Hoyle suspension upgrade kits - a step change in improved handling
The improved handling and ride characteristics provided by fitting the front
and rear upgrade kits supplied by Hoyle Engineering are reported by V8 enthusiasts
as a "marked change" and "handling more like a modern car".
So we have taken a closer look at the information available from Hoyle Engineering
and gathered comments from Geoff King, a V8 member who has installed the kits
on his V8 Roadster Conversion. (Jun 04)
suspension upgrade kits are a step change in improved handling for the MGB and
its derivatives, including the V8 powered models. There are two kits - a replacement
double wishbone, coil-over front suspension system and a complete independent
rear suspension with a supporting sub-frame. They provide greatly improved
handling and ride characteristics which are comparable with the comfort and precision
of more modern cars some 40 years younger. The kits were designed and developed
by Gerry Hawkridge of Hawk Cars and John Hoyle, the former owner of NG Cars. Both
firms are highly respected specialist car manufacturers producing Cobra replicas
and thirties style roadsters based on MGB components.
key feature of these upgrade kits is they have been designed for easy fitting
and they maintain the track dimensions. No cutting of the bodywork or the chassis
is required and the original components could easily be refitted at a later date.
All parts are manufactured from good quality materials to very high standards
with powder coating being employed throughout. Every last nut and bolt is included
in each kit. Another feature is the suspension systems are adjustable - each telescopic
suspension unit is adjustable for ride height and damping, is factory tested,
and comes with its own performance report and a three year warranty. For those
who want a softer or firmer ride, optional springs are available.
Front suspension with the coil-over damper upgrade. (Photo: Geoff King)
coil-over suspension kit
The kit consists of upper and lower tubular
wishbones with dial-in camber adjustment and shims for caster adjustment, coil-over
shock absorbers, top turret, rose jointed anti-roll bar links, and all fittings
and fixings. The existing lower wishbone pivots and stub axles are retained, while
the cross member requires a minor modification by cutting and welding. A powder
coated pre-modified cross member can be supplied for an MGB on an exchange basis.
Both top and bottom wishbones can be fitted with standard MGB rubber bushes or
V8 metalastic, polyurethane or nylatron bushes if preferred. This kit is available
for the MGB, MGC, MGBGTV8, and MGBV8 Roadster Conversions. The kit is not available
for the RV8, but with additional modification it can also be used on the MGA.
The Hoyle replacement double
wishbone, coil-over front suspension system has been specially designed to overcome
some of the criticisms of the original front suspension set up and indeed some
of the alternative options that have been supplied as upgrades since. The wishbones
are fabricated using high grade tubular steel that improves the structural strength
and rigidity, the springs are positioned closer to the wheel enabling a much softer
spring to be used. This combination together with a high quality damper results
in a more supple suspension.
coil-over damper units are specially made with "click" adjustable, re-buildable
units with adjustable spring seats to enable the ride height of the car to be
changed. The springs supplied are a standard 2.25 inch I/D which are used in a
variety of special and race cars. These can be obtained in a wide variety of stiffness
anti-roll (sway) bar links are supplied with a spherical joint to provide a more
positive reaction. The bottom stub axle bolt is replaced with a special high tensile
bolt that has a small flat machined on it which carries two small snail cams.
This enables the camber angle to be adjusted simply and quickly. Several shim
washers used at the top end of the stub axle provide a small degree of castor
fabricated parts and springs are black coated, the dampers are chemically blacked,
and the nuts and bolts are bright zinc plated. Standard MGB lower inboard bushes
are used for the inboard ends of the new top and bottom wishbones. Polyurethane
replacements for normal road use are recommended and can be supplied by Hoyle
the front suspension upgrade kit is straightforward
some of the normal MGB components which are:
> Four front wishbone arms.
> Two spring pans.
> Lever arm shock absorber.
> Bolts and nuts
from the shock absorber mount, top and bottom kingpin assembly.
> Bump stop and spacers.
> "Rubber bush"
part of the anti-roll (sway) bar link arms.
