3T Strada sub 6kg goal with cable disc and mechanical shifting

[easyv]

I looked at the Bontager Aeolus RSL but the reach of ~100mm isn't going to work for me. I have that with my 3T Aeronova now and I'm actively working towards finding a more standard (70-80mm reach) bar so that I can have a longer stem... Pretty sure the Strada (and most race-oriented road bikes for that matter) wasn't intended to be run with an 80mm stem which is what I have now to make the Aeronova bars work for me. And even then, clearly its a kluge solution because the tops of the bars are too close for comfortably using them for climbing.

[takolino]

I looked at the Bontager Aeolus RSL but the reach of ~100mm isn't going to work for me. I have that with my 3T Aeronova now and I'm actively working towards finding a more standard (70-80mm reach) bar so that I can have a longer stem... Pretty sure the Strada (and most race-oriented road bikes for that matter) wasn't intended to be run with an 80mm stem which is what I have now to make the Aeronova bars work for me. And even then, clearly its a kluge solution because the tops of the bars are too close for comfortably using them for climbing.

I hear you. It's no fun if it's not comfortable. Since the Strada has a steeper seatpost angle, I'm not sure where I'll end up as far as actual fit so I bought a cheap carbon bar on ebay. My go-to weenie bar is the Bontrager xxx integrated with 100 stem and it has a 93 reach according to their specs. It works for me. Not sure what the addtional 7mm will be like. The tops are flatter so maybe it will give me some leeway. I plan to go with a 90 if I decide to go that way.

[takolino]

Alright, I'm posting some photos here for the first time. It may be boreing though. Bike's not built yet.
This is an update on the 3D printed guides to run bare cable internally. I did around 4 iterations to get to this point and I'm pretty satisfied with the results. I've installed them in the frame without glue and tested the right lever with the brakes and derailleur. Both guides feel smooth and they don't bend or move so the lever feel is good and shifting seems precise. I'll glue them in with a bit of epoxy so they stay put but still be removable if I end up changing my mind. You never know. I may end up giving up and going with 9170.

Here's the 3D printed parts with the teflon tubing inserts. I cut them in half so it's easier to rout the cables.
The Jagwire POP ferrules are perfect for inserting the teflon tube for the cable exit at the chain stays. They fit real tight.


Here's the guide inside the top tube. You can see the 3T cable port in the foreground. I was able to use the Jagwire ferrules here as well.


The rear guide inside the BB. Please excuse the dust from sanding ABS to fine tune the fit.


And, here's my Strada frame with the test setup. I got the right lever hooked up with the rear brake and derailleur so I can test the cable guides.


So far so good. After this, I'll build it up for a test ride to make sure everything works flawlessly. I'm also thinking about doing some decals to spice up the build. I may post some ideas if I'm feeling brave. More to come.

[Klaster_1]

Did you consider a non-wifli Red RD and a longer RD hanger? Regular Red can be tuned quite a bit, there's even one for sale.

[takolino]

I didn't. My understanding is that shifting quality would suffer since I'll probably need to use a roadlink to clear the 32t and the smaller cogs would be slower to shift. But I'm open to learn if there's another way. BTW, I cant see what's on that link. It says I'm not authorized. Maybe I'm too new?

[takolino]

Oh, I see it now. Copied the link to another browser. Wow! That would save another 60g. Also looks kind of fragile. Road link is 17g so that would reduce the saving to 43g. Hmmm. Maybe I can tune the wifli. A short cage would work since it's 1x.

[takolino]

Another hurdle: brake caliper modification.
I knew going into this build that I would have to mod the Juin Tech brakes to make them fit in the rear triangle. A few years ago, I built another bike with the dual piston Juin Tech F1 and shortly after, they came out with the GT-F flat mounts. Eager to try the new 4 piston brakes, I got them only to discover that the rear caliper did not fit. The new 4 piston design was slightly bigger than the original two piston calipers. I ended up installing the GT-F in the front and left the F1 on the back. So I ended up with a spare mixed set of GT/F1 calipers. This turned out to be a good thing.

Fast forward to the 3T Strada build, I tried the GT-F and it wasn’t even close but the F1 could be coerced. It would fit if I partially actuated the caliper. The arm and adjuster knob of the F1 contacted the seat stays with about a millimeter of interference.

So it’s time to mod the brakes. I have a few options. The knurled adjuster knob seems to be glued onto the threaded plunger shaft. It seems pretty well bonded. I could try to dissolve the glue with solvent. If that doesn’t work, maybe heat? That would be risky since I could melt the seals. I could also just cut off the knob with a dremel, then remove the stud and thread the knob back onto the shortened shaft. Probably easier said than done. Wish me luck.

[Klaster_1]

Not familiar with Juin Tech, but what if you remove the knob and either a) flatten some thread so you can turn the bolt with pliers or b) add a flat screwdriver slot to to end of the bolt, if it's thick enough?

[takolino]

Yes, that's a pretty simple solution and totally doable. But, I had my mind set on keeping the knob so I could adjust it tool-less while on a ride. And I just finished it now. I was able to remove the stud out of the knob after cutting it. The heat from the cutting loosened the adjesive. I have a shorter adjustment range but I think it's good enough and still looks factory original.

[takolino]

"I think it's good enough" might come back and bite me. I thought about it and figured I should check this to be sure. The knob functions as a way to keep the pad clearance constant as the pad wears. It doesn't self adjust like a full hydro system. The pads are 2mm new. The minimum wear thickness spec is 1mm. So the knob needs to be able to adjust pad clearance at least 1mm per side. I tried it with the current knob on the shortened shaft and it bottomed out before I can move it 1mm. Good thing I checked. Otherwise I'd be changing pads more often.

I was able to get more adjustability range by grinding down the knob. I put it on a drill and spun it against a file at an angle and I now have sufficient clearance. Glad I thought about it before I glued the knob back on.

Here's a close up of the downsized adjuster knob, before and after.

Before - hardly enough clearance to get a decent life out of a set of pads.


After - was able to get about 1mm adjustment on each piston.

[Mr.Gib]

Very clever work there.

I am curious if the 4 piston JuinTechs are that much better then the 2 piston version?

[takolino]

Thank you, Mr. Gib.
I really couldn't say. My guess would be that they are not that different. I've had the 2 pistons in the back of my Focus Paralane for about a year and on long descents, I naturally alternate between front and rear brakes, (from riding carbon rim brakes) they feel just as strong as the front 4 piston brakes.

If anyone is interested in using the Juintech brakes, make sure there's enough clearance in the rear triangle for your setup. The GT-F 4 piston version is bigger than the F1 so if it's tight, go with the F1. If your frame is a 140mm setup, you may be able to get some clearance using 160mm adapter plates. Also, this maybe obvious but dropped seat stay bikes have less clearance.

[takolino]

A new part came in the mail today.
A carbon narrow wide chainring from Lightworks. I got their smallest chainring, 42t. 46g on my scale. I've been using a 40t chainring with the 3T 9-32 cassette on my non-aero road bike but I figure with the Strada, I can use a taller gear... wishful thinking maybe?
The 40t Fibre lyte chainring on my build list is only 33g but it's not narrow wide. I don't think stiffness will be an issue as there's no front shifting and the teeth are pretty close to the bolts. Narrow wide is the main difference.
Which one would you run?

Lightworks 42t narrow wide


40t fibre lyte

[easyv]

I'd consider using the Lightworks for now because if you're using SRAM Red mechanical, that means that if you went with the Fibre Lyte, you would have neither a narrow-wide chainring nor a clutched read derailleur for chain retention. So I would at least start with the Lightworks until, in your experience, you feel comfortable that your drivetrain is not going to be dropping the chain before experimenting with the Fibre Lyte.

[Klaster_1]

Which one would you run?

With Vumaquad, I didn't have much choice: it's either a FibreLyte or drilled out MTB chainring, went with the first option. Only had two chain drops in a year, one of these could have been prevented (don't shift into 9t over a bump). For SkyPivot, I plan to arrange a custom chainring, if NW would fit into weight budget, I'd go with it for sure.