Timing Chains


RM Fowler Limited can supply inverted tooth and roller type timing chains. RM Fowler cannot supply timing chains for any modern vehicles. We specialise in pre-1960 vehicles.

Roller Chain - RM Fowler can supply simplex, duplex and triplex type roller chains from a number of manufacturers including IWIS and Morse.

To supply customers with roller type chain we will need to know the following details:

  • Roller chain type – simplex, duplex or triplex
  • Chain pitch – distance between the pins
  • Chain roller diameter – the diameter of the rollers that engage with the sprocket
  • Distance between the inner plates

For more information on roller chain measurements please go to our Roller Chain page.

For imperial inverted tooth chain also known as silent tooth timing chain we supply Ramsey chain.

Ramsey Products are located in North Carolina USA and have been manufacturing inverted tooth chain for 85 years. In that time Ramsey have made several technological advances such as developing a modified link to improve the strength and durability of the chain.

Ramsey chain has two pin joints which replace most round pin types from obsolete makes shown in the below pictures. In circumstances where the sprockets run on both sides of the chain we can supply duplex chain.

Your Chain

1. Check your chain to see if it is a center guide chain (known as SC chain) which has a guide link running down the middle of the chain with a corresponding groove in the center of the sprocket.

2. Alternatively your chain could be a side guide type chain (known as DSG or SSG) with the guide links running down the side of the chain. These chains are measured by the width between the guides.

3. The chain pitch is the center distance between the chain pins. If the chain has as uneven number of pitches then an offset link must be fitted.

Chain Pitch and Guides

Now you have identified the type of chain you require you will need to take some measurements of your existing chain (if you have one). The required measurements are shown below.

  • Pitch = distance between pins
  • Length = total length of chain
  • WBG = Width Between guides
  • WH = Width Over Heads
  • WL = Width Over Links
  • WC = Width at Connector

SSG and DSG side guides

SC center guide

Nominal Width - The nominal width of a chain is not an exact measurement but it is used by Ramsey and RM Fowler as an approximate width of the chain. It fits somewhere between the WL and WC measurement.

Clearance - The exact width of the chain is only important if the chain runs in a very confined space or crosses close to another chain. If the chain runs in plenty of space the nominal width is sufficient, however if space is tight we will need very accurate measurements of the total width including the connector pin.

Ramsey Chains

For a full list of available sizes of the centre side guide Ramsey silent chain click here.

The available sizes of side guided Ramsey chain are shown in the table below.

Pitch Part no Nominal width WBG
3/8 SSG302 1/2 3/8
3/8 SSG302.5 5/8 1/2
3/8 SSG303 3/4 5/8
3/8 SSG303.5 7/8 3/4
3/8 SSG304 1 7/8
3/8 SSG304.5 1 1/8 1
3/8 SSG305 1 1/4 1 1/8
3/8 SSG305.5 1 3/8 1 1/4
3/8 SSG306 1 1/2 1 3/8
3/8 SSG306.5 1 5/8 1 1/2
3/8 SSG307 1 3/4 1 5/8
3/8 SSG307.5 1 7/8 1 3/4
3/8 SSG308 2 1 7/8
1/2 SSG402 1/2 3/8
1/2 SSG402.5 5/8 1/2
1/2 SSG403 3/4 5/8
1/2 SSG403.5 7/8 3/4
1/2 SSG404 1 7/8
1/2 SSG404.5 1 1/8 1
1/2 SSG405 1 1/4 1 1/8
1/2 SSG405.5 1 3/8 1 1/4
1/2 SSG406 1 1/2 1 3/8
1/2 SSG406.5 1 5/8 1 1/2
1/2 SSG407 1 3/4 1 5/8
1/2 SSG407.5 1 7/8 1 3/4
1/2 SSG408 2 1 7/8

When replacing timing chain it is also advisable to check the condition of the sprockets as these are just as important to the running of an engine as the timing chain. RM Fowler have close ties with a number of specialists who can manufacture high quality sprockets to suit all the chains we supply.

Metric (10mm) Chains

Due to the difficulty in obtaining metric chains RM Fowler can only supply 4 different sizes of 10mm pitch inverted tooth chain which are shown below. If the chain you require does not match any of the 4 chains then you may need to consider modifying your sprockets to fit.

Pitch Part Number WBG WH WL Weight per meter
10mm 1110 9.6mm 17.6mm 19.2mm 0.64kg/m
10mm 1112 16mm 24.1mm 25.7mm 0.93kg/m
10mm 1114 28.9mm 37.1mm 38.7mm 1.56kg/m
10mm 1115 35.2mm 43.4mm 45mm 1.88kg/m