Advice on TT bike build

huskie69

ravey1981 wrote:

Sounds like you're in way over your head here to be honest. Genuine advice, send it back and use the money to buy a built bike, if you've got £2500 to spend you have plenty of options. Planet X, Dolan scala etc come to mind. I recently built up a TT bike for around £500 and its still quicker than I am....

I actually snapped it up for £1200 because of an issue with their site - they honoured the sale price so I've got it for half their advertised price. 8) 8)

Also, I'll get at least some satisfaction in knowing that I sourced and fitted the components myself.

huskie69

It's just this second arrived

Yes, it comes with a seatpost, so at the very least I can use one of the seats from my donor bikes!!!

It also comes with brakes (TRP, not sure which model - are they just rebranded Tektro?) already fitted - the front brakes are hidden out the way inside the fork. The pads are already on, though I'd be hard pressed to figure out what compound they're made of and if they're adequate for carbon rims.

Looking forward to building it up.

meesterbond

TRP brakes can be a real nightmare to work on btw - there's not a lot of alternatives out there for integrated brakes but it's worth taking a bit of time to work out what's going on with them before building.

huskie69

meesterbond wrote:

TRP brakes can be a real nightmare to work on btw - there's not a lot of alternatives out there for integrated brakes but it's worth taking a bit of time to work out what's going on with them before building.

Thanks for the heads up.

fenix

Luckily you don't want to be doing much braking on your TT bike anyway !

huskie69

Fenix wrote:

Luckily you don't want to be doing much braking on your TT bike anyway !

huskie69

Ok, so the build list so far:

Front Mech -

Bought: Ultegra 6800 braze on
Crankset - Bought: Ultegra 6800 50/34
Rear Mech: Not Bought
Chain: Not Bought (will probably go down the KMC route)
Bottom Bracket: No bloody idea!
Tyres: Not Bought
Brake Lever: Not Bought
Gear Shifters: Not Bought
Pedals: Got SPDs from donor bike
Seat: Got From donor bike (assuming it's compatible)
Mudguards:

2 questions....

1) With my gear combination of 50 - 11, do I need a medium cage rear mech?

2) What tubs?..... as a tub virgin, I'm going with the tape option. I normally ride 25mm conti GP4000IIs - I'm assuming a totally different tyre is the norm for TTs? I want something in the lower end of the market (getting a bit tyred of spending more on bike tyres than car tyres). I have a pair of 80mm carbon rims with 19mm Vittoria something or other clinchers on them. I've not yet managed to get them off with my delicate hands so I'm assuming Vittoria are rather a tight fit?

Grill

1) No. That said, I have no idea why you're running a compact unless you plan on riding loads of SPOCOS (and even then there are better options).

2) Front tub needs to be narrow for most benefit. Conti Podium in a 19c is the easiest to source, otherwise 22c Vittoria Cronos generally come up a bit narrower if you can't find the 20mm. Rear doesn't matter so much from a width standpoint, so you can run something a bit wider with lower Crr (Vittoria Speed or Crono being the best out there).

huskie69

Grill wrote:

1) No. That said, I have no idea why you're running a compact unless you plan on riding loads of SPOCOS (and even then there are better options).

a) it's a secondhand Ultegra crankset with minimal wear at about a quarter of the price of a new crankset and I'm used to that gear ratio combination on my road bike, I've gotten used to that ratio with the Snowdonia hills right on my doorstep, where just getting to a decent flat piece of road requires about 700 ft of climbing...and...

b) from what I've read, a 50-11 is a bigger gear than a 52-12 so in theory (from what I understand) I can go faster with the compact crankset?

Grill wrote:

2) Front tub needs to be narrow for most benefit. Conti Podium in a 19c is the easiest to source, otherwise 22c Vittoria Cronos generally come up a bit narrower if you can't find the 20mm. Rear doesn't matter so much from a width standpoint, so you can run something a bit wider with lower Crr (Vittoria Speed or Crono being the best out there).

Cheers Grill, useful info - and they don't seem to cost that much more than the contis I buy at the moment. What kind of pressure do these run at? I'm 110kg and my 25mm clinchers are at about 115psi. Can they be run with significantly less pressure?

Grill

The reason testers use large chainrings isn't necessarily to go 'faster' (although you will when there's a gift hill), it's to give a more efficient chainline.

At 110kg, you'll need to run quite high pressure as tubs don't stretch out the same way as say clinchers on a wide rim.

Send me a PM if you want, I have most of what you still need laying about.

simon_masterson

As Grill says, Conti are good for (current production) narrow tubs, but they are horrible to get on. I have been getting on well with Challenge Cronos this season; not the fastest, but cheap (try Planet X), and a good balance of speed and durability.