[Closed] Pro XC Tweaks

tomhoward - Member
tomhoward - Member
Closer inspection of the seat/Top tube join looks like a decoupler... But for the size of the seat tube?
POSTED 3 WEEKS AGO #
I'm claiming that!

Do at least TRY and keep up at the back, would you?
http://singletrackworld.com/forum/topic/not-very-soft-tail

CaptainFlashheart - Member

Trek bring the "decoupler" to hard tail XC bikes.

Sauce

POSTED 2 MONTHS AGO #

Scooped.

Interesting to see Next SL chain sets on the MTBs, they've obviously given up on BB90.

Top Fuel looks great, comparatively good value too - the old 26" Top Fuel was £3000 for a frame in 2010.

they've obviously given up on BB90.

Kinda want a go. On a related high jack stylee, that Madone is rank.

I want to try the Madone, but it looks more shit in colours that aren't TFR, and the H2 ones look wrong, and like the Emonda you have to get the expensive ones to get H1 fit, grrr!

I kind of get the decoupler for a mtb but surely something like the BMC would make more sense to me.

At least the BMC softtail is still working if you're not sat down!

Flashy, I was referring to the Madone....

That's the superfly off my list of frames. New hub standards and mega expensive g2 forks.

You assume the Superfly gets dropped from the range...

At least the BMC softtail is still working if you're not sat down!

Barely, id assume.

surely the decoupler still allows rear wheel movement in the same way as the BMC, only using the flex in the bow shape of the seatstays and top tube rather than an elastomer, with the elastomer being a re-bound stop? Or am i missing something?

I took it that the trek system relied on the seat post itself moving (the seat stays might have a bit of give as well) whereas the bmc has the elastomer in the seat stays so it still has some give when you're not seated.

Ah, got it. Well done, Tom! 😉

But without the mass of the rider to oppose the movement the back wheel will just bounce up.

Glued on Garmin mount?
[img] [/img]

http://www.pinkbike.com/news/xc-bike-check-dan-mcconnells-trek-top-fuel-2015.html

Always think those Di2 displays are in a dumb position. Can you mount 'em over the stem in a barfly styleee? (Pointless question as I'll never be able to afford Di2!)

For most bikes, that mounting position is completely out of the way of any potential crash damage. Seems a good idea to me.

I'd hit it with my knee.

Good news is you only need the XTR display if you want to use the "syncro shift" on the front mech. For 1x or 2x (with the shifters operating like normal shifters), you can use a normal junction box and hide it all inside the frame.

The Bonty XR12 front tyre looks interesting- looks like a XR1 meets an XR2, exactly as the name implies.

^^ if you don't use the display you need a EW90 junction so you can charge the battery, mines mounted on the seat tube at the moment, with a long wire from the shifter

XTR works with the D-Fly so you can have all the data straight to the Garmin anyway

can you hide the EW90 in the frame? any examples?

I'm half tempted to buy the Pro Tharsis stuff just to get it all neater

pics in the TrainerRoad thread

http://singletrackworld.com/forum/topic/trainerroad-stw-approved-sessions/page/33

Some guys on Tririg (not XTR but some good internal setups) and Weightweenies (some nice XTR Di2 CX builds without using the "STI's" for shifting but a climbing satellite shifter instead) often use one of the original, much smaller Junction A boxes with the splitter box if more connections are needed. It seems so long as you have a shifter with a PCB (i.e. not the sprint shifters) then you can mix and match any ETube stuff however you like.

You can drop the Junction box into the downtube (when the fork is removed- cable comes out through drilled out front mech cable ports) if there is enough gap to give access for charging around the BB (99% sure my frame should be fine as the gap is quite big). There are also SLS junction box mounts replacing a 5mm headset spacer if you want to keep it out in the open but can't be doing with the straps on the stem. Under a Garmin out front mount is another option.

The Pro Tharsis stuff looks nice on the face of it (Flow MTB hid a junction B box in the stem but kept the XTR Junction A for example) but it is designed around keeping the XTR Junction A and however you decide to use it you will always need to have the wire for the rear mech exiting the stem somewhere messy (at the headset top cap most likely). Plus the bar and stem aren't the lightest 😆 I do like the idea of the battery in the fork steerer though like the Tharsis stuff lets you do and McConnell has done on his bike....

