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Discussion Starter · #1 ·
I ride an '09 GF Wahoo disc that I absolutely love, but I noticed there is some play between the disc and hub. This is my first bike with disc brakes (the LBS didn't have anymore v-brake bikes, so they gave me a deal on the disc version) so I was wondering how much play is normal? It has not-so-expesive Shimano M65 centerlock hubs on bontrager ranger rims with Shimano M416 mechanical disc brakes.

At the end of last season my wife and I went to Sun Valley and I got the brakes nice and hot flying down the ski slopes, and I really started losing braking force. I put it away thinking they brakes were simply fading. So I pulled them apart a week ago to scuff up the rotors and sand down the pads for that were a little torn up. Anyways, after I adjusted them, I checked pad engagement and whatnot and noticed that if I have the brake locked and push the bike back and forth (as if I were stopping), the disc holds perfectly still, but the wheel rotates a few degrees. Is that normal? Do I just need to tighten them with my cassette tool? Or is there some bigger issue here? Both the front and rear hubs do it.

I wouldn't say that I am hard on my gear, but I'm not easy on it either. I just expect things to work. I'm sure the LBS is tired of my bugging them to get all the kinks out. I was also thinking of upgrading the cables to compressionless Jagwire Ripcord, Alligator Super Fortress, or XTR (though I don't think they are compressionless). I know there are several threads on here about brake lines, but a few more might not hurt.
 

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It's not normal for the rotor to move on the hub when you brake, so try to tighten them up.

Are you sure this is what's happening? There's often some movement of the pads when you rock the bike back and forth: this isn't applying the same forces as when you brake.

Tim
 

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Discussion Starter · #3 ·
Thanks for the reply. I thought that perhaps it was the pads, but upon further inspection is quite definitely the hub rotating separate from the disc. If I'm standing over the bike and push the handlebars forward and back with one of the brakes locked (so as to simulate the direction of forces when braking) the wheel turns a bit. I flipped my bike over to double check, held one of the brakes and could rotate the tire a few degrees. With nose just about on the disc for a closeup, I verified that it didn't rotate at all, but the hub does. I'll try to tighten them a bit and see what happens. Thanks!
 

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Are they proper centrelock rotors??

If they are then the interface with the hub is not the issue as it is toothed and cant move (as long as the lockring is tight naturally). You may have some play between the centre alloy section and the riveted outer steel section. The caliper bolts for the fork/frame might be loose too. If these are all good then this is one where you'll want to visit the LBS, as brake issues are deadly if ignored
 

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Discussion Starter · #5 ·
They are proper centerlocks that came as stock hardware on the bike - I haven't upgraded the rotors or any of the brake components. I pulled them off this morning to take a gander, thinking perhaps the locking ring had loosened. When I pulled the rotor off, the gear teeth on the rotor side had an unusual wear pattern on them. None of them had been stripped, but you could see where the teeth were worn. Which is strange because they aren't like the teeth on a cassette or crank where they are only in contact with the chain for part of a rotation and that constant on-again-off-again contact, combined with shifting gears, wears the teeth. These are permanently meshed so I wouldn't expect any wear, really. The rivets holding the rotor to the centerlock piece are holding solid - no play or movement.

I torqued them back down to 40 Nm and checked for play again. It's still there... Blast... Maybe I just have to raid my fun-fund for money for some new parts. Of course, this could snowball on me and I might end up buying a whole brake/wheel/shifter/derailleur/crank/etc package. Tricky dangerous those online shopping sites are: add one item to the cart and next thing you know you're replacing everything but the frame... I'm sure my wife would LOVE me to do that, especially since everything else works fine on my bike (meaning, it hasn't broken in 2 years). Hmm... flat screen tv? or new components?
 

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Discussion Starter · #6 ·
So I took it to the bike shop - the guy was flabbergasted and had never seen that happen before. So he'll take a look at it, talk to Shimano or whomever, and hopefully have some news for me by Wednesday. That means I actually have to drive my car around town if I wanna go anywhere. Blast! Or maybe I'll swipe my dad's cannondale for a while.. I really hope I don't need a new wheel set and brakes - that would be lame. Of course, there's always a deal on XT hubs and wheels so I could upgrade... but that would still mean spending money. Doh! Anyways, I'll forward the news when I get it, just in case anybody is interested...
 

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Discussion Starter · #8 ·
Yeah, the bearings are tight. You can literally watch the hub rotate while the rotor is locked in place. If you grab the front wheel with the front brake locked you can rotate it forward or back a few degrees and feel the teeth grinding where the hub and rotor mesh. Unless I hear better news next week, I'm prolly in for new discs at minimum or new discs and wheels worst case. Thanks for the reply, though. I really want to know if anybody has seen this happen before or if I'm the odd case...
 

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I've not heard or seen any such case. Its really hard to imagine how this could have happened unless there was 1. a case for warranty replacement, or 2. a bad install causing some initial play between the surfaces.

Rotors are pretty cheap though all things considered.
 

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I have read a bad review at rosebikes from a rider that bought SLX rotors who had exactly the same problem. I couldn't believe it, but recently a friend of mine with the same rotors has the same problem after year of trouble-free riding. I'm bit worried because I have this rotor on my rear wheel. So let us know how things go.
 

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Discussion Starter · #12 ·
I'm sadly glad to see that I'm not the only one that has seen this - sad because it is a problem, glad because it refutes my insanity.

AlexRandall - I initially thought that it could have been a bad install and I just never noticed it before because I chalked it up to a barely loose headset or play in the fork stantions. But perhaps now that the wear is accelerating it has become very noticeable.

