2023 TT Regulations

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2023 TT Regulations

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Re: 2023 TT Regulations

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APPENDIX E
SIDECAR TT TECHNICAL REGULATIONS

Sidecar TT machines must comply with the following requirements.
1. ENGINE TYPES
1.1. Only serial production engines are permitted for this class and can be of the
following type:
1.1.1. Maximum 600cc, 4 stroke, 4-cylinder, production based.
1.1.2. Maximum 675cc, 4 stroke, 3-cylinder, production based.
1.1.3. Maximum 900cc, 4 stroke, parallel twin cylinder, production based.
1.2. V-Twin engines are not permitted.
1.3. Rotaryengines are not permitted.
1.4. Turbo charging and super charging is not permitted.
1.5. Over-boring is not permitted. Standard bore size for the chosen production-based
engine must remain unchanged.
1.6. Crankshaft stroke must be as found on the chosen production-based engine must
remain unchanged.
2. ALLOWED INDUCTION SYSTEMS
2.1. Carburettor engines are not permitted.
2.2. Fuel injection systems are permitted using only the throttle bodies for the engine
brand and type utilized. Injectors may be changed or modified.
2.3. Primary Butterfly cannot be changed or modified. Where fitted a secondary butterfly
or slide may be locked in the fully open position or removed.
2.4. Any fuel pump may be used.
2.5. Any fuel pressure regulator may be used but the fuel pressure must remain as
homologated.
2.6. The Engine Control Unit (ECU) and wiring loom is free.
2.7. All engine, gearbox and clutch modifications are allowed with the exception of bore
and stroke. This must remain as found on the homologated machine.
2.8. All external engine oil drain plugs must be correctly torqued and be security lock
wired.
APPENDIX F PAGE 170
2.9. Where practical, all external oil gallery plugs, pressure / temperature sensors
containing positive oil pressure must be correctly torqued and secured with lock wire
or some other form of security devise. As an absolute minimum all external plugs
must be installed with the use of a high strength thread locking agent and paint
marked to verify that this is the case.
2.10.Any external oil lines containing positive oil pressure must be of a suitable material
and construction. All oil line fasteners should be lock wired or at the very least be
secured with a high strength locking agent and paint marked to verify that this is the
case.
2.11.External oil filters (including those fitted with a drilled HEX) must be secured using a
suitable hose clamp (Jubilee type) and secured with lock wire in such a way as to
prevent it from undoing.
3. GENERAL CONSTRUCTION
3.1. The Sidecar may be placed either side of the motorcycle. Hinged sidecars and
steerable sidecar wheels are forbidden. Neither the competitor nor passenger may
be attached to the machine. Remote steering linkages and the use of articulated
joints in the steering mechanism are not allowed. By definition an articulated joint is
one allowing movement in more than one plane.
3.2. The three road wheels may be disposed as to give two or three tracks.
3.3. If three tracks are made then the centres of the tracks of the motorcycle shall not be
more than 75mm apart.
3.4. A passenger must be carried and must always be protected from the road wheels
and both primary and final drives either by mudguard or some other means.
3.5. The main frame (See Figure 1A) must consist of a minimum, of a steering head, a
frame to accommodate the engine, and a main spar to the sidecar wheel, which will
be made from good quality steel tube.
3.6. The tubing used for the construction of the frame may be of a circular or noncircular section. If circular, the outside diameter shall not exceed 101.6mm. If noncircular, the maximum cross section shall not exceed 101.6mm, measured at right
angles to any flat face.
3.7. These three components must be permanently fixed by TIG welding or brazing.
APPENDIX F PAGE 171
3.8. The rear swinging arm outer pivot housings (See Figure 1B) may be detachable from
the main frame, the pivot housings must be made from either steel or a suitable
solid aluminium alloy billet. The finished article if made from aluminium alloy must
be hard anodised. The use of castings for the outer pivot housings is forbidden.
3.9. The sidecar wheel upright or flange plate (See Figure 1C) at the end of the main
sidecar wheel spar may be detachable. The upright flange plate must be made from
either steel or a suitable solid aluminium alloy billet. The finished article if made from
aluminium alloy must be hard anodised, while any supporting tie rods to the upright
or flange plate must be made of steel. The use of castings for the sidecar wheel
upright or flange plate is forbidden.
