Short chainstays, fat tyres with sticky-out knobbles, front mech clearance. Pick two

Personally I'd use a slightly smaller tyre rather than have an offset drivetrain and even further-out chainline, but then I seem to use middle-big quite a lot and that's bad enough with a 50mm chainline. Moving the cranks out another 2mm would be a bit nasty. But that's just me

I havent had any trouble with shifting mike.  I use mine as a double with bashguard so maybe its not as pronounced effect.

Strangely i will be changing back to triple and 2.1 tyres soon (Winter is over) so will be able to take the extra spacer out.

John, i think mike put it better than i could.  Not flawed, just as with most things, its a compromise.

I havent had any trouble with shifting mike.  I use mine as a double with bashguard so maybe its not as pronounced effect.

You probably stay away from "middle" (your outer) ring - big sprocket. With two chainrings your chainline's better with the chainset further out  

By flawed I'm implying they've made the wrong compromises. I'll happily accept chainstays a centimetre longer.

Can't argue with that. Again, in general (and depending on the rest of the geometry, for in some cases I'd prefer longer stays and you can't take any one number in isolation) I'd take 3mm off the width of the tyre if it got me 10mm out of the chainstays.

I thought the fashion for the long travel, steel framed bikes was for them to have short chainstays.  If thats not your bag then you buy a different design.  Doesnt make them flawed.  Thats like saying your bmx is flawed compared to your road bike.

I'm saying these designs are flawed compared with what they're claimed to be suitable for. They are claimed to be strong bikes suitable for hard-nut trail riding, light free riding and even light jumping duties. 

A long-travel, hard-nut hardtail is the kind of bike on which a fatter back tyre is just the ticket. It can be run softer without risk of pinching (if the owner still runs tubes) or dinging the rim. Softer means a modicum of suspension for landings, better grip and more comfort. The designer should expect riders to fit a 2.5 tyre. An expectation backed up by the fact so many riders on this thread have tried and failed. It isn't the riders that have got it wrong, it's the designers.

If you design a hardtail around a long-travel fork you make sure there's enough space for a 2.5 tyre at the back. Designs that don't have enough space are flawed. 

The pipedream sirius was never marketed as a hard nut frame.   

I appreciate that John but werent they also marketed as bikes that would be jack of all trades & master of none.  I mean the 456 seems to be encompassin such a big gap in fork size i always wondered how it could do it without some big compromises.

Wasnt the benefit of short stays a steadier climbing bike which gave more traction (Not really clued up on these things). 

It's more a long travel XC frame than a hardcore hardtail.

I think if you want to run 2.5" tyres and do AM stuff, there's much better frames out there, intended for just that purpose. (And include little Fox shocks on the back *wink*)

I guess it's me then, I dropped the Pipedream into the same box as the Dialled Bikes Prince Albert - a trail bike designed to take a fair bit of abuse, and a wide tyre (with 424mm chainstays after much searching in BM reviews).

Start a hardtail versus FS for hooligan riding thread Mark.  

I've tried the 2.5" back wheel out of my KHS in a few bikes to see what the limiting factor is. The KHS has the shortest chainstays of any of my MTBs at 42cm but still provides the most clearance, even with a 47.5mm chainline crankset. A 92 Giant Cadex CFM accepted the wheel no problem but none of the recent 100mm hardtails would (XTC, M4 Stumpy and an aluminium thing).

Frame arrived and it looks lovely.

Only minor niggle is the dropout, disc brake side at the back, has been pinched a bit, and the axel for the rear wheel doesn't slide in. If I take the QR skewer out and then tighten it into place it goes in ok. Just a bit of a pain really. CBA to send it back and when I get the frame faced I'll get a frame expert to give me some advice - presuming a steel frame can be worked back into shape a bit?

Also, Stuart agreed on getting the rear disc mounts faced, but said the BB isn't worth doing. Now bearing (lol) in mind I'm putting HTII and exteral BB on, surely it's worth getting this faced? I thought Shimno wouldn't warranty their external BB if the frame hasn't been faced and chased?

Can anyone confirm this needs doing?

Got everything now bar the forks.

I'm considering either an 18" or 19.5" frame. Do pipedream have any distributors in the South of England that have sizes in stock to try? I'm 5'11" with a 32" inside leg. Have had other hardtails in 18" and they've been spot on although recently bought a Kinesis XC120 & that was too short in top tube.  My intention is to run with 130mm fork at 10mm sag and 60 or 80mm stem - what's the suggestion? Anyone ride either size that is similar height and can recommend. thanks  Also are these frames generally available in most colours?

I'm 99% sure that they only sell direct from themselves via the website. Where do you live? As soon as mine's built up you're welcome to have a go on it.

Thanks for the info. & offer - Did your frame take long to arrive after ordering?

 I live near Reading in Berks. 

About the paint finish, is it powder coat - if so do you think it's more durable than on-one's inbreds.?  

Couple of days. Stuart sent it to my work address. They are superb to deal with - just talk to them.

Here's a pic of the paint and welds. Might help you a bit?

Welds & paint look good - has a durable layer of clearcoat then..

May I ask what size that is & whether your build is nearly completed to assist me specifying size? I understand that the 18" & 19.5" frames are quite long in the top tube which is good, I 've got a 450mm thomson layback post (27.2) where I'd like to get away with smaller size if poss. 

I've got a maxlight xc120 17.5" which is too small (especially reach/top tube) that's for sale here http://www.bikemagic.com/classifieds/advert.asp?c=17824&t=Kinesis+xc>120+single+speed&sp=&v=2    I wonder if the weight will be noticeable compared to this? The sirius weighs 5lb - so it's 2kg+

The 631 Sirius weighs about 3.9lbs and it's a stronger, tighter frame than the standard sirius. I've got an 18" frame and I'm 6'1" - got all the parts bar the forks and I'm putting coil u-turn revelations on. Got a 300mm Post Moderne SMICA post on with a layback and it feels like it will be about right for me - elbow on front of seat puts my index finder exactly where the top cap of the stem isand plenty of scope for the seat to go a couple of inches up or down. Probs built in a couple of weeks. Soon as it's done I'll be over Cannock Chase to ride it, so if you're up that way i a few weeks you're more than welcome to have a wee blast on it.

 My last rides were 03 Enduro S-Works and a 07 Pace RC303 so I'm really excited about getting back to steel.

Nice one Mr Sampson - hopefully 18"s are available at the minute. 631 tubed variant preferable. I'll give them a call today. Cheers for the guidance size wise & the offer of a spin around the chase.