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Michael’s custom titanium 29er by XACD

Michael contacted me before Christmas as he had a few interesting ideas he wanted to try out on a custom XACD build, things like removing the chainstay bridge and mounting the rear brake ‘inboard’. I thought the results would be rather interesting – and they are! I’ll let him take up the story…

I was happy with my old carbon hardtail 26″ and had no intention of upgrading it until I noticed a squeak and, on closer inspection, a crack around the BB. I considered buying a new frame and keeping the components but instead decided to go for a ground up new bike based around a 29er titanium frame.

Michael’s very smart looking rigid 29’er with a few neat little details…

At this point (and until my new frame arrived) I had never ridden a 29er, so it took quite a bit of research on the internet to tie down angles, tube sizes, and BB/headset sizes. I am a bit of a weight weenie at heart and compete in mainly cross country and endurance mountain bike events so the obvious place to start was with a rigid fork and based the rest of the concept around that.

The money transfer and ordering process took a bit longer than I thought it would and also the quoted 6 weeks turned into double that by the time the frame arrived at my door. The quality of the welds and finish of the frame are extremely good, the only issue I had was that I specced a direct mount for the rear disc brake and the weld from the seat stay to the mount was slightly wider that I expected so encroached too far onto the flat surface, tipping the brake at an angle when screwed down. To get round this I used a spacer to raise the brake 1mm clearing the weld.

Liking the smooth use of the tapered headtube to match the fork…

The build itself went without a hitch, all of the tubes were clean of debris so installing the BB, headset and seatpost went smoothly.

I had decided to go without a chainstay bridge to increase mud clearance and a casual squeeze of the rear dropouts showed an alarming amount of movement especially as I had chosen to go with Rotor Q chainrings (oval) which took the teeth perilously close to the chainstay. Once the rear wheel went in it seem to firm up the area and after a couple of rides and a large amount of pushing down on the BB area with my foot to test for flex it has not caused any chainstay/ring interaction.

BB30 bottom bracket and no chainstay bridge mark this one out as a one-off.

It’s a shade under 9kg (19.8lbs), with the frame itself coming in at 1.84kg (4lbs) obviously there are a few areas I could have save weight: different grips and brakes etc. but I wanted something I could hammer that was comfortable.

The first proper ride was a little deflating, it isn’t as wildly different from a 26″ bike as everyone was saying and even more annoying it wont suddenly rocket me to the front of the pack!  It’s more about the subtle differences, the big wheels are slightly slower out of corners but the stiff front end and BB allows you to carry a little more speed through the corner itself.

The real area that the 29er shines is fast single track and fire roads where the big wheels allow you to keep the speed up. The other area that 29er’s are meant to be good is smoothing out bumps and to be honest at slow speeds its very hard to tell if it makes a great deal of difference but crank up the speed and the 29er defiantly floats over rough stuff much better.

There is nothing I would change on the bike as far as function goes but from a purely aesthetic point of view I might look at a more elegant way to configure the rear brake mount. On the component front I already have a few spec changes in mind, a 1×10 setup (I have another bike for big mountains) and the new grip shift XO. Obviously this will be after my wallet gets over the shock of this build!

Awesome job, it’s always good to see someone with a vision in mind putting the plan into metal. 29er’s are perfectly suited to the larger gent and Michael’s bike looks pleasingly balanced, he also doesn’t have any issues with the front end being too high as smaller riders would.

It’s a large frame (480mm / 19″ seat tube) but we’re both surprised that it’s not a little lighter given the addition (or reduction!) of the double butted tubing. Perhaps the extra metal in the tapered headtube or the BB30 shell is adding weight. As we’re only going to know for sure by sawing it in half, Damien Hirst style, I think it’s probably best to concentrate on how well it rides and Michael sounds like he’s nailed that first time! The quality of the components certainly make for a practical, featherlight, build.

Unique ‘inboard’ rear brake caliper post mount.

All credit to XACD for being able to figure out the rear calliper mount; Micheal said he just told them what he wanted, gave them a few drawing/pictures, and let them work out the seatstay bend and post mounts. It’s certainly a cheaper option than speccing a custom dropout which is the usual way of doing things.

When I first saw the drawings it looked like the post mounts weren’t attached to much but seeing it in the flesh it looks very workable, only long term use is going to confirm it for sure though.

The drawing it all came from (slight mistake on it, the tube wall thickness should read 0.9×0.7×0.9 to reflect the double butting)

I can see why Michael went without a chainstay bridge too, given how short the chainstays are I’m not sure there was much room anyway! With a matching bend in the seat tube he’s been able to tuck the rear wheel in nicely while avoiding anything too drastic like Adrians raised chainstays.

The BB30 shell gives scope for plenty of options too, although XACD could have probably welded the stays a little further out to save having to bend them so much. An alternative could have been a wider BB86/BB90 shell that would have allowed for even straighter chainstays but cut down on the choice of bottom brackets. Given the reputation of the current press fit bottom brackets Michael probably chose the best route.

I like the idea of turning it into a 1 x 10, I think that would suit the minimalist nature of the build – as would going the whole hog and single speeding it 😉 Which reminds me, I’m sure it’s time I starting thinking of a minimalist frame; integrated seat mast, split stays for belt drive, eccentric BB, concealed rear brake hose, hmm…

Have you had a frame made by XACD? If so I’d love to hear about it and maybe feature it in the Gallery so drop me a line via the contacts page.