right made my mind up! i'm going for a custom build rock lobster 853 from merlin. have mailed asking what size i should go for and they reckon a 15 inch?? i'm 5"9 with a 30inch inside leg. seems small to me i've always felt suited to 17inch frames,maybe a 16..
so how tall are you and what size is your rock lobster? ta.

I would try to get your leg over one.
Find out the TT length.
I had one and got rid of it as was top small in the top tube

had same dilema as you at same height so got a 16 inch Rock lobster B52 …not helpful eh.
I thought 15 to small and 17 too big and they dont do a 16" not much help then. Best get yerself there and try one out I am afraid

I'm 5' 8" & i have a 17.5". Fine for me..

I'm 5'8", and so is MrsPP. We've both had 17in Lobsters and they fitted perfectly. They are also on the short side, so 15in WILL be waaaaaaaaaaaay too small for you. FACT!

This any help?

Would definetly say a 17

My first bike was a malt 2 and they told me a 15" would be the right size for me, and by the way my measurements are the same as you. They sent it to me and i sent it straight back for them to replace with a 17" as it was just not right(too small). since then i have also had a rock lobster 17" which was perfect also.

Sorry for the ramble but if your measurements are correct then you need a 17"

I am 5'10'' with a 30 inside leg and my 17 is a good fit.

They have built bikes in the showroom. Worth a visit. Not far off M6 or M61 on outskirts of Chorley.

5'4" with 30ins inside leg (jeans fit). Ride a 15in Lobster.

as above 5'9" and 17" fits me fine, 15 would be way too small for you

Chop if you decide to go for a 15" I can save you a heap of cash. I've got a mint RL 853 15" I'm about to put up for sale. Email in profile if interested.

5'11" with a 31 or 32 inside leg. I had a 17" and had to sell as it was too small.

A friend has a Ti lobster which is 15" and I sat on it just yesterday and it was to small for me in the TT but the height wasn't bad. I am 5.8 and a bit and ride a 16 small soul which fits fine. so I would think the 17" for sure.If that helps?

I used to have a 15" and I'm 5'5" but with long legs. Even though I had a layback seatpost, it was really just a bit short in the top tube.

ok thanks so far.i'd like to be able to try one but merlin is over 100 miles away from me..

i think i'll be going with the 17" will let u know how i get on.

chop, where are you based?

have a 17", am 5' 10" with 30" inside leg, good fit, top tube a touch short but i have set it up to really suit me. love it

I'm same height & my 16" Inbred sometimes feels too cramped.
Not sure if they had same geometry but I had a Rock Lobster Expert a few years ago, was really harsh alloy thing. That was 17" & was a perfect fit.

You've probabley made your mind up by now but I'm 5'10" with long legs and ride a 19". The top tubes are short on these bikes and the stand over height is relatively low. I can't believe they've recommended a 15" frame.

Is your inside leg of 30" from crotch to floor, or your trouser inside leg? If you are 5'9" then a 17" should be fine, but if your legs are 30" from crotch to floor then you won't have much standover height. I'm 5'9" with a 32" inside leg and I would ride a 17". If in doubt you can pop down to Merlin to try.

Also make sure you are actually 5'9", I've met loads of blokes who think they are 5'9"/5'10" who seem to come up about 2/3 inches shorter than me! I suppose thats just short man syndrome and they can't bear to admit they are shorter than average!

well the missus has just measured me up and, i'm actually 5 9" and a bit..
my trouser size is 30" so i reckon it's gota be a 17

right,just ordered it!

17" with xt/raceface deus upgrade @ £1105 i'm now officially skint 😥

Nice one. Here's one I completed earlier to look at while you wait for it to arrive.

Got my 17' 853 1 month ago. One member of staff told me to get a 15' another 17', I went for the 17 as it was identical virtually to my 17' Rockhopper Comp, I am 5'8" with 31' inside leg. Brilliantly comfortable bike.really pleased with it.