Sram Rival discs + fitting and tinkering tips and tools

daniel_b

Hi guys,

I've managed to bend one of the discs on my bike, and the rear is a pain to setup, so I am thinking to buy a new pair.

I thought they would be SRAM discs, but they are not, they are a super cheapy brand called Prmoax, and I have found them online for £6 and £7 each, with free p&p.

So my question is, do I just buy the same as replacements, or would it be worthwhile spending a bit more on something potentially of better quality, that may give better braking performance, and not warp as easily?

Perhaps something trusty like a Shimano XT rotor?

Any suggested brands if so?

Cheers

Dan

ryanshattered

Daniel B wrote:

Hi guys,

I've managed to bend one of the discs on my bike, and the rear is a pain to setup, so I am thinking to buy a new pair.

I thought they would be SRAM discs, but they are not, they are a super cheapy brand called Prmoax, and I have found them online for £6 and £7 each, with free p&p.

So my question is, do I just buy the same as replacements, or would it be worthwhile spending a bit more on something potentially of better quality, that may give better braking performance, and not warp as easily?

Perhaps something trusty like a Shimano XT rotor?

Any suggested brands if so?

Cheers

Dan

SRAM rival hydraulics come with Centerline rotors and these are what I have on my good wheels. They are around 27.99 per rotor and they seem fine. They are very quiet and smooth feeling as you'd expect from the blurb, still honk when wet.

My winter wheels have got Avid G2 Clean Sweep which are about a tenner less than the centerlines and these come with a bit more vibration but still pretty quiet.

Shimano XT have a very good reputation

Also, you mention 180mm in the title - are you sure your road bike has a 180mm rotor? 140 or 160 are the normal sizes...

daniel_b

ryanshattered wrote:

Daniel B wrote:

Hi guys,

I've managed to bend one of the discs on my bike, and the rear is a pain to setup, so I am thinking to buy a new pair.

I thought they would be SRAM discs, but they are not, they are a super cheapy brand called Prmoax, and I have found them online for £6 and £7 each, with free p&p.

So my question is, do I just buy the same as replacements, or would it be worthwhile spending a bit more on something potentially of better quality, that may give better braking performance, and not warp as easily?

Perhaps something trusty like a Shimano XT rotor?

Any suggested brands if so?

Cheers

Dan

SRAM rival hydraulics come with Centerline rotors and these are what I have on my good wheels. They are around 27.99 per rotor and they seem fine. They are very quiet and smooth feeling as you'd expect from the blurb, still honk when wet.

My winter wheels have got Avid G2 Clean Sweep which are about a tenner less than the centerlines and these come with a bit more vibration but still pretty quiet.

Shimano XT have a very good reputation

Also, you mention 180mm in the title - are you sure your road bike has a 180mm rotor? 140 or 160 are the normal sizes...

Thanks Ryan, and a good call, I DID mean 140 and 160 - good job someone is paying attention!

Sigh.

Agreed, the internet tells me the groupset comes with those rotors, but this is a stock Cannondale bike and comes with the much cheaper Promax ones - nice bit of costcutting there.
Perhaps that is part of my issue, maybe both discs have a bit of play in them, and that is why it is such a pain to get them rub free.

Have you had to adjust your callipers at all, and how easy or hard did you find it - any tricks?

I'll take a look at those centreline ones, but presumably as long as I get a 6 bolt 160mm (Not 180!) rotor, then it appears it would fit.

EDIT: Found a centerline 160 for £20 delivered, will order that and see how I go, if it's a vast improvement I'll get a 140 as well - the place I ordered from only had 160's though.

meanredspider

Which brake calipers are you using?

daniel_b

meanredspider wrote:

Which brake calipers are you using?

The callipers are sram rival, unless I've misunderstood, still not au fait with disc terminology.

As to the pads, I assume they are just Sram factory spec, whatever that is.

I tried tinkering with the rear again tonight, and by some miracle I adjusted it to the best it's ever been, probably 85% rotation without rub. Don't dare try and tinker with it!
Can't attack the front until the new rotor arrives, hopefully by the weekend.

daniel_b

My rotor has arrived.

But the sender thought it wise to sellotape it inside the packaging, on the actual surface of the rotor, so there is now sticky residue left.......

What's the best way to clean it off - some kind of solvent, though not sure what I have got that might be suitable.
I do have some fairly strong 'label remover' that you put on, leave 10 seconds, and then wipe it off, would that be suitable does anyone know?

Don't want to damage a brand new rotor is all.

