Right…..got my choice of new frame down to a Nicolai Helius AC and looking at sizing and rear shock, before i have to decide on colour.

My lbs who are Nicolai dealers dont have a demo bike. I have had the oppurtunity to sit on a medium frame and it didnt feel quite right although that may be due to the setup.

My current bike is a large 5 Spot and comparing geometry it looks as if i should go for a large Nicolai. I am 5’11” and after correspondence with Nicolai they are split between a medium/large and so need a little STW assistance.

I have been over to MTBR on the Nicolai forum and read through lots of information which has been helpful.

In addition to the above what rear shock should i go for? Should i stick with the tried and tested Fox RP23 or go for the DT Swiss either XM180 or M210?

I’m the same height as you and ride a large Helius CC, it’s smaller than a large 575 and the same size as a medium VF2!

Shock wise, unless you’re the typical well heeled IT boffin Nicolai owner stick with the RP23, if you are one of them types get a CCDB

what’s your inside leg vs. height? – I have a medium AM and am 5’11” too… with my inside leg being longer than average (apparently), the medium is perfect since I don’t want long top tube in comparison.

IIRC my inside leg is approx 33.5″

MisterT – inside leg is around 30-31″ so does that mean large?

Giant – where are you located? I have a large AM you can try if you’re in the South East. I’ve had it made with a custom seat tube, so it’s cut down to 16″ but you can still, ahem, get a feel for the length.

I’m also 5ft 11″ but I prefer the longer top tube and, crucially, the longer wheelbase as I use the bike for riding DH courses and the Alps and the extra length gives more high speed stability. I also run a 50mm stem; wouldn’t consider anything longer than that so if you’ve been using something longer or planned on something longer, then get the large and run a 50mm stem. Or alternatively, get the medium and run wider bars.

I’m not helping much am I?

You really could have either (the AC and the AM are more or less the same in terms of size) so choose the medium if you prefer something shorter, more compact, slightly more manouverable and longer if you want extra stability or you like to really move around on the bike and ride over the front quite a lot.

Regarding shocks, don’t get the DT, don’t even consider it. I’ve tried them and think their crap, other people i know have said the same thing and lab test done in MBR show that there’s no almost no compression damping on them; it’s just an air spring. You end up having to ride the thing with loads of air pressure to get it to sit correctly at which point it feels awful. Things may have changed in the last year or so of course.

Go medium. I’m 5’11” and had a large FR, which was too big (way too long). Even medium AC’s have an 18″ seat tube and 23″ top tube.

Medium was perfect for me when I bought my ST.

EDIT: reading Geetee’s postabove, I can see where he’s coming from, and thinking about it I like to be able to move around the bike a lot. The large has something like a 24″ top tube and my FR with similar numbers just felt plain wrong.

looking at the data for the AC the medium has a TT = 22.65″ and the large TT = 23.43″

I currently run a 70mm stem on my Turner with a TT of 23.6″.

I also have a rigid commuter/winter bike and the TT of that is 23.75″

I have DT Swiss forks and i really get along with them hence the reason for asking about their shocks.

GiantJason, have you come across the notion of ‘reach’ (and stack, but reach is what’s relevant right now) as a key measurement on frames?

It’s actually a very helpful way of comparing two bikes. The TT measurements of bikes can be very misleading and two bikes with more or less identical TT measurements can end up feeling very different.

The reach measurement is calculated on as a line drawn horizontally from the top of the head tube until it bisects a line drawn vertically through the centre of the bottom bracket (the vertical measurement is the stack). The ‘reach’ measurement will tell you how long the front of the bike really is and therefore how large it will feel.

Fortunately both Turner and Nicolai quote these on their sites.

The headline is that while the large Helius AC has more or less the same quoted TT as the large 5-Spot, the reach on the large AC is actually 422mm whereas on the large 5-Spot is only 406mm.

The medium Helius AC has a reach of 402mm.

Therefore if the 5-Spot is your benchmark and it feels just right to you, then the size you should go for is definitely the medium Helius AC.

Hope this helps.