3.10.The sidecar wheel stub axle housing (See Figure 1D) may be detachable from the
sidecar wheel upright/flange plate; the housing must be made from either steel or a
suitable solid aluminium alloy billet. The finished article if made from aluminium alloy
must be hard anodised. The use of castings for the sidecar wheel stub axle housing is
forbidden.
3.11.Reinforcement of the steering head is allowed. The steering head may be fully boxed
in. Should any lightening or inspection holes be added to the “fully boxed in” section
they will be deemed as still “fully boxed in” and not open.
3.12.The front forks are to be either a leading / trailing fork, or links with the wheel
equally supported on each side. The construction of the front forks and yokes must
be made of good quality steel and must be TIG welded or brazed during
construction. The lower loop must be made of good quality steel and TIG welded or
brazed during construction.
3.13.Minimum suspension travel to be 20mm.
3.14.The rear swinging arm must be made of good quality steel or aluminium, single sided
swinging arms are allowed, and must have minimum of 20mm of travel in a single
plane. The rear swinging arm pivot spindle must be 90 degrees to the fore and aft
centre line of the rear wheel. The swinging arm must either be welded or brazed
during construction; the dimensions for the swinging arm are free. Wishbone type
swinging arms fitted to monocoque chassis are forbidden.
3.15.The use of composite construction is forbidden with the exception of the sidecar
platform, i.e. aluminium or carbon fibre skinned honeycomb.
3.16.The use of titanium in the construction of the frame, front forks, handle bars,
swinging arm and wheel spindles is forbidden.
3.17.For wheel spindles, the use of light alloys is also forbidden.
3.18.Under trays must be detachable.
APPENDIX F PAGE 173
3.19.Monocoque construction is forbidden.
3.20.For the avoidance of doubt, the use of Brazing as a method of construction or repair
may only be adopted if the chassis, forks or swinging arm were originally produced
using this method.
4. ENGINE POSITION
4.1. The engine must be positioned in such a way that the centre line of the engine (by
definition a position midway between centre lines of outermost cylinders) shall not
exceed 160mm beyond the centre line of the rear wheel of the motorcycle.
4.2. The engine must be positioned behind the steering head and in front of the driver.
4.3. The drive must be transmitted to the road through the rear wheel of the motorcycle.
An engine positioned behind the competitor and in front of the rear wheel is
forbidden.
APPENDIX F PAGE 173
5. DIMENSIONS
5.1. The minimum weight for all sidecar outfits competing at the TT is 220.0kg. At any
time during qualifying or racing, the weight of the whole outfit (including the tank, its
contents and all bodywork) must not be less than the minimum weight.
5.1.1. There is no tolerance on the minimum weight of the sidecar outfit.
5.1.2. During the final inspection at the end of each race, the machines chosen will
be weighed in the condition they finished the race.
5.1.3. The addition of ballast in order to reach the minimum weight is forbidden.
5.2. Width (Overall Maximum) 1875mm.
5.3. Wheelbase (Maximum) 1651mm.
5.4. Track 800mm minimum, 1105mm maximum. The distance is measured from the
centre of the track left by the rear wheel to the centre of the track left by the sidecar
wheel.
5.5. Height (Overall Maximum) 800mm.
5.6. The ground clearance measured over the entire length and width of the vehicle in a
race ready condition, fully loaded with Driver, Passenger, and fuel must not be less
than 65mm with the steering in the straight-ahead position. Tyres pressures must be
set to recommended operating pressures and not over inflated. Note that the
ground clearance will be measured with all Bodywork fitted and secured to the
outfit. A tolerance of a maximum 3mm may be granted only if authorised by the
Chief Technical Officer.
APPENDIX F PAGE 174
6. STREAMLINING AND BODYWORK
6.1. All streamlining and bodywork must, when mounted and secured, be ridged enough
to prevent excessive flex and movement in order to eliminate the possibility of it
contacting / interfering with the steering system throughout its full range of
movement.
6.2. All main mounting pins/plates such as forward of the steering head must be secured
to the bodywork with a steel plate no smaller that 100mm square. This must be both
riveted and bonded (e.g. fibreglass/resin) to the bodywork in order to render it a
permanent and secure fixing point. For verification purposes all Rivet Heads must be
intact and visible on the outside of the bodywork.
6.2.1. For the avoidance of doubt. A main mounting point is defined as a fixture or
fitting that robustly secures the bodywork directly to the chassis.
