[CBR400RR]

I just finished the prototype for an underhung rear caliper kit I'm going to be making this month. The one in the pic is not the finished product as it will be angled foward another 1/2" towards the bottom of the swing arm and still has to be machined out of billet aluminum and anodized, what do you guys think?
You’re going from a single 34mm piston to twin 32mm pistons and from a cast bracket to a billet bracket that is almost twice as strong, easier tire changes, less weight and a lower center of gravity.
http://img.villagephotos.com/p/2006-...4/100_0658.jpg

[fc3s driver]

It's funny your working on one of these because I am also in the process of making one but for my 954. not sure but do you know if are bikes use the same caliper bracket, because I know they use the same rear caliper. also, are you making the bracket to use the stock hanger location or are you making it so it has a set scre in it? would love to more pics.

[CBR400RR]

Originally Posted by fc3s driver

It's funny your working on one of these because I am also in the process of making one but for my 954. not sure but do you know if are bikes use the same caliper bracket, because I know they use the same rear caliper. also, are you making the bracket to use the stock hanger location or are you making it so it has a set scre in it? would love to more pics.

I don't have a 954 in my shop right now to check but I'm sure there not the same. My bracket is using the stock bracket holder location as its safer then modifying the swingarm.

[fc3s driver]

Originally Posted by CBR400RR

My bracket is using the stock bracket holder location as its safer then modifying the swingarm.

totally agree, I see the ones they sell for the 1krr and most just use a set screw against the bottom of the swing arm.

[fc3s driver]

when I get mine to place where it actually looks like somthing I will post up some pics so we can compare

[Doomwitha929]

WELL, since you asked wht I think... I think A putting the rear brake UNDER the swing arm mean more downward force on the bike under hard braking. That being said I also think it would have virtually no effect on the handling or breaking or traction under braking at anything less then 10 tenths usuage on a race track. I also think that if you are breaking on the street or in a corner on the track with enough force on the rear break to require an even larger more powerful caliper then the one that it comes with one of two things will happen. One you are going to low side and crash because the rear wheels is going to lock up and wash out or two the force of gravity on your race track is far higher then everywhere else on earth. I also think that for the street you are more likely to get crap like dust, water and other road debris on the pads, caliper and disk then on a top mounted unit.
Also the top one looks cleaner and more integrated to the bike.

[CBR400RR]

My caliper is smaller than the stock unit and not any more powerful. Also a lot of bikes over the years including new ones have calipers under the swing arm and nothing bad has ever happened to those bikes. HRC has been running them on most of their race bikes too without any problems. If you don't like it that is fine as I'm making this kit for me and anyone else that wants it.
When I said it lowers the center of gravity I meant of the part as the closer to the ground you move parts on the bike the less it will affect the handling from left to right as the parts being lower will have less leverage. The bike basically pivots at the tires and the more weight you have higher up the harder it is to pivot from left to right.

[Doomwitha929]

I see your point.

[Doomwitha929]

I wonder what it would take to build a unit that goes on the indise of the swing arm instead of on the bottom. It would really clean up the lines.

[CBR400RR]

Originally Posted by Doomwitha929

I wonder what it would take to build a unit that goes on the indise of the swing arm instead of on the bottom. It would really clean up the lines.

Thorsten Duban in Germany makes one for the RC51 but it's so small you can't stop the bike at all as it's very weak and cost $500-$800 or something like that. The pads are the size of a quarter.

[Doomwitha929]

that blows. Too bad would be cool it if worked.

[CBR400RR]

Originally Posted by Doomwitha929

that blows. Too bad would be cool it if worked.

It looks very trick but you can only see it when it's off the bike....lol

[jonathan]

Originally Posted by CBR400RR

....

When I said it lowers the center of gravity I meant of the part as the closer to the ground you move parts on the bike the less it will affect the handling from left to right as the parts being lower will have less leverage. The bike basically pivots at the tires and the more weight you have higher up the harder it is to pivot from left to right.

