birdii
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| posted on 18/9/06 at 08:22 AM |
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Modifying XR4x4 brakes to fit RS 13" rims.
Hello,
After realising that the RS 13” rims I have won’t fit over the Sierra disc brakes I have been trying to find a way to alter things to work. Basically
the caliper needs to be moved into the car by approximately 20mm. The diameter is fine, it’s the offset of the caliper that causes it to foul the
wheel.
Anyway to do this I need a brake disc with more offset. So far the best I have found is an Orion front disc. It has an extra 25mm offset to the
standard Sierra disc. The problem is that the sierra hub has a larger diameter than the Orion even though the wheel stud PCD is the same, so the disc
as it is won’t fit the hub. Apart from this niggle with the hub diameter everything looks like it will fit fine (I hope!). I plan to make a bracket
for the caliper that bolts behind the hub carrier, this will then replace the original lugs.
Before I machine these hubs down I just wondered if anybody knows of any other brake discs that I could try which might fit the sierra hub better? I’m
not too happy about reducing the diameter of the hub although I do think it will be ok, after all it worked ok on the Orion and a seven is a much
lighter car than the Orion. The sierra hub was obviously designed for a heavy car with a V6 motor! After machining there will be about 5 - 6mm of
material between the edge and the stud but the worst problem is the two large holes drilled in the hub, these will break through.
I would really appreciate any info you have and your opinions on my plans.
Thanks very much
Dan
 
XR4x4 Rear Hub
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oliwb
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| posted on 18/9/06 at 09:08 AM |
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hmmm...tricky, I guess what your really need is a sierra hub without the 2 bigger holes. I take it there's no way you can merge a sierra and
orion hub?? Not sure I follow the bracketry plans to fit the calliper either - maybe a pic would help...Oli.
If your not living life on the edge you're taking up too much room!
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Wadders
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| posted on 18/9/06 at 09:08 AM |
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Hi Dan
I did what you are describing to fit MK3 escort front disks, which i guess are the same as orion, The large holes remained intact, (just). Machining
down the hub wont cause you any problems, but the calipers still might foul the rims, only way is to try it. AFAIK there are no other off the shelf
discs that will fit and solve your offset problem. My final solution was to machine up some ally bells , that way you can have almost any offset.
13" rims and discs are a pain.
Good Luck
Al.
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birdii
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| posted on 18/9/06 at 09:57 AM |
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Thanks for your replies!
Yep Escort Mk3 discs are the same as the orion discs. I'm suprised that it didn't give you enough clearance with the extra 25mm offset,
hope i don't have that problem after the effort of changing things! I tried the caliper on the brake disc and put that inside the wheel, only a
rough guide i know but it looked to have at least 5mm clearance.
In your archive (alloy bells look nice by the way) you are using pug calipers, is that what you tried on the Escort discs? I measured the pug calipers
on my 205 and they stand out from the disc quite a bit more than the sierra calipers do, so now i'm hoping that it was these that you tried with
the Escort discs and thats maybe why it still didn't fit!
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bigbravedave
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| posted on 18/9/06 at 11:32 AM |
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would it be easier to fit some 17mm wheel spacers so that the calliper clears the inside face of the wheel or is this not an option
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birdii
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| posted on 18/9/06 at 11:39 AM |
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Yeah that would be the easy option but it is something that i don't really want to do.
Why did you quote 17mm, do you know first hand that 17mm is whats needed to clear the calipers? Thats quite a big chunk for a wheel spacer isn't
it.
I'll post pics of the brackets once i have made them as thats the easiest way to explain how i want to fit them.
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Wadders
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| posted on 18/9/06 at 01:11 PM |
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Yes, it was the pug/citroen calipers, and also GolfMK4 (Raldes Hydra) which i tried with the escort discs, i never had a pair of sierra calipers to
try, so with a bit of luck you might be ok. Some 13" rims seem to have more clearance than others, again this might be in your favour.
Let us know how you get on.
ATB
Al.
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birdii
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| posted on 21/9/06 at 02:38 PM |
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Update:
The hubs are now machined so the escort/orion discs fit! I'm quite pleased with the results, there is more material than i had thought on the
hubs, they don't look like they will be weakend around the stud holes and the two large holes didn't break through, theres about 4mm of
material still left around them so overall its much better than i thought.
Hopefully tonight i'll have the caliper brackets finshed and i can trial fit the whole lot on Friday night! I'll keep you posted!
Dan
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chockymonster
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| posted on 21/9/06 at 06:51 PM |
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I'll be really interested to see how you get on with this as I'm in the same boat as you at the moment.
My alloys don't clear the rear calipers.
PLEASE NOTE - Responses on Forum Threads may contain Sarcasm and may not be suitable for the hard of Thinking.
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chockymonster
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| posted on 2/10/06 at 01:13 PM |
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Did you have any luck with this Dan?
PLEASE NOTE - Responses on Forum Threads may contain Sarcasm and may not be suitable for the hard of Thinking.
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birdii
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| posted on 2/10/06 at 07:12 PM |
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Yeah i think so!
Sorry i've been a bit slow updating my progress, got side tracked after hitting a tyre wall in my tin top
Anyway a few pics of what i've done:
Making a bracket, the long way!
 
Bracket 1
Finished Bracket:
 
Finished Bracket
Assembled on new bracket with escort disc:
 
Assembled 3
Wheel clearance with caliper pushed out to the max (like it would be with new pads):
 
Wheel Clearance
Everything seems to be ok. Obviously the axle width is now 12mm more in total because of the extra bracket. I have trial fitted the driveshafts and
they seem ok, at full suspension travel they still have plenty of movement in the joints so it should be good.
Anything i've missed or things that don't look too clever on this setup?
Dan
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