Rotors replaced

Discuss light weight issues concerning mountain bikes & parts.

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Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

Replaced my original Shimano rotors with Ashima AI2 (Apperently the lightest rotors on earth)

Original Shimano rotors
Image

New Ashima AI2 Rotors
Image

Braking feels a bit soft, but that's maybe because they're new.
But they look very very nice :)
Image

Anyone else experience with these rotors?

PS I have no idea how accurate my kitchen scale is :P
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

by Weenie


skiandbikecmh
Posts: 81
Joined: Thu Jan 05, 2012 1:26 am

by skiandbikecmh

I have been using them on my mountain bike for the past summer. They are not the lightest on earth, maybe the lightest steel rotors on earth, but certainly scrub alum are lighter. I love how light they are and they work very well.
My Bike:
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Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

Seems like theres a bit of coating on the rotors.
Just took the bike out for a very short road trip (5km)

In the beginning, the braking was very soft, with no feel at all.
When I got home, braking was somewhat better.

Hope it will improve, cause I never had this issue with the original Shimano rotors.
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

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Zen Cyclery
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by Zen Cyclery

It is perfectly normal for brand new rotors to not stop as well as used ones, simply because they still have the factory glaze on them. Whenever I get new rotors, I always make a point of sterilizing them with alcohol and then sintering them. That should help to clean them off a bit.
Just keep on riding yours though. With time, the stopping will get more powerful.

Nice choice on a rotor though. They sure do look pretty sweet!

Steve Curtis
Posts: 162
Joined: Thu Jul 31, 2008 12:20 pm
Location: Hampshire UK

by Steve Curtis

I always clean new rotors with ipa and a white cloth prior to fitting.
You can always see grease (hence using the white cloth) so you may have lightly contaminated the pads.

Personally, I'd wipe the rotors with alcohol and remove the top layer of pad material with sandpaper.

TheRookie
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Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

You need to bed any new disc/pad combo in, braking is actually pad against pad material deposited as a (very) thin layer on the disc, Shimano gives a simple procedure for this involving 20 'stops' at 'moderate' braking from about 15mph to not quite a stop - simples.
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Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

Going to do a road run of 40k tonight.
Will gently abuse them :P to see if braking gets better
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

TheRookie
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by TheRookie

No need to abuse, but repeated moderate braking to get some (but not too much) temperature in them is what is needed, fortunately minimalist discs like that (I run Alligators) warm up more quickly!
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Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

Got a strange problem.

Rear rotor is just perfect.
But the front doesn't brake as hard as the original Shimano's (BR-M446) do.
If I lean to the right on the bike, I can hear one of the pads grinding against the disc.
When straight on the bike or leaning to the left there's no problem.

Sound familiar to someone?

Will change front and rear tomorrow and see if something changes.
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

TheRookie
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by TheRookie

That shouldn't affect braking at all.....which sounds like pad contamination, you did degrease the new discs didn't you?
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Cif
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Joined: Tue Oct 02, 2012 8:36 am

by Cif

Just keep on riding yours though. With time, the stopping will get more powerful.


Nope :shock:

But that doesn't explain the pad grinding the rotor when the bike is tilted.....
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

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Zen Cyclery
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by Zen Cyclery

Cif wrote:Got a strange problem.

Rear rotor is just perfect.
But the front doesn't brake as hard as the original Shimano's (BR-M446) do.
If I lean to the right on the bike, I can hear one of the pads grinding against the disc.
When straight on the bike or leaning to the left there's no problem.

Sound familiar to someone?

Will change front and rear tomorrow and see if something changes.



Is the front skewer tightened adequately? This could be the issue. The caliper may not be completely centered over the rotor too. They caliper may be sitting too far outboard which could be explaining the rubbing.

Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

Skewer is OK, If the bike is picked up, the wheel can spin freely without the pads rubbing against the rotor.
Problem only occurs when I'm riding and I lean to the right.

Will try to shift the caliper today.
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

Steve Curtis
Posts: 162
Joined: Thu Jul 31, 2008 12:20 pm
Location: Hampshire UK

by Steve Curtis

It will be the skewer. What are you using?
Sometimes with the lightweight stuff such as kcnc, the shorter lever lacks ....ur leverage :D
No biggie just another turn should do the trick.

As per my previous post, did you clean the rotors before fitting them?

Cif
Posts: 36
Joined: Tue Oct 02, 2012 8:36 am

by Cif

The skewers are the original Shimanos.
Never had an issue with the original rotors. So can't imagine that being the problem, but I will try giving them another turn.

For the rotors I was stupid enough not to clean them :oops:
First time I've replaced rotors, so apperently I have a lot to learn.
Will try to get the top layer off from the pads. Or just buy a new set of pads.
Cannondale Bad Boy 4 (2012) Original weight minus 1541 Gram

by Weenie


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