Author Topic: Wheel alignment with rear disc adapter (Read 8239 times)

Thunderchild · « **on:** February 17, 2003, 04:13:06 pm »

I was examining my Hammerhead rear disc adapter on my Proflex 5000. I noticed that the part of the adapter where the quick release attaches does not match the shape of the dropout. Might this affect the postion of the rear wheel when you install it if it was mounted a tad low? I think my adapter is a tad low. It seems that you could eliminate this and shape the adapter exactly like the dropout as the axle determines the fit of the rear wheel in the drop out. Did any of you who made their own use the exact shape of the drop out or something like the Hammerhead adapter?

5500C · « **Reply #1 on:** February 17, 2003, 04:20:17 pm »

I had the same concerns at first as well. If you install it and flip the bike over, you will notice that the rear wheel fits into the dropout and the only thing that will come through the Hammerhead adaptor is the QR skewer. You should have plenty of clearance, although from the side, it looks like it will interfere.

One thing to be careful of when installing your brakes is that there is enough clearance between the calipers and discs. I had to place spacers in the rear on my Avid's to give me space. I hope I just didn't drill out the wrong place.

Any thoughts Hammer?

Hammer · « **Reply #2 on:** February 17, 2003, 08:43:34 pm »

I posted an indepth reply to the question, posted it,
forgot my email address and the post was lost.. even
the back button didn't take me back there.. very
annoying.

So I posted this on the 855heads and will cut and paste and edit it here:

Basically though to answer the query:

As long as the instructions were followed and the
wheel and axle were in the correct position before the
adapter plate was put into position, clamped up
tightly and the holes drilled in the swingarm then everything will line up nicely.

If a step or two of the instructions were skipped
over, then just about anything could happen. Why do
us men always read the instructions after we have
either done the job or screwed it up..! ;-)
Not that I am saying that you did this Thunderchild.

Anyway, even if the swingarm was drilled
incorrectly, it can't be that far off.. ( a tad!??) and to salvage
the installation the 5mm holes (IN THE HAMMERHEAD PLATE, NOT THE SWINGARM!) can be
increased by a suitable amount in diameter (start with a 5.5mm drill, increase to 6mm if necessary) this should bring
the positional tolerance back into line, therefore
effectively lining everything up again.

Do not alter the QR skewer slot in the HH plate though. This is critical to keeping the calliper at the correct international standard radial distance from the wheel axle.

However, reading the post again, it isn't clear whether or not you have drilled anything incorrectly.

May I suggest that you remove the two 5mm allen bolts that hold the adapter plate onto the dropout, push down on the bike with the wheel loose to ensure it is sitting in the swingarm, then push the HammerHead plate down onto the QR skewer, tighten the skewer and then refit the 5mm bolts, if they will not go in, try loosening the skewer and rotating the adapter plate radially until they line up, but keep pressure on the rear of the bike so that the wheel axle is ALWAYS sitting snugly against the dropout. If the bolts will still not go in, then your swingarm is incorrectly drilled, but don't panic yet.. all and you'll need to do is increase the size of the holes in the adapter plate. A Tad.

With the plate correctly located there should be a slight clearance between the adapter plate location slot and the QR skewer on the sides, the top edge will always be exactly flush.
Depending on the brand of skewer you have the clearance at the edges may vary. Mavic for example have skewers that are a few tenths smaller in diameter than shimano. So more clearance will be seen with a mavic skewer... but we are talking about tenths of a mm here...

Any more problems then email me direct and I'll be happy to help you out.

Take it easy,

Hammer.

hammer@telia.com

Edited a few times as it looked as though IFO had infected my spell checker... ;-)

Thunderchild · « **Reply #3 on:** February 18, 2003, 01:58:10 am »

Thanks for the reply Hammer. I haven't had any problems with the adapter. It works great in mud snow rain, etc. I have been using it for over a year. What made me examine this was that my brake pads line up a tad

above the rotor. This is evidenced by the wear on the pads. My front disc,which is on a Marzocchi fork, sits more fully on the rotor. So I thought that maybe the left side of the wheel was a tad

low and this could be altered.

Now I did read the instuctions

Felt like a surgeon working on my own child, but I could have been off a tad

Later

Matno · « **Reply #4 on:** February 18, 2003, 03:30:58 am »

I wouldn't worry too much about it. Mine didn't line up perfectly either, which really made me think I had goofed (I actually had, but not enough to really matter) until I realized that my rear pads lined up the same as my front ones on the Manitou post mounts. I figured if I couldn't get them any closer with the factory setup, it couldn't be too bad. (I did shim the rear with a single washer to make it line up just like the front).

Then I checked up on it on MTBR and found out that it's not a big deal. The only possible drawbacks are: 1) you lose a little power (although if you're so sensitive that you can tell the difference with your fingers, you can probably read Braille too); and 2) you might have to file down that part of your brake pads that don't contact the rotor (because when the rest of your pads wear down by 1/2 the thickness of the rotor, there's a possibility that the unworn parts of both pads can actually contact each other and prevent further clamping of the pads!)

I'd be willing to bet that a large percentage of disc pads are being run without perfect alignment. A lot of people don't even know you can use shims. (With the Avid's it's pretty easy so you might want to give it a shot just for fun. Plain old 6mm washers fit perfectly. Just make sure they're in between two flat spots (not on the concave side of those "special" washers Avid uses).

Steve O · « **Reply #5 on:** February 18, 2003, 05:29:47 am »

Disc brakes on bikes follow a lot of the rules that automobile disc brakes do (20 year auto tech). They also follow many of the adjustment/repair procedures. The alignment of the rotor/caliper is one of the most crucial adjustments that can be made. The brake pad riding completely on the rotor brake track is important. Some of the problems with the pads overhanging the edge of the rotor are:

Loss of power. This is not as big a deal on bikes as cars, but is noticable. 1/10th of the pads is 1/10 of your power.