Aside from that I guess I have gt85 or Vinegar, or could just try hot water and washing up liquid if required.

luv2ride

definitely don't use gt85! it's a lubricant, the very worst thing to put on a rotor. The sticky stuff remover might also leave an unwelcome residue. isopropyl alcohol is recommended for cleaning them (I got some from eBay for a couple of quid). hot water and soap probably best option from those you listed...

daniel_b

Luv2ride wrote:

definitely don't use gt85! it's a lubricant, the very worst thing to put on a rotor. The sticky stuff remover might also leave an unwelcome residue. isopropyl alcohol is recommended for cleaning them (I got some from eBay for a couple of quid). hot water and soap probably best option from those you listed...

Ok mate ta, I always thought GT85 was kind of a degreaser of sorts (In contrast to wd40), obviously not!

What about petrol on a rag?

Is the isopropyl alcohol the same stuff you tend to get on the surgical wipes?
If so, I bought some an age ago to clean the frame prior to fitting frame protection - I would just have to see if I can locate them...

luv2ride

GT85 = "Lubricates every metal and composite part with LONG LASTING protective PTFE coating. Safe on carbon frames."

Isopropyl alcohol = surgical wipes, so sounds like you're sorted if you can find your stash!

DKay

Alternatively, just buy some actual disc brake cleaner...

luv2ride

Never understood why, but TRP specifically advise against cleaning the rotors with disc brake cleaner:
"Clean the disc and hub-mounting surface with isopropyl alcohol (DO NOT use disc brake cleaner)." They dont explain why though...this is from their installation instructions, so maybe not an issue after everything's bedded in?

daniel_b

Well I managed to locate my alcohol wipes that I bought ages ago, they were tiny, but 4 of them and some elbow grease has removed all of the sticky stuff - cheers :-)

I will get some disc brake cleaner, just need to wait til I have a £20 order to make at Amazon.

Thanks for the help all, much appreciated.

Next to fit it, and try and adjust that sodding front calliper.

luv2ride

Maybe try one of these?

Idea is you place the thin metal part over the rotor and roll it into the calliper. Then, with mounting bolts loosened, apply the brake. Tighten bolts then you (should) be done. This should leave an extra mm of clearance either side of the rotor, accounting for any slight distortion when the rotor spins through the calliper. Very cheap, free delivery from Tredz.

daniel_b

You are a leg end sir, thankyou kindly.

Just ordered it for free basically, as Tredz have £5 off vouchers, so popped that on with a 140mm rotor, and a 10mm headset spacer, and got the lot for less than £26 :-)

bendertherobot

I know this is not needed now, but, got some 160mm Shimano XT RT76 rotors from Evans today. 16.99 each which is as cheap as the cheapest online place. Seem excellent. Floating as well.

daniel_b

bendertherobot wrote:

I know this is not needed now, but, got some 160mm Shimano XT RT76 rotors from Evans today. 16.99 each which is as cheap as the cheapest online place. Seem excellent. Floating as well.

Nice one BTR - notice they don't seem to go down to 140mm though.

Out of interest, what does 'floating' relate to......?

bendertherobot

I've no idea. I think it's where they are two piece (steel outer, alu inner) and the expansion allows thermal something or other.

The inners here are composite. Pretty sure the box says floating. No idea if same thing but

THEY LOOK NICE!

daniel_b

Luv2ride wrote:

Maybe try one of these?

Idea is you place the thin metal part over the rotor and roll it into the calliper. Then, with mounting bolts loosened, apply the brake. Tighten bolts then you (should) be done. This should leave an extra mm of clearance either side of the rotor, accounting for any slight distortion when the rotor spins through the calliper. Very cheap, free delivery from Tredz.

So I finally have all the bits together, and had a go today - initially I forgot I had bought the tool above!

Once I remembered, it was a fair faff to get it in inbetween the pads, nothing like as easy as it appeared on the pics or video I saw.

I spun the wheel around a few times, pumped the brake lever, held it and tightened the bolts up.

End result is the best it has been, though still not as good as the foruitous setup I managed for the rear last time.

However I san see a kick in the disc, as it rotates, so assuming the disc was perfect, I wonder if that means the mounting points on the wheel is marginally out.

Basically it only rubs in one place - if I look from above, I can see a gap on one side, which then dissapears and rubs, on the ither sideit gets very close but does not touch, so I have no leeway to move it across, so looks like that is as good as it will get, but hoping that after some heavy braking it will either straighten the disc, or the pads might 'learn' to accomadate the not perfectly flat disc?

