scootz
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| posted on 17/11/09 at 11:32 AM |
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An Old Chestnut... Bike Brakes on Se7ens!
Seen a few threads on this where folk have said they'll give it a go, but the thread usually peters out without a definitive 'yay, or
'nay'...
So, has anyone done it, and if so, how did you get on???
Also, I'm guessing the 'worry' has more to do with the (lack of) disc thickness as most sports-bikes tend to run a 5mm rotor???
It's Evolution Baby!
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tegwin
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| posted on 17/11/09 at 11:55 AM |
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I had bike calipers on my little race car with custom made disks.. they were 8mm IIRC
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www.verticalhorizonsmedia.tv
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matt_claydon
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| posted on 17/11/09 at 12:16 PM |
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Lack of thermal capacity is the problem. The disc needs to be able to absorb the kinetic energy of the car into thermal energy in the metal rotor
which then takes some time to co0l down.
A car has considerably more kinetic energy than a bike!
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blakep82
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| posted on 17/11/09 at 12:40 PM |
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^ was thinking that myself
the heat generated in a car will be much more than a bike, but there will be twice as many discs as on a bike...
how much does a bike weigh, and how much does a 7 weigh?
if the 7 is less than double the weight of a bike then might be ok
if its more than double the weight of a bike, forget it
in any case, i wouldn't trust it
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don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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scootz
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| posted on 17/11/09 at 12:45 PM |
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That's pretty much what I thought too, however, I've seen plenty of Se7ens with 10mm x 232mm discs which stop perfectly adequately... an
R1 has a 5mm x 310mm disc, so has more area.
Is this a factor???
It's Evolution Baby!
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ashg
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| posted on 17/11/09 at 12:49 PM |
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i do recall seeing a busa powered mini with bike brakes but dont recall the name of the chap.
a larger disc surface area will aid cooling but being thinner increases the risk of warping.
[Edited on 17/11/09 by ashg]
Anything With Tits or Wheels Will cost you MONEY!!
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Exocet (Finished & Sold)
New Project (Started)
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Miks15
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| posted on 17/11/09 at 12:51 PM |
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quote:
Originally posted by blakep82
^ was thinking that myself
the heat generated in a car will be much more than a bike, but there will be twice as many discs as on a bike...
how much does a bike weigh, and how much does a 7 weigh?
if the 7 is less than double the weight of a bike then might be ok
if its more than double the weight of a bike, forget it
in any case, i wouldn't trust it
Not quite, most sports bikes will have two discs on the front
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Miks15
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| posted on 17/11/09 at 12:51 PM |
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quote:
Originally posted by blakep82
^ was thinking that myself
the heat generated in a car will be much more than a bike, but there will be twice as many discs as on a bike...
how much does a bike weigh, and how much does a 7 weigh?
if the 7 is less than double the weight of a bike then might be ok
if its more than double the weight of a bike, forget it
in any case, i wouldn't trust it
Not quite, most sports bikes will have two discs on the front
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MK9R
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| posted on 17/11/09 at 01:09 PM |
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how about just using them on the rear?? It would save a good bit of unsprung weight
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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jacko
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| posted on 17/11/09 at 01:14 PM |
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Have a look at the car grass track world
a lot of people use bike brakes my mate used them on his race car
Jacko
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blakep82
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| posted on 17/11/09 at 01:25 PM |
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quote:
Originally posted by Miks15
quote:
Originally posted by blakep82
^ was thinking that myself
the heat generated in a car will be much more than a bike, but there will be twice as many discs as on a bike...
how much does a bike weigh, and how much does a 7 weigh?
if the 7 is less than double the weight of a bike then might be ok
if its more than double the weight of a bike, forget it
in any case, i wouldn't trust it
Not quite, most sports bikes will have two discs on the front
oh yeah, forgot about that. i never really looked at bikes 
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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blakep82
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| posted on 17/11/09 at 01:26 PM |
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quote:
Originally posted by scootz
That's pretty much what I thought too, however, I've seen plenty of Se7ens with 10mm x 232mm discs which stop perfectly adequately... an
R1 has a 5mm x 310mm disc, so has more area.
Is this a factor???
i've got a feeling (as far as heat goes) its not the area of the disc thats important, but the volume. ie how much metal there is to take the
heat
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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wilkingj
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| posted on 17/11/09 at 01:26 PM |
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Make sure whatever you do stands up to technical scrutiny.
If its not engineeringly sound for whatever reason, and you are involved in an accident, the insurance Co will reduce your payout or not pay at
all.
OK it may have passed a SAV/IVA, but is it worth the risk?
The weight saved is only really relevant if you are building a race car. These cars are for the Road, where the general public idiots abound.
Is it really worth taking ANY risk with your car, your life or someone elses?
Do it Right, Do Properly, and right first time.
You CANNOT be TOO SAFE.
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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beagley
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| posted on 17/11/09 at 01:36 PM |
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I would also think the amount of force applied to the brakes would be considerably higher than what they would receive from a bike. I know 7s
don't weight much, but when the car dives under hard braking the weight transfer has got to be much higher than what bike brakes are engineered
for. I would imagine that the front rotors would go away rather quickly.....
I'm not scared!!! I'm just marking my territory.
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tomgregory2000
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| posted on 17/11/09 at 02:11 PM |
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My 2 pence:
On a bike the rotors are exposed to full airflow over them!
On a car they are hidden in the weel so less airflow over them!
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russbost
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| posted on 17/11/09 at 02:17 PM |
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I can see absolutely no reason why they would not be perfectly adequate for road use & I would expect them to be fine for anything but the most
extreme track use. (this is of course assuming a light, sub 500kg car & that it does not have to carry 2 x 20 stone occupants).
The only time I think it likely you'd run into trouble is where you were on a circuit with several short to mid length straights with heavy
braking into tight turns & a car with big power that would generate a lot of kinetic energy very quickly & no long straights or long
accelerating turns to cool the discs off.
I have seen a disc completely "wrung off" its centre, but it had been worn by metal to metal contact near the centre to only around 2 -
3mm thick!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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Bluemoon
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| posted on 17/11/09 at 02:25 PM |
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Surprise, looks like your not going to get a yes or no!.. Personally I'd stick with the known car brakes.. If it was for track only I might be
tempted to try it and see..
Like said if insurance company finds out you are using bike brakes, they could indeed start to argue that car brakes would have been more suitable..
If we can't make our minds up then I expect an insurance based one would say bike brakes were in-sufficient (even if this is not the
case!)...
Dan
Dan
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ed1801
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| posted on 17/11/09 at 02:35 PM |
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Kinetic energy is 0.5 x mass x velocity squared
An R1 can do 190mph, and in doing an emergency stop from that would put 1.8 times as much energy into the brakes as stopping a 7 that is twice the
weight from 100mph... The twice as heavy 7 has to do 135mph to use the same energy to stop.
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RickRick
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| posted on 17/11/09 at 03:11 PM |
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it's my winter project, got the calipers of a fz6r, 2 piston opposed, and the front disks to match there going on the rear of the car,
keeping the car brakes on the front piston area is almost the same so i'm hoping blanace bar will be enough to take out the difference just
waiting on my brother making up the caliper brackets before i can work out the dism mounting
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scootz
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| posted on 17/11/09 at 03:28 PM |
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Hmmm.... some interesting thoughts there - thanks all! Keep 'em coming!
The 'technical scrutiny' aspect mentioned earlier is the one that's got me thinking the most... not so much from the insurance point
of view, but more in relation to being involved in a serious accident where someone else gets injured and my choice of brakes was to blame. I'd
have to be sure that the concept was sound for a road going car and I guess I'm never going to have that reassurance without there having been
some kind of study into the subject!
It's Evolution Baby!
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dinosaurjuice
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| posted on 17/11/09 at 04:06 PM |
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quote:
Originally posted by ed1801
Kinetic energy is 0.5 x mass x velocity squared
An R1 can do 190mph, and in doing an emergency stop from that would put 1.8 times as much energy into the brakes as stopping a 7 that is twice the
weight from 100mph... The twice as heavy 7 has to do 135mph to use the same energy to stop.
a lot of that energy is absorbed by air resistance.
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Richard Quinn
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| posted on 17/11/09 at 04:29 PM |
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I wouldn't get too hung up on the "bike brakes" being "bike brakes". Tokico 6 pots are 6 pot calipers just designed to
fit a smaller disc.
One thing to watch is the price of the pads. They can be hugely expensive for what is a very small pad!
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scootz
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| posted on 17/11/09 at 04:37 PM |
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Not got a problem with the calipers... I'm sure 4 x bike six-pots will do the business. It's more the necessary disc thickness (5mm).
It's Evolution Baby!
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russbost
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| posted on 17/11/09 at 05:28 PM |
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You can always go for a thicker disc & have a bit machined off the pads if necessary, pads won't last long mileage wise, but how many miles
a year are you going to do?
Also I have to take issue with wind resistance supplying much of the stopping power in an emergency stop!!! At 190mph, if you take your hand off the
throttle you'll slow down fairly quickly to about 100mph, but it will still have taken 3 football pitches, that's hardly an emergency
stop!!!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Wadders
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| posted on 17/11/09 at 05:32 PM |
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5mm on the rear works fine including heavy track use. Personally i would worry about using 5mm on the front, with anything much over 350kg, 8mm would
be a safer bet.
Al
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