Don, I would leave the roll bar and front brakes / hubs alone. I'm aware of a
recent front hub problem which caused a wheel to fall off on a TR-3 based car.
Same hubs are used on the TR-4's. Most of us run stock front hubs and rotors,
but there's been recent discussion about making new aluminum front hubs to
eliminate this as a possible failure. Since we're generally running the stock
hubs, we don't have experience with the heat transfer from the stock rotors -
boiling the lube out of the bearings can cause interesting (and not in a good
way) failures too. The roll cage is a bit more questionable to me, but you've
got to keep in mind that the TR-4 frame and body was marginal from the
factory. It does definitely stiffen the front suspension and give you a
performance advantage (as do the ventilated disks), but in my mind it also adds
to the safety of the car. Since you've detuned the engine somewhat and you're
driving a TR-4, you're still not going to win a bunch of races. The 356's will
blow your doors off like they do ours. And keeping all the wheels attached is
a VERY desirable thing.
We certainly welcome another Triumph to the middle of the pack!
- Tony Drews
TR-4 vintage project under construction
co-driver of the uncle jack TR-4 (also under construction due to the rear axle
deal)
http://208.214.219.23 ("interesting" in-car video posted here among other
things)
Don Marshall wrote:
> At 10:11 AM 11/30/00 EST, WSpohn4@aol.com wrote:
> >In a message dated 11/30/00 3:00:41 AM Pacific Standard Time,
> >nobozos@ix.netcom.com writes:
> >
> >> You forgot to add the part about tying your roll cage to your suspension
> >> pick-up points - for safety, of course...
> >
> >And why do the Jag guys, who already have 4 wheel discs, fit either
> >ventilated discs from later models, or bigger Camaro discs? Safety, of
> course.
>
> I guess this is as good a time as any to ask some questions, since these
> two issues are at the top of my list..
>
> I'm in the process of retrograding a former SCCA TR4A for vintage, and all
> the basic work is done (stock bodywork, detuned and legal engine, stockish
> ignition, etc). What I haven't done yet is cut the cage loose from the
> front frame and replace the aluminum front hubs and ventilated disks with
> stock parts.
>
> I'm a novice driver and am reasonably sure I don't care about winning
> anything.. I'm also old enough that I value my body parts and would like to
> keep them functioning at their current level, such as it is. So my
> interest really is in safety. I know the front bars increase chassis
> stiffness, and that in the hands of a good driver that could be a
> competitive advantage, but I also have video of this very car T-boning
> another car at speed, doing serious damage to the front end but no damage
> to the driver. I don't know if there were no injuries because the cage was
> connected at the front, but it seems reasonable that it's safer the way it
> is than without the bars going to the front.
>
> The other issue is replacing the front aluminum hub and ventilated disk
> with 35 year old British iron, which is what I think originally started
> this discussion. There's been a rash of Triumph rear axle breakage
> recently and I believe there have also been some front hub problems
> reported. My understanding is that the replacement hub I already have on
> the car takes care of that, but that the heat from non-ventilated discs can
> then cause problems for the aluminum hub, hence the combination of hub and
> vented disc. I'm also aware that cooler brakes provide better stopping and
> might allow a driver to go deeper into a corner before braking, but again,
> I really am interested in the safety part of the equation.
>
> I'm willing to cut the cage and replace the brakes if necessary, but before
> I take the time and spend the money to downgrade them, I'd be interested to
> know whether there's anything to this and if I may actually be compromising
> safety in the interest of originality. I'm aware that some groups are more
> liberal in their interpretation of "safety" upgrades than others, and that
> if I decide to keep the bars and brakes I might be limited as to where I
> can race. I'd also hate to downgrade the car and then roll it into a ball
> because something broke that could have been avoided.
>
> Any input is welcome..
> Thanks,
> Don Marshall
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