And there was me nearly buying another disc bike this morning! :roll:

Anyway, as it stands I thikn I am just going to ride it and see what happens., but in summary that tool is very useful, if not the ultimate answer in my bikes situation.

ryanshattered

Daniel B wrote:

Luv2ride wrote:

Maybe try one of these?

Idea is you place the thin metal part over the rotor and roll it into the calliper. Then, with mounting bolts loosened, apply the brake. Tighten bolts then you (should) be done. This should leave an extra mm of clearance either side of the rotor, accounting for any slight distortion when the rotor spins through the calliper. Very cheap, free delivery from Tredz.

So I finally have all the bits together, and had a go today - initially I forgot I had bought the tool above!

Once I remembered, it was a fair faff to get it in inbetween the pads, nothing like as easy as it appeared on the pics or video I saw.

I spun the wheel around a few times, pumped the brake lever, held it and tightened the bolts up.

End result is the best it has been, though still not as good as the foruitous setup I managed for the rear last time.

However I san see a kick in the disc, as it rotates, so assuming the disc was perfect, I wonder if that means the mounting points on the wheel is marginally out.

Basically it only rubs in one place - if I look from above, I can see a gap on one side, which then dissapears and rubs, on the ither sideit gets very close but does not touch, so I have no leeway to move it across, so looks like that is as good as it will get, but hoping that after some heavy braking it will either straighten the disc, or the pads might 'learn' to accomadate the not perfectly flat disc?

And there was me nearly buying another disc bike this morning! :roll:

Anyway, as it stands I thikn I am just going to ride it and see what happens., but in summary that tool is very useful, if not the ultimate answer in my bikes situation.

Did you make sure the contact points on the hub were clean and debris free before mounting the disc? Also, is the wheel definitely properly located in the dropouts?

MikeBrew

Just bought a Caad 10 disc frameset and Sram Rival HRD to go on it. I'm thinking about fitting 180 front/160 rear discs on it. Does anyone know if there's any reason why this won't work ? Also, I need to know what size post adapters(caliper mount brackets) to get for this configuration ?

bendertherobot

MikeBrew wrote:

Just bought a Caad 10 disc frameset and Sram Rival HRD to go on it. I'm thinking about fitting 180 front/160 rear discs on it. Does anyone know if there's any reason why this won't work ? Also, I need to know what size post adapters(caliper mount brackets) to get for this configuration ?

Should work but, to be honest, no need. 160 f and r is fine. And pretty standard. I had 140's on my Ritchey and didn't notice any issues with stopping power.

If you do need 180 rotors then you'll need 160 to 180 convertors.

The Rival calipers are top mount so I think it's a post mount adapter. Not entirely sure! Basically, take a look at the adapters that come with the Rival calipers then find the 160 to 180 version

(But unless you already have a 180 rotor I'd not bother)

MikeBrew

Well being as I bought the bare frame, it would be not so much an upgrade as a "first fit", so to speak. Frame came with no mounting brackets at all. Looking at pics of similar bikes on Google, it appears that a caliper bracket is needed on the front for the standard 160mm disc and the rear caliper mounts direct to the frame bosses for a 140mm.
My thinking is that as I have to buy all brackets and discs from scratch, why not go bigger for better heat disipation. The only "extra" I'd be buying would be the rear mounting bracket.

daniel_b

Did you make sure the contact points on the hub were clean and debris free before mounting the disc? Also, is the wheel definitely properly located in the dropouts?

Good call, no I had not. Whipped the disc off after work, and there was a tiny amount of the blue threadlock stuff there, but not convinced it was enough to cause the kick I saw.
Ran out of time at that point, so just left it in the garage sans front disc. Lovely to hear the front wheel rotate without a scraping noise.

Maybe I just go out with a rear brake. Joke.

And I am sure as I can be that the wheel is seated properly, it seems centered in the fork, spacing looks spot on.

Hoping this rotor isn't buggered too, this low maintenance lark is going to get pretty pricey otherwise. Perhaps I am just allergic to Sram

MikeBrew

Did you use CPS mounting washers ?

daniel_b

MikeBrew wrote:

Did you use CPS mounting washers ?

Not heard of them. The original cheap disc had none, and this new pricey one came with no washers either.
Might they be the magic bullet?

bendertherobot

MikeBrew wrote:

Well being as I bought the bare frame, it would be not so much an upgrade as a "first fit", so to speak. Frame came with no mounting brackets at all. Looking at pics of similar bikes on Google, it appears that a caliper bracket is needed on the front for the standard 160mm disc and the rear caliper mounts direct to the frame bosses for a 140mm.
My thinking is that as I have to buy all brackets and discs from scratch, why not go bigger for better heat disipation. The only "extra" I'd be buying would be the rear mounting bracket.

