BMC Teammachine SLR01 TWO Di2 Disc

[iamraymond]

Ride Impressions
It took me a few rides to get used to shifting on the Di2 levers. At first I kept mixing up the shift up/down because the shift buttons on the Di2 STIs are very similar, whereas on a mechanical STI the big/small levers are very distinct. Now that I’m accustomed to the ergonomics, Ultegra Di2 is awesome. The auto-trim, semi-syncro shifting, trouble-free operation/maintenance, and predictability of the shifting would make it very difficult for me to go back to a mechanical setup.

My previous carbon bike was a Canyon Endurace (picture attached) spec’d with Ultegra 6800 and DT Swiss RR21 alloy wheels. Compared to that bike, the SLR01 feels much more planted on the descents and the disc brakes help with fatigue on the long, steep descents which are common around me.

Climbing on the Canyon and the BMC is similar though I’d give the slight edge to the BMC. It might just be new bike syndrome, but I feel more motivated to ride climbs off the saddle on the BMC… as if it’s telling me to push harder. The Canyon was slightly lighter at 7.4kg with cages and pedals so my plan is to get the BMC to match or better that weight.

On the flats, there’s no difference between the two bikes.

The Canyon was certainly more comfortable due to the flexy VCLS seatpost and wider Continental GP4000 tires (27mm measured). I feel the road surface more on the BMC compared to the Canyon. While the ride is not harsh, it’s not as plush… after all, the BMC is a race bike not an endurance bike like the Canyon. I may try 28mm Vittoria’s or 25mm GP4000s when I need to get a new set of tires.

I admit that this bike is far better than a meager rider like myself would ever need. I also have no problem admitting that aesthetics is one of the primary reasons I chose it… Nevertheless, I love it!

Disc Brakes
This was also my first foray with disc brakes and I’m not as impressed I was expecting to me. I thought there would be a massive improvement from rim brakes on alloy wheels, but there simply isn’t. In my experience, braking distances did not decrease and my confidence level on the descents has not changed.

I did not experience any of the enhanced modulation with discs that bike reviewers so often praise. Maybe they are comparing discs to braking with carbon wheels (which I have no experience with), but with alloy wheels I’d say that the modulation is WORSE on disc brakes. On my rim brake bikes, I have the pads 2mm from the wheel surface so I’m used to having very little lever pull before the brakes start engaging. With discs, I find that there’s no effective braking for the first half of the lever pull and I only start feeling the pads contact the rotors after the half way point. On some rapid descents, I still get a quick scare that I have no brakes, then I realize I need to pull them further. Is that normal? I’ve bled the brakes twice now and that doesn’t change anything.

When the conditions are dry (which is like 90% of my rides) it’s difficult for me to justify the need for disc brakes. I chose the disc version of the SLR01 because 1) I like having all the cables/hoses hidden inside the frame and 2) I wanted a future proof bike. I guess for those two reasons, I’m completely satisfied albeit slightly disappointed.

[bilwit]

Disc Brakes
This was also my first foray with disc brakes and I’m not as impressed I was expecting to me. I thought there would be a massive improvement from rim brakes on alloy wheels, but there simply isn’t. In my experience, braking distances did not decrease and my confidence level on the descents has not changed.

...

When the conditions are dry (which is like 90% of my rides) it’s difficult for me to justify the need for disc brakes.

Exactly the same impression I got when I got my disc bike. In the dry there's nearly no difference. In the wet, definitely a difference from carbon rims (non-textured) but not a whole lot from alloy at all. Sometimes I even prefer the bigger bite I get from rim brakes rather than the improved modulation from discs. I can confidently say that the hardcore "rim brakes are like VHS tapes" disc fanboys are wearing rose tinted glasses now that I own a disc bike myself and live in a hilly place where it rains nearly half the year on average.

[StellarPatellar]

I did not experience any of the enhanced modulation with discs that bike reviewers so often praise. Maybe they are comparing discs to braking with carbon wheels (which I have no experience with), but with alloy wheels I’d say that the modulation is WORSE on disc brakes. On my rim brake bikes, I have the pads 2mm from the wheel surface so I’m used to having very little lever pull before the brakes start engaging. With discs, I find that there’s no effective braking for the first half of the lever pull and I only start feeling the pads contact the rotors after the half way point. On some rapid descents, I still get a quick scare that I have no brakes, then I realize I need to pull them further. Is that normal? I’ve bled the brakes twice now and that doesn’t change anything.

The disc calipers are also probably not more than 2mm from the rotor. Personally, I appreciate the modulation of the disc brakes more over time as I get more experience with them. I never noticed any extra lever pull.

[iamraymond]

@StellarPatellar Yes you're right. I should clarify... the pads are 2mm from the rim with my rim brakes, and the pads are 2mm (or less) from the rotor with my disc brakes. However, with the rim brakes it I only need a bit of lever pull for the pads to contact the rim and I start decelerating. Whereas with discs, the levers need to be pulled much further back before the pads contact the rotor and I start decelerating. I assumed that Shimano would design the rim and disc levers to have the same ‘throw’. Once the brakes are engaged, the performance of rim and disc is the same (in dry conditions).

@bilwit, seeing as you have a SLR01 with rim brakes and RM02 with discs, do you have the same experience with the discs? Specifically, do they start engaging that the same point in the lever as your rim brakes, or is it much lower in the lever pull?

I’ve bled the brakes twice now and bed them in properly by doing a number of hard braking efforts without fully stopping. I’ve cleaned the rotors and sanded down the pads between bleeds to remove any material which might impede the braking performance.

