Is a damaged thread on rear derailleur fixable?

Arequipa

Hi!
I hope you are all well..
Quick question.. I have a roadbike with an Ultegra r8000 rear derailleur.
It works perfectly...but... the thread in the derailleur body, which the cable clamp bolt screws into, is sloghtly damaged.

So the clamp screw wont hold the cable tight against the plate.. if you know what I mean...

Is it possible to get this thread repaired?

To save me buying a new derailleur...

Is it just me.. or are shimano bolts very fragile and take very little punishment .. I have found that barrel adjuster screws etc.. dont last very long...

Thank you,

A

Tony04

You can fix it with helicoil, might be hard to find with a small thread pitch though, you can get kits off ebay if you want to diy it.
Best probably to get a new rear derailleur but with the lack of availability and price hikes i might hold off.
Tbh theres no need to tighten the cable down really tight you want it tight enough not to slip but not so much you crush it
I stripped the thread on a r8000 front derailleur before although i did overtighten a little, so yeh maybe the threads are weak, aluminium rather than steel to save weight perhaps?

cletus

Arequipa wrote: »

Hi!
I hope you are all well..
Quick question.. I have a roadbike with an Ultegra r8000 rear derailleur.
It works perfectly...but... the thread in the derailleur body, which the cable clamp bolt screws into, is sloghtly damaged.

So the clamp screw wont hold the cable tight against the plate.. if you know what I mean...

Is it possible to get this thread repaired?

To save me buying a new derailleur...

Is it just me.. or are shimano bolts very fragile and take very little punishment .. I have found that barrel adjuster screws etc.. dont last very long...

Thank you,

A

Depends on the damage. If they're marred a little, running a tap through them can clean it up.

If they're stripped, you're looking at drilling out, retapping, or helicoil (don't even know if helicoils come that small)

TheBlaaMan

Could you just lock the cable in place - ie so no adjustment was possible - and then fit an inline cable adjuster on the outer cable up at the headtube?

Arequipa

Evening,

Thank you for the replies...
I have tightened the cable under the bolt...without the plate..

With the plate..the bolt will not bite..
The gears shift to most cogs but not perfectly..

The inline adjuster is an option..

Is tappìng the thread difficult?
How do you figure what tool to buy/ borrow?

Thanks again!

07Lapierre

Can you screw the bolt in from the opposite side? If you can, that could repair the damaged threads, but it depends on how badly damaged the threads are.

G1032

Tony04 wrote: »

You can fix it with helicoil, might be hard to find with a small thread pitch though, you can get kits off ebay if you want to diy it.
Best probably to get a new rear derailleur but with the lack of availability and price hikes i might hold off.
Tbh theres no need to tighten the cable down really tight you want it tight enough not to slip but not so much you crush it
I stripped the thread on a r8000 front derailleur before although i did overtighten a little, so yeh maybe the threads are weak, aluminium rather than steel to save weight perhaps?

Did the same recently with an R7000 FD. They're very very weak and soft. Well it wasn't actually the thread I stripped but the nut cracked on me. And I didn't tighten it down that tight. Poor quality really tbh and not what I've come to expect from Shimano. I've generally found their parts very good quality.

Arequipa

Yea.. u have to watch the torque specs for all nuts and bolts...
Add that.. cycling right through the Irish winter ...all the rain...grit and dirt...

The parts are getting lighter and lighter.. but they dont last long.. i suppose it encourages us to buy replacement parts!

G1032

Arequipa wrote: »

Yea.. u have to watch the torque specs for all nuts and bolts...
Add that.. cycling right through the Irish winter ...all the rain...grit and dirt...

The parts are getting lighter and lighter.. but they dont last long.. i suppose it encourages us to buy replacement parts!

It does more than encourage us!! It leaves us no option

cletus

Arequipa wrote: »

Evening,

Thank you for the replies...
I have tightened the cable under the bolt...without the plate..

With the plate..the bolt will not bite..
The gears shift to most cogs but not perfectly..

The inline adjuster is an option..

Is tappìng the thread difficult?
How do you figure what tool to buy/ borrow?

Thanks again!

Sounds like the threads are stripped. You would need to drill out the hole, and thread the new hole with a tap. The problem here is the hole will now be bigger than the original, so you'll need a different bolt.

The other option is to drill out the hole, and install a helicoil. This looks like a spring, but essentially creates a new thread.

Option a requires a tap and preferably a tap handle. The size of the tap directly corresponds to the size of both the hole and the thread you are cutting

Option b requires a helicoil kit, which usually includes the tool needed to seat the helicoil

Arequipa

Thanks mate...

So how much is a repair vs a new derailleur?
I would be happy with a 105 r7000 rd!

cletus

Here's an m2.5 helicoil kit (I don't know if that's the size you need, it's just small). It's ten pounds plus delivery

https://www.ebay.ie/itm/30Pcs-Set-M2-5x0-45-Thread-Tap-Repair-Cutter-Kit-Helicoil-Damaged-Thread/352829917970?mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338356710&toolid=10049&customid=101_130_277&pageci=1c5f8e45-328f-4ab1-9493-23c12978763e

phelixoflaherty

You said the bolt will bite without the clamping plate.
If so its sounds like the bolt is your problen.
If so you could replace bolt or use a few washers betweet bolt head and clamping plate.

cletus

phelixoflaherty wrote: »

You said the bolt will bite without the clamping plate.
If so its sounds like the bolt is your problen.
If so you could replace bolt or use a few washers betweet bolt head and clamping plate.

I missed that part of the post.

OP, could you post a picture of the threads on the bolt?

If it is the bolt, that's much simpler, and depending on the size, I probably have some here

David6330

phelixoflaherty wrote: »

You said the bolt will bite without the clamping plate.
If so its sounds like the bolt is your problen.
If so you could replace bolt or use a few washers betweet bolt head and clamping plate.

^^^ This or get a slightly longer bolt and fit some extra washers on it if the bolt is bottoming out.

68 lost souls

Yep before going messing with the hole have a look at the bolt. In properly designed equipment the bolt should be the failure point as it’s cheap and replaceable. Sounds like the first few threads of the bolt are damaged.

Tony04

As above a longer bolt should probably work as it sounds like the first few threads or damaged however once you start stripping thereads its easy to dsmage the rest unless you cross threaded

Tony04

Arequipa wrote: »

The parts are getting lighter and lighter.. but they dont last long.. i suppose it encourages us to buy replacement parts!

Shame in the past and with mtb shimanos non wear and tear parts were always serviceable and would last years
Excuse for campy on the next bike?

cyclocross!

I have an R8000 spare rear derailler screw here in North Kildare if that helps.

Arequipa

Afternoon!

Thank you for the replies...
Thank you cyclocross for the offer of a bolt.. you are a gent! I actually ordered and got one from my lbs.

I think the first part of the thread is damaged as it only bites after a few turns...

A longer bolt would work i think.. where to find one?!!

Thanks again!

This is the bolt...

Shimano Ultegra RD-R8000 Cable Fixing Bolt & Plate - Y3E998050

jimm

I stripped the cable clamp threads on an Ultegra RD-6600 some years ago. Fixed it with a longer hex bolt and a nut at the rear of the clamp bolt hole. I remember hack-sawing the nut in half to make it fit. Can't remember why I had to cut it....maybe there was only space for a slimmed nut!! Worked for years.