Alignment of Front Brake Callipers?

Alignment of Front Brake Callipers?

Postby daveskinner1 » Mon Jul 16, 2012 7:08 am

I am in the final stages of reassembly of my rebuilt 91 XV1. (Piccies soon). I notice that the front brake callipers don't align with the rotors well. The join between the two half blocks of each calliper which I'm assuming is the centre of the calliper is about 1mm too far inwards towards the wheel on the RHS and the LHS is about 2mm too for in. In fact on the LH calliper the centre of the calliper aligns with the inside surface of the rotor rather than the middle of it.

Obviously I need to space the callipers further away from the wheel which means that I can't use calliper mounting shims. Do I just use washers of the appropriate thickness to space the bottom of the forks slightly further apart from each other? If so I presume the RHS washer would go between the fork and the RH Collar and the LH washer would go between the fork and the speedo pickup unit?

Advice appreciated.
Dave.
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Re: Alignment of Front Brake Callipers?

Postby Ndwedwe » Mon Jul 16, 2012 7:31 am

Hi dave
Do post those pics, always nice to see the build progress and final product
Your observation on your calipers is unique to me, I have only witnessed a caliper coming off and going through the wheel, my mates lower leg just below the knee looked like an old wooden stake that split from being reused too many times. I would hesitate to space caliper mounts, is it not better to space behind the pads?
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Re: Alignment of Front Brake Callipers?

Postby ybk » Mon Jul 16, 2012 8:13 am

Too be honest you shouldn't need to add shims, they should align OK once assembled - there shouldn't be any real adjustability that can put the calipers out of alignment. Once you've tightened everything up take it for a quick spin round the block - the calipers should even themselves out. (when assembling first tighten the allen pinch bolts then the nut on the axle. Check the manual for torque settings.)

I'll check mine at home..
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Re: Alignment of Front Brake Callipers?

Postby Neal » Mon Jul 16, 2012 10:14 am

I believe the racers do it , they want it perfectly dead centre . Something about the pistons apply equal pressure blah blah . You either have to mill a fraction off the calliper or off the fork leg . I have not done it before so am not sure exactly . My brakes have allways been good enough for me .
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Re: Alignment of Front Brake Callipers?

Postby Louis » Mon Jul 16, 2012 8:11 pm

I'm not a 3xv expert, but you could check your wheel spacers.
If for some reason they are to short, you will pull your callipers towords the discs

But as I sad, I'm not a 3xv expert
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Re: Alignment of Front Brake Callipers?

Postby Neal » Mon Jul 16, 2012 8:25 pm

I think Louis has a point :idea:
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Re: Alignment of Front Brake Callipers?

Postby daveskinner1 » Tue Jul 17, 2012 7:08 am

yep Excellent point. here is a shot of the bike
TZR Nearly Finished.jpg

Here is a close up of the RH Caliper taken on my iphone from the front of the bike. As you can see the centre line of the calliper sits about 1mm too close to the wheel.
RH Calliper.jpg

And the left front sits almost 2mm to close the wheel. Sorry about the poor quality of the photos
LH Calliper.jpg
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Re: Alignment of Front Brake Callipers?

Postby Neal » Tue Jul 17, 2012 5:03 pm

That is it ! I can see exactly what you are saying and i think Louis is spot on too . I am going to rag my know it all mate that was talking kak .
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Re: Alignment of Front Brake Callipers?

Postby ybk » Tue Jul 17, 2012 5:23 pm

Unless something is worn out it must be an assembly issue or bent forks? How does it get of alignment in the first place :?: Compare with the parts diagram to see if you have all the bits and pieces around the front axle ?

Image
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Re: Alignment of Front Brake Callipers?

Postby Neal » Tue Jul 17, 2012 8:48 pm

What happens is the some guys overtighten the nut/bolt on the front wheel spindle when the were supposed to line everything up and tighten the fork pinch bolts first and nip up the last nut / bolt .
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Re: Alignment of Front Brake Callipers?

Postby daveskinner1 » Tue Jul 17, 2012 11:48 pm

My model doesn't have an axle nut. It threads directly into the LH Fork assembly. Not sure if this changes anything? I've also realised that the rotors float and that this bike hasn't been for a run yet but I would have thought that the rotors would not float by +/- 2mm. That seems a lot to me?
D>
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Re: Alignment of Front Brake Callipers?

Postby ybk » Wed Jul 18, 2012 7:30 am

Hmm yes, mine also thread into the fork itself. The rotors shouldn't float either to be honest.
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Re: Alignment of Front Brake Callipers?

Postby Jools » Wed Jul 18, 2012 8:54 am

So....

when is a floating disk not a floating disk .... :lol:
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Re: Alignment of Front Brake Callipers?

Postby Neal » Thu Jul 19, 2012 9:06 am

Drop it in a bucket of water to check :lol:
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