6.3. There must be no fewer than four main mounting pins/pegs secured with “R” clips
dispersed appropriately around the main bodywork. All bodywork fixing pins/pegs
must always be secured with “R” clips or similar.
6.4. The streamlining and bodywork must be fixed securely to the outfit in such a way as
to ensure the integrity of the whole installation in the event of failure of any
individual mounting point.
6.5. The streamlining must be detachable for technical inspection.
6.6. Aerofoils or spoilers are not permitted on streamlining.
6.7. Whatever the position of the steering, there must be a minimum space 20mm
between the inside of the bodywork and any part of the steering mechanism or front
wheel/tyre. This includes but is not limited to: control levers, forks, dampers etc.
6.8. A solid and effective protection must be fitted between the competitor and the
engine. This protection must prevent direct contact between competitors’ body or
clothing and escaping flames or leaking fuel or oil.
APPENDIX F PAGE 175
7. PASSENGER PLATFORM
7.1. Minimum dimensions 800mm by 300mm measured 150mm above the platform.
7.2. The orientation is free.
7.3. DRIVER: The competitor in the normal riding position must be completely visible,
with the exception of the arms, legs, and feet from above.
7.4. PASSENGER: The passenger must be able to lean out to either side of the sidecar, for
this purpose the vehicle must be fitted with suitable handholds for the passenger to
hold on to when leaning out. The hand-holds must be of the closed loop type, a
single projection hand-hold is not permitted.
8. AIR INTAKES
8.1. Cooling air intakes must be so constructed that there is NO forward
projection/protrusion to catch or foul in the event of accident.
9. OIL AND COOLANT CONTAINMENT
9.1. In the area directly below the engine, the oil containment tray must be constructed
to hold, in case of an engine break down, at least half of the total oil and engine
coolant capacity used in the engine (minimum 5 litres).
9.2. The surrounding edges of the tray must be at least 50mm above the bottom of the
tray, measured vertically from the tray oil containment material must be fixed to this
tray and the sides.
9.3. The frontal edge of the oil tray wall must be extended upwards to arrive just below
(within 20mm) of the exhaust ports of the engine.
9.4. The rear face of the tray should be to the height of the swinging arm and the
minimum width should be equal to the width of the rear tyre.
9.5. The gear lever must exit via a rubber boot or two rubber curtains.
9.6. The chain slot must have a rubber/brush curtain fitted.
9.7. Holes for the engine mounts (hangers) must be sealed.
9.8. From a vertical view, the engine must be located completely inside the oil tray
platform.
9.9. The rear wheel must be protected from any possible oil spray. To make this
protection, the engine and rear wheel compartment must be separated. This
separation must be created by installing a solid divider (wall) running from the top of
the inside of the bodywork to the bottom of the oil tray. This divider (wall) must
overlap the rear edge of the oil tray down to the bottom.
APPENDIX F PAGE 176
9.10.Holes for the engine mounts (hangers) must be sealed.
9.11.From a vertical view, the engine must be located completely inside the oil tray
platform.
9.12.The rear wheel must be protected from any possible oil spray. To make this
protection, the engine and rear wheel compartment must be separated. This
separation must be created by installing a solid divider (wall) running from the top of
the inside of the bodywork to the bottom of the oil tray. This divider (wall) must
overlap the rear edge of the oil tray down to the bottom.
9.13.All machines must use this tray.
9.14.All sidecars shall attach oil absorbent materials of no less a quality than 3M Product
number T156 or CEP Sorbents product number CEP-EP100.
9.15.This material shall be securely fixed to the following areas of the sidecar:
9.15.1. The entire oil-tray, both the bottom and the inside walls of the same. The
volume of material used in this area, according to the manufacturers
specifications, shall absorb not less than 3 litres of oil.
9.15.2. Any bodywork directly covering the engine.
9.15.3. In the event that oil is absorbed by the material, it must be replaced before
the next track session.
9.16.The material must be attached in such a way that it should be easily replaced, yet
must not become dislodged whilst on the track, and its effectiveness is not inhibited,
i.e. if an adhesive is used it must not clog the material, causing it to lose its absorbent
properties.
9.17.All absorbent material shall be non-flammable by design.
9.18.Oil-lines containing positive pressure, if replaced, must be of metal reinforced
construction with swaged or threaded connectors.
9.19.Oil coolers must not be mounted on or above the bodywork of the sidecar.
9.20.The location of the oil tank and the oil cooler should be placed in a location where it
is least likely to be damaged on an accident.
9.21.Ignition pick-up covers must be lock wired.
9.22.Clutch centre covers must be lock wired.
9.23.All external engine oil drain plugs must be correctly torqued and be security lock
wired.
APPENDIX F PAGE 177
9.24.Where practical, all external oil gallery plugs, pressure / temperature sensors
containing positive oil pressure must be correctly torqued and secured with lock wire
or some other form of security devise. As an absolute minimum all external plugs
must be installed with the use of a high strength thread locking agent and paint
marked to verify that this is the case.
9.25.Any external oil lines containing positive oil pressure must be of a suitable material
and construction. All oil line fasteners should be lock wired or at the very least be
secured with a high strength locking agent and paint marked to verify that this is the
case.
9.26.External oil filters (including those fitted with a drilled HEX) must be secured using a
suitable hose clamp (Jubilee type) and secured with lock wire in such a way as to
prevent it from undoing.
9.27.Any machine wishing to use a chain oiling device for primary or secondary drive chain
lubrication may do so only if that system is fully enclosed to ensure the complete
containment of any excess lubricant.
10. AIRBOX
10.1.An airbox must be used with all engines.
10.2.The airbox intake sizes are restricted as follows:
10.2.1. If 1 intake is used a maximum of 103mm internal Diameter is permitted.
10.2.2. If 2 intakes are used a maximum of 73mm Internal Diameter per intake is
permitted or equivalent area if none circular section(s) are used measured
within 50mm of the point of entry into the airbox.
10.2.3. The maximum number of intake holes at the point of restriction i.e. within
50mm of the point of entry into the airbox will be either one for a single intake
or two for a double intake
10.3.The airbox must completely close around the induction bell-mouths
10.4.The throttle-bodies may be entirely within the airbox.
10.5.The engine must have a closed breather system.
10.6.The engine breather must be connected and discharge in the airbox.
10.7.The airbox must cover and collect fluids discharged from the bell-mouths.
10.8.The airbox must be constructed in such a way as to prevent any oil discharged in the
airbox from spilling on the track.
10.9.This oil containment must hold a minimum of 1000 cc of oil.
10.10. The airbox must be sealed to prevent spillage of oil or fuel.
APPENDIX F PAGE 178
11. OIL CATCH TANKS
11.1.Motorcycles must have a closed breather system. The oil breather line must be
connected and discharge into the airbox.
12. WHEELS
12.1.The minimum diameter of an inflated tyre must be 400mm. All wheels must be of
metal construction, any modification to the rim or the spokes of the original cast
composite wheel as supplied by the manufacturer is prohibited.
12.2.The use of magnesium wheels is forbidden.
13. STEERING
13.1.Steering of the front wheel must be accomplished by non-adjustable handlebars
securely fixed to the forks or yokes of the motorcycle. They must be secured to
steering members turning the front wheel and its supports directly with no
intermediate push or pull rods. Handlebars and all steering bearings must be located
on the sprung portion of the front suspension.
13.2.Any form of remote steering is forbidden.
13.3.Handlebar width 450mm minimum.
13.4.Steering lock angle each side of straight ahead position to be 20 degrees minimum,
measured at the headstock.
13.5.Whatever the position of the handlebars the front wheel must never touch the
streamlining.
13.6.Handlebar clamps must be carefully radiused and engineered so as to avoid fracture
points in the bar.
14. THROTTLE CONTROLS
14.1.Throttle controls must be self-closing when not held by the hand.
15. CONTROL LEVERS
15.1.All handlebar levers (clutch, brake etc.) must be ball ended. The ball diameter must
be as least 19mm permanently fixed and forming an integral part of the lever.
APPENDIX F PAGE 179
16. BRAKES
16.1.All three wheels must be braked. The brake system must consist of:
16.2.One main system with at least two circuits operating separately, one of the circuits
must operate on at least two of the three wheels.
16.3.If one circuit fails the other must work efficiently.
16.4.An emergency system operated by a handlebar lever with a simple circuit operating
on either the front or rear wheel of the motorcycle.
16.5.Only ferrous discs allowed.
17. TYRES
17.1.For all meetings the use of slick tyres is permitted. The wheel rim shall be at least
254mm in diameter and 64mm in width. The diameter of the tyre must be as least
400mm and the width 100mm, maximum front tyre width 220mm.
17.2.The surface of a slick tyre must contain two or more hollows at 180 degree intervals
or less, indicating the limit of wear on the centre and shoulder areas of the tyre.
When at least two of these indicator hollows become worn on different parts of the
periphery, the tyre must no longer be used.
18. MUDGUARDS AND WHEEL PROTECTION
18.1.The rear driving wheel must be covered down to the level of the sidecar platform on
the nearest side to the sidecar wheel.
18.2.The sidecar wheel must be enclosed from the sidecar platform.
19. EXHAUST PIPES
19.1.Exhaust fumes must be discharged in a manner so as to not raise dust, foul the tyres
or brakes or inconvenience a passenger or any other driver. The furthest extremity of
the exhaust pipe must not exceed a vertical line drawn at a tangent to the rear edge
of the sidecar platform. The exhaust exit pipe must be no more than 45 degrees to
the vertical
19.2.On the side opposite a sidecar the exhaust pipes must not extend beyond the
streamlining. On the other side the exhaust pipes must not extend beyond the width
of the sidecar.
19.3.Exhaust pipes must be fitted/positioned so that it is impossible for them to become
entangled with another machine.
APPENDIX F PAGE 180
20. FUEL TANK
20.1.Fuel tanks must be sufficiently independently protected from the ground. A nonreturn valve must be fitted to the petrol tank breather pipe. This pipe must discharge
into a suitable catch tank, minimum capacity 500ml.
20.2.The fuel filler cap must be fitted in such a way that it does not protrude from the
fairing and cannot be torn off in an accident.
21. BATTERY
21.1.The battery must be covered in such a way that neither the driver nor the passenger
can come into contact with the battery or its contents.
22. CUT-OUT DEVICE
22.1.An ignition cut-out must be fitted to operate when the driver leaves the machine.
This cut-out system must interrupt the primary circuit and must be wired for both
the supply and return current. The cut-out must be placed as near to the centre of
the handlebar as possible and must be operated by a non-elastic string of adequate
length and thickness and strapped to the driver’s body. A spiral cable (similar to that
of a telephone wire) of maximum 1m extended length is permitted.
22.2.Any electric fuel feed pump must be wired in such a way as to cut out if the engine
cut-out device is operated.
23. RED SAFETY LIGHT
23.1.Sidecars must be equipped for the duration of the event with a functional rear-facing
red anti-fog lamp, measuring a minimum of 30 sq.cm and producing a minimum of
1500 MCD continuous light. Pulsating lights are not permitted.
23.2.The light must be installed at least 100mm off the ground, located in the area
between the back wheel and the sidecar platform. The light must be mounted on a
part of the suspended body, (not on any unsuspended parts) and ensure no
obstruction from the fairing and/or the passenger.
23.3.The red safety light must be switched on at all times during every practice/race
session.
24. REAR VIEW MIRROR
24.1.External rear view mirrors having suitable dimensions and mountings are optional.
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Re: 2023 TT Regulations

Unread post by steve-e »

6. STREAMLINING AND BODYWORK
6.1. All streamlining and bodywork must, when mounted and secured, be ridged enough
to prevent excessive flex and movement in order to eliminate the possibility of it
contacting / interfering with the steering system throughout its full range of
movement.
6.2. All main mounting pins/plates such as forward of the steering head must be secured
to the bodywork with a steel plate no smaller that 100mm square. This must be both
riveted and bonded (e.g. fibreglass/resin) to the bodywork in order to render it a
permanent and secure fixing point. For verification purposes all Rivet Heads must be
intact and visible on the outside of the bodywork.

6.2.1. For the avoidance of doubt. A main mounting point is defined as a fixture or
fitting that robustly secures the bodywork directly to the chassis.
6.3. There must be no fewer than four main mounting pins/pegs secured with “R” clips
dispersed appropriately around the main bodywork. All bodywork fixing pins/pegs
must always be secured with “R” clips or similar.

6.4. The streamlining and bodywork must be fixed securely to the outfit in such a way as
to ensure the integrity of the whole installation in the event of failure of any
individual mounting point.
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Twirl
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Re: 2023 TT Regulations

Unread post by Twirl »

This modification of the rules regarding fairings is VERY welcome .
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