Dolan Pre Cursa / PreCursa / Track Champion

I'd also be interested to know, I did actually look at this myself but some of the information needed was missing from Dolans geo chart. For example, BB drop isn't published, which affects reach. I suspect your numbers are at least in the ballpark though.

Geo chart from dolan, bb drop (55mm) was mentioned by someone earlier in this thread.

e. And yes, calculators aren't always 100% accurate, but gives you atleast something. having owned 52, can confirm its low and long

Don't quite understand how you get it to show such a low stack..?

Sorry, had 50cm headtube length in it. With 52 its still only 512. Alpina fork a-c 368, ht 120mm and high bb (plus integrated headset) add to low stack anyway.

Does the BB drop vary across the frame sizes? The reach is only a couple of mm different between the 50 and 52 with the same BB drop but I don't know if it's consistent.

Usually yes, but the difference is miminal.

Track frame; long and low.

Indeed, low I like, long my body doesn't agree with unfortunately. I usually end up going a frame size down as a result but even the small Pre Cursas are relatively long for their 'size'. May as well go for the 50 on balance, it's slightly lighter, I'm definitely not going to run out of adjustment in any direction and I'm going to need a short stem whichever size I go for so may as well go for the smallest I can get away with.

How tall are you, and what's your inseam?

. (double post)

5'7, inseam unsure to be honest. I know my saddle height/setback to the mm (72cm, 58mm setback to saddle tip based on a 280mm saddle - or 198mm to saddle centre point), it's the reach I struggle with on frames. I invariably end up with an 80/90m stem. I have an 80mm stem slammed on a ribble 7005 with a 53cm TT and it feels good.

Then the 50cm sounds good!
Was just curious - I normally think people ride frames that are too small, but with top tube and reach you're used to, the 50 sounds spot-on.

Yeh, the reach difference between 50/52 is minimal, the 50 would give me a bit more adjustment on cockpit height and a few mm less reach, the 52 gives a standard 73 degree head angle as opposed to the slightly awkward 72 on the 50. To be honest either would probably fit me with 5-10mm difference in stem length.

As the geo charts have historically not been too accurate, you may end up with a steeper head angle than expected anyway... @svendhöek measured his accurately and it was something like 74 or 75.

Remember with reach/stack numbers that a larger size bike measures reach higher up the "virtual" headtube so even if the numbers are close the larger size does have more reach at the point where you place your stem.

Does this make sense (I can make a crude drawing...)?

2cm more headtube at 73 degrees gives ~6mm "less" reach
75 degrees gives ~5mm less reach

tldr: the difference between size 50 vs size 52 "effective reach" will be about 4mm more than you expect....

Ah ok, good to know. I'll hold out for a 50 then, as I'm not particularly precious about buying new where my bikes are co I'd be happy with a used frame but 50's aren't so common so may end up just buying one, especially for the money you can't really go wrong.

Ah ok, I always thought reach was measured to the centre of the top of the headtube, is it measured at the centre point usually then? Just to confuse things further there's almost certainly differentiations in the way measurements are taken between manufacturers...

50 is probably safest bet then as the reach is already at the higher end of what I need. Ta!

Ah ok, I always thought reach was measured to the centre of the top of the headtube

yes this is right.

But imagine you buy both frames and put a 15mm spacer on the small one (to get the bars at the same height). The 15mm spacer goes up and back (at a 72 or 74 degree angle , nobody knows...) so your bars would end up an extra ~4mm back compared to the large frame on top of the difference in reach between the frames.

(edited a bit)

Yeh that makes sense. Not thought of that before but worth remembering!

Anyone got a current Dolan discount code?

What are you after? There's quite a lot in their outlet
http://www.dolan-bikes.com/factory-outlet.html?limit=all

Dolan has put stack/reach numbers on the pre cursa up:

(new to me..)

Maybe, since the Omnium debate, @user70368 and the chaps at the factory have been keeping an eye on this thread, and added those measurements in the last few days to help people like @ThePeginator.
If that's actually what's happened, how good is that!? Cheers guys!

The more manufacturers put those up the better, noice job dolan

Thumbs up Dolan!

Hey Pifko, I wanted a pair of chain rings but they didn't have them in the finish I wanted though. Shame. Though the dude I spoke to was really helpful.