Am I missing something here?
It is (or maybe was) a known fact that recent years bikes have an ever higher
CG to enable them a better turn in capability.
The low CG was the most problematic issue in the 89 NSR of Freddie Spencer,
same goes for valentino's 01 NSR where the worked hard on placing the motor
higher in the chassis to enable once more a better turn in.

One of the main diffrances in the SP2 chassis vs. the SP1 is the motor hanger which where made
more rigid and also carry the motor higher in the chassis.

Now you suggest that lowering the CG is better deal - has I know for sure you have a good reason for stating this - can you provide us, the non-professionals
with some explenation for this practice.

Thanks J.

[CBR400RR]

Originally Posted by jonathan

Am missing something here?
It is (or maybe was) a known fact that recent years bikes have a higher
CG to enable them a better turn in capability.
This was the most problematic issue in the 89 NSR of Freddie Spencer,
same goes for valentino's 01 NSR where the worked hard on placing the motor
higher in the chassis to enable once more a better turn in.

Now you suggest that lowering the CG is better deal - has I know for sure you have a good reason for stating this - can you provide us, the non-professionals
with some explenation for this practice.

Thanks J.

It's hard for me to expalin where everyone can understand what I mean. It's like having 5lbs on your hand and moving the weight or puttiong the same weigth at the end of a stick. The farther the weight gets from you the heavier it will be as it has more leverage. I guess having a bike with a higher CG will drop in faster but trying to pick that weight back up will be harder then a bike with a lower CG. Besides look at most race bikes and all most all of them have underhung rear brake caliper mounts, I'm just trying to make my bike and anyone else who wants to be diffrent, not change the world.

[CBR929RE]

I think its a good idea.

Fc3s keep us posted on yours. I think it would be a pretty nice little mod.

[christopherdrc]

I think it is well worth the try, and to top it off looks hot!! Keep us posted as to your finished product and whether you plan on making a few more after you have tested it. I am looking for wavy discs at the moment for my RC, where did you find yours and for how much?
Nice wheels dude!!!!

[CBR400RR]

Originally Posted by christopherdrc

I think it is well worth the try, and to top it off looks hot!! Keep us posted as to your finished product and whether you plan on making a few more after you have tested it. I am looking for wavy discs at the moment for my RC, where did you find yours and for how much?
Nice wheels dude!!!!

I have already had 12 people place a pre order as I hope to have the kits done this week. I like the wheels too there 10+lbs lighter than stock. The Wave rotors are $120.00 and I'm a dealer for Galfer and 60 othere companies.

[christopherdrc]

Originally Posted by CBR400RR

I have already had 12 people place a pre order as I hope to have the kits done this week. I like the wheels too there 10+lbs lighter than stock. The Wave rotors are $120.00 and I'm a dealer for Galfer and 60 othere companies.

Thanks dude, I have sent you an inquiry via e-mail....cheers.

[CBR400RR]

Originally Posted by christopherdrc

Thanks dude, I have sent you an inquiry via e-mail....cheers.

I'm not sure I got your e-mail.

[slammp]

I'll setttle the argument as to the physics for you. If you could send me a free set including the carbon wheels shown in the picture (I have a 2001 RC) I will run it all summer and give you rave reviews. On a personal note I think it looks nicer down low like you've done.

[CBR400RR]

Originally Posted by slammp

I'll setttle the argument as to the physics for you. If you could send me a free set including the carbon wheels shown in the picture (I have a 2001 RC) I will run it all summer and give you rave reviews. On a personal note I think it looks nicer down low like you've done.

No problem, I just need a $4000.00 security deposit.

[cbr900cycle]

I want one for the rc51, how much???
cbr900cycle@hotmail.com
Tim

[CBR400RR]

Here is a pic of the final product on the bike and it's 9oz lighter than stock and I think it cleans up the swingarm a lot IMO, also it was easier to change the tire.
http://img.villagephotos.com/p/2006-...4/100_0751.jpg