Building a Boardman CX

[expatscot]

Hi

I'm building up a new CX bike shortly, and it will be my first foray into the world of disc brakes.

I have a few canti Specialized CXs that I use for commuting, winter work and the occasional ride in our local woods. These have been gradually updated but there's only so far you can polish a mid-range bike.

I collect my frameset at the end of the month from the LBS, where I managed to get a killer deal on a QR version of the carbon Boardman CX 9.8. The shop had built it up as a 105 bike, but I have a garage full of bits, and an urge to make the most of this lightweight chassis, so I want to build it "right" from the off.

My plans are as follows:
Frameset Boardman CX9.8 carbon small (53.5 eff TT)
Seatpost: USE alien from the parts box, with shim 27.2 to 31.6
Saddle: Selle Italia SLR 135 from the parts box
Stem: Kalloy uno F7 to be purchased (I got one last autumn for my Cervelo P2, and it's great). I'll build it up initially with a Bontrager RXL from the parts box, then buy the kalloy when I get my position sorted.
Bars: 3T ERGOTERRA TEAM CARB 42-CRED. 42 (flaring to 45 at the ends).
Shifters: SRAM Red 10s from the parts box.
Mechs: SRAM Red 10s from the parts box.
Cassette: SRAM Red 10s or Ultegra 10s from the parts box.
Pedals: XTR SPDs from the parts box.

All my bikes are still 10s, and I don't want to go 11s. Whilst I won't be swapping wheels between bkikes, it helps that everything uses the same chains, cassettes, mechs and shifters. I have a ton of 10s kit, and see no reason for the extra cog.


Stuff still to decide upon:

Wheelset. I've been offered a decent Kinesis Crosslight CX wheelset alongside the frame. They are decent 1600g. My plan is to replace these in a year with something better: either Reynolds attack disc, or the new Hunt disc 50mm (UK new guys who are getting rave reviews). I'm not sure whether it would be better to build up a decent wheelset now, using Hope hubs. But I can't find any decent aero rims that are clincher and disc-specific (other than the £900 Enve). I'd be happy to build (I have built many sets over the years).

Chainset. I have a few spare GXP chainsets kicking around, including a Bontrager, Rotor and FSA SLK in compact. My frameset is PF30, which I've never had before.
I'd like something light (obviously!). 172.5 in 110 bcd.
I don't know whether it's better to try and use one of my existing ones, with a BB adaptor, or to try and get a 2nd hand pair of cranks BB30, and use a Praxis BB. I'm looking at eBay for stuff like Rotor 3d+ or Red. I know there are lighter options, but I'm not sure how cost-effective these are. I've not ventured into the world of non GXP BBs before (exception: my Look 695 came with the BB and crankset, and I've left these well alone).

Brakes. I'm new to discs, but it looks like cable disc options of TRP Spyre (perhaps SLC) are the lightest and get good reviews.
It seems like 160 front / 140 rear is the optimum. Rotor choice seems to be Ashima for WW.

Cables. I've not ventured into the WW world of cables before. I've always used Gore or the cables supplied with the shifters, and bog standard Shimano outer housing. What should I be looking at, for lightweight outers and inners?

I will be posting build notes, weights, photos as I progress.

Thanks for any guidance / thoughts!

[Exar]

If you want to ride 1x10, a SRAM Red BB30 Exogram crankset weighs 363 grams, ended up around 450-460 with a Race Face 42T NW ring and bolts. What's the frame weight? The alloy Boardman CX bikes were boat anchors if I recall correctly.

[expatscot]

If you want to ride 1x10, a SRAM Red BB30 Exogram crankset weighs 363 grams, ended up around 450-460 with a Race Face 42T NW ring and bolts.

That's a good suggestion. It would also save the front mech, cables and shifter innards as well.
I'm not quite sure if I am ready for 1x10. It's something I am considering. If I went 1x10, then I would probably get a 130 bcd chainset, as they seem to be a lot cheaper on eBay, and I have a few rings of that size kicking around.

What's the frame weight? The alloy Boardman CX bikes were boat anchors if I recall correctly.

This is the carbon frameset - https://www.boardmanbikes.com/products/ ... et-qr.html

1050g for frame; 460g forks (according to manufacturer website). The reviews I've read suggest that the weights were pretty accurate. I will obviously check when I pick them up from the LBS.

