Any tips for building a TT bike?

[sandman77]

I have entered the London Triathlon in July and also next March am going to NZ to do Ironman. All my riding up until now has been done on my Specialized Allez road bike.
My brother (who just done this years NZ Ironman) is sending me over his old TT frame and bits and bobs. He was hit by a car and the bike was written off but he is sending over the bits that survived the crash. This includes a Planet-X stealth Pro frame, the crank, cassette and handlebars. I need to buy brake leavers, shifters, and a front fork. My brother is sending over a set of wheels and tyres and saddle from another bike. The shifters and leavers I know what to get and I could always go to planet-x and buy the fork that matches the frame for £100. I would however like to save a few (more) pennies and try to pick up a bargain on the fork. There are always people selling carbon forks on ebay but I am not sure how much steerer tube I require. Is there a way to determine this or should I just buy the brand new one?

Also does anybody have a link to a site that will help me when building the bike?

Oh, I will b e taking the bike to NZ with me next year for the Ironman after which I will be giving it back to my brother.

 

[accountantpete]

Re the forks - I presume they are 1 1/8th steerer. You just need to add up the height of the Headtube and stem and then add on 30-40mm for luck and that will give you an indication of the steerer length required.

If you are looking at 2nd hand full carbon forks they are pretty robust objects but make sure there is no obvious damage. The main problem I have found is wear to the carbon steerer from ill fitting/badly maintained headsets - you will see wear marks 50mm down from the top of the steerer where the compression ring has sat -if buying I'd ask the seller what the wear to this part is like.

 

[Will1985]

I've never heard of this stem formula that accountantpete has mentioned...can't be very scientific if you add extra length for luck Be aware of carbon forks on ebay - you never know if someone has crashed it badly and there is a fracture in the carbon....it happens. If in doubt on the steerer go for as long as possible - cut it incrementally. It's also perfectly acceptable to have spacers sitting above the stem.

I would say that you should try lots of different stem lengths as well as the stack. An adjustable stem would help you in this respect. You will want a more relaxed position (higher) for IMNZ as comfort is important. As you need to run off the bike, the position is different from a full on TT position which compromises comfort for all out aerodynamics.

If you have a turbo, spend a bit of time on it tinkering with position to give you a rough idea of where you are, then refine it when you're out on the road. For tri you can push the saddle as far forward as possible which will open up the hip angle.

 

[accountantpete]

Well to be honest Will, I didn't want to get into stack heights,spacers and where to measure the length of the steerer from etc etc - I think the 30-40mm for luck covers this as it will be a semi-integrated or hidden headset anyway.