The lower wishbone pivots and
stub-axle assembly are retained.
order to be able to fit a full size spring/damper unit of this type it is necessary
to modify the ends of the front cross-member to provide clearance. Hoyle Engineering
can do this for you or they can supply a ready modified, powder coated unit on
exchange. Some customers carry out the modification themselves, which involves
cutting off the end of the cross-member and welding in a gusset. That gusset is
also supplied in the kit.
kits are suitable for both chrome and rubber bumper cars. The ride height
of a rubber bumper car can be lowered using the spring height adjuster but this
will result in a similar amount of bump travel being lost.
rear suspension kit
The rear suspension kit provides a radical
change with a complete replacement of the rigid axle, leaf springs and lever arm
dampers with the IRS set up. It has been designed to cope with 400bhp and fit
around the existing bodywork, battery boxes, and fuel tank without modification
being necessary. The installation adds rigidity to the bodyshell and reduces the
un-sprung weight by 55 kilos with the overall weight the same as the standard
axle arrangement. Together with the softer springs and high quality dampers, this
results in a more supple suspension. Unlike the original system each wheel reacts
independently to the change in road surface so not upsetting the balance of the
car. The unequal length double wishbones ensure that for hard cornering, the small
camber change induced keeps the maximum amount of rubber in contact with the road.
kit provides a radical change with an IRS set up which is simply bolted on
The kit consists of a new sub-frame that supports the differential, upper
and lower tubular wishbones, coil-over dampers, machined alloy hub carriers, and
tiebars (with eight bolt fixing) to the spring eyebolt location. The upper and
tubular wishbones are shimmed for camber and tracking adjustment. The shims, in
the form of quick-change C washers, can be fitted between the wishbone pivot yokes
and the sub-frame to make minor adjustments to camber and tracking. Also included
in the kit are stainless steel braided brake hoses, handbrake cables, inner and
outer polyurethane wishbone bushes, and all fittings and fixings. The dampers
used are the same specification as those used in the front suspension kit. The
fabricated parts are black powder coated and the aluminium uprights are anodised.
drive train equipment is readily available from the Ford Sierra and Granada models
The differential, drive
shafts, hubs, stub shafts, drive flanges and disc brakes are sourced from the
or Granada. The half shafts require shortening to retain the standard track dimension
and can be supplied by Hoyle. Ford drive flanges can be used for centre-lock wheels
with a bolt-on splined adapter. Hoyle can supply a new flange with MGB stud pattern
for bolt-on wheels. All these Ford parts can be supplied as new or reconditioned,
or can be sourced second-hand very cheaply. There is a range of differential ratios
available with 3.1 to 3.9 (Sierra) and 3.3 to 3.6 (Granada). The Sierra unit has
a 7inch crown wheel and can cope with engine power of up to 250bhp whilst the
7.5inch unit from the Granada will withstand higher engine outputs. For those
with V8 powered cars that want to drive them hard, or use them for track days
or competition work, both differentials can be fitted with the standard Ford viscous
coupling type limited slip unit. Alternatively a Quaiffe torque biasing LSD could
and disc brake conversion. (Photo: Geoff King)
Fitting the kit is straightforward once the original axle, springs, and
dampers are removed. The replacement unit can be pre-built off the car and then
is raised into position. It is attached to the original damper mounts with four
bolts, the rear spring front eyebolt mounts via the tiebars with two bolts, and
the check strap brackets with two bolts. The stainless steel brake hoses mate
with the existing pipework and the dual handbrake cables and their linkages attach
to the handbrake drop link. The rear suspension unit can be supplied fully built
ready for bolting to your car.
The instructions with the kit cover setting
up both suspension systems. Hoyle Engineering note that some customers may find
this a little daunting with all the variables available - ride height, damping
rate, spring rate, and geometry adjustments - in which case Hoyle Engineering
say they are always available to discuss and advise on settings based on their
own experience and feedback from customers. This kit is available for the MGB,
MGC, MGBGTV8, MGBV8 Roadster Conversions, and the RV8.
with fitting Hoyle upgrade kits
Geoff King (Tartan Red 4309) )
from Kincardineshire mentioned he had fitted both Hoyle suspension upgrades in
his article on his conversion project. He changed the front suspension first and
found "the "hop, skip and jump" attitude around corners was
changed so the car then gave confidence that it will turn in and hold the line
without drama. Of course the dampers on the original front end were probably passed
their best but I am sure that the improvements I have seen from the Hoyle upgrade
kit are much greater than simply fitting new dampers could have achieved. To update
the front suspension and brakes I modified the rubber bumper type cross-member
with a John Hoyle coil-over damper conversion with unequal length double wishbones
replacing the standard lever arm dampers. The suspension has SuperFlex® bushes
and is fully adjustable for ride height, damper rate, and caster and camber angles.
