is lower gears possible

[jackthelad]

guys need to replace the rear sprocket and chain on my son brompton.The bike is a standard 2010 3 speed brompton.Can I replace the 13t sprocket with say a 16t sprocket,if so what size of links of new chain would i need I am under the impression the present chain is 98 links.Would the 16T sproket make much of a difference

any help appreciated

jackthelad

 

[alicat]

Yes you can replace the 13t sprocket with a 16. Yes it will make a difference. I thought you were buying a new chain so just measure it or RTM.

I am sure a guy will be along in a minute if I am wrong.

 

[jackthelad]

ali thanks for getting back to me greatly appreciated,its my son bike bought secondhand, he need chain,sprocket and brake pads

 

[T4tomo]

depend on your front sprocket 102 if you've got a 54. 100 with a 50

From brompton support website:​

The chain must have the correct number of links for a given sprocket combination, as set out below. Bear in mind that traditional joining links are usually unsuitable for use on a Brompton because the pin is too long; instead, the joint should be made by pressing in the rivet pin. We recommend SRAM PC1 (1/8") and PC10 (3/32") chains.​

Non-derailleur configurations (1- & 3-speeds)
Size 1/2" x 1/8", max. pin length 8.5mm
98 links on a 50T/13T combination, 96 links on 44T/13T and 44T/14T arrangements.​

Derailleur configurations (2- & 6-speeds)
Size 1/2" x 3/32", max. pin length 7.3mm
102 links on a 54T/16T combination, 100 links on a 50T/15T arrangement and 98 links with a 44T/15T set up.​

 

[Brommyboy]

Easy to work out length of chain for Brompton: take no of teeth front and back (the larger if there are two) and total then divide by two. If odd no, add one. Now add 66 for single rear sprocket or 68 for double. That is your chain length. eg: 44T x 16T=60. /2=30. +66 for single sprocket =96L