Disc Brake Road Bike, What's Feasible?

[HJ]

Interesting, I may be out on spokes, I was using:-

XTR hubs with skewers - 535g
Alpha 340 Rims - should be 680g but I allowed 720g
Spokes and Nipples - I've allowed for 64 at a total of 400g
Rim tape - as per yours 45g
Cassette - I'd allowed 250g
Tyres - I was going with 700x32 at 700g the pair
Tubes - allowing 250g

That gets me the 2.9kg, Open Pro rims would add another 150g but they're only rated up to 28mm tyres, I know you can run bigger but that's from the Mavic site. Whereas they do rate the Open Sport rims up to 700x32, which would be a weight penalty over the OPs of a further 110g. I am tempted by the Open Sports as they are fairly tried and tested whereas the Alpha 340s are only just out. Plus I can get them for £45 the pair as opposed to £165 for a pair of the Alphas, a full £120 off the wheelset price.

The Open Pro can take 19mm to 32mm tyres safely, as I say I am mostly looking at road use, but I have started thinking about using a Alex Crostini T1.1 rim which can take 25mm to 40mm tyres safely with only a 45g (each) increase in weight. I have got a price of the Alex rims yet and that maybe the determining factor.

 

[P.H]

How many bikes are you building  

I don't think you'll have a problem building to that weight, if you're prepared to spend enough and loose a little durability.  I'd go the other way, build for purpose and accept that's the weight it is.  

Currently looking custom build myself with cantis or vees on the rear and disc (or even hub?!?) at the front, but options do look VERY limited.

I like this idea, but can't see why the choice is limited.  I'd have thought if you're going to add just a disk fork you could use just about any frame.


I nearly went for a front disk on my new project, in the end I decided for me the cons outweighed the pros, though this was partly influenced by already having a hub dynamo.  Instead I went for Rigida Carbide rims and good cantis which I have and like on another bike.  These have some of the benefits of disks, decent all weather breaking, long lasting rims, clean, with the advantage of simple brakes and less no weight penalty.  They don't have the outright stopping power of good disks, then that's not something I've ever missed on the road.

 

[HJ]

do you know the CdF frameweight HJ?

I decided that Mrs HJ need some new kitchen scales and now has one that go up to 5Kg. So I now know that the CdF frame weighs 2.225Kg...

 

[MacB]

I decided that Mrs HJ need some new kitchen scales and now has one that go up to 5Kg. So I now know that the CdF frame weighs 2.225Kg...

aha, is that frame only or frame and forks?

I spoke to IF Bikes about getting a disc brake road frame done and no problem, geometry wise it would be close to their Crown Jewel model and clearances similar to their Planet Cross. They recommended staying with 135mm dropouts to give the range in rear disc hubs. They also recommended staying with steel forks, they custom make their own, rather than trying for a carbon disc fork. If I go titanium then the f&f's would be about 2.2kg, steel would be closer to the 2.5kg mark.

These were guestimates but, as it'll be a largish frame, they shouldn't be too far out.

 

[HJ]

That is the frame only (it's Reynolds 520 butted Cr-Mo), the 09 carbon forks add 617g, so that 2.8Kg all up.

 

[MacB]

That is the frame only (it's Reynolds 520 butted Cr-Mo), the 09 carbon forks add 617g, so that 2.8Kg all up.

seems reasonable, that's about the same weight as my XCheck frame, though the disc forks in steel come at 1.1kg so I'd guess something similar for the 2010 CdF. So the IF Ti option, with steel forks, at about 2.2kg is pretty good. This could be dropped down by about 300g if I switched to a carbon disc fork at some point in the future.

Are the disc forks on yours branded in any way?

 

[HJ]

No branding, I assume it is just something Genesis had made for them selves, it is notable that it is disc only. The nearest thing I have seen to it is the Kinesis DC19 which weights in at 680g.

