THE VeloSoleX S 3800 uses Direct Transmission (via an automatic clutch). A Transmission Roller, consisting of a coating of Carborundum Sand on an Aluminium Alloy Collar, presses against the tread of the front tyre and turns it using the power of the engine.

The VeloSoleX S 3800 speed is dependent on the Roller Diameter and the Engine RPM. The engine RPM has a maximum limit of about 4000 RPM but with certain modifications can be increased.

Changing the Diameter of the wheel has NO EFFECT on the Speed or Acceleration but a smaller wheel will give a bumpier ride.

Although a 42 mm diameter roller can be changed with one from another model listed below, the Torque and Acceleration will be affected and it is thus NOT RECOMMENDED to change it.

The calculator below illustrates the typical speed of the VeloSoleX S 3800 with a roller diameter of 42.0 mm. You may enter your own values in the  yellow  boxes below:

There was a steel Transmission Roller available from http://solexium.free.fr/produits2.htm. There were two kits available on their website, one kit with a fixed diameter, the other kit with a choice of three diameters. Unfortunately it seems that they no longer produce this item.

Back in October 1998, there existed a Tabouret "Competition Solex" Catalogue (Tabouret Accessoires, 4 Impasse Pierre et Marie Curie, BP 31, Saint-Yrieix, 16710, France) selling reinforced re-designed Crankcases, Crankshafts and Bearings, Reed-valve Inlet Side Plates, Dell'Orto Carburettors (up to 21 mm), ribbed steel Transmission Rollers (40 mm to 48 mm diameter), 5-port Cylinders and Malossi Cylinder Heads, Electronic Ignition Rotors, Exhaust Systems, etc. Unfortunately, the company no longer appears to exist.