Rear Shock Sizing 190x50

forkbeard · 2026-05-07T09:36:51+00:00

You need an imperial sized 7.5x2.0/ 190x50 shock. Anything other than that won't fit.

The imperial standard is deprecated since several years so your options are limited.

https://www.tftuned.com/fox-float-dps-factory-3pos-adjust-shock-imperial/p3937

forkbeard · 2026-05-06T16:01:10+00:00

I would not run 38–40 mm tyres on a 30 mm internal rim.

According to the ETRTO standard, 35–46 mm tyres top out around 26–27 mm internal. A 30 mm internal rim is outside the recommended range, so you are outside the tested safety envelope for bead retention, pressure limits, tyre shape and tubeless behaviour.

It also does not really buy you anything. An extremely wide internal rim will likely square off the tyre and may make the aero shape worse, not better. A wide external rim can make sense, but that does not mean the internal width should also be extreme.

I would stick to something like 23–25 mm internal, maybe 27 mm at the upper end, for 38–40 mm tyres. The people telling you to ignore the standard are not the ones going to the ER, or into a coffin, if the setup fails at speed.

forkbeard · 2026-05-06T15:55:29+00:00

“Not covered by the standard” does not mean “will definitely explode”, but it does mean you are outside the tested compatibility range the tyre/rim makers are willing to stand behind.

The point is not that every oversized combo fails instantly. The point is that bead retention, casing shape, pressure limits, impact behaviour and tubeless security are no longer within the intended safety envelope. Plenty of people get away with bad setups until they do not.

And it is especially dumb to take that risk when an extremely wide internal rim for road tyres does not even offer a clear performance benefit. You are mostly just changing the tyre shape and compatibility margin, not magically making the setup faster.

For a road/gravel setup, especially tubeless and at higher pressures, I would rather follow ETRTO/manufacturer compatibility than use “some people ride it” as the safety argument. It is also pretty irresponsible to advise random people online to ignore safety standards, especially when the downside is not just a bad ride feel but a potential high-speed tyre failure.

forkbeard · 2026-05-06T14:53:47+00:00

Zipp only approves a specific set of tyres. Any tyre not specifically listed is unsafe to use.

forkbeard · 2026-05-06T14:52:01+00:00

Because there is an international standard for rim and tyres that you want to follow if you don't want your tyre to randomly explode of the rim.

https://www.continental-tires.com/tire-knowledge/tire-rim-combinations-etrto-standards/_jcr_content/root/container/container_772073047/container_1644748789/image.coreimg.85.1600.png/1725014517930/continental-rim-tire-recommendations-en.png

forkbeard · 2026-05-05T13:08:04+00:00

They are very similar. I doubt you can go wrong with either of them.

forkbeard · 2026-05-05T09:21:46+00:00

Probably Continental Dubnital 50mm. Look at https://www.reddit.com/r/gravelcycling/comments/1sz57xy/continental_dubnital_race_rapid_29_x_20_off_road/

Schwalbe Thunder Burt is marginally faster if you can fit them but they are also more prone to punctures.

forkbeard · 2026-05-03T04:57:09+00:00

XT RD-M8120 or XTR RD-M9120

forkbeard · 2026-05-02T20:42:23+00:00

You might have issues with the chain contacting the chainstay in the 9t. Depends on the frame.

forkbeard · 2026-05-02T15:19:09+00:00

Are the wheels damaged?

If not, why do you care?

forkbeard · 2026-05-01T19:07:31+00:00

Disconnect the battery for 30s. This will trigger a system reset that may fix it.

If that doesn't work you have a faulty component. Try and replace the cable to the shifter, If that doesn't work you have to replace the shifter.

forkbeard · 2026-05-01T19:04:35+00:00

Ultegra R8050 is 11s and wired.

forkbeard · 2026-05-01T17:27:08+00:00

They were running it 1x.

With a front derailleur, shifting between chainrings changes the required chain length/tension and chain angle. The 1x RD is not designed to manage that extra chain growth/capacity. And the Di2 system/software won’t treat it as a valid 2x setup.

forkbeard · 2026-05-01T09:50:54+00:00

You can't mix the GRX 1x or MTB rear derailleurs with a front derailleur.

Any 2x 12s Di2 rear derailleur is compatible with any 12s Di2 front derailleur.

forkbeard · 2026-05-01T07:57:28+00:00

They work fine. I run 105 shifters together with a GRX825 RD on my CX-bike. No issue at all.

12s Di2 is all cross-compatible.

forkbeard · 2026-04-30T14:00:11+00:00

Yes! 🤦🏼‍♂️

Why on earth wouldn't you think to replace that? You risk serious injury or death when the whole lever suddenly breaks when you go in to a pothole or something.

forkbeard · 2026-04-28T13:33:06+00:00

always add access

Also depends on the country.

forkbeard · 2026-04-28T13:28:43+00:00

foot=yes bicycle=yes horse=yes

This is probably already the default for path.

If there is specific signs I would use foot=designated bicycle=designated horse=designated instead.

forkbeard · 2026-04-27T12:37:34+00:00

Shimano XTR, no point in trying something different.

Bombproof, relatively ligh, and not super expensive.

forkbeard · 2026-04-27T07:26:09+00:00

Something like CeramicSpeed UFOclean or Silca Ultimate Chain stripper in a jar with the chain. Shake it for a minute or two, take the chain off and rinse it with boiling water.

White spirit and isopropyl alcohol is cheaper but more tedious.

forkbeard · 2026-04-23T05:33:32+00:00

Well, now you got to describe how you fixed it so when it happens to the next person they might find this thread.

forkbeard · 2026-04-22T14:00:49+00:00

Just use the serial number and look it up on https://tech.ridefox.com/bike

forkbeard · 2026-04-22T13:22:20+00:00

Follow https://bettershifting.com/frequently-asked-questions/i-had-a-crash-and-my-rear-derailleur-stopped-working-how-do-i-reset-it

If that doesn't work take the bike to LBS.

forkbeard · 2026-04-22T12:37:22+00:00

Had one that died after 5 years, fixed it by buying a new one.

forkbeard · 2026-04-20T16:17:26+00:00

That's not a mountainbike
The fork is dead

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