To complete the front suspension I fitted a 7/8 inch anti roll bar and modified
the steering with a 'quick rack' assembly to reduce the number of turns lock to
then moved to the rear suspension. "I fitted the refurbished rear axle,
rebuilt with a 3.07:1 ratio crown wheel and pinion, but after less than 500 miles
the antiquated live axle and cart springs were sold and replaced with John Hoyle's
independent rear suspension kit. Like the front suspension, the IRS kit from John
is a high quality product, well designed and manufactured. The ride height, damper
rate and camber are all fully adjustable and the bushes are again SuperFlex®.
Incidentally, all the bushes used in the front and rear suspension are standard
MGB size (front lower wishbone) so future replacements should not be a problem.
The total weight of the suspension is slightly more than the live axle but the
unsprung weight is much less. The tube axle assembly, springs and dampers weighs
close to 100 Kgs, 85 Kgs unsprung. The IRS is approximately 105 Kgs with less
than 46 Kgs unsprung.
purchased a refurbished Sierra differential with 3.14:1 CW&P (the highest
standard ratio available), exchange-shortened drive shafts and new drive flanges,
dust shields, discs, pads, wheel bearings & seals and calliper overhaul kits.
A scrap Ford Scorpio donated its hubs, drive shafts and brake callipers; these
were refurbished prior to being reused. Assembly of the rear suspension was straightforward
with Sierra discs and rebuilt callipers; the completed sub-frame was then offered
up and bolted to the chassis. No new holes are necessary; the existing front spring
eye, the lever arm damper and check strap mounts are used - 8 bolts in total.
A new, heavy duty propshaft to mate the Rover LT77 gearbox to the Sierra diff
was purchased from GKN Driveline - suppliers of the original MGB propshafts."
What does a V8 feel like on the road with these Hoyle upgrade kits fitted?
Geoff King found the difference before and after fitting the Hoyle upgrades quite
marked and was clearly pleased commenting "the improved ride and handling
on the road with the modern suspension is excellent. Driving the car around the
Highland roads is a real joy; no more front wheel patter on rough surfaces, there
is very little roll and the back end stays firmly planted to the road. Axle tramp
has been eliminated and on hard acceleration the car just squats a little. The
brake balance seems perfect with the four pot Rover SD1 callipers at the front
and single pot Sierra callipers at the rear".
The Hoyle IRS kit offers many advantages
Hoyle independent rear suspension offers so many advantages it is difficult to
know where to start. Comfort has been improved as the suspension has much less
unsprung weight and the wheels react to bumps in a more controlled manner. In
damp conditions, when traction can be a problem, the wheels may still spin if
provoked, but axle tramp is eliminated and the whole car is much easier to control.
Axle location is greatly improved and I have just 3 or 4 mm between the tyre and
the arch, but know that rubbing will not occur as it could with a live axle".
John Hoyle on his stand at one of the shows he attends with his display
of Hoyle suspension upgrade kits. (Photo: Gavin Bailey)
toe in, caster and camber as well as damper settings are all adjustable and although
the suspension is too hard to be up to Mondeo comfort standards, there is a big
improvement compared with a standard MGB. Time spent experimenting with spring
rates could probably improve it even more." Probably for many enthusiasts
with modest technical understanding will find dealing with these variables a little
daunting and choose to see help from John Hoyle with suggested settings.
helpful backup service
supportive and helpful response provided by John Hoyle will be something you will
value and admire. It's where this small firm stands out as an example to many
larger traders if Geoff King's experience is anything to go by. Geoff comments
that "I can certainly confirm that John Hoyle is very helpful, I have
met him and his wife Barbara several times at motor shows, talked with them on
the telephone and have exchanged emails. He replaced my front springs without
charge when I felt the items supplied were too hard, and when I had a problem
with one of the dampers he immediately resolved the situation - in complete contrast
to some other suppliers!" Clearly this important but particularly so
when supplier and customer are over 500 miles apart in Geoff's case - it's not
so easy just to pop down! Other customers have commented on the splendid support
and service from John Hoyle. Gavin Bailey (Glacier White 0199) has met John Hoyle
and also reports he is a very pleasant person to deal with.
kits deserve their growing reputation for improved handling and ride performance
deserve their growing reputation for improved handling and ride performance. With
the support and service that comes with the Hoyle suspension upgrade kits, the
combination is a good quality offering for MGB and V8 enthusiasts. These suspension
upgrade kits are available from Hoyle Engineering at Epsom who have a useful
website with full information on their kits and a price list. Their contacts for
further information are:
John Hoyle by email
0208 393 2555
reserved by the V8 Register of the MG Car Club, PO Box 251, Abingdon-on-Thames,
Oxfordshire OX14 1FF