[svinyard]

Was looking at those ultralight Ashima Ai2 rotors. 180mm are about 100g. I need some rotors anyways and they aren't a fortune. Hard to tell if going that route is a good thing or bad thing for kid on XT brakes.

 

[TimTucker]

I have a clone of the 160mm version from Aliexpress on my son's bike and it seems to perform pretty well at even lower cost:
https://www.aliexpress.com/item/68g...-Road-Racing-Bike-Brake-Disc/32887975517.html

Looking at what's out there for 180mm, I see these at a similar weight to the Ai2's, but only $7 for a pair -- would be a pretty cheap experiment to try them out:
https://www.aliexpress.com/item/bik...-brake-rotor-180mm-SH-rotor-3/1956831517.html

 

[scatterbrained]

Personally, I wonder how well a rotor can work with so little friction surface. Tim Tucker, have you compared them to more conventional rotors?

 

[TimTucker]

My only comparison on his bike was vs. the stock v-brakes and it performs far better than those.

If you consider the scale of rotor vs. wheel, a 160mm rotor on a 16" wheel is already akin to putting a 290mm rotor on a 29".

 

[dookie]

Trailcraft uses them (or did at least) on their 24" and they have plenty of grab with my 180 lbs aboard (Deore calipers). FYI.

 

[Shayne]

My only comparison on his bike was vs. the stock v-brakes and it performs far better than those.

Curious about what your performance parameters are?

My son actually preferred the modulation and power of the XTR and Paul cantilever brakes on his old bike versus the Hope hydros on his new bike. New bike is disc only so he has to live with them.

 

[TimTucker]

Curious about what your performance parameters are?

My son actually preferred the modulation and power of the XTR and Paul cantilever brakes on his old bike versus the Hope hydros on his new bike. New bike is disc only so he has to live with them.

He's only 4, so my assessment is based on:

• Does he mention any problems or comment on them?
• Can he stop consistently?
• How quickly does he seem to stop when using them?
• How quickly does the bike stop if I roll it forward a little and try pressing the lever?
• Can I move the bike forward any with the brake applied? / If so, how much force does it take to do so?

He didn't really seem to notice the change when I put on the disc brake -- putting on an air fork along with it when I made the change seemed to gather all his attention.

For your son's bike, what's his complaint / what have you tried for adjustments?

I have some older Avids on my bike that I absolutely hated until I found a variation on the bleed procedure that got got the lever throw to feel how I wanted.

Standard instructions called for the pad contact adjustment to be all the way out when bleeding, but I found that I was much happier with the result if it was all the way in when bleeding and then adjusted back out slightly afterwards.

 

[Suns_PSD]

Small children stop so effortlessly and don't really go that fast anyways. I don't think you need much rotor, which is why my kids bike has the Aliexpress imitation ones for $9 delivered for a pair.

Would I put them on my enduro bike with my 180# smashing in to things ass, heck no!

 

[svinyard]

Apparently the new Ashima AiNeon is REALLY light. Composite inner or something like that. 88g for a 180mm rotor! 40$ is getting spendy tho.

 

[Steve-XtC]

They stop a kids weight no problem however they damage very easily in transport or shuttle type uplifts.

 

[POAH]

brakes are one area I wouldn't bother going to stupid light weight items. Samuel's ice tech 180mm rotors are 155g. The SR-66 rotors are 140g. Put proper rotors on the kids bike.

 

[Kingfisher2011]

Si is on his 2nd rig with 160mm Ai2's, they've been solid for us. No maintenance or other issues and plenty of stopping power on both his 24 and 26" bikes. We haven't hit the local lift park here yet, so I can't comment on that but as minimal as they seem we have managed to not damage them on the North Shore rack on the back of my truck. If I hadn't done the Ai2's, I would've thrown some Shimano RT66's on and got on down the trail. Don't overthink it.