 

[simon62w]

I don't know if this helps but in latest edition of Cycling Plus mag they review 2 bikes with discs..A steelie from Salsa and a alu from Trek called Portland which I think has carbon forks..Both about £1200, but it could give you some idea's about sourcing parts
simon

 

[Norm]

I don't know if this helps but in latest edition of Cycling Plus mag they review 2 bikes with discs..A steelie from Salsa and a alu from Trek called Portland which I think has carbon forks.

Isn't that Cycling Active rather than C+? Or have they both got the same two bikes to review this month?

 

[HJ]

seems reasonable, that's about the same weight as my XCheck frame, though the disc forks in steel come at 1.1kg so I'd guess something similar for the 2010 CdF. So the IF Ti option, with steel forks, at about 2.2kg is pretty good. This could be dropped down by about 300g if I switched to a carbon disc fork at some point in the future.

Are the disc forks on yours branded in any way?

I noticed when I was out on the ride today, that Scook 94 (of this forum) has built a Ti road bike using the wheels and brakes from the CdF (he then gave me the frame). He had planned to just the fork as well but there was some problem with the head tube on the Ti frame and so he used a Kinesis DC19 instead. He is really pleased with the bike.

 

[MacB]

I noticed when I was out on the ride today, that Scook 94 (of this forum) has built a Ti road bike using the wheels and brakes from the CdF (he then gave me the frame). He had planned to just the fork as well but there was some problem with the head tube on the Ti frame and so he used a Kinesis DC19 instead. He is really pleased with the bike.

My word, how did I miss that, not only do I not need to look very far, it was right under my bloddy nose. Have posted on Scooks thread and also sent him a PM re more detail. I have had a couple of chats with Justin Burls about a frame anyway.

 

[MacB]

I don't know if this helps but in latest edition of Cycling Plus mag they review 2 bikes with discs..A steelie from Salsa and a alu from Trek called Portland which I think has carbon forks..Both about £1200, but it could give you some idea's about sourcing parts
simon

I saw the Trek Portland but was a bit put off by the drop in spec for this years model and the fact that it's brown, not a colour I could bring myself to spend £1200 pounds on!

 

[MacB]

Hmmm, another one to throw in the mix is the Kinesis Decade Tripster:-

http://kinesisdecade.co.uk/product.php?id=1

can only find as frameset RRP of £500 but going for £450 several places and apparently there's been the odd offer on at £350. You get alu frame with rack and guard mounts and the rear disc mounts are inboard, comes with Kinesis DC19 carbon cross disc fork, headset, seatpost and clamp, reckon F&F will be about 2.4kg for a large size. Basically a tweaked crosslight frame as far as I can see, bigger head tube and more road/commuting orientated.

All seems ideal except for the integrated headset, that makes me wary.

 

[gaz]

What about the 2011 Genesis Day one?

Biggest news for next year's range is that Genesis have bitten the bullet and gone ahead with making the Alfine-equipped Day One, a bike we saw in concept at the February show. So what we have here is a hub-geared, drop-barred cyclocross iron with a Reynolds 520 frame. The Day One uses the Versa 8-speed integrated lever to shift the hub – it has a bit of a Sora-esque long sweep but it works – and Tektro Lyra mechanical disc brakes to do the stopping, which James at Genesis reckons are just as good as the Shimano ones even though they're a bit cheaper.

There's plenty of attention to detail too: note the lengthened rack mount braze-ons which give you a bit more clearance on the disc, and also a bit more thread to hold the bolt if you still need to space it out with a couple of washers. Best of all, Genesis have managed to spec the bike so that it sneaks under the £1000 Cyclescheme limit by a quid, so if your ride to work includes a bit of singletrack and some hurdles then this might be the bike for you. Or you could ride it on the road. Anyway we've scrawled our name at the top of the list for testing, so as soon as we've had a go we'll let you know whether hub-geared cyclocross is the future.

Source: http://road.cc/content/news/20605-genesis-unveil-2011-bikes-icebike

 

[Norm]

What about the 2011 Genesis Day one?

I think I just did a little wee! That's nice, that is.