[kidwoo]

I got a 180mm talas with the intention of running it at 170mm to match some frame a-c specs with the wrong size wheels and the right size fork. I didn't realize the 180mm version came with 200mm specific rotor brake mounts. Pedaling around with a 200mm rotor sucks. Brakes work and listening to that 'sha-shing, sha-shing' on climbs sucks.

It looks like there's enough thread purchase left over if I were to cut down the mounts so I could get a 180mm rotor on there. What would be the best way to do this? Having something centered in the bolt hole would be pretty necessary I'd think.

And yeah the lowers from a 160mm version are shorter and hence, would be a bad time.

 

[Dogboy]

 

[kidwoo]

That exists?


Okay thread title change: Who has a Park Tools DT-4 I can borrow?



That's just the tool for making sure the mounts are flat right? Is that bit agro enough to take off a few mms of magnesium within a week?

 

[kickstand]

well, isn't that fancy.

 

[Nick]

That's just the tool for making sure the mounts are flat right? Is that bit agro enough to take off a few mms of magnesium within a week?

Even if not I bet you could use a proper cutting mill tool with that alignment jig.

 

[lobsterCT]

That exists?


Okay thread title change: Who has a Park Tools DT-4 I can borrow?

I've got it, yes it cuts mag pretty fast. Pm me , I'll mail it to you to borrow if you pay shipping.



That's just the tool for making sure the mounts are flat right? Is that bit agro enough to take off a few mms of magnesium within a week?

 

[ianjenn]

is 20mm difference rotor gonna matter? I have a 203/185 on the trail bike....

 

[kidwoo]

I know. Lots of people do. But I definitely don't need it and 8" rotors bend and warp easily. I've only had it out on a few rides but it's annoying. Every time I stand up to pedal it starts rubbing. It's the sound that gets ya.

 

[Kanye West]

Dumbest thread ever.

Worst reason to sacrifice braking power ever.

"I don't like the noise, so I will chop my shit up to run a weaker brake so I don't have to listen to it."

Jesus, pull your skirt out of the chain and ride the bike.

 

[Nick]

 

[kidwoo]

Dumbest thread ever.

Worst reason to sacrifice braking power ever.

"I don't like the noise, so I will chop my shit up to run a weaker brake so I don't have to listen to it."

Jesus, pull your skirt out of the chain and ride the bike.

Person who's opinion I give least fucks about ^



evar

 

[Adventurous]

Jesus, pull your skirt out of the chain and ride the bike.

Do they make a jig for that?

 

[Adventurous]

I'd have to imagine that Park tool could take the mount down a sufficient amount. After all, magnesium is pretty soft stuff, if it can take off what's required to face the mount I don't see why it couldn't knock off a bit more. Just make sure to clean those threads up all perty like before you run a bolt in.

 

[Kanye West]

Person who's opinion I give least fucks about ^



evar

 

[HAB]

That Park will definitely do it. Just be really careful to take down the same amount of material off each tab. If you get them out of plane you can end up with some pretty nasty vibrations and noise out of the brake.

 

[Nick]

If you get them out of plane you can end up with some pretty nasty vibrations and noise out of the brake.

moar shimz?

 

[lobsterCT]

As long as you get it set up good when you start, it uses set screws on the cutter head to make sure you cut both posts the same amount. This is DT-4.2

 

[StiHacka]

Anyone has one like that for a rear triangle?

 

[Dogboy]

Anyone has one like that for a rear triangle?

That one can be used on the rear triangle as well, just a different axle adapter.

 

[maxyedor]

Will that actually move the caliper where you need it? Remembering my 180m 36 Talas, the posts were higher and longer than those on my new 150mm 36. Shaving the posts would move the caliper forward, but will it end up in the right location vertically? Unless it's all an optical illusion.

 

[jstuhlman]

just gnaw it down you pansy

 

[kidwoo]

Will that actually move the caliper where you need it? Remembering my 180m 36 Talas, the posts were higher and longer than those on my new 150mm 36. Shaving the posts would move the caliper forward, but will it end up in the right location vertically? Unless it's all an optical illusion.

You're right, each 'version' of lowers has the mount in a different spot. The 180mm version is higher up.

Using science™ I held up a 180 to 200 adapter to the post mounts with the top face of each lined up. I'll actually end up taking most of the material off the top one, and very little off the bottom so it will also kind rotate it around and down to fit the smaller rotor. There are some small differences in the face angle with the adaptor that I'll have to duplicate. Gotta figure that one out.

I found a buddy with a dt-5 which must be better because it goes to five. I'm actually going to face it down to 160mm rotor size, then put a 200mm adaptor on and send a pic to hacktastic so he can understand how life works.


Thanks for the help y'all!

 

[Westy]

just gnaw it down you pansy

A cutting torch works well on magnesium.

