anga

Note 1
Added after first 2 responses.
My RD came perfectly setup and with a spoke protector. Chain never slipped while shifting into the lowest gear. Chain slipped twice when going thru potholes and over bumps and the spoke protector saved the rear wheel.

Note 2
This thread is NOT about need for spoke protectors.
​​​​​Nor ​​about alternatives to using rotors as spoke protectors.
Nor about how to buy spoke protectors from outside India.

Metal (and plastic, as well) spoke protector discs for freehubs are not easily available in India.
C​​​​​an I use disc brake rotors as spoke protector discs?

If yes, have the following questions.

1. Should I use centerlock or 6-bolt rotors?
​​2. ​​​For a 11-36T cassette, diameter of 36T cog is 150mm (6 inches).
Is it better to use 180mm or 203mm rotors?
3. Should I attach the rotor to the spokes or the 36T cog?
4. How close to the 36T should the rotor be to prevent chain derailment?

Thanks

Iride01 

I suppose you can use anything you can fit on there in the proper position. A old lid off a pail, metal or plastic. Just whatever is pleasing to you for any reason.

However if your bike has the DR limits properly adjusted and nothing else is wrong to make the chain come off the rear cassette or freewheel often, then why do you need spoke protector?

1. Which seem easier for you to make fit?
2. Don't know, spoke protector design and engineering doesn't get mentioned much. I think you should use your own judgement.
3. Either will work. You might not want to have the protector firmly attached to the spokes by bolts or other fasteners that alter the stress points of the spoke. But maybe nylon zip ties or something. Or fasten it to the big cog.
4. Protector isn't to prevent chain derailment. It's there to protect the spokes in the event the chain does come off the cog while you are sprinting with all your might from a dead stop. Other times you probably aren't putting out enough power to damage the spokes. Unless you foolishly keep pedaling. Again, the DR low limit are what keeps the chain from coming off the big cog and correct adjustment and condition of everything else. IE, the DR hanger.

tyrion

No idea how you'd mount a rotor to the drive side (maybe zip ties?). Most experienced riders remove the spoke protecter disc because it's not needed if you adjust your rear derailleur properly.

alcjphil

Spoke protectors are very thin and are contoured to follow the dish of the spokes. A disc rotor is much thicker and perfectly flat. Your derailleur would probably hit the rotor when you shift to your largest cog

tyrion

I'd make something out of scrap plastic (e.g. the jug below) before trying to use a rotor. Might need 2 or 3 layers of plastic, depending on thickness. Zip tie them to the spokes.

sweeks

... and heavier.

Chuck M 

Amazon has more spoke protectors under 10 bucks than you can shake a stick at. If you want something blingier than plastic, chrome ones are about 5 bucks more. I don't know that it would be worth the effort for most people to try to use a disk brake rotor unless they want to aggravate the people the eschew spoke protectors AND disk brakes.

Nyah

I highly recommend this idea to all disc brake-coveters while they hold out for a thru-axle bicycle, rather than buying a QR-disc bicycle that will forever be a lemon. I'm serious. People are better off making their rim-brake bicycle look like it has disc brakes, than to settle with the QR-junk being passed off as disc brakes in the era of thru-axles.

anga

Hence my post here.

Most sellers don't ship to India. One sold by Amazon is shipped to India. Here is the cost.
Spoke protector costs $8.64
Delivered to India cost is $28.86

cobba

You can get them much cheaper here: https://www.aliexpress.com/premium/s...ke.html?dida=y

anga

It used to be a useful alternative.
AliExpress and similar sites cannot ship to India!

cobba

Why are they listing India as a shipping destination?

anga

How should I know?
Can't access their website from India.

bboy314

I’ve read this claim here on BF, and yet I’ve been riding such bikes for years without issue.

To the OP, I agree with the above issue raised about a rotor being flat and not contoured, and being relatively thick. I think you’d have issues with your derailleur hitting it when in low gear.

cobba

Strange how they list India as a shipping destination and have Indian Rupee in the currency list but you can't access the website.

Sy Reene

Looks like it's a government block by India

https://economictimes.indiatimes.com...0.cms?from=mdr

HillRider

OK, but what does a disc brake rotor cost?

grumpus

Nothing for one that's reached the wear limit, I expect.

squirtdad

this and setting the high/low correctly would be the best bet IMHO for the OP considering a) shipping logistics b) unsuitability of a disc rotor for the task

even easier would be finding a flat plastic lid of suitable thickness

grumpus

Possibly.
I don't think it matters as you'll have to remove the centre anyway.
I just checked a 32t cassette against a 160 mm rotor and that looked a bit close, so I'd go for the 203 mm on 38t.
Probably more effective bronze welded to the back of the cassette than zip tied to the spokes.
The regular spoke protector doesn't prevent chain drop, it just catches it before it chews the spokes or jams the freewheel. You'll need it far enough back that the derailleur doesn't hit it in normal operation.

anga

Between $10 and 15. Shimano.

Appreciate the useful responses, grumpus.
Inner diameter of centerlock rotors seems to be 35mm and BCD of 6-bolt rotors is 44mm. I was thinking of using bolts, nuts and washers to setoff the 6-bolt rotor from the cassette and then attach to cassette and spokes to maintain position.
Even if the centerlock rotor fits the freehub, it may interfere with the derailleur, as you warned.


​​​​​

grumpus

Or cheap/free if you can get worn rotors from somewhere.
Eh?

dedhed

paint can lid