Electronic & Hydraulic Shifting (Di2, Ui2, customisations)

I was hopeing @edscoble can 'acquire' me one!

Thanks @fussballclub I'll try a bike shop that will help me if i can't just simple buy one easily.

As Dammit pointed out.

You need the whole group on the same firmware. So it all needs updating together really.

Don't have access to find out! However SJS should have some olive and the like in stock.

I'm thinking of upgrading the calipers on my cielo to the saint m820 calipers. Anyone know if they're compatible to the r785 levers?

My understanding is that that would be fine.

Is that four pot calipers on a road bike?

Oh you not at LBW anymlre!?

SJS sell the whole thing. Tedious but not too expensive.

http://www.sjscycles.co.uk/shimano-sm-bh90-banjo-bolt-and-ring-prod31124/

"banjo bolt"

snigger

It lives! Just got back from Condor,and you guys were right. Had to update every single one to the latest firmware. They only charged me £10 which I think was very cheap compared to buying the interface box that costs £100'ish+.

have to say I'm quite impressed with the adjustment! only took me less than a minute to adjust everything compared to me adjusting a mechanical which takes me at least 20 minutes+ just to stop that clicking chain on cassette noise. So far so good. Have to say i'm quite happy with my installation aswell. Hid some of the cables properly even though it's an external cabling system on an old'ish steel frame.

That's good news. I'd ask Ribble for the £10 back but I wouldn't hold your breath...

that's the plan

But...why?

Have to says I concur, it's simply not necessary.

Especially, most especially on the rear, even 140mm is way too big.

four pot calipers on a road bike;

Why is that?

I have Shimano rs785.

For me the brakes don't limit me. Only the tires' grip.

Four calipers wouldn't make my braking distance any shorter.

Might make your time-to-tarmac shorter

On Me Julie's bike (with R-685) I can cover the final part of the hill upon which I live on the front wheel, which I'm guessing is because the wheelbase is shorter, allowing the seated stoppie.

It's also a lot lighter than my bike, with R-785.

But that aside, the level of modulation is what is key to not eating tarmac whilst behaving like a 7 year old on a BMX.

Would a four piston allow greater modulation? I don't know the answer to this - honest enquiry.

For me the brakes don't limit me. Only the tires' grip.

Bingo.

If you really want to increase stopping distance, get bigger tyres, and I mean bigger.

I think you mean decrease, Ed

Would a four piston allow greater modulation? I don't know the answer to this - honest enquiry.

Someone who knows about mechanical advantage might pop along in a bit, but my working knowledge of this is...

Assuming more pots means more surface area for the fluid to work on, and you use the same lever, then the pistons will travel a shorter distance to obtain the same mechanical advantage.

So I reckon by the time your pads hit the rotor you'd have got through more lever stroke. And when the pads hit the rotor, they'll be working at a higher MA.

Combine this with a larger contact area - more friction - and I reckon you'll be losing modulation for power. So, grabby brakes with a long lever throw I reckon.

Lethal on a road bike when you haven't got a 2.4" biting the dirt. Or tarmac in this case.

wont greater leaver throw to pad movement give you more modulation?

Longer throw doesn't always mean more modulation, in Howard's scenario, with those brake it likely to bite a lots sooner compare to the standard calipers.

more modulation mean the braking power gradually increase allowing you to "feather" the brakes (by lightly touching it to shave speed).

I get amazing modulation from my 4 pots.

But even with 4.7" studded tyres the wheels will lock just before the brakes are fully engaged.

Thats largely down to super adjustable mtb levers. So I have them dialled.

With Road levers/tyres you're giving yourself loads of top end brake force you don't need, with less pad travel before lock up to try and use for modulation.