[AdyM]

Only have one criticism of the HUNT wheels, their hubs aren't the best. They are pretty slow to pick up (although so are the kinesis ones!) So if you are racing you might want something more snappy to pick up. Which is why I'm currently building some with Hope pro4. 44POE compared to 27? or 30? DCR wheels will do a good value carbon build, their road disc hubs are 56POE, or you can spend more on some very tarty light hubs!

[expatscot]

Only have one criticism of the HUNT wheels, their hubs aren't the best. They are pretty slow to pick up (although so are the kinesis ones!) So if you are racing you might want something more snappy to pick up. Which is why I'm currently building some with Hope pro4. 44POE compared to 27? or 30? DCR wheels will do a good value carbon build, their road disc hubs are 56POE, or you can spend more on some very tarty light hubs!

Thanks! I noticed that Hunt also sell the aero carbon rims, meaning replacement is possible and self build also possible.
I'd not seen DCR before - they look a decent outfit.

[expatscot]

Almost ready to collect the frame at the weekend.

Quick question re rotors.
I have picked up a set of TRP Spyres, but without rotors.

I've read that the Ashima AI2s are pretty lightweight, but want to make sure I am on the right track.
Any problems with Ashima (or other lightweight) rotors? Anything to watch out for?
I've never had a disc brake bike before, so have no experience here.

[fresherjohn]

I wouldnt recommended the kinesis wheels, mine have been back twice under warranty and their new crosslight v4 set are 200g heavier, I believe with stronger dt swiss spokes and steel nipples

[AdyM]

In my first CX race I mysteriously bent my rotor, still not sure how (inspection seems to have bent outwards, so it's not like I kicked it on a dismount), to be honest I'd stick with a standard flat rotor (floating are a pain to clean!)

Again, goes down to usage, I want that bit of extra robustness for this reason, I've bent light rotors on the XC bike before, but in terms of performance, I've had no issues with braking power. Hope this helps.

[expatscot]

Thanks.

I will have the final decision on the wheels at the weekend - whether to go with the Kinesis, or selfbuild.
I'll chat to the shop and get their views, when I pick up the kit.

[AdyM]

Only other thing to consider is spoke counts. My custom build are 28/28. I'm 80kg, for all round use. A lot of others are 24/28 for racing/road disc, or 32/32 for strength and weight!

Custom build gives you that flexibility

[cdtf]

I would not use superlight rotors.

They wear in an uneven way, they warp under too much force, and they lack power.

Don't try to save weight on your brakes.

[expatscot]

I would not use superlight rotors.

They wear in an uneven way, they warp under too much force, and they lack power.

Don't try to save weight on your brakes.

Ah! I was just about to "Buy it Now" on a pair of KCNC lightweight rotors. (they seem identical to Ashima Air2)
What's the recommended rotor then, if the Ashima superlight (73g /160mm) is too light?

[philipBer]

I use SRAM Centerline, no reason to complain after lots ok km. not super light though...

[VPR]

I built up a Boardman CXR in September - October last year. I initially ordered a black 9.8 from the Boardman Factory Outlet but the thru axle version was sold out so I got a white 9.4 frame with 15x100 and 12x142 thru axles instead. I built it up with Ultegra 6800, RS685/RS785 brakes, ZTR Grail/DT240s wheels and parts I had lying around (3T Ergonova bars, 3T Arx stem, Fizik Pave saddle, Rotor 3D cranks, XT pedals). As this is a more of a gravel grinder/commuter/everyday bike I put on lights, pump, saddlebag and full mudguards. Weight savings were not a target with the bike but saved about 500 g over the previous aluminum cantilever bike, about 11 kg with everything. Some small changes since this pic http://indyville.fi/villen_muut_tiedost ... -10-13.jpg

[expatscot]

I built up a Boardman CXR in September - October last year. I initially ordered a black 9.8 from the Boardman Factory Outlet but the thru axle version was sold out so I got a white 9.4 frame with 15x100 and 12x142 thru axles instead. I built it up with Ultegra 6800, RS685/RS785 brakes, ZTR Grail/DT240s wheels and parts I had lying around (3T Ergonova bars, 3T Arx stem, Fizik Pave saddle, Rotor 3D cranks, XT pedals). As this is a more of a gravel grinder/commuter/everyday bike I put on lights, pump, saddlebag and full mudguards. Weight savings were not a target with the bike but saved about 500 g over the previous aluminum cantilever bike, about 11 kg with everything. Some small changes since this pic http://indyville.fi/villen_muut_tiedost ... -10-13.jpg

Looks great! Quite a lot is similar with mine - the frameset is (almost) identical. Mine is the QR version, but otherwise identical.