QUOTE(Halia @ Sep 2 2013, 11:35 AM)
My apology for the uncleared question. To restate, I am looking at to increase current 8 speeds to may be 18-20 speeds. I am considering 2 options; 1) to fit my bike with the old XTR group set; or 2) get a new road bike groupset/upgrade. there are obviously some issues related to XTR option #1. My objective is to have a more energy efficient ride (most efficient way of ride in response to the challenges of the terrain - up, flat or down). I do not have budget for high perfomance gears. many thanks
Too bad you are using a 16 inch foldie, else if you are riding a 20 inch,
. A foldie with XTR components, wahlao eh! I don't know which bike you are using but I am sure if you install the XTR long cage rear derailleur, the cage will hit the ground. Other than that most components can be used. The cranks though will be a wee too small. So, the shifter can be used but it will be a waste if you have an XTR shifter but other components are different. I also have to know what bike you are using as some folding bikes have 34.9 mm seat tube which can accommodate a front derailleur (largest non braze on FD) and many like Dahons have 40.9mm which will require you to get an adapter which acts as the braze on bracket for the FD.
You can install a 20 speed or a 18 speed groupset onto your foldie. First you have to check the hub if the frewheel is the newer or the old type. The newer ones will acommodate a 10 speed but can only accept 9 speed for the older versions but then again for a 16 inch wheel, 18 speed is more, more than enough for any elevation!
The only components needed are the compatible shifter (left and right) , RD, FD with braze on adapter , cassette, compatible chain, crank (preferably 55T/39T) but a normal 53T/39 will do fine. Also the cabling housing and cables. For a folding bike a Sora 9 speed is good enough, couple it with a MTB cassette, it's more than enough. If you have more budget, you can opt for a Tiagra groupset. I think it will be an overkill to use anything higher than that but there are mini velos running on Shimano 105s. The cheapest components that is acceptable is Microshift.
To get a clearer picture, I will post photos of my bike later.
P/S also you have to get a wider bottom bracket, at least 118mm and also compatible to the crank choosen.
This post has been edited by etigge: Sep 2 2013, 09:04 PM