crankset advice.

[jags]

is it possible to buy the thorn crankset triple and choosing my own combo 170/ 50 /34/28 and will it work to perfection with tiagra front rear mechs 10 speed .
that's basically all i want to know.

oh what bottom bracket will i need with those thorn cranks, i have outer bearings fitted to the new audax.

cheers

anto.

[alfie1952]

Anto,
SJS have a hollowtech 2 triple, item code 24749L170 .It is silver and comes with bottom bracket , you can get it 170, although it does not say that you can get it in black. Also no chainrings supplied, so you decide on sizes.

How is the build coming along.

Alfie

[Danneaux]

...50 /34/28 and will it work to perfection with tiagra front rear mechs 10 speed .

Anto,

I'm concerned the chainrings you specified will not play play well in practice. I think the gap between the 50t and 34t chainrings is too large and the gap between the 34t and 28t is too small. The result is likely to result in unpleasant shifting.

Typically, crossover gearing (which I think you are trying to duplicate) works best with no more than a 10-12t jump between chainrings.

It appears the longest-cage rear Tiagra mech (RD-4700-GS) is a GS, not the greater capacity SGS. Shimano is sometimes a bit conservative, but still lists total windup capacity as 41t when used with a triple front mech and 20t difference in chainrings. Your 50/34/28 chainrings have a 22t difference, leaving 19t difference in the rear. This would probably accommodate a 12-32 cassette, but it would be close.

I would suggest instead you choose a Shimano rear mech with longer S-GS cage and greater windup capacity if you wish to keep this overall range. However, I'd choose a different combination of chainrings.

I know you are planning to use bar-end shifters. Please note you will need a 9-sp MTB rear mech if you wish to shift a wide-range 10-sp cassette using 10-sp road shifters.

Have you looked at Thorn's latest Audax Mk3R brochure and their gearing suggestions?: http://www.sjscycles.com/thornpdf/thorn_audax_mk3.pdf
They offer the following suggestions...

TRANSMISSION CHOICES.
We offer many different options,
the 3 most popular options are:-
###
[1] 30Sp ULTRA WIDE range gearing
The transmission we’ve selected really is very special -
we’ve used a Shimano Deore equivalent 10 speed
26/36/48 chain set and a 11-36 10sp MTB cassette - this
gives an absolutely awesome range of gears - 19" to 117"
We use a Shimano Deore 9* speed rear MTB mech - this
isn’t a typo - it needs to be a 9sp MTB to work properly
with 10sp road STI.
We use a 10sp Shimano Tiagra road triple front mech and
Tiagra 10sp STI levers.
This 100% Shimano transmission works really well and
should give most people a gear for every situation likely to
be encountered on the Mk3.
[2] 30Sp WIDE range gearing
If you want a tighter spread of gears, we can substitute a
Shimano Tiagra 12-28 cassette with a medium cage
Tiagra mech. This gives gears from 25" to 107".
[3] 20Sp COMPACT DOUBLE gearing
We also offer a Compact Double 20sp full Tiagra spec with
34/50 rings and a 12-30 cassette.
This gives gears from 30" to 112".
For extra cost upgrade gearing options, please
see pages 75 and 88 of the Mega Brochure.

A quick question to ask yourself: How high a gear can I pull? How low do I need for the hills I'll encounter. If you carry even light cargo for touring, keep in mind you may want lower gearing than on your road bike.

All the best,

Dan.

[jags]

Thanks lads i'm still only window shopping  so want to get things spot on.
Dan i changed my mind yet again on the shifters i'm going for Tiagra 10 speed triple  STI  i'm just to used to STI shifters to change now besides there awesome on my dolan never miss a beat 

yeah i want enough low gears to get me up these steep hills especially if im carrying camping gear,
i want to keep the look of the bike BLACK the VO hammered mudguards look class  they will set the bike off  for sure ,they will be mine oh yes they will be mine.

the Tiagra is more gray than black  but it looks good ,probably make a lot more sense to go with the SJS build but the deore chainset is heavy i don't like the look of the chainrings  (stronglight or TA) would be my choice,the 11to36 sounds good so the 9 speed  mtb deore mech is going to work with the Tiagra ?

so where am i now 
Tiagra 10speed triple sti leavers
Tiagra triple chainset 48/39/30
deore MTB 9 speed rear mech......instead of tiagre  medium cage
mountainbike 11to 36 cassette....instead of 11to32
tiagra 10 speed triple front mech
bling wipperman gold chain 10 speed  .

going to be a lovely bike if ever i get it on the road 

[Danneaux]

...going to be a lovely bike if ever i get it on the road

I have a feeling you'll get it on the road much faster than any of us can imagine. 

The frame -- which you now have -- is the narrow end of the wedge. Everything else will follow in lock-step.

All the best,

Dan.

[jags]

i will certainly do me best