McConell's bike is actually remarkably clean for something with so many wires! Shouldn't be surprising as he is one of Shimano's poster boys for XTR Di2

There are also SLS junction box mounts replacing a 5mm headset spacer if you want to keep it out in the open

I've got one of the RaceWare 5mm junction spacers on my road bike, it seemed fragile when fitting as i managed to break a bit off, but its rock solid one fitted properly

Excuse my ignorance for asking but I see a lot of slammed front ends on the xc race bikes - whats the reason? I get it on a road bike that it's more aerodynamic, is this the same reason for doing it on an MTB? Are there really aero advantages to be gained this way? I guess possibly that the top xc riders also ride road so maybe its to keep their body position as close as possible across the different disciplines?

It's mostly body position- I believe (and found, though I'm not sure of the science of it) that it allows you to produce more power than a more upright position. Also, they probably need the lower front end to ride that sort of bike properly.

Looking at set ups like that above though does make me question the "29ers for all" approach. It looks bodged to fit him.

even for a pretty cr@p rider I think the aerodynamics is noticeable, especially on fire-road grunts. factor in a head wind and it definitely makes a difference. My bike has saddle only a cm or so above bars and if I'm hammering along a fire-road, i feel a hell of a lot less resistance if i drop my elbows and get into a more aero tuck.

I have also heard you can lay down more power in a tucked position

Saves on front wheel lift when you're pinning it up steep climbs too.

...and puts you more over the front wheel for grip during those mega-fast turns.

Course preview from Fumic for this weekends WC at Lenzerheide

Aerodynamics at 20mph and above on a MTB matter as much on a road bike and with the rider being the biggest obstacle it makes sense to get lower when riding along at 20mph plus on flat sections.

If you don't go above 10mph unless on downhill sections then may not matter quite as much.

I can also feel a big difference in power delivery between an upright position and a lent forward position.

Sometimes you see riders with their hands on the fork crown to get lower on flat sections

I was thinking with 29ers it's to get there front end low to achieve their same position as a 26 inch wheel.

Front end grip definitely a huge part of it.

PB claimed 19.5lbs for McConnells bike.... then followed up with a scale shot 😀

[img] [/img]

😆

close... No wait!

thats surprising, although we know that a pound here or there won't make a difference when racing, my Tallboy isn't even a pound heavier than that and I've got some Heavy bits on it AM ENVE Rim, Tubes, 203mm Rotor, etc

It was impressive watching him washing his bikes at a race last year, they were cleaner when he took them for their final was than most peoples were leaving the bike wash. (I was drinking beer instead)

thats surprising

Kind of but anything under 22 would be light considering they are tied to sponsor only parts. Bonty wheels are typically ~1400g, Bonty tyres aren't light, Di2 is heavier than mech, iCD must add some weight, fork isn't the lightest, cassette isn't the lightest, XTR pedals aren't light... so it all adds up quite quickly.

Well, it's Pro XC, and it's certainly tweaked!

[img] [/img]

[b]STEEEEEZY[/b]!

Not as awesomez, me,

[img] [/img]

Doesn't count if you don't have a race number on monkeyfudger.

[img] https://lh3.googleusercontent.com/zHybcaQfgMRX4Ft5yPjRWVL2BkJbBLhnbLie1jDCufIg=w354-h551-no [/img]

Yer can see my number, and why else would I be wearing a skinsuit outside of kinky Wednesday's 😉

nice shots!

so the new procalibersl

£1800 frame only or £2250 as a complete bike with Rebas and SRAM GX 😕

im assuming the only difference in the frame is the colour?

Same as Cannondale/ Canyon/ Giant/ everyone really. I guess if they've committed to a load of OE stuff in bulk to be able to have attractively priced full bikes (what the majority would buy?) then they have to make the alternative unattractive enough to get rid of the full bikes 😀

Frames are quite light too, significantly lighter than my Superfly. Tempted to swap.

aye i guess, never really paid much attention to the price of high end bikes as i rarely go in shops and build up everything normally using a used frame,

annoyingly though, i like the trek, but I've just bought the mrs a bike in a very similar colour to the cheapest build 🙄