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PostPosted: Thu Aug 12, 2010 10:58 am 
Retro Guru

Joined: Wed Apr 08, 2009 2:35 pm
Posts: 265
So its that time again when my mordern bike gets a revamp.

This year its the frame!! and i've decided to go Ti custom!!


I'm 5'10" and always found sizing difficult, its either an xc friendly 18" or a 'play bike' friendly 16" (yes i could go 17" but then choice is limited). Ireally like the extra standover hight an 'wippyness' of 16" frames - the last 4 bikes have been 16's, but the downside is climbing ability. I've got around this in the past by running 90 or 100mm stems but then the steering is slow and i loose the advantage of having a small frame so its not ideal.

The idea is to build a 16" frame with an equivilent to an 18" toptube. Which sound like my perfect 'do it all bike', one i'll keep for years.

Only down side is i can't afford the realms of Lynskey, IF etc. so i'm going to China :shock: .

Well, no actually going, morelike ordering. From Xacd.com.cn to be exact. I've heard and seen good things from them and had enough email conversations with them over the last 2 weeks to feel confident enough to order.

If you've not heard of Xacd (they're more well known in Road circles) before heres a couple of web sites that'll give you an idea of the stuff they have produced for people in the past:
http://www.xacd.com.cn/index1.htm
http://www.spanner.org.uk/
http://ronniethescot.blogspot.com/2007/07/wwwxacdcom-finished-bike.html
They're own web site is not that great, but there are some interesting examples on there (some good, some, well interesting).

So next step geometry....
after a couple of revisions heres what i've come up with:

Head Angle 70
Fork Offset (Rake) 43mm
Chainstay Length 425mm
Seat Tube Angle 73
Horizontal Top Tube Length 564
Effective Top Tube Length 589 (23.25" or equivalent to an 18" xc bike)
Bottom Bracket Drop 305mm
Standover 710mm

BB height is quite low (normal xc bike would be around 310-315 i guess), but i'd like it to be quite stable and fun to ride, i generally run 170mm chainset so 5 mm lower sounds like a good idea.

I sent these specs over to Xacd and heres the Cad drawing they've come back with:

Image

This is the second drawing they've done for me and have been great in comunication, the drawings being emailed over within 24hrs. The low standover and toptube/seattube brace is a must (although added extra cost) and i've also added the bend in the down tube (at request, and extra cost) to
aid fork clearence.

Final thing the cost, which is the hard part as i still need to raise the funds (and get them past the wife)....

£550 ish posted. delivery time less than 4 weeks.


So what are your thoughts?


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PostPosted: Thu Aug 12, 2010 11:06 am 
Gold Trader / rb Rider / Special
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didnt look at the websits or such but i think your onto a winner here, i mean generally a lot of production is out sourced to taiwan/china etc so why not go direct. they often lead the markets for quality and technology and as such can do that sort of thing on a larger scale/cheaper. i guess they know what theyre doing and the cad drawing seems pretty spot on. you obviously know what your talking about so that helps
i like your idea of small bike with longer top tube. i like my frames small (16'') and am roughly same height as you.
what spec have you got planned for it?


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PostPosted: Thu Aug 12, 2010 11:11 am 
Retro Guru

Joined: Wed Apr 08, 2009 2:35 pm
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The spec is coming straight of my current xc bike which is an xt/xtr, RS Reba WC forks, raceface (Dues cahainset, Next sl seatpost), thompson stem, Ritchey WC bars and headset. The seat postwill change to a 27.2 moots style ti one (again from Xacd for £50) and the stem will change to a 70mm thompson but the rest will remain the same. Its a bit of winter pic but here you go:
Image
i also have a tripple rings but they're just not needed around Bristol, so only get put on when i visit Wales.


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PostPosted: Thu Aug 12, 2010 11:17 am 
Gold Trader / rb Rider / Special
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cool 8)
that bike needs its own thread
what finish are you going to get? im unfamiliar with how people finish ti
i guess most would just leave it raw
possibly lacquer?


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PostPosted: Thu Aug 12, 2010 11:22 am 
Retro Guru

Joined: Wed Apr 08, 2009 2:35 pm
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Its got its own thread some whare on here....

Finish wise it'll just be the standard sandblasted - i'd rather have brushed but thats an extra £50 i think, and i could always do it my self further down the line.
Image
you can see the qaulity of welds here (and the finish), as well as a small crack on the down tube. But it looks like its on a double butting line to me (another possibility at extra cost), and i'm not getting mine butted so i'm not that fussed. Also that bike was built for AM 150mm forks and the rider was well over 6ft and quite a heavy hitter. As its in an unusual place they sorted this crack out on the 5 year warrenty, replacing the entier front end of the bike,which also gave the owner the opertunity to mod the TT length and angle a bit.


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PostPosted: Thu Aug 12, 2010 11:50 am 
Gold Trader / rb Rider / Special
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wow! those welds are some of the nicest i have seen! :shock: :shock:
that 'crack' does look like a butting line though
brushing for 50 quid seems steep! i guess its probably a fair price though.
its great that you have so many options
im amazed at those welds
looking at he quality though i wouldve thought theyd give a longer warranty, 5 years is good though


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PostPosted: Thu Aug 12, 2010 12:14 pm 
retrobike rider
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Location: Leeds
Before I got hit with this site I had some confab with xacd. I asked for some photos of welds that weren't brochure type. They sent these

Image

and


Image

Looked good to me. I shall enjoy your journey. How did yo come up with measurements?


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PostPosted: Thu Aug 12, 2010 1:50 pm 
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Location: Whiskey bent & hellbound!
Look good, TBH for the money does it really matter if the welds aren't perfect!


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PostPosted: Thu Aug 12, 2010 3:43 pm 
Gold Trader / rb Rider / Special
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Neil G wrote:
Look good, TBH for the money does it really matter if the welds aren't perfect!


but they are :D


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PostPosted: Thu Aug 12, 2010 6:30 pm 
Retro Guru

Joined: Wed Apr 08, 2009 2:35 pm
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Neil G wrote:
Look good, TBH for the money does it really matter if the welds aren't perfect!


It matters because its very easy to contaminate titanium welds as the tubes have to be welded in and envioment that is devoid of oxigen (usually the area is floded with an inert gas, although some manufactures weld there frames in a seald air tight bow filled with gas). Titanium welding also demands greater attention to cleanliness and to the use of auxiliary inert gas shielding - if its done incorectly the weld is very brital and will sheare easily.

paininthe wrote:
How did yo come up with measurements?


erm just a mixture of classic uk hardtails really. A bit of on one (head tube) cotic (toptube length) and pipdream (rear triangle).

To be honest i may still change a couple of things prior to ordering/manufacture, the head tube is quite short and its not as renforced as a On ONe Scadal which its baised, so i'm thinking of increasing to 115mm (the extra 10mm between top and down tubes, which will also aid in cable acess). This should aid front end stiffness and steering precision - it wont be as low or 'racey' but it'll also be a trail bike so thats good.

The top tube length is more the equivelent to a 17" or 17.5" frame, Pace and Cotic both use this dim. I'm aiming to use a 70/75mm stem so i'm hoping that this will work well - The top tube length is kinda the dark science bit so its more guess work than any thing else at the mo to be honest, again i dont want it to feel to racey.


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