Noise The part of the pad that overhangs will drag on the outside edge of the rotor which is not machined causing a loud annoying brake noise.

Quicker Pad Wear The less pad material that meets the rotor, the faster they wear out.

Heat Less rotor contact equals less heat dissapation.

You can get by with a lot less brake(XC vs DH) if they are set up properly. As good as Hammer's adapter are, even the K2 adapter needs to be adjusted and shimmed. Differences in paint thickness are enough to change a caliper alignment. As important as your brakes are, spend the time to make sure they are DEAD square, you only have to do it once and it'll be worth it.

Steve O

Professional driver, Closed Course...

Andy · « **Reply #6 on:** February 18, 2003, 05:50:12 am »

When I made my own adapter I was not perfect in replicating the exact position of the drop-out. This is not a major concern, since (as stated in one of the posts above) no part of the hub extends beyond the width of the bike's hub. Remove the skewer & quick release from the wheel and install on the bike without it and you will see what I mean.

Since my adapter's drop-out does not match perfectly to the bike's drop out, I must remove my entire QR & skewer, if I need to take the rear wheel on or off. Since I haven't had many rear wheel flats, and I never find the need to remove the rear wheel otherwise, I keep forgetting to fix this.

As long as the skewer can be inserted into the wheel when it's on the bike, you will not have any major problem, just a minor inconvienece when removing the rear wheel.

I hope this made sense!

Matno · « **Reply #7 on:** February 18, 2003, 06:51:24 am »

I'm having a hard time visualizing why you would have to remove your entire skewer to take off the rear wheel. Does your adaptor have a round hole for the skewer instead of an open one shaped like the dropout itself? Seeing as how the sides of the dropouts are flat, I can't picture any other possibility. You wouldn't happen to have a close up picture would you? Just curious...

Hammer · « **Reply #8 on:** February 18, 2003, 07:51:35 am »

TC.. (thunderchild)

What sort of brakes are you using...??

Is there any radial adjustment possible..??

The reason I ask is that the HammerHeads are all made to International Standard, and as long long as you have an IS calliper and disc rotor that are matched, they should line up prefectly.

A more worrying risk with an overhanging pad is that once each pad wears 1mm (40 thou = 0.040") on a 2mm disc, they will hit each other instead of clamping the disc.. and the brakes will not work! Hence why some folks suggested filing the lip off the pads..

I strongly reccommend that you have a look at this and get it sorted out.

Hammer.

IFO · « **Reply #9 on:** February 18, 2003, 09:58:05 am »

r u using a mix-matched disc/rotor brand combo ?

such as a Avid brake with a Hayes rotor?

keep us informed...

Andy · « **Reply #10 on:** February 19, 2003, 12:13:59 am »

Quote

I'm having a hard time visualizing why you would have to remove your entire skewer to take off the rear wheel. Does your adaptor have a round hole for the skewer instead of an open one shaped like the dropout itself? Seeing as how the sides of the dropouts are flat, I can't picture any other possibility. You wouldn't happen to have a close up picture would you? Just curious...

Matno,

I have the drop out cut into my adapter at a different angle than the frame's drop out (again, this was just sloppiness/laziness on my part.) Imagine if the adapter were made correctly and just held on with the skewer only, now imagine if you bumped it out of place just a bit. The skewer is still aligned, but now the drop-outs would be slightly off.

However, the brake caliper is aligned perfectly, with the pads engaging the rotor in the correct spot. thankfully, I did the important part correctly!

I don't have a picture, since I gave it to an engineer at work to make me a new one. They are going to try and make it from some extra scrap (the metal they primarily use is an alloy made out of incanel (?sp?) and nickel). they said it would be the best metal since it's strong and has good heat dispersion properties. I'll keep my fingers crossed

Hammer · « **Reply #11 on:** February 19, 2003, 04:24:23 am »

inconell is probably the stuff. which grade..?

Ciao..

Hammer.

5500C · « **Reply #12 on:** February 19, 2003, 04:42:45 am »

Hammer,

I didn't get the conical lock washers for the swingarm bolts in the bag for my 5500C. I ordered it through RDI and haven't heard back from them from my email.

Were they missing or are you not suggesting it to be used anymore? I went to my local hardware store and couldn't find the conical lock washers.

Please help

rapiddescent · « **Reply #13 on:** February 19, 2003, 05:15:59 am »

Thre are 3 types of washers that we have shipped at one time or another. i am having real trouble finding the serrated washers and so kits for the last 6 months haven't had them. The thin washers should have been there, some people use these for fine tuning the HammerHeadproximity to the rotor.

when I get them in, i'll send out to any customers who want them free.

apologies for the confusion.

callum
rdi

Thunderchild · « **Reply #14 on:** February 19, 2003, 02:52:49 pm »

Thanks for all of the responses. I have an avid mechanical with an avid rotor.

I measured an old set of brake pads from my rear brake. The amount of pad that was outside the rotor was approximately 1.5 mm to 2 mm. I have radially adjusted the brake onto the rotor as much as is possible. I did have a bad problem with a strange harmonic frequency noise (maybe some of you will remember the post from about a year ago) at speeds above 9 mph to about 20 mph. I have readjusted the brakes many times and have finally eliminated most of this noise. Maybe this was attributed to the edge of the brake pad coming into contact with the outer edge of the rotor as SteveO pointed out. I will try and realign the adapter per Hammer's instructions and see what happens.

Again, this adapter has worked great all year around. I wouldn't want anyone to not buy one based upon this thread as it has worked well and allows us to breath disc brake life into a non disc brake frame.

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Author Topic: Wheel alignment with rear disc adapter (Read 8239 times)

Steve O