Ask the experts

[zion zig zag]

ZZZ have you ever tried just clear? I went clear for MTB years ago because I couldn't see in the shadows. Photochromics of the time were really bad in that regard. Now I ride all the time in clear prescription Smiths. Never been a problem for me. It does help a lot to have a functional visor on your helmet. My Bell Super DH and previous gens of Supers have generous visors and I dremel out the slot so I can put it down further. Gotta flip it all the way up for the descent of course.

I don't feel like I actually *need* sunglasses unless I'm driving or on snow. Bringing extra lenses or glasses and switching mid ride sounds for the birds to me. If you really need them I bet you'd be fine with a modern photochromic with high VLT but nothing beats clear for shadows and low light.

As a redhead with pretty sensitive eyes, I feel like I need some tint when out in the sun, even if its brief on most rides, and yeah, I don't really want to switch back and forth either.

[SchralphMacchio]

Are these the ones you are using? 15% on the dark end seems so dark. I’ve not yet had a good experience with photochromic lenses for dirt or snow but am sure you know our dank PNW forests well. I’ve seen friends struggle when they ride into a clearing, their photochromic lenses get dark, then they turn the corner into dim forest and the lenses take ages to become clear again.

https://a.co/d/09be199o

Not quite, but I’m sure they all have the same lenses. I’m on these with the clear to gray 85% to 15% VLT:
https://a.co/d/01AKjR2L

I will say I had a hard time today in high noon riding conditions where canopy gaps create super bright spots and super dark shadows across the trail and obscure roots and stuff in landings, but I think most lenses other than high vis amber or pure clear would really struggle in those conditions. Forests are always easier to ride when it’s cloudy as the light is so much more even.

[anotherVTskibum]

Have you checked Zenni? https://www.zennioptical.com/

I may give them a try, but I'm trying to find some first-hand reports because the similar pricing to Optical Factor makes me nervous. I strongly suspect that what I really want (big lenses with correction built in) is either impossible or nearly so, but if I have to deal with corrective inserts it may mean I need main lenses that don't curve so much to allow the inserts to be closer.

[SchralphMacchio]

Mullet experts,
Would a 27.5+ tube work as a single “just get back to the car” backup spare for a mullet setup of 29 x 2.4 and 27.5 x 2.4?

NFW I’m carrying two tubes for a “just get back to the car” setup.

[Andeh]

I hope so because that's what I do. Haven't had to use it yet. Specialized makes some "universal tubes" for that purpose. I've got a Pirelli TPU (heavier than a Tubolito but lighter than a butyl) tube that's supposed to fit both as well.

[XXX-er]

I carry a 29" tube from when I was running full 29 so the plan is to cram that into the 27.5

I think stretching a 27.5 into a 29 would also work

Duno for sure, I havent had a flat in years

[mcski]

Either works fine. You can stretch a 27.5 or downsize a 29.

[Tailwind]

Honestly a normal 27.5 tube works fine in 29 or 27.5”. Heck even a 26” tube can work in a 29’er. I ride 29’ers but only carry 27.5 tubes to cover friends and random people as a 29’er tube won’t fit 27.5.

This doesn’t apply with Tubolito type tubes.

Mullet experts,
Would a 27.5+ tube work as a single “just get back to the car” backup spare for a mullet setup of 29 x 2.4 and 27.5 x 2.4?

NFW I’m carrying two tubes for a “just get back to the car” setup.

[Dee Hubbs]

Specialized have though of everything, get one of their mullet tubes [emoji12]

[Lvovsky]

I also enjoy photocromic lenses for cycling in variable conditions. They don't change fast enough for sun-to-shade riding, more for changing cloud cover.

They don't work at all when it's near or below freezing. I've had multiple Smiths, Julbos, and others and they all just go full dark and stay that way when it's cold.

FWIW Smith just denied a warranty claim on some that have a spot in the middle of one lens that won't change along with the rest of the lens. So buyer beware on the spendy ones.

The $25 RockBros ones we have work perfectly fine too.

Another vote for non-dentist option with rockbros. This pair served me well for a few years now:

https://a.co/d/04Jv3uAh

[SchralphMacchio]

Thanks for the info guys!

[Cocximus]

I have some 5 years old Shimano MTB brakes. They were never perfect, but lately they feel very spongy. It takes a pump to even get them to bite. Yes, this is the symptom of air in the line, but how does she air keep getting in there? A good bleed will fix them for a bit then they need the extra pump. There are no outside leaks. Is this the master cylinder seal?

[Cocximus]

Also wtf is up with gp5000 pricing. They are stupid expensive these days. Any sources or alternatives that are 32?

[Dee Hubbs]

I have some 5 years old Shimano MTB brakes. They were never perfect, but lately they feel very spongy. It takes a pump to even get them to bite. Yes, this is the symptom of air in the line, but how does she air keep getting in there? A good bleed will fix them for a bit then they need the extra pump. There are no outside leaks. Is this the master cylinder seal?

