Today I (brag thread) V2

You are correct a well bled system has no air in it. However if you look at the image below you can see that when the lever is in the released position the brake line is open to the reservoir. With hard braking the line pressure can exceed 2000 psi. With a second actuated lever in the system there is no way that the reservoir/badder container can hold that kind of pressure. And with the air chamber on the vent side of the badder all the air would have to be expelled before any pressure was built up in the line.

With the vent in the system the reservoir is only designed to hold the fluid at no pressure. If you look close you should see the vent hole in the body of the lever on any hydraulic system.

Simply adding a Y in the system with two normal brake levers will not work. If it did there would be no reason for the SHIMANO GRX - Hydraulic Disc Sub Brake Lever

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Thanks for detailed reply. It makes perfect sense. I’d still like to put it to the test as I find that kind of thing entertaining, but I really have no need for a double brake system.

Shimano xt,xtr,saints levers and all round reservoirs have round cap on the end of the reservoir which has a rubber bladder inside as a pressure relief valve.

If you push caliper pistons back without removing lever bled cap then fluid squirts out the bladder and can split it.


As JimT says, the GRX sub-brake levers do exactly what you want – I put these on my gravel bike, albeit with drop-bar GRX brake-levers as the primary brake (which is what they are designed to work with) – having a set of these was the main reason I put Shimano parts on the gravel bike instead of SRAM. They work just fine, a bit of a pain to bleed, but they are pretty neat. I’d imagine they would work with a Shimano straight-bar lever too.

Anyway, there is a thread on here about them, which is probably best for this discussion:

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Your speed is quite something. Who needs a 36er apparently! :laughing:

It’s a marathon speed. When riding long distances, I am closer to 18-19 kph.
And a 36er allows even higher speeds. Currently I reach 27-28 max when sprinting with a top speed ever at 30,1 kph during at least 3 seconds. A 36er allows to keep speeds up to 30 kph for minutes. And if you add a schlumpf hub, you can keep more than 33 kph for more than an hour (if you are @toutestbon ).

Anyway, I would like to go a bit faster to finish the unicon marathon in less than 1h45 (=24 kph mean), but it might be really hard.

I ride a 3 mile loop around my neighborhood almost daily on my 29” Nimbus and have ridden up to 9 miles a couple times (with a lot of stops😄). Best I have done is a couple stops; either UPD or stops for traffic. Today was able to do it non- stop and was also able to conquer a steep hill that has been my nemesis.


That’s great! Congratulations, @MontanaRyder!!

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Find a nice uninterrupted bike trail where you do not have to stop for traffic crossings. You will really get into a nice groove and the miles will melt away.

Yes. Our city is working on it. I’m still refining the free mount so an occasional break doesn’t bother me too much.

Today, I changed the pedals location on my KH36 to the 127mm position for the first time and averaged 24km/hr on a 3.7km bike path loop. Not as scary as I thought… Now I really am looking forward to the Schumpf hub - coming soon I hope. To start with, I’ll probably not change gears on the move, and try to start in high gear with 150mm crank length.

In Sydney there is a dedicated bike lane around Centennial Park. 3,7km.
I did a lap with the usual setting at 150mm. I feel comfortable with this for the hilly commute to work - 14km - it was impractical (spinning pedals) in Centennial Park due to not having to stop for lights or ascend hills.


24km/h is really fast without gearing on a 36er.

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I built my second light wheel. My new son’s wheel in my frame. About 4.8kg


Today, I was able to ride 1 Km for the first time!


Congratulations!! What did you do differently in that ride compared to previously?

Congratulations, @gregatron !

Hard to say. Each time out, I’m averaging longer distances, so I think the longer you ride, the more you can efficiently practice. I’m starting to find a comfortable rhythm, but it comes and goes during the ride.