I'll let you all know the verdict sometime this week... same bat-time, same bat-channel...
 

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Discussion Starter · #13 · (Edited)
Arrgghhh... The bike mechanic says I need new rotors because the splines are shot on mine. They are el cheapo Shimanos (seriously, the cheapest ones available) and would cost me ~$18 each to replace. But if they are just going to wear out on me and give me problems after one season, I'd prefer not to get them. However, the next step up are Avid centerlock rotors at $50 a pop - youch! And the part replacement warranty is up on my bicycle, so no freebies...

So here's my thinking... I've been less than impressed with the braking performance of the setup that's on my bike right now, so I'm really tempted to buy some Avid BB7's that are on sale at pricepoint for $47 each. Granted, all I need is new rotors, but I almost can't resist it... They come with rotors, but are 6 bolt. So I'd also need adapters, which add to the cost. But I'm thinking that a little more now could save me alot more down the road. And I'll be sure to have brakes that can stop me without worry.

P.S. - anybody know if a 185mm rotor will fit on the front of an '09 Wahoo with the XCM V2 fork? It may be overkill to put something larger than 160mm on there, but it sure would be fun :)
 

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Discussion Starter · #15 ·
As far as I understand, they work with any v-brake type lever. So for now, they should fine with my stock setup that has the shifter and brake lever integrated (shimano Acera, I think) - yes? However, I'm having issues with the cost of centerlock adapters - almost as much as the brake kit itself! I've read on other posts that DT or Shimano is the way to go, but at the cost of $35+ a piece I'm having second thoughts... Of course, those Alligator adapters are tempting me at $10 a pop. Again, other posts say that the Alligator lockring can't handle the 40 Nm so perhaps if I use the stock lockring with just the Alligator adapter piece? Or are they different lock rings? Ughh.. Who knew this would suck so much of my life?!? Then again, being able to stop IS a top priority on a mountain bike...
 

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Discussion Starter · #16 ·
Ha ha ha ha ha!! Vertichy - I just noticed what your avatar was and picked up on your name - AWESOME! I had one of those as a kid! It was a hand-me-down from my older brother, along with the first 6 books in the series. I think I ended up with about 30 books by the time I was done reading the series. Very cool... ha ha ha...
 

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Avid makes Centerlock rotors, you might as well go that route and skip the adapters.

I've never seen the spline interface develop play, but I guess it's possible. I've seen the riviets on Shimano rotors come loose many times though and that gives the symptoms you describe.
 

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Discussion Starter · #18 ·
So I decided that my brakes needed an upgrade and went for the Avid BB7's front and rear since it was either $50 per wheel for rotors or $55 per wheel for BB7s with an adapter. I ordered the Alligator adapters so we'll see if they're any good. If not, I guess I'll pony up the cash for DT Swiss or something of the like. I also threw some Alligator Super Fortress compressionless cables in the order since they were on sale for ~20 at pricepoint. I ordered them Thursday and paid to 2-day air them, but it looks like they won't get here till wednesday - guess that was some money not-well-spent... Oh well. So that's the plan!
 

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Discussion Starter · #20 ·
Ughhh... So I posted a few days ago, but I guess it didn't like me and didn't show up. So here's the scoop...

I got all the parts for my bike and slapped them on Thursday night in hopes of getting rid of the play and brake shuddering. The BB7's when on without much issue, as did the new cabling. The rotors also went on without issue using the Alligator adapters. However, I'm really not a fan of the Alligator adapters because the don't actually let you bolt the rotor to the hub - it just has six little nubs that are a bit smaller than the bolt hole to center the rotor. It comes with a slightly larger than stock lock-ring that clamps the rotor to the wheel. But this combination still allows the rotor a little bit of wiggle room and the tire slides back and forth with the disc locked.

My hack-attack side kicked in and I decided to murder one of the adapters since I was going to end up tossing it anyways. I lined up the holes on the rotor and centerpunched them so that I could drill holes in the adapter. After tapping them with and M5 tap, I tried bolting the rotor to it. But using the bolts means that I had to trim the smaller stock Shimano center lock ring to clear the bolt heads. I put two bolts in to verify proof of concept and slapped it back on the bike. And it worked! Well, sorta. The rotor is now solidly held to the adapter, but guess what... there's still play between the splines. Poo. I would chalk it up to using a cheaper adapter, but I don't think that it's the case because even though there is less play, it is still very noticeable on the front wheel. This tells me that the front hub splines are bad. Crap.. The back is a little bit improved, but not a whole lot. I didn't drill and tap that adapter so that I could do a comparison.

So today I decided to call Shimano and see what they say about it. The guy I talked to was friendly and courteous, but said I needed to take the bike back to the bike shop and have them call in to warranty the parts. Play between those splines is definitely not normal. Unfortunately, I don't really want to have my bike in the shop for a couple of weeks to wait for warranty parts. And I don't really want stock replacement parts if they are just going to wear out again and fail like these ones. I've already put an extra $150 into fixing the brakes, but it looks like I'm in for new hubs as well. And if I have to get new hubs, I might as well get new rims because hubs suck to lace (at least for a someone like myself who doesn't have a nice wheel stand). So another $150 or $200 for those. Ugghhh... I'm really just peeved that stuff fails like this since I decided to make the jump to disc brakes from v-brakes. Sad thing is, I almost went OTB on my wife's bike while tuning it up and taking it for a little spin because I pulled on the brake levers like I normally do on my bike and - WOW - those little V-Brakes stopped in a hurry. We bought both our bikes at the same time, FWIW. Oh well. Brakes should brake, not break...
 
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