Frames generally won't. Brakes or groupsets will. Have you bought the Rival brakeset separately? Looks like the rear is set up for 160 directly to me. Not sure.

MikeBrew

Daniel B wrote:

MikeBrew wrote:

Did you use CPS mounting washers ?

Not heard of them. The original cheap disc had none, and this new pricey one came with no washers either.
Might they be the magic bullet?

Basically they are male and female dished washers that allow the calipers to swivel slightly on the mounting bolts before the bolts are tightened, to aid alignment. As I understand it, everything is bolted up together loosely, the the brake is applied and held on whilst the bolts are tightened. Depending on the calipers you have, these washers are either fitting under and over the caliper OR just over the caliper. Under = between caliper and mount.


http://www.chainreactioncycles.com/avid-caliper-mounting-bracket-bolt-kit/rp-prod110395?gs=1&gclid=CJOvs9zM_8oCFRVmGwodQ3AIhA&gclsrc=aw.ds

@ BTR : yes bought the frame and brakes seperately. Brakes came with no mounting brackets, presumably because the hardware needed would vary depending on what frame it was mounted to. I'm new to the world of disc brakes, but as I understand it direct mount on one frame/fork might only allow (for example)140mm, whilst direct mount on another frame/fork might accommodate (eg)160mm discs.
To me, this is where it gets slightly complicated as the mounting brackets are plus (for example) 20mm of disc size, but without knowing the direct mount disc size that doesn't help much
Direct mount (minus any spacers/bracket) on the Caad frame appears to be 140mm front and rear, as the complete bikes already have a step-up bracket on the front. By that reckoning I'd need a plus 40mm on the front and a plus 20mm on the back. Not sure that this correct and wondered if any one could confirm before I buy the brackets. Hate having to send stuff back !

daniel_b

MikeBrew wrote:

Daniel B wrote:

MikeBrew wrote:

Did you use CPS mounting washers ?

Not heard of them. The original cheap disc had none, and this new pricey one came with no washers either.
Might they be the magic bullet?

Basically they are male and female dished washers that allow the calipers to swivel slightly on the mounting bolts before the bolts are tightened. As I understand it, everything is bolted up together loosely, the the brake is applied and held on whilst the bolts are tightened. Depending on the calipers you have, these washers are either fitting under and over the caliper OR just over the caliper. Under = between caliper and mount.


http://www.chainreactioncycles.com/avid-caliper-mounting-bracket-bolt-kit/rp-prod110395?gs=1&gclid=CJOvs9zM_8oCFRVmGwodQ3AIhA&gclsrc=aw.ds

Ah ok, my misunderstanding, I thought you meant for attaching the actual rotor.
The rear does have a couple of these type of washers on it, but the fact the rotor is only rubbing in one place, well it was when it was attached to the bike, tells me that either the 2nd rotor is also warped, rubbish under the mounting points knocked it out of true, hopefully not permanently, or the mounting points for the rotor are not level, and this forces the rotor out of perfect alignment.

Was hoping to take it out for a ride on Saturday, looks like it will have to be the old bike again, as I can't see any spare time coming up between now and then.

Re the bracket you need - more than happy to take pics of what is on my Synapse if that would be a help, and measure them if need be?

MikeBrew

Hi yes photos would help cheers
if your rotor needs a tweak , http://www.highonbikes.com/special-offe ... wwodSEMCWw

daniel_b

MikeBrew wrote:

Hi yes photos would help cheers
if your rotor needs a tweak , http://www.highonbikes.com/special-offe ... wwodSEMCWw

Thanks Mike - do you know how that rotor straightener works?
EDIT - ok, worked it out, you just bend the bugger away from where it currently is!
Found this well rated X-Tools one for less than a tenner: http://www.chainreactioncycles.com/x-tools-pro-rotor-truing-fork/rp-prod55958?gs=1&gclid=CL_pjpyAgcsCFSMcwwodgncMrA&gclsrc=aw.ds
Just ordered it, might have it for the weekend.

Do you have to bolt it to the fork somehow, and then spin the wheel?

Ok, I took 5 photos this AM before work, not used onedrive before, but hoping this will work:
Synapse SRAM brakes

let me know if not eh.

MikeBrew

Thanks for the photo's Daniel , pretty sure of where I'm going after looking at those

As for the disc tool. I'm guessing you just slot it over the disc and use it as a lever to bend it back t'other way, where it's kicking over .

https://www.youtube.com/watch?v=BctnmNKVr1Y