[JScycle]

@StellarPatellar Yes you're right. I should clarify... the pads are 2mm from the rim with my rim brakes, and the pads are 2mm (or less) from the rotor with my disc brakes. However, with the rim brakes it I only need a bit of lever pull for the pads to contact the rim and I start decelerating. Whereas with discs, the levers need to be pulled much further back before the pads contact the rotor and I start decelerating. I assumed that Shimano would design the rim and disc levers to have the same ‘throw’. Once the brakes are engaged, the performance of rim and disc is the same (in dry conditions).

I would say disk brake levers would have more lever throw in general.
However in saying that 2mm for rim brakes is very little gap. This probably just means that you like your lever throw shorter than Shimano intended

[iamraymond]

@JScycle I'm going to have to try more disc brake bikes to see if it's a setup issue or really something that I just need to get used to.

If I recall correctly, the recommended distance between the pad and the rim is 1.5 to 2mm as per the Shimano manual

Shimano BR-6800 Manual

[bilwit]

@bilwit, seeing as you have a SLR01 with rim brakes and RM02 with discs, do you have the same experience with the discs? Specifically, do they start engaging that the same point in the lever as your rim brakes, or is it much lower in the lever pull?

I think we're on the same page. On discs it takes more lever pull throughout in order to get to maximum bite, so there's more "control" of how much force is put onto the rotor. It engages immediately but it is much lighter in the beginning of the pull. This is the "improved modulation" with discs. In general, my rim brakes are setup to take much less pull to reach maximum bite (which I actually prefer).



The pic is an extreme exaggeration but you can see the idea here. My rim brakes would be more akin to the one on the far left and discs on the far right.

I do have to say that I have much more confidence in discs than rim-brake carbon clinchers if I need to really dig into the brakes or if it's either pouring or ridiculously hot outside, even as a pretty light rider at 61kgs/180cms. However, I would have the same confidence in alloy rims as well.. biggest difference is that it looks cooler to be on carbon rims than having that silver brake track

[Calnago]

The pic is an extreme exaggeration but you can see the idea here. My rim brakes would be more akin to the one on the far left and discs on the far right.

That’s a great diagram @bilwit, and I don’t even think it’s exaggerated at all. My rim brakes are set up pretty much to operate exactly like the far right example. I feel I have every bit the modulation of the Shimano disc brakes that I have used. This comes from perfectly smooth running cables, levers, and perfect pad adjustment to the rim along with a true rim. I had to do a complete panic stop from 20mph a couple of months ago due to a car stopping broadside in front of me when he realized he went when he shouldn’t have and had to stop. And that’s not to say I just grabbed as much brake as I could squeeze, as that would have locked up the wheels. The modulation I could feel was perfect and while experience plays a large part, rim or disc, I would not have been able to stop any quicker or more controlled regardless of the braking system in use. I was essentially on the progressive limit of the tire breaking loose the entire time from initial application of the brakes to full stop. It was like the human controlled bike version of ABS in cars.

[iamraymond]

Thanks for your input bilwit and Calnago.

I recently learned from a YouTube video about the ‘free stroke adjustment’ available on the Shimano R9170 and R8070 shifters. Shimano states that with the free stroke adjustment “the distance from initial lever position to pad contact point can be adjusted to suit any hand size, type of riding and individual rider preferences.” I was hoping the free stroke adjustment would be the equivalent of adjusting the cable tension on rim brakes, but this unfortunately was not the case. My testing found that the free stroke adjustment does very little in terms of the lever pull even when set to full maxium/full minimum.

On the other hand, the reach adjustment had a noticeable effect on the lever pull and setting it to the maximum would make the lever pull similar to the left image that bilwit posted above. However, adjusting the reach also meant that the levers were much further away from my fingertips when riding in the drops. I will just need to get used to it I guess.

[superyeho]

Hi, could you please tell me what is your BB to saddle height? or better yet , what is the max seatpost length that can be out of the frame.
Im trying to find out if size 51 will suit my 75cm from saddle to BB

[bilwit]

Hi, could you please tell me what is your BB to saddle height? or better yet , what is the max seatpost length that can be out of the frame.
Im trying to find out if size 51 will suit my 75cm from saddle to BB

I'm pretty confident that you wouldn't have a problem with the 51 (don't forget your saddle is also a big factor in how much seatpost is used). I ride a 54 @ 74.5cm saddle to BB with a 120mm -12D stem no spacers (~56cm from tip of the saddle to center of the bars).. I sometimes wonder if I could have saved a few grams with a 51 frame but then I would have likely needed a monstrously long stem for it

[superyeho]

Interesting , I have 55cm from saddle to bars.
I have an ISM pn3.0 , total stack of 6cm. So I need 69cm from BB till end of seatpost. On a 51 with a 300mm seatpost , that would leave 8cm of seatpost in the frame.
I dont know if that would be enough...
On the other hand , 54 may be ok but I would not be able to lower the front much more.
I am right now riding a 530mm stack and 324mm reach frame (scott) with 120mm stem, 2cm spacer (which gives 550 stack?) , although it is a -6 degrees....

[Miller]

La Barillette, that's the climb from Nyon on Lac Leman up to a radio tower, isn't it? Solid 1000m ascent, I did it once in 59 minutes, probably the only time I have ever actually climbed 1000m in an hour.

That was a long time ago.

Lovely bike and excellent work you did on it. A Swiss bike in Switzerland.

[shaunmbull]

nice build looks cool just a quick question did you mount the unction (A)
(EW-RS910) in the frame or bar as i cannot seem to find the correct part for my own conversion for the frame mount as pictured below hopefully you can help cheers

[bilwit]

nice build looks cool just a quick question did you mount the unction (A)
(EW-RS910) in the frame or bar as i cannot seem to find the correct part for my own conversion for the frame mount as pictured below hopefully you can help cheers

it's a proprietary part from BMC, you'll have to request one from a bmc dealer