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Originally Posted by sixshooter
(Post 1569380)
Very interesting. A unconventional solution for an unusual circumstance.
Will the pedal throw be too long? Some of the things i still need to figure out:
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About leg press of brake pedal. You should be able to press more than your body weight. I'm 160lb with zero gym/workouts and I think last time I did leg press it was over 250lb. Also press strength may be different for how that force is applied to pedal. Typically you never hit 100% brake pedal pressure I thought and on top of that when you hit it your in a thrusting action which will result in higher forces applied to brake pedal than a slow push. Kinda like kicking a door down vs pushing it down. I may be way off, just thinking out loud.
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Originally Posted by Joker
(Post 1569410)
How to run the lines? I guess i need to buy a flair tool. Wonder if they have them for rent?
Titan Flaring tool |
Originally Posted by IanIsInTheGarage
(Post 1569638)
About leg press of brake pedal. You should be able to press more than your body weight. I'm 160lb with zero gym/workouts and I think last time I did leg press it was over 250lb. Also press strength may be different for how that force is applied to pedal. Typically you never hit 100% brake pedal pressure I thought and on top of that when you hit it your in a thrusting action which will result in higher forces applied to brake pedal than a slow push. Kinda like kicking a door down vs pushing it down. I may be way off, just thinking out loud.
As thrust vrs. ankle action goes - its particular as well. My seat positioning is much higher than the normal diver positioning (Like a bus driver rather than knees up). This really limits my leverage to ~90 lbs max. I've got a new seat and seat riser on COVID backorder from Kirkey. Plan is to lower the steering column and seat riser to help with a better and more orthodox leg position. https://cimg8.ibsrv.net/gimg/www.mia...1da55183bf.jpg https://cimg1.ibsrv.net/gimg/www.mia...093ade1caa.jpg
Originally Posted by oreo
(Post 1569651)
Link to my thread on the Titan flaring tool, and Amazon copper/nickel brake lines.
Titan Flaring tool |
I was worried about pedal stroke length because of your leg length. I thought it would be really uncomfortable to operate at some point as that got longer.
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Originally Posted by Joker
(Post 1569410)
Yes, the smaller bores and extended pedals are probably going to be very long.. but like you said, the circumstances are weird.
Originally Posted by sixshooter
(Post 1569706)
I was worried about pedal stroke length because of your leg length. I thought it would be really uncomfortable to operate at some point as that got longer.
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Some good and bad news. Good news is I am stronger than I thought. I ran a pull scale on the current set up and estimate around 105 lbs of force at what i can only describe as "comfortable track pressure". I was able to gather around 160-165 lbs when I really put my back into it. (Guess you were right Ian). Not bad for 75lbs and one leg.. but I don't ever want to be in that position willingly.
The bad news is, after briefly speaking with someone who has experience designing brake systems (not sure if he wants to be identified)... his first thought is it cant be done =( I was learned that you need approximately 210lbs for manual brakes and my whole idea on extending the pedal is flawed. My understanding of where the fulcrum is was incorrect, and I was wrong in thinking adding height to the pedal would show a linear increase in force. In reality the fulcrum is between the pedal face and the plunger inside the master, and not between the pedal, and the master cylinder arm. https://tiltonracing.com/wp-content/...nstall-dwg.pdf I might need to go to plan B.. |
Originally Posted by Joker
(Post 1569754)
I was learned that you need approximately 210lbs for manual brakes and my whole idea on extending the pedal is flawed. My understanding of where the fulcrum is was incorrect, and I was wrong in thinking adding height to the pedal would show a linear increase in force. In reality the fulcrum is between the pedal face and the plunger inside the master, and not between the pedal, and the master cylinder arm.
For floor mount pedals, the mechanical advantage ("pedal ratio") for the system below is just (A+B) / B https://cimg0.ibsrv.net/gimg/www.mia...28969e8205.jpg |
Well - prototyping and testing took longer than expected. I knew that it would be about 50/50 chance I would be able to operate the manual brakes.
After some more research and feedback - I went with .811 front and .70 rear MC. https://cimg7.ibsrv.net/gimg/www.mia...0526153221.jpg https://cimg0.ibsrv.net/gimg/www.mia...df20fb6cc2.jpg https://cimg4.ibsrv.net/gimg/www.mia...4ea60f2e9a.jpg https://cimg0.ibsrv.net/gimg/www.mia...843fd2083e.jpg https://cimg2.ibsrv.net/gimg/www.mia...4291166e5d.jpg https://cimg4.ibsrv.net/gimg/www.mia...98ef472230.jpg https://cimg6.ibsrv.net/gimg/www.mia...a376828339.jpg |
Ignore the prototyping mess. To my surprise, I was able to comfortably work the brakes pretty well. However, any type of extra element or other non-optimal factor like heal-toe would put me into a unfavorable position. Especially at track speed, fatigue or brake fade.
This means I will scrub this plan and go with plan B - a combination of factory power brake MC with Tilton clutch and throttle pedals. This blows.. lost $400 on that test. |
How about relocating all three factory pedals by moving the mounting pivot points and extending the rods the appropriate amount?
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Originally Posted by Joker
(Post 1572791)
Ignore the prototyping mess. To my surprise, I was able to comfortably work the brakes pretty well. However, any type of extra element or other non-optimal factor like heal-toe would put me into a unfavorable position. Especially at track speed, fatigue or brake fade.
This means I will scrub this plan and go with plan B - a combination of factory power brake MC with Tilton clutch and throttle pedals. This blows.. lost $400 on that test. I present to you... Plan B. https://cimg9.ibsrv.net/gimg/www.mia...fa80238e6f.jpg https://cimg0.ibsrv.net/gimg/www.mia...fd1c988c8c.jpg https://cimg1.ibsrv.net/gimg/www.mia...13dff6c86e.jpg |
That looks like an excellent solution, especially for the brakes. The brake master would have been terrible to relocate and it looks like your solution maintains the same travel and effort. Good call.
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Looks great man. Love this build.
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Nice livery!
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