What groupset for a TT bike?

daniel_b

Morning all,

I will want to be kitting out my recently purchased Planet X Exocet 2 frame in the spring.

Limiting factors is that I have some chinese carbon wheels which will only take a 10 spd cassette, which rules out 105 5800 for example.

I do have a 105 5700 groupo hanging about, but it's a compact, and I think my brother will make more use of it as he needs a new groupset on his CAAD 3.

So I started wondering if it made more sense to look lower down the groupset range, especially as mileage is obviously going to be a lot lower than a normal roadbike, and in theory perhaps something 2 rungs down from 105 is now as good as 105 was say 4 years ago..........?

What about a Tiagra Double 10spd setup - decent idea?

The only downside that I can see, and it's purely an aesthetic one, is that the bike is all black, and the cheaper groupsets just seem to come in silver, and a black groupo would look nicer to my eye.

The 105 5700 is now more pricey than the 5800 so makes zero sense, unless prices plummet, but looks unlikely.

I have a load of Shimano tools, so don't want to consider Campagnolo (Aside from the wheels not being compatible) - is SRAM worth a look, or will that require additional tools? I know the cassettes will fit on Shimano wheels etc etc.

Or as I will be using dedicated TT shifters and brakes, perhaps there is an argument to source all of the bits seperately - not sure if that saves any money or not, as presumably I can sell the groupset shifters/levers with ease.

Kieran_Burns

You will be limited by BB choices in the frame - SRAM use BB30 fpr example so you check what you can use before deciding what groupset to use.

asprilla

Why don't you just sell the 5700 compact crankset and get a double? Or you can probably get some chain rings that will fit the bcd and have an appropriate number of teeth.

BB won't be a limiting factor (Sram use GXP) as there are all manner of adapters available.

daniel_b

Kieran_Burns wrote:

You will be limited by BB choices in the frame - SRAM use BB30 fpr example so you check what you can use before deciding what groupset to use.

Thanks Kieran,

Twould appear to be BB30:

BB30 bottom bracket for maximum rigidity and power transfer

Shimano is 24mm (?) so an adapter required if wanting to go the Shimano route?

daniel_b

Asprilla wrote:

Why don't you just sell the 5700 compact crankset and get a double? Or you can probably get some chain rings that will fit the bcd and have an appropriate number of teeth.

BB won't be a limiting factor (Sram use GXP) as there are all manner of adapters available.

That's not a bad call, arguably my brother would be better off with a mildly more expensive (Than what I would sell the 5700 to him for) 5800 11 spd groupset.

leeefm

Tiagra is really reliable and pretty decent performance-wise. It's becoming quite standard now on ~£1000 bikes. Cassettes are pretty decent too, albeit heavy, but it is easy to upgrade to an old 105 or ultegra 10 speed.

I'd probably buy the bits separately if you can wait for decent offers to come up, you could get a nice TT specific chainset that's compatible with your BB, and just buy the tiagra derailleurs (although the 105 front mech is better than the tiagra IMO).

asprilla

Daniel B wrote:

Asprilla wrote:

Why don't you just sell the 5700 compact crankset and get a double? Or you can probably get some chain rings that will fit the bcd and have an appropriate number of teeth.

BB won't be a limiting factor (Sram use GXP) as there are all manner of adapters available.

That's not a bad call, arguably my brother would be better off with a mildly more expensive (Than what I would sell the 5700 to him for) 5800 11 spd groupset.

54t 110mm bcd: http://www.spacycles.co.uk/products.php ... 0s113p1729

I'm sure you can find a 39 to do with it if you wanted.

However, it's probably cheaper to get a used 5700 double crankset from ebay. I just bought a 6800 double because it was cheaper than buying the rings on their own.

daniel_b

Thanks for those replies gents.

As I think about it, I am thinking I have some new 10spd cassettes and chains knocking about.
I also have some new 105 5700 brakes from upgrading my gf's bike to Ultegra, I have cables and outers available.

And I already have TT brake levers, and will need to buy TT shifters.

So that would just need me requiring front and rear derailleur - and a crankset, and a BB of course - although the frame might come with one fitted.

That would then open up the door to specific TT chainsets which hadn't even crossed my mind - this one says it is BB30:
http://www.chainreactioncycles.com/vision-trimax-pro-tt-bb30-crankset/rp-prod104400

What I am not sure about, is the Boltcircle measurement (52/39) only available in 130 as opposed to 110.
And also it states:
Q-Factor: 146mm
BCD: 110mm
Chainline: 43.5mm

I would usuaully ride a 175 crank, but this is only 170 - is it traditional/advisable to ride a shorter crank for a TT bike?
My inseam is a genuine 34".

leeefm

The 5700 brake calipers have a different cable pull to older models, IME it is better to match the pull ratio of the levers with the calipers. I've used 5700 levers with 6600 calipers with less than brilliant results. I think if you use old levers with new calipers, it might be ok.

I went to shorter cranks - I'm 5' 8" - and it generally helps me to keep a good smooth cadence. Not so good for sprinting i think as you have less leverage, as your power acts over a smaller time, although this is marginal as it is balanced out by the other leg coming in earlier. Best advice on crank length is to just go and try a bike with shorter cranks and see what you think.

Kieran_Burns

You can use a Praxis kit to convert the BB30 to Hollowtech II. I use one and it is VERY good, not cheap though, so you need to consider the expense.

spasypaddy

di2.

ultegra di2.

shifters on ski extensions and on bullhorns.

hstiles

From what I have read, converting the freehub to 11 speed could be achieved with a bit of filing.

daniel_b

Well thanks to this thread I have decided to:

Use existing 10spd 105 chain, cassette, and brakes, cables and outers
Have today ordered 10spd dura ace shifters (Now have two 9 spd pairs to sell!) and that Vision 52/38 crankset from CRC for £111 using the BC discount code.
Realise I should have ordered the rear and front derailleur from them at the same time, as the code was onetime use only, until hopefully they issue a new one in Feb.
At the mo CRC have the rear for £13.99, and the front for £24.99, so they would come down to a ridiculous £12.60 and £22.50 respectively.
And unless I am mistaken (As I already have some aero brake levers) that should be me pretty much done - can't lay hands on the frame right now, and cannot recall if it came with a BB30 fitted, but suspect it might do.
it comes with a seatpost, and I have saddles, and handlebars/tape etc etc

So I can hang onto the boxed 5700 groupo for my brother, will probably let him have it for £225 (Cost me £350...) and can also get shot of the Fulcrum 5's I bought for no reason at all (Other than that they were £143) as his current wheels are junk - and Campag only.

gloomyandy

Hi,
I built a bike up from this frame late last year. It will not come with a BB fitted (well mine didn't), but I'm pretty sure that the crankset will come with one (mine did!). I went with SRAM Shifters/mechs/brakes and 3T bars. I had to cut a chunk of the seatpost (mine is a small frame), and the steerer, which was a little scary. Don't forget cables. Oh and check the front mech "braze on" bolts, mine was a little loose and as a result I thought the front mech was slipping and over tightened it and damaged the hanger. The folks at Planet-X were very good though and provided a replacement FOC (I've always had excellent service from them).

Now I just need to get used to riding it and find the best position on it (easier said than done when everything seems to be adjustable!).

daniel_b

gloomyandy wrote:

Hi,
I built a bike up from this frame late last year. It will not come with a BB fitted (well mine didn't), but I'm pretty sure that the crankset will come with one (mine did!). I went with SRAM Shifters/mechs/brakes and 3T bars. I had to cut a chunk of the seatpost (mine is a small frame), and the steerer, which was a little scary. Don't forget cables. Oh and check the front mech "braze on" bolts, mine was a little loose and as a result I thought the front mech was slipping and over tightened it and damaged the hanger. The folks at Planet-X were very good though and provided a replacement FOC (I've always had excellent service from them).

Now I just need to get used to riding it and find the best position on it (easier said than done when everything seems to be adjustable!).

Thanks a lot for your reply Andy.
Good tip on the bb, otherwise I'll just have to source one seperately.
Mine is a medium, I am 5ft 10, but 34" inseam, and short upperbody/short reach.
What height/inseam are you?

Feel free to pm me any pics of your finished steed

Thanks for the tip on the front mech too, I will make a note of that for when I get to build time.

I have cut carbon steerers before, but can't quite figure out what or why you had to cut the seatpost - would it not go far enough down unless you chopped some length off?

gloomyandy

I'm 5'6" inseam 30". Yes the seatpost had to be cut as it would not go far enough into the frame, the shape of the seat tube only allows it to go so far (less far on a small frame!). Had to cut a fair chunk off mine and even now it is pretty much as far in as it can go. It is an awkward shape to cut. I ended up using a mitre block and some G-clamps along with masking tape and a high tpi hacksaw. All went pretty well though.

The only thing I don't like is the saddle clamp. It has ridges on it which means that the angle of the saddle moves in jumps. I would like to have mine slightly nose down for comfort, but the ridges make it hard to get exactly the position I would like. May end up trying a different saddle though, especially for longer events, I don't think I could ride the one I've got (Planet-X Exocet) for much more than an hour or two. May give one of the Adamo saddles a try.