The bleed is not getting all the air out. Orientation of the caliper during the bleed is crucial. Air can remain in the system without bubbles coming out during the bleed. The air bubble gets trapped and the bleed will feel firm, but if the air bubble gets moved to the wrong spot after the bleed you will get soft brakes.
Here is the best/simplest explanation:

[XXX-er]

The bleed is not getting all the air out. Orientation of the caliper during the bleed is crucial. Air can remain in the system without bubbles coming out during the bleed. The air bubble gets trapped and the bleed will feel firm, but if the air bubble gets moved to the wrong spot after the bleed you will get soft brakes.
Here is the best/simplest explanation:

so tell me why do Shimano have an infamous wandering bite point,

tell me why people say " often half a bleed is all your Shimano's need "

why does a brake need bleeding again if they got the bubbles out last time

cuz i don't get it

that vid is pretty good for showing the principals which i don't think a lot of people understand

[Dee Hubbs]

See in Bold:

so tell me why do Shimano have an infamous wandering bite point, Air in system, at the lever

tell me why people say " often half a bleed is all your Shimano's need " Air in system, air is at the lever, 1/2 bleed gets that air out of the lever body

why does a brake need bleeding again if they got the bubbles out last time Mineral fluid gains contaminates past piston seals, contaminated are abrasive and break down seals and intervals, thus putting more contaminated into the mineral oil, breaking down the seals further which leads to air ingress pass the seal. The bleed process is rot keep the mineral oil contaminate free, not to remove newly introduced bubbles. If your system is totally air free, and the integrity of the seals are intact, no new air can be introduced.

cuz i don't get it

that vid is pretty good for showing the principals which i don't think a lot of people understand

[XXX-er]

How can you tell what going on in there, why not bleed the whole system ?

[toast2266]

How can you tell what going on in there, why not bleed the whole system ?

Because it's Shimano, they're super notorious for this issue, and both the problem and the fix are well established. And doing a lever top off on a shimano is super easy, whereas doing a full bleed is a minor hassle, so people do what's easy because it fixes the problem (at least for a little while).

If it was any other brake brand, you are correct - the fix would be to just bleed the whole system.

[jdadour]

Also wtf is up with gp5000 pricing. They are stupid expensive these days. Any sources or alternatives that are 32?

Vittoria Corsa N.EXT. I've switched and havent looked back. Check Bicycle Rolling Resistance

https://www.bicyclerollingresistance...d-bike-reviews

[XXX-er]

Because it's Shimano, they're super notorious for this issue, and both the problem and the fix are well established. And doing a lever top off on a shimano is super easy, whereas doing a full bleed is a minor hassle, so people do what's easy because it fixes the problem (at least for a little while).

If it was any other brake brand, you are correct - the fix would be to just bleed the whole system.

Yeti was in the stand I had bleed tools out I didn't know any better so I bled the whole shimano brake which worked awesume for a long while until I sold it, little while sounds not really fixed,

[Cocximus]

Last time I said fuck it, I had enough I took the brakes off and hung them on the wall. I tapped the lines and cylinder and let it rest for a few days. If I can any other Shimano brake it feels good, to me coming from mine. I'm almost wondering if the PO put DOT fluid at some time. So what seals degrade but don't leak,

Thx I'll check out the Victoria. They come in 34, awesome.

[Dee Hubbs]

How can you tell what going on in there, why not bleed the whole system ?

Because it's Shimano, they're super notorious for this issue, and both the problem and the fix are well established. And doing a lever top off on a shimano is super easy, whereas doing a full bleed is a minor hassle, so people do what's easy because it fixes the problem (at least for a little while).
If it was any other brake brand, you are correct - the fix would be to just bleed the whole system.

Not all air bubbles in the system affect the braking performance, an air bubble can remain in a specific location that the fluid dynamics, movement of the fluid, and compression of the fluid are not affected by that air bubble.
The wandering bite point happens when an air bubble makes its way to a specific place in the lever/master cylinder. When an air bubble makes it way to that specific place, you pull the lever and the fluid dynamics directly tries to compress that bubble, and your bite point moves (because air compresses, fluid does not). This action of compressing the bubble also pushes it and moves that air bubble to a different location in the lever. Now when you pull the lever the second time the bubble is not in such a critical position, more fluid is compressed and the lever/master cylinder is no longer compression a major an air bubble (as much). This is why the first pull bites closer to the bar (longer in the stroke) and the second pull instantly bites further away from the bar.

To answer XXX's question you've asked 27 times:
Once my brakes have experienced the wandering bite point, I know that an air bubble has migrated to the lever location. As long as I'm not doing inverted jumps, or turning my bike upside down like a 10 year old pretending to fix his bike, that bubble is going to follow Newton's Law of Universal Gravitation and stay at the top of the system, aka in the lever.
This is where the "1/2 bleed" (your name, not mine) procedure can be very effective. The funnel will remove that air bubble from the highest point of the system, that bubble will not go down the line or down to the caliper, thus not needing to push fluid from the bottom (aka a full bleed).
A lever only bleed will remove that bubble. The procedure is to rotate the lever on the bar with the funnel attached, and make a flicking motion on the lever blade, all of these movements help move and migrate that bubble to the highest location where the funnel is attached.

[toast2266]

little while sounds not really fixed,

Agreed. Only way to properly fix a shimano wandering bite point is to take the brake off and replace it with literally any brake from any other brand.

[XXX-er]

well I made it work but i didn't know any better

[Dee Hubbs]

Also wtf is up with gp5000 pricing. They are stupid expensive these days. Any sources or alternatives that are 32?

Conti GP 5000-S-TR retail is $96, and in the US the minimum advertised price can not be lower than $84.95.

Does it need to be tubeless? The 32c, TLR, high performance tire market is an expensive category.
Some other 700 x 32 TLR options:
Pirelli P-Zero Race TLR RS is $99
Pirelli P-Zero Road TLR is a good option at $70
Schwalbe Pro One is $91 (but can be found on good sales)
Vittoria Rubino Pro G2.0 $75
Vittoria Corsa Pro G2.0 $105
Vittoria Corsa N.EXT Tire G2.0 $89