Sidecar mounting details are illustrated on Page 6 of the Rider's Handbook, 6th and later Editions, and further reference is made to Diagram M021, M022 and M025 of the illustrated Spares List. 

Page 6 Riders Hanbook
Diagram M021
Diagram M022
Diagram M025
page 6 riders handbook MO21

Mounting Bracket
Any normal type of sidecar can be fitted with either right or left hand mountings. The point that must be most carefully noted is that in no circumstances is it permissible to attach the rear fitting of the chassis to the rear fork of our motor cycles. There may be a tapped hole at the bottom end of the rear fork which may appear as if it is intended for this fitting. This is not so: the rear attachment for the chassis is a point adjacent to the rear fork pivot bolt. A special part obtainable from the factory, part number FT170 Sidecar Mounting Bracket, is the correct fitment. This consists of a triangulated bracket with a hole in each corner; these holes accommodate the pivot bolt, the bottom pillion foot rest plate bolt, and in the case of the 1000 c.c. models, the horn bolt. In the case of the 500 c.c. models; there is a hole in a similar position.

Horn Mounting
The first mentioned bolts are left long for the purpose of accommodating the bracket. The horn bolt on the 1000 c.c. models, however, is of the correct length for solo use due to the necessity to keep the horn clear of the pillion passenger's foot, so that when mounting the sidecar bracket it is necessary to shorten the horn distance piece by 5/16 in. (7.94 mm).

Sidecar Attachment Points
The four point attachment is made by attaching one point through the front prop stand pivot, the second through the head lug immediately beneath the front of the tank with the third attachment being made just below the rear frame springs' front mounting, occupied by the horn of the 500 c.c. machines. This component should be moved to the position it occupies on the 1000 c.c. models, i.e. on the left hand pillion footrest plate. The fourth attachment is to the mounting bracket
FT170 described above, which is tapped 3/4 in. x 20 TPI.

Fitting a Sidecar
This operation is best carried out by the sidecar manufacturers, retail distributors who are familiar with mounting sidecars alongside our motorcycle products, or alternatively our own Service Department. There are several acknowledged schools of thought with regard to sidecar fitting but broadly speaking, attention to the following points will give complete satisfaction:

1) The sidecar should be as close to the machine as possible, taking into consideration handlebar clearance with the sidecar windscreen, leg room between the motor cycle tank and sidecar body, and sufficient leg room between chaincase and chassis member. Attention to these details will undoubtedly improve performance, but at the same time it must be borne in mind that in the case of a light sidecar the weight may be insufficient to guard against "lifting", the narrower the track becomes.

2) It is generally accepted that the sidecar wheel should be between 2 and 3 in. (50.80 and 76.20 mm) in front of the rear wheel. Greater lead of the sidecar wheel is permissible if dictated by personal preference or design of the chassis, the maximum being approximately 9 in. (228.6 mm.).

3) For perfect steering it is necessary to have a toe-in between 1/2 and 1.1/2 in. (12.70 and 38.10 mm) and the best setting will be found by experiment. The toe-in is quite easily calculated by putting a straight length of wood or straight-edge, alongside the two motor cycle wheels allowing, of course, for the difference in tyre sizes, then placing a similar straight-edge alongside the two motor cycle wheels allowing, of course, for the difference in tyre sizes, then placing a similar straight-edge alongside the sidecar wheel, and on measuring the distance between the straight edge and the front of the front tyre, and the rear of the rear tyre, the amount of toe-in can be ascertained.

The motor cycle should have a slight lean-out, approx. 1/2 in. (12.70 mm) away from the sidecar, as this tends to ease the stresses on the cycle and chassis.
As Vincent machines have a long movement spring frame it is desirable to have the right hand rear corner of the sidecar chassis slightly higher than the left-hand sidecar wheel side, this instruction of course applies to the left hand mounted sidecars, and is reversed for a right hand mounted chassis. Correctly positioned, and the rider seated, the rear chassis tube should lie parallel with the ground.
When adapting a sidecar from a rigid frame machine for use with a Vincent motor cycle, it is most desirable that the special fittings are obtained from the manufacturers as some sidecars will not easily lend themselves to home adaptation.

Cycle Modification
A) In the case of Vincent machines fitted with Brampton forks, the No.6 Top Fork links will be needed to give the forks sidecar trail, but in the case of Series 'C' machines, this trail variation is provided for by rotating the eccentrics at the bottom of the head stem through 180 degrees, see Instruction Sheet No. 14, Vincent Girdraulic Forks.

B) It will be found that the solo frame springs on Brampton forks, especially on 1000 c.c. machines, are not sufficiently heavy for sidecar work and sidecar springs are normally recommended.

C) Regearing is, of course, necessary, but with a Vincent Motor Cycle this is easily accomplished by fitting a larger rear wheel sprocket to the brake drum; by reversing the rear wheel fitted with two sprockets, solo or sidecar ratios may be obtained. On 1000 c.c. models a 52, 54 or 56 tooth sprocket is normally required according to the weight of the sidecar and load carried, or the type of country normally traversed. On 500 c.c. models, 56 or 58 teeth sprockets will usually cover all requirements.

Conversion Set
The standard sidecar conversion set comprises the undermentioned components.
1ea H5/--Rear wheel sprocket (when ordering, the number of teeth required to be inserted after the oblique stroke).
2ea  F84/0           Sidecar frame springs "0" SWG - 0.324 in. (8.23 mm) dia. - All models
1ea   FT170         Sidecar mounting Bracket
1ea   FT213/1R   Top Fork Links - Brampton Fork models only.
1ea   FT213/1L
1ea   FT230/l       180 lb. Fork Spring. Brampton Fork models only (if not already fitted).
10ea   589           1/4 in. x 5/8 in. BSF Setscrews
10ea   91              1/4 in. BSF Nuts
10ea   413           1/4 in. Shakeproof Washers
6ea    PR2            Links of 5/8 in. x 3/8 in. Roller Chain - 46T to 56T Sprocket
1ea    PR2A          5/8 in. x 3/8 in. Spring Link
1ea    657             3/8 in. x 1.3/4 in. BSF Bolt ) 500 c.c.
1ea    198             3/8 in. BSF Nut   ) 500 c.c.
1ea    361             3/8 in. Spring Washer ) 500 c.c.

Depending upon personal preference, load normally carried, weight of sidecar or nature of country normally traversed, the standard handlebars may not give sufficient leverage, and if so sidecar bars should be fitted. Spigoted handlebar extensions HB15 were available for the very early machines. The bars and spigots were drilled through, a 3/16 in Mills pin fitted and the assembly brazed. The extensions increased the overall width by 3 in.

Part number HB1/3 is as the Vincent straight pattern but 3 in. wider and soon replaced HB15 which became obsolete; also available are "Touring" bars part number HB1/2. The latter are of the "Cow Horn" variety, and these bars are suitable for riders who prefer a more upright position.

Control Cables
If sidecar type Vincent pattern handlebars HB1/3 are fitted the right hand front brake cable must be the extended front brake cable assembly (long), part number HB9AS; and the throttle cables are changed as follows:
Comet and Meteor HB7/3AS/1 *
Rapide  HB7/AS/1 *
Black Shadow HB7/2AS/1 *
[* Revised Part Numbers for use with "Touring" Handlebars (HB1/2), as shown in the 1952 Spares List Supplement.]

Single Cylinder Models
Series 'C' 500 c.c. machines feature outer fork springs only. If a heavy sidecar is used the addition of inner front fork springs part number FF13 may be advisable.

If cutting out is experienced on sharp bends the reason may be that centrifugal force causes petrol to surge away from the jet. This can be cured by moving the float chamber(s) as much forward as possible relative to the mixing chamber(s). Experienced sidecar riders are normally in a position however to enter sharp bends with sufficient engine revs to avoid cutting out altogether.