cam belt width

Hi bought myself a 2007 135 tf earlier this year and have been collecting a few spares in readiness to give it a thorough service. Is there an easy way of finding out what width cam belt is fitted as it seems most suppliers list two widths. Thanks Stephen

When I got my cambelt for my 2004 k series i just gave them the reg number and away you go new cambelt fitted...haven't heard about different widths...the vvc version of this engine has 2 belts is this what's giving you 2 belt widths or is it because yours being a 2007 has the n series engine and the widths have changed?? can someone else add to this

MG Rover did change the belt width on the K series from 23mm (manual tensioner) to 26mm (auto tensioner).

So belt width depends on what type of tensioner you have.

I cant find anything about when this change happened so i guess i will have to take a look before ordering. Although my car is registered in 2007 I think its a 2005 model.

A 135 TF will have an auto tensioner, so the belt width is 26mm.