 

[kidwoo]

A cutting torch works well on magnesium.

I tried so hard to light up some magnesium skateboard trucks so it would give off the blinding white brilliance of freedom but I couldn't get them to ignite. Stupid stable alloy bullshit.

 

[Westy]

I tried so hard to light up some magnesium skateboard trucks so it would give off the blinding white brilliance of freedom but I couldn't get them to ignite. Stupid stable alloy bullshit.

I threw an old Manitou Mach 5 lower into a bonfire. It just melted, but after a while the pool of molten metal got hot enough to start burning. It was much slower than expected but still really really bright. It can be done with great amounts of heat.

 

[Nick]

Manitou Mach 5 lowers can't melt steel beams.

 

[big-ted]

I'm guessing that tool is gonna take you a while. Might want to stock up on hydrating fluids before commencing work.

This coming from someone that once used a BB facing tool to take a 100 mm BB down to 83 mm, and will not be doing so again.

 

[maxyedor]

I'm guessing that tool is gonna take you a while. Might want to stock up on hydrating fluids before commencing work.

Depending on how much you're taking off, there's no reason to use the tool for most of the material removal. Port-a-band them to roughly where they need to be, then just face the last .5mm or so to get the fit dialed and flat.

You're right, each 'version' of lowers has the mount in a different spot. The 180mm version is higher up.

Using science™ I held up a 180 to 200 adapter to the post mounts with the top face of each lined up. I'll actually end up taking most of the material off the top one, and very little off the bottom so it will also kind rotate it around and down to fit the smaller rotor. There are some small differences in the face angle with the adaptor that I'll have to duplicate. Gotta figure that one out.

I found a buddy with a dt-5 which must be better because it goes to five. I'm actually going to face it down to 160mm rotor size, then put a 200mm adaptor on and send a pic to hacktastic so he can understand how life works.


Thanks for the help y'all!

Interested to see how this turns out, seems plausible that they could be in about the same spot, and it's simply a rotation issue, just throw some wobbly-washers from a 160pm-180pm adapter on there and you may be golden.

If all else fails, braze some v-brake bosses on there.

 

[kidwoo]

Okay new thread title: Does anyone have a porta band I can borrow?

I may have to resort to a perma band since that's what I have access to.

 

[HAB]

 

[StiHacka]

I am a disappoint that you aren't putting a Charger in it.

 

[jimw]

Well good luck with that and all.

Take this FWIW, but I just wanted to add that I've been running a Van 180 on my trail/DH/do-everything bike for like 3 years now, and the 200mm rotor has not been an issue. I am the most anal guy about random bike noises too, so if it was rubbing every time I stood up to pedal it would bug the shit out of me. Any time there does happen to be some rub from the rotor, it's super easy to bend back. And it's not like I end up needing to do it regularly, it's pretty rare. If anything it happens more often with the rear 180mm rotor. The extra power up front is worth it.

 

[dump]

Hand file, then face - done.

 

[kidwoo]

I started actually measuring things out and there's no way in hell that's going to work

I'd have like three threads of purchase on the top one. Oh well. I went for a ride and was annoyed for two hours.

Then I went and bought a new rotor.

 

['size]

i only read the first post, but why isn't setting up the brakes correctly the first solution?

-signed- guy who loves getting rotors back to true with a crescent wrench...

 

[kidwoo]

How does this new fangled disk? (am I spelling that right?) braik technology work again?

I've heard of em, but dayum if I understand where they go. So it's a brake..........that uses a disk?

And you gotta set em up?


Shit I need wikipedia

 

[AngryMetalsmith]

If it's just the noise that you can't stand just switch to resin pads. Much easier than taking cutting tools to your fork.

I tried so hard to light up some magnesium skateboard trucks so it would give off the blinding white brilliance of freedom but I couldn't get them to ignite. Stupid stable alloy bullshit.

You have to use filings or saw dust, not large chunks. Works well with titanium too.

 

[kidwoo]

 

[AngryMetalsmith]

Well alright then.

Start by marking a line on the post with a sharp scribe all the way around, where you want the end of the post to be. If it's a lot more than what the cutting head can manage with a few turns, then use a hacksaw or jewelers saw to cut it.

Start a 1-2 mm above the scribe mark and go slowly and check to make sure its straight.

File the cut mark with a flat bastard file just enough to even it up a bit.

Make sure to leave the line.

Now use the tool.

 

[kidwoo]

Man that is totally what I was going to do.

But it can't be done without boring out the top hole deeper in the lowers.
I'm not going to do that to a brand new fork.


I did learn that park dt 4 and dt 5 tools exist though. And given how annoying it was to setup a new and pretty damn straight rotor, I think I might need them for their intended purpose anyway. Shit just ain't right here.