Since the car is a street car (with probably some track time/autocross in
it's future, I hope!) I'd say that you probably have a workable solution for
street use. I'm with the guys that don't really worry about the rear brakes
on a front engine production type car - I've run stock rear pads on both the
Mini's and the Midget, paired with Hawke pads on the front. BTW, watch the
disc wear - Hawke Blue takes out discs very quickly compared to a streetable
pad - we took the discs on a Midget below spec in probably 6 races.
Brake locking is just like the difference between understeer and oversteer -
if the fronts are locking you see the wall when you hit it, if the rears are
locking you don't ;)
Cheers, Brian
At 01:22 PM 5/10/99 -0400, you wrote:
>I definitely suggest you try it again with the new tires first. See, this
>is why when you ask a question, it helps to provide the background up
>front. Knowing that you upgraded the front calipers, but ran the test on
>old tires does make a difference.
>
>Under hard braking, you are transferring weight to the front. The more
>weight you transfer to the front, the more grip your front tires have. If
>the tires are old and hard, they will reach their limit sooner, therefore
>you will not get to the max weight transfer you will see with new ones.
>The weight transfer has a lot to do with the brake balance. Ideally, you
>do want the fronts to lock slightly before the rears, but a big imbalance
>does not inspire confidence. Again, with new tires, you will get more
>weight transfer, which changes the brake balance. That's why a balance bar
>for a dual master setup or a proportioning valve (where legal) is a good
>thing. You can adjust the car for changing conditions.
>
>Gavin Ivory wrote:
>>
>> Thanks everyone for all the help. Though not yet a participant in vintage
>> race, I enjoy all the mail, and soak up the advice. I should have made clear
>> my car is not vintage eligible, and never will be. Hopefully it's a
>> transition car, until I can find out how to make my "other life" fit with a
>> growing vintage obsession.
>>
>> The car is a '79 TVR Taimar 5000 [302 Ford], "street legal" [well... sort
>> of] . I've already spent too much on it [her words, not mine]. But the
>> handling is getting there [2300lbs; 50/50]. The power is certainly there
>> [close to 300hp]. Re: the lock-up problem: It is definitely the front brakes
>> locking ... I did have a friend watch while I stomped the brakes on the
>> front straight at Shannonville during a driving school. I was wearing at
>> the time a set of very old, hard Yoko 008's. Just replaced these with new
>> Kumho V700's: maybe this will help?? MC is original Girling [off the TRs, I
>> think]. Front brakes: I replaced the orig. TR6 solid disc 2 pots in favor of
>> 4 pot Wilwoods, Hawke blues, and 11" vented rotors. Supposed to be a
>> similar volume of fluid as the original set-up. But they sure stop fast.
>> Whatta difference. I didn't feel safe with the original brakes.
>>
>> So I'll check that the rear brake line is good all the way, then look
>> further in to an different MC arrangement.
>>
>> Mosport in July sounds like it'll be a blast. I might get there for a few
>> hours, as a spectator [there, doesn't that sound wistful]. One day...one
>> day...!
>>
>> Gavin Ivory
>> Toronto
>
Brian Evans
Director, Global Sales
UUNET, An MCI WorldCom Company
|