linked brake calipers from the rear of a VFR or whatever other bike used it could be set up keeping the rear brake master cylinder to operate one or the other set of pistons while the front master cylinder worked the other ones. I know one is sealed off from the other, they don't have a complete fluid link from any one master cylinder, there are two complete independent circuits. The link is that the pedal operates part of both ends as does the hand lever. Now THAT would be easy while still maintaining a remote operating rear brake for really slipper situations. That is what I'd do if it was me. I like the idea of having a rear-brake-only for gravel, mud on the road, or grassy surfaces.
Now you have me thinking about it for the Zephyr. I kind of like the idea of some light brake drag from the rear when using the handlebar brake. I'm going to have to check into it. I'm gonna hit ebay right now to see what it would cost me.
Now you have me thinking about it for the Zephyr. I kind of like the idea of some light brake drag from the rear when using the handlebar brake. I'm going to have to check into it. I'm gonna hit ebay right now to see what it would cost me.
And one piston at the time should be plenty to be linked to the front, or independantly controlled by the pedal... And the same applies as to the VFR, when you need all of it, clamp down on both...
Also, there should be plenty of old VFR calipers lying on shelves from people tearing them off... eBay might not be the right place, check the VFR forums...
#28
I'm with Jamie on this one...back brake? whats that for?
Since starting to ride on the track I rarely ever use the back brake, the only instance I can think of is leaving a certain driveway which is gravel going downhill onto a busy flat road, don't want to the front to slide there....
So far the arguments I've seen for keeping the rear brake are controlling wheelies and making sound effects haha
Since starting to ride on the track I rarely ever use the back brake, the only instance I can think of is leaving a certain driveway which is gravel going downhill onto a busy flat road, don't want to the front to slide there....
So far the arguments I've seen for keeping the rear brake are controlling wheelies and making sound effects haha
Well, there's one other reason as my fomer employer/dealership owner learned on his old CB900F back in 83. If you don't use 'em you lose 'em... He had the pistons stick on his rear brake, dragging down the bike until it pretty much was shut off. Had to pull the caliper and rebuild them. They need a bit of movement off and on to keep things working and maybe to "burn off" any moisture back there.
So even if you use them lightly, use them so you don't have a long walk home - without the bike, it may not be able to be pushed if the brake stuck hard enough.
#29
Actually, that sounds like a very simple, and effective way of creating a decent linked brake setup, no adjustment or checkvalve needed...
And one piston at the time should be plenty to be linked to the front, or independantly controlled by the pedal... And the same applies as to the VFR, when you need all of it, clamp down on both...
Also, there should be plenty of old VFR calipers lying on shelves from people tearing them off... eBay might not be the right place, check the VFR forums...
And one piston at the time should be plenty to be linked to the front, or independantly controlled by the pedal... And the same applies as to the VFR, when you need all of it, clamp down on both...
Also, there should be plenty of old VFR calipers lying on shelves from people tearing them off... eBay might not be the right place, check the VFR forums...
#30
Here you go:
GP Tech Thumb brake - Speedzilla Motorcycle Message Forums
Seller is member on this forum too......
GP Tech Thumb brake - Speedzilla Motorcycle Message